Dynamic Conservation of Plant Genetic Resources

DYNAMIC CONSERVATION OF PLANT GENETICRESOURCES P. K. Bretting’ and D. N. Duvick’ ‘USDMARS, North Central Regional Plant Introduction Station Department of Agronomy Iowa State University Anies. Iowa 5001 1 ‘Department of Agronomy Iowa State University Ames. Iowa 5001 I

I. Introduction A. ’Types of Plant Genetic Resources B. Roles of and Uses for PGRs C. Plant Genetic Resource Conservation D. In Sit// Conservation and ex Sit//Conservation: An Artificial Dichotomy? E. Scope and Content o f This Review 11. Dynamic Conservation and Its Management A. Assessing Key Abiotic and Biotic Factors B. Assessing Key Ethnobotanical and Economic Botanical Factors C. Rapid Assessments D. Data Management and Analysis E. Strategic Planning and Prograinmatic Management F. DC Reserves C;. On-Farm I X , Breeding, and Rural Develop~nent El. Incentives for D C I. Access to PGRs and Their Interrelationship with D C J. Education, Puhlicity, and Political Support for P G R C 111. DCS Future Prospects A. Priorities for DC B. Ilallmarks for Assessing D C Programs C. Complementary D C and SC Programs D. Concluciing Remarks References

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I. INTRODUCTION A. TYPES OF PLANTGENETIC RESOURCES Plant genetic resources (PGRs) (synonymous with plant germplasm) comprise the genetic information encoded by genomes; the biological mechanisms for translating that information into phenotypes; and the form and level of biological organization whereby genes, phenotypes, or groups of phenotypes perpetuate (e.g., seeds, plants, populations, species, and communities). In the context of this review, “resources” imply that this genetic information has an actual or potential utility to humanity. Plant genetic resources can be categorized according to a variety of criteria but, from a conservation management standpoint, their most important biological attributes are level of biological organization (McNeely e f al., 1990; Frankel et al., 1995a), ecogeographical adaptation, genetic profiles, breeding systems, longevity, the intensity of human selection to which they have been subjected, and their roles in and uses by human cultures (Brush, 1991; Bretting and Widrlechner, 1995; Graudal et al., 1995).

B. ROLESOF AND USESFOR PGRs In the form of wild or weedy flora, PGRs serve as keystones of natural and human-managed ecosystems (Wilson, 1988; Oldfield, 1989; McNeely et al., 1990; World Resources Institute er al., 1992; Meffe and Carroll, 1994). In the form of annual and perennial crops, PGRs are the foundations for human economies and subsistence (Plucknett et al., 1987; Heiser, 1990; Harlan, 1992). Crop PGRs may help renew abandoned or endangered traditional agricultural systems and/or human cultures (Board on Science and Technology for International Development, 1989), where “traditional” refers to “indigenous” or “local” agriculture conducted by those “who have gained their ecological knowledge from empirical observation of nature and from communication with other people in their culture” (Martin, 1995, p. xxiii). Plant genetic resources are essential components of the infrastructure for basic and applied plant science research (Frankel et al., 1995a): Plant breeders employ wild and crop PGRs to develop or improve commercial crops (Simmonds, 1979), whereas other plant scientists use PGRs as experimental subjects. Plant genetic resources provide raw materials for developing new crops and new sustainable production systems (Janick and Simon, 1990, 1993; Frankel et al., 1995b). Crops may be “new” in an ecogeographical sense, e.g., soybean [Glycine n ~ a x(L.) Merr.], cultivated for millennia in China, but introduced relatively recently to the United States and Brazil. “New” may also refer to new uses forge-

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netically modified “old” crops, e.g., “canola,” low erucic acid, and low glucosinolate varieties of Brassica nupus L. (Downey, 1990). Wild and weedy species may be the donors of the genes that transform the preceding “old” crops into “new” crops (White et al., 1994). Finally, “new” may connote incipiently or relatively recently domesticated crops derived from essentially wild plants, such as oil palm [Elaeis guineensis Jacq.] or rubber [Hevea brusiliensis (A. Juss.) Mill.-Aug.] (Simmonds, 1993). In view of the preceding variety of new crops, almost all wild or weedy flora could be considered potential genetic resources to be conserved (Graudal et al., 1995; Simmonds, 1995) as potential sources of valuable genes for improving extant crops [e.g., genes for lauric acid production extracted from the wild plant Umbellularia califomica (Hook. and Am.) Nutt. and inserted into the canola genome; Davies et al., 19931 or as candidates for domestication as novel sources of critical products [e.g., the wild genera Lesquerella S. Wats. or Cuphea P. Browne, which produce rare fatty acids (Dierig and Thompson, 1993; Knapp, 1993)].

C. PLANTGENETICRESOURCECONSERVATION Plant genetic resource conservation (PGRC) involves managing and using resources in a manner that does not deplete them. The major objective of PGRC is to safeguard plant genetic diversity from, or to compensate for, deterioration or loss by a variety of causes. In doing so, PGRC may also help traditional farming cultures survive (Alcorn, 199 1). The needs of burgeoning human populations have caused habitat destruction through conversion (e.g., clear-cutting of woodlands and paving of agricultural fields; Noss and Peters, 1995) and habitat deterioration through climatic change (Graudal et al., 1995) and chemical contamination, etc. These habitat changes are currently the primary causes for extinction of plant communities, taxa, and their constituent genes. For example, Wilkes (1 99 1) reported that during a 25-year period, many Mexican and Guatemalan populations of teosinte (species of Zea L.), the wild relative of maize (Z. mays L. ssp. mays), were reduced to fractions of their previous size through habitat conversion. Perrino (1994) estimated that in recent years 90% of the traditional wheat varieties in Italy have been extirpated because their habitat, traditional Italian farming villages, has been transformed into modern communities emphasizing nonagricultural employment. Deterioration of genetic integrity may also endanger PGRs, such as the wild populations of Brassica L. in Italy that are being introgressed with “alien” genes from elite varieties of Cole crops (Perrino, 1994). Genetically diverse traditional PGRs may be lost when they are replaced by genetically homogeneous, elite germplasm (e.g., in Ethiopia; Worede, 1993), although substitution by elite germplasm should not be considered an inevitable (Brush, 1995) or necessarily

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detrimental phenomenon (Duvick, 1984). This replacement may stem from changes in a variety of environmental, socioeconomic, political, and cultural factors (Worede, 1993; Bellon, 1996a,b).

D. IN SZTUCONSERVATION AND EX SZTUCONSERVATION AN ARTIFICIALDICHOTOMY? To date, PGRC has often been dichotomized semantically into in situ (“on site”) or ex sifu (“off site”) components, primarily according to the ecogeographical setting for the conservation activity (Frankel and Soul6, 1981; Oldfield and Alcorn, 1987; Plucknett et al., 1987; Brush, 1991; Hawkes, 1991; Shands, 1991; Primack, 1993; Wilkes, 1993).Although this dichotomy may serve to distinguish conservation of wild plants in botanical gardens (Falk and Holsinger, 1991) from conservation in nature preserves, a manifest distinction may not exist for crop PGRC (Cherfas, 1994) because of the complications issuing from selectionhusbandry by humans and from the interactions of the latter with natural selection. For example, should we consider a traditional fruit tree variety, maintained with other trees in a polyculture by a subsistence farmer according to traditional husbandry practices, to be conserved in situ, but categorize the same variety maintained by a scientifically trained germplasm curator in a contiguous, intensively managed (fertilizer, pesticide, and herbicide applications), monocultural orchard to be conserved ex situ? Such ambiguities led Chauvet (1994) to term in situ conservation (ISC) of crops as “in agro,” whereas Blixt (1994a) would use “inter situ” conservation. Like Frankel and Soul6 (198 l), Hawkes (1991), and Shands (1991), we consider ISC and ex situ conservation (ESC) to be intergrading phases of a continuum of PGRC strategies. We deem that these strategies would be better categorized primarily by their specific objectives, and approaches for attaining those objectives, rather than by the PGRC program’s location. Thus, we substitute “static conservation” (SC) for ESC, and “dynamic conservation” (DC) for ISC to provide a nomenclature better suited for the conceptual framework of this review. In this context, the term “static” is not used as a perjorative, nor does “dynamic” imply that DC is intrinsically superior to SC as a conservation strategy. This terminology was inspired by that used by Frankel and Soul6 (198 1) and Frankel et al. (1995a), although it is not precisely congruent with the latter. The SC phase seeks to dramatically alter the original evolutionary trajectories of the PGRs so that a “genetic snapshot” of sorts is conserved. The products of natural (wild plants) and/or human selection (crop varieties) are safeguarded often outside of their original evolutionary context in order to minimize the risk of their loss while facilitating easy access by the scientists, breeders, and educators who are the immediate beneficiaries of such efforts (Shands, 1991). The SC programs

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are often conducted by government agencies, universities, or corporations that, together with the “userheneficiaries,” generate demand for, and assign value to, these PGRs. Although it is not widely recognized, traditional people may also engage in SC of PGRs (see Section 111,C). Planning for SC programs proceeds according to a time scale generally calibrated in decades, and the context for such programs is often interinstitutional. The international “system” for implementing this PGRC phase for crops was originally formulated and developed in the late 1960s and early 1970s (Frankel and Bennett, 1970; FAO, 1976; Lacy, 1995) and reflects the philosophy and technology of that time. The DC phase seeks to conserve or reconstitute PGRs, their associated evolutionary trajectories (Browning, 1991 ), and the biological, agroecological, andor human cultural processes that comprise their original evolutionary milieu. For crops, the original evolutionary context may be a traditional farmer’s field rather than the “wild.” Frankel and Soul&( 1 98 1 ), Chauvet (1994), and others considered this approach to be “dynamic” because it seeks to conserve ongoing processes, although preexisting systems and conditions may not be replicated precisely. Dynamic conservation of traditional crops often involves conserving traditional folk knowledge-“what local people know about the environment” (Martin, 1995; p. xxiv)-and perhaps traditional agrarian societies (Oldfield and Alcorn, 1987).The DC programs may be conducted by traditional people themselves, by nongovernmental agencies, by government agencies, by a combination of the preceding, or by others. It has been postulated that these programs may enable PGR-rich but capital-poor countries and people to participate more equitably in PGRC (Brush, 1995). The immediate usersheneficiaries of DC of PGRs are often traditional people who may generate demand for, and assign value to, PGRC via mechanisms different from those operating in the SC phase, partially because their time scale of concern is often gauged in human generations, and its context is often intergenerational (Brush, 1995; Bellon, 1996a,b). Local commerce, ecotourism industries, and “modern” people who wish to conserve traditional varieties and practices may also benefit, as may scientists, when DC reserves serve as valuable field laboratories and as sources of PGRs for experimentation and crop improvement. Thus, we agree with others (Shands, 1991; Brush, 1995; Engels, 1995; Graudal et al., 1995) in not considering DC and SC to be mutually exclusive endeavors but rather to be different emphases or phases in a continuum of PGRC enterprise. Indeed, the complementary nature of DC and SC (Brush, 1995; Engels, 1995) and the frequent congruence of many of their objectives and approaches are themes that pervade this review (see Section 111,C). We hope that these perpectives will benefit readers who, by the nature of this periodical, may not be conservation biologists but rather are agronomists or plant breeders more familiar with SC of PGRs in germplasm banks rather than with the DC phase of PGRC.

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E. SCOPEAND CONTENTOF THIS RJZVIEW This review appraises the progress, promise, and prospects for the DC of PGRs which are actively exploited and managed as sources of human food, fiber, drugs, shelter, or as animal forage. In some respects, its scope overlaps that of earlier seminal reviews of this subject by Ingram and Williams (1984), Brush (1991), and Ingram (1996), but it emphasizes recent publications and covers a wider variety of subjects than those treated by the preceding authors. This review concentrates particularly on plants, representing a broad spectrum of breeding systems, genetic profiles, and longevities (i.e., annual or perennial), that are selected, saved, and sown (or otherwise propagated) especially by traditional people rather than by scientific breeders. “Elite” crop cultivars intensively bred according to statistical genetic principles are not discussed in-depth herein because they are generally maintained by SC in genebanks or by DC in breeders’ nurseries. When germane, we discuss conservation of weedy or wild crop relatives, especially if their evolution has been tangibly affected by humanity. Conservation of essentially wild flora never purposefully selected by humans is reviewed comprehensively elsewhere (Wilson, 1988; McNeely et ul., 1990;World Resources Institute et al., 1992; Meffe and Carroll, 1994) and is considered herein only relative to DC of crops and their close relatives. The scope and content of this review have been determined by the accessibility of key data or literature references, editorial constraints, and the authors’ personal interests, training, language competencies, and experience. We have devoted most of our careers to the genetics, breeding, evolution, and/or SC of maize, but we have some ancillary experience with managing the PGRs of other major North American commercial field crops. We have served as administrators or managers in the public, private, and/or nongovernmental organization (NGO) sectors. We have spent most of our careers in the United States, but the junior author has traveled worldwide as an advisor, consultant, and participant in the oversight of SC programs at international agricultural research centers (IARCs) and of DC programs for wild biota conducted by an NGO (The Nature Conservancy) in North America. The experience of the senior author with DC of PGRs is limited to the Americas (primarily the southwestern United States, Mexico, and Jamaica). We are conducting this review now because historically SC and DC phases of PGRC have not been very strongly linked (Frison and Bolton, 1994), although there are some exceptions, e.g., the Center for Plant Conservation, which from its inception integrated the DC and SC phases of PGRC of wild flora (Thibodeaux and Falk, 1984). National governments and IARCs, which may not previously have strongly supported SC (Castillo, 1995) or DC (Browning, 1991; Shands, 1991; Brush, 1995) programs, are now attempting to coordinate such programs more closely (e.g., Begemann and Hammer, 1994; Graudal et al., 1995) so as to allocate relatively limited resources most effectively. We hope that this

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review may suggest some mechanisms for closer coordination of SC and DC efforts. Furthermore, like Graudal et al. (1995), we recognize that the FA0 Global Plan of Action and the Convention on Biological Diversity (CBD) charge nations to assign the DC of PGRs a high priority, although it is unclear whether any or all crop plants fall under the mandate of the latter convention (Blixt, 1994a). Partially as a result of the CBD (Lacy, 19951, and because of DC’s potential role as a politically palatable mechanism for compensating gene-rich but capital-poor people for access to their germplasm, financial support for DC efforts is likely to increase in the future (e.g., the recently initiated DC project in Turkey funded by the Global Environmental Facility; Strauss and Gallagher, 1995). The prudence and feasibility of particular DC objectives, approaches, and programs deserve scrutiny before this support expands and before such compensation, formally encouraged by the CBD, becomes large scale. We hope that the information contained in this review might encourage the careful assessment of extant DC efforts and foster sound strategic planning for future programs. Compared to the conservation efforts of traditional people, DC programs established relatively recently by external agencies (i.e., nonlocal governments, NGOs, and IARCs) may lack the longevity requisite for accurately accessing their efficacy and durability. Examples of short-lived, costly DC or SC failures abound (Chapin, 1991). To ensure that DC comprises a tangibly larger share of the total PGRC effort, such “externally imposed” programs will become increasingly pivotal. Traditional farming cultures, successful PGR conservators for millennia, may not survive, in their present form, the rapid cultural and environmental changes of the next decade (Alcorn, 1991; Clay, 1991), let alone the next millennium. Consequently, we hypothesize, as have others (Oldfield and Alcorn, I987), that a blend or network of SC institutions (Simmonds, 1979), DC by traditional cultures, and/or “external” DC programs that incorporate traditional people as active participants may prove the most effective PGRC mechanism in the future.

II. DYNAMIC CONSERVATION AND ITS MANAGEMENT Section I1 describes strategies for planning, establishing, and managing DC programs and cites examples of various DC approaches and organizations. It is organized according to the developmental sequence of many DC programs, from the initial programmatic stages of data collection and assessment, through data analysis and database management, strategic planning, establishing, monitoring, and managing DC programs, to fostering incentives for sustaining PGRC. Access to PGRs and the role of education in DC programs are also considered. Some of the leading DC programs are currently refocusing their efforts on conserving natural

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processes rather than on the products (e.g., PGRs) of the processes (Sawhill, 1996). Nevertheless, the initial phases of DC programs inevitably emphasize compiling lists of PGRs and of factors influencing their conservation status. Although abiotic, biotic, and human cultural factors affecting DC are presented separately herein to facilitate discussion, this segregation should not obscure the complexity and richness of the interplay among these factors (Anikster and Noy-Meir, 199 I).

A. ASSESSINGKEYABIOTICAND BIOTICFACTORS An accurate, thorough mapping of PGRs’ extant geographical distribution and associated ecological, genetic, and evolutionary factors provides a valuable ecogeographical, spatial perspective for optimizing DC programs (Zimmerer and Douches, 1991 ; Stein, 1996).The ongoing series of abiotic and biotic surveys and monitoring can be considered the heart (Ingram, 1996) of a DC program. Such data also provide a baseline for retrospective comparisons that may be quite important for guiding DC programs. Dalla Ragione and Perrino’s (1994) survey of the house yard and monasterykonvent gardens of highland Italy recorded not only the occurrence of extant old varieties of fruit trees but also included historical data uncovered in monasterykonvent archives and local libraries. This approach, linking contemporary surveys with historical research, may help place certain crop PGRs’ current rarity in the context of their historical role in human culture, especially relative to how much diversity has already been lost (Noss and Peters, 1995). Rare crop varieties that have never been abundant nor widespread because of their minor role in human affairs should be treated differently in strategic plans for DC programs than once ubiquitous varieties that are now restricted to a fraction of their former range (see Alcorn, 1995). In addition to the standard abiotic parameters of longitude, latitude, topography, elevation, climate, and soils (Bellon and Taylor, 1993), the biotic features of and context for particular PGRs should be identified and recorded whenever possible (Anikster and Noy-Meir, 1991; Brush, 1995; Clinebell et ul., 1995). The taxonomic identity, abundance, and flora and fauna associated with PGRs should be recorded together with ecological interactions (Anikster and Noy-Meir, 1991). Anderson’s (1952) description of traditional Mesoamerican farm plots is a classic because it depicts not only the biotic but also the human cultural features influencing PGRs’ evolution, and it introduces innovative graphical techniques for depicting the temporal and spatial distribution of useful plants with different habits (annual or perennial herbs, shrubs, and trees). The quality of abiotic and biotic data actually available for guiding DC programs may deviate substantially from the ideal because surveying, monitoring, and documentation practices and methodologies are still “remarkably undeveloped” (Ingram, 1996, p. 469). The paucity of suitable baseline data led Brush (1995) and

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colleagues to employ “cross-sectional” comparisons of contemporary human cultures and geographical locales to analyze DC of PGRs by traditional cultures. Furthermore, although some herbaria are transcribing ecogeographical data from PGR specimen labels onto electronic databases, “the failure of the majority of collectors to record ecogeographical data on specimen labels makes the drawing of ecological conclusions from an herbarium survey hazardous” (Maxted, 1995, pp. 18-19). The current trend for adopting global positioning systems for surveying the distribution of PGRs (Guarino, 1995; Stein, 1996) may dramatically improve the quality of the ecogeographical and biotic data available in the future. The factors measured to help guide DC programs should be recorded by standard systems for classifying or categorizing PGRs, but often such systems are lacking (Noss and Peters, 1995). Perhaps more important, excellent extant systems, such as Rabinowitz’s (198 1) well-established categorization of the types of rarity, must be more generally adopted. The approach advocated by Steiner and Greene ( 1996) for recording abiotic and biotic information, and for “retro-classifying” PGRs according to the preceding information, is also worthy of careful assessment. Martin (1995) is an excellent general reference for developing optimal practical approaches for collecting key baseline data for DC. Written for traditional people or scientists who work with traditional people, it covers field methods not only for collecting abiotic and biotic data but also for anthropological, economic, and linguistic data (see Section 11,B). Ignorance of the kind and apportionment of genetic diversity within and among PGRs may severely hamper the development of DC strategies (Smith, 1994) and contribute to the “central dilemma of gene resource conservation . . . a recognized need for conservation without knowing exactly what to conserve” (Graudal et al., 1995, p. 127). Ideally, genetic profiles of PGRs would be generated by surveys with genetic markers (Horovitz and Feldman, 1991; McCormick et a/., 1993; Avise, 1994; Bretting and Widrlechner, 1995; McDonald and Hamrick, 1996) carefully chosen for optimal effectiveness (Avise, 1994; Bretting and Widrlechner, 1995). There are currently distressingly few such profiles available for guiding PGRC programs (Schaal et al., 1991; Bretting and Widrlechner, 1995). Thus, conducting genetic marker surveys such as that of Grauke et al. (1995) for guiding a DC program for pecan [Carya illinoinensis (Wangenh.) K. Koch] and that of Zimmerer and Douches (199 1 ) for traditional Andean varieties of potato (Solanurn L. species) should be considered a priority (Horovitz and Feldman, 1991). In addition to Anderson ( 1 952), the following syntheses of biotic and abiotic information for the purposes of guiding DC programs warrant mention. Anikster and Noy-Meir (1991) surveyed abiotic (climate and soil) and biotic factors (associated vegetation and pathogen susceptibility) associated with populations of wild tetraploid wheat [Triticum turgidurn L. var. dicoccoides (Koen. in Schweinf.) Bowden]. The detailed abiotic and biotic data, when compared with variability in isozyme and seed protein traits, revealed clear associations of genetic profiles with

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ecogeographical factors that were potentially applicable to planning the Ammiad DC reserve. Maxted’s (1995) systematic ecogeographical study of Vicia L. subg. Vicia provided vital baseline data for DC of wild and weedy relatives of domesticated vetch. It led to priority being placed on establishing DC reserves in Syria to protect and monitor populations of an ecogeographically restricted species. Although another endemic vetch species occurs in an extant national park in Turkey, it was considered a candidate for SC because extensive plantings of introduced conifers endangered it there. An analysis (Zimmerer and Douches, 1991) of the microregional (areas of ca. 10-1 000 h2, defined by socioeconomic and ethnological factors) and taxonomic distribution of genetic diversity in traditional highland Andean varieties of potatoes demonstrated that, contrary to previous assumptions, each traditional variety did not represent a genetically homogeneous clone but rather comprised up to a dozen different genotypes. Also. unlike what was expected based on patterns in genetic variation found in wild PGRs, the traditional potatoes in different microregions were relatively undifferentiated genetically, probably because of frequent interregional exchange of rubers via markets, subsequent interbreeding, and propagation of hybrids via tubers or seeds. These findings led Zimmerer and Douches (199 I ) to conclude that knowledge of the ecogeographical and human cultural distribution of traditional crop PGRs was required to optimize subsequent DC programs. Wilkes (1991) and personnel of the Instituto Nacional de Investigaciones Agropecuarios y Forestales (INIFAP), Mexico’s agricultural research organization (SBnchez G. and Ordaz S . , 1987), have monitored the biological status of central Mexican and Guatemalan populations of reosinre for several decades. The report of Sanchez and Ordaz (1987) represents a model survey of the abiotic and biotic factors associated with the ecogeographical distribution of these allogamous annual wild crop relatives. In addition to recording standard ecogeographical parameters, they collected seed for genetic studies and for SC. Population size and surrounding vegetation were noted and compared with reports by earlier plant explorers to provide a baseline for time series analyses of the risk that these populations might be extirpated.

B. ASSESWNGKEYETJXNOBOTANICAL AND ECONOMIC BOTANICAL FACTORS The study of the interactions between plants and people is termed ethnobotany (Ford el al., 1978;Martin, 1995; Schultes and von Reis, 1995). Ethnobotanical information includes folk names, uses, customs, crop management practices, technological features (e.g., farming implements) and ceremonies associated with

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PGRs, and patterns of land usage (e.g., fallowing cycles), of which land tenure is particularly important (Clay, 1991; Fingleton, 1993). In general, ethnobotany focuses on the role of plants in traditional cultures rather than in modem societies. Folk names and taxonomies provide clues to particular plants’ relative importance to specific human cultures. Martin (1995) gives a thorough and practical introduction to recording, organizing, and analyzing linguistic data in the context of ethnobotanical surveys conducted for DC programs, whereas Berlin ( 1992) presents the general theoretical underpinning for the approaches described by Martin (1995). Traditional folk names and classification may provide important clues for generally unrecognized economic uses for plants (e.g., Bretting, 1984). The correspondence between scientific and traditional plant taxonomies may provide one measure for the taxonomic acuity of local people, of plant taxonomists trained scientifically, and of the potential for traditional people to maintain PGRs via DC. Discordance between traditional and scientific taxonomies may serve as an index for the comparative importance of particular plants in traditional societies and provide clues regarding former or nonobvious uses of certain plants. For example, Boster’s (1984) study indicated that a traditional culture’s taxonomy for manioc (Munihor esculenfu Crantz) cultivars resolved many more different biotypes than did the scientific classification for this crop and corresponded to manioc’s role as a staple of this people’s diets. Retention of traditional languages and folk traditions may indicate that a particular site is potentially well suited for a DC program, but this is not always the case (Brush, 1995). Describing and recording the cultural elements of traditional people (termed ethnography) has been characterized as an art form (Van Maanen, 1988). Consequently, the style and content encountered in ethnobotanical and economic botanical literature are quite variable, e.g., contrast the content and writing style in Plotkin’s ( 1993) narrative of ethnobotanical field studies of traditional Amazonian people with Alcorn’s (1 984) account of field studies of traditional people of Mexico. This stylistic diversity, highly desirable in some respects, may inhibit the cross-cultural and cross-crop comparisons of information regarding uses for PGRs that are potentially valuable for setting priorities for PGRC programs. A potentially valuable standard system for recording traditional uses for plants in their indigenous cultural context, an activity sometimes termed economic botany, has been developed by Cook (1995). This system classifies not only plant uses but also useful plant parts, and it may facilitate cross-cultural comparisons. A conceptual framework proposed by Bellon (1996a) may be very useful for recording and analyzing key cultural factors that influence traditional farmers’ decisions whether to maintain or discard crop PGRs. In this approach, PGRs are viewed as tools by which traditional farmers manage risk of crop failure, reduced yield, etc. When descriptions of human uses of PGRs and relevant production and processing technologies are interwoven with documentation of religious beliefs and other human cultural factors, economic botany and ethnobotany may intergrade

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as in Hernandez X. (197 1). The latter is a classic primer for collecting, recording, analyzing, and integrating abiotic, biotic, and human cultural information to understand the evolution of the PGRs and traditional agriculture and how to optimally conserve them. Prime examples of applying this approach to a specific ecogeographical region (Yucatan, Mexico) is Hernandez X. (1985) and Kunstadter’s (1978) detailed depiction of traditional village agriculture in northern Thailand. Although we use the terms “traditional agriculture” and “traditional people” consistently throughout this review, we are not implying human socioeconomic homogeneity by these semantic conventions. Bellon (1996a,bj has categorized traditional farmers by the degree to which their agricultural production is integrated with markets: (i) subsistence farmers, who produce crops primarily for their own consumption; (ii) surplus farmers, who produce crops for their own consumption and for the market; and (iii) commercial farmers, who produce crops exclusively for the market. The success of some DC programs may depend on accurately categorizing farmers and agriculture according to these types. When developing plans for DC of pecans, Grauke et al. ( 1995) distinguished pecans harvested from wild stands from those produced in commercial orchard plantings. Unfortunately, key biological and human cultural data such as those cited previously and on the size and distribution of PGR populations, number and proportion of traditional PGRs cultivated relative to elite cultivars, degree to which cultivation of traditional and elite PGRs are integrated, and the different kinds of traditional agriculture occurring in a country and how traditional PGRs are integrated into the national economy (Oldfield and Alcorn, 1987) are often unavailable for strategic planning of DC programs. Rather than implement a DC program without the data described under Sections II,A and II,B available for guidance, it may be prudent to conduct a rapid assessment (see Section 11,Cj to generate at least some guideposts for optimizing progress.

C . RAPID ASSESSMENTS During a brief symposium in late 1993 regarding crop DC in Mexico, a team of ca. 20 Mexican and U.S. researchers (including the present authors) visited a traditional Mexican village for a day to appraise the locale’s crop biodiversity and traditional agriculture. We learned then that an experienced team could quickly record much information regarding abiotic and biotic factors, human cultures, PGRs, and evolutionary or human cultural processes or interactions at a particular site. Consequently, we wondered then whether rapid assessments resembling those for wild biota often based on indicator species (Research Unit for Biodiversity and Bioresources, 1993; Daily and Ehrlich, 1995) would be feasible during the initial planning for DC programs for PGRs. We discovered that “rapid ethnobotanical appraisals” (Martin, 1995) are indeed feasible and potentially valu-

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able for guiding subsequent DC efforts. Martin ( I 995) describes this approach and discusses “participatory rural appraisals,” a promising rapid method in which “local people are full participants in the study rather than being merely the objects of the investigation” (p. 4). Bellon’s report (1996a) is an instructive example of such a participatory assessment. It may be that rapid assessments should precede the initiation of any extensive DC program. In addition to its utility for assessing various abiotic and biotic factors relatively quickly, rapid assessments can maximize the impact of the limited resources available to accumulate baseline data, to conduct environmental monitoring, and to assess DC programs’ efficacy (Beattie et al., 1993). Information gained from preliminary appraisals would be key for determining whether “externally imposed” DC was actually required or if periodic monitoring of PGRs’ status (see Sections II,A and II,B) for a particular region would suffice. Rapid assessments may also be more cost-effective than conventional methods whenever they facilitate the incorporation of amateur naturalists, graduate students, etc. into DC programs (Majer, 1993). Nevertheless, rapid assessments do not represent a panacea for DC. The data emanating from these appraisals may be unsuitable or indefensible as bases of important managerial decisions (Wilson, 1993),especially where highly rigorous criteria for decision making are legally specified by governmental agencies. Rapid assessments that are conducted during only one season may also not precisely evaluate seasonally dynamic agricultural systems. Furthermore, methods that rely heavily on specific indicator species or a suite of species may produce data that cannot be readily compared across regions, sites, or even suites of PGRs and so are of limited use for setting broadscale PGRC priorities. Thus, elements of the rapid assessment method will likely be melded with more conventional approaches (Sections II,A and II,B) to contribute optimally to DC programs. The Nature Conservancy, a U.S. NGO primarily devoted to DC of wild biota, has employed a hybrid of rapid and more traditional assessments for generating data applicable to designing DC reserves (Stolzenburg, 1996). Importantly, whenever possible the conclusions drawn from rapid assessments should be validated by pilot projects, such as that in Ammiad, Israel (Horovitz and Feldman, 1991), before they are applied to designing a DC reserve or program (see Section 11,E).

D. DATAMANAGEMENTAND ANALYSIS Superior methods of managing and analyzing data recorded according to the precepts noted in Sections II,A and II,B must be continually developed because optimal information management and analysis systems are vital to the success of DC programs (Ingram, 1996). For instance, Nabhan ( 1990b) demonstrated that quantitative analyses of ecogeographical ranges reported on herbarium specimens

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and from genebank passport data could help identify regions in northwestern Mexico that potentially included the greatest number of wild species of Phaseolus L., species that were genetically highly divergent, and unique ecotypes of those species. Although these analyses were conducted to guide future germplasm explorations, they could also be applied to setting priorities for establishing DC reserves that conserve genetic diversity of wild crop relatives effectively. A widely used method for analyzing the distribution of wild biota is “gap analysis” (Noss and Peters, I995), whereby the ecogeographical locations of particular PGRs are compared by computer mapping programs with locations of extant or proposed reserves for DC. Another method was described by Charmet and Balfourier ( 1995), who conducted detailed computer simulations employing ecogeographical criteria to select French populations of perennial ryegrass (Lolium perenne L.) with the highest potential for successful DC. The ecogeographical distribution of agricultural practices and agricultural societies might be weighed when planning DC of crop PGRs (Zimmerer and Douches, 1991). A recent regional analysis for setting priorities for DC of biota in Latin America and the Caribbean (Biodiversity Support Program et al., 1995) included biological importance, conservation threat and opportunity, and human utility (including occurrence of crop PGRs) as criteria for setting priorities. Notably, “human utility” was treated as a secondary criterion invoked only when the primary criteria were ineffective. Although human utility incorporated the ecogeographical distribution of crop PGRs, it did not consider the geographical distribution of traditional agrarian societies (Biodiversity Support Program et al., 1995). As Brush (1991) has noted, if improved databases could efficiently and effectively identify specific ecogeographical regions where traditional agriculture persists, this information would greatly facilitate choosing optimal sites for DC of PGRs. Before such databases can be compiled, research is needed to identify the minimal biotic, abiotic, ethnobotanical, socioeconomic, and other human cultural information required for effectively assessing a particular region’s suitability and priority for DC of PGRs (Brush, 1991j and to reconcile cases in which the geographical distribution of wild biota and of physiographical features do not coincide with “human geographic territories” (Zimmerer and Douches, 1991>.Quantitative statistical tools for resolving the preceding incongruities must be developed so that the process of setting priorities for DC conserves both crop and wild PGRs optimally. The value of the data listed in Sections II,A and II,B for implementing and guiding DC programs is maximized when they are incorporated into geographic information systems (GIS; Guarino, 1995) and databases that are linked through remarkable new communication network technologies such as the World Wide Web. The long-awaited seamless linkage, or even integration, of databases for traditional knowledge with those composed of biotic and abiotic data is now technically feasible, given the availability of the World Wide Web. Such globally acces-

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sible linkages via hypertext transfer protocol, if they can be established between disparate PGRC organizations and even between the latter and various traditional human cultures, would greatly benefit PGRC programs and PGR users by contributing to a potentially “equitable exchange of information” (Martin, 1995, p. 241). Conversely, lack of effective means of communicating news and information may hinder the development of DC programs and their integration with complementary SC efforts (Cherfas et al., 1994). Maxted (1995) noted that although wild vetch PGRs surely must occur in extant DC reserves, it has not been possible to quantify the amount of vetch material that is currently actively conserved in situ. Few reserves have checklists of the species included and the lists that have been produced are not widely distributed. It is easier, however, to assess ex sifu holdings, as these are more commonly published as catalogues or are included in germplasm databases. (p. 105) Maxted’s experience, the efforts of Dalla Ragione and Perrino (1994) in Italy, and the incisive analysis of the European informal PGRC sector by Cherfas (1994) suggest that it is often relatively easier to obtain information from SC germplasm banks than from DC programs or organizations, especially those of the “informal sector.” This disparity may be associated with the intrinsic properties of the data managed by DC and SC programs, with differences between SC and DC programs in the relative priority placed on information management, or may be related to the funds and technology available to each. Many of the national SC programs (Begemann and Hammer, 1994) and multinational crop germplasm networks (Frison and Bolton, 1994) currently have wellestablished computer networks and databases because their value for managing a PGR collection’s inventory was recognized early (Simmonds, 1979). Consequently, SC programs such as the U.S. National Plant Germplasm System (NPGS) have devoted the substantial resources needed to construct databases and management systems such as the NPGS’s Germplasm Resources Information Network (GRIN; Mowder and Stoner, 1989). Nonetheless, Maxted (1995) reported that certain SC genebanks could provide no or only highly incomplete information in response to his query regarding vetch PGRs-a deficiency that Goodman ( 1990) and Shands (1991) noted for genebanks of other crops. Although failure to fulfill an individual query may result from the failure to manage data optimally, or lack of time for curators to respond to requests, certain data are simply not conserved by SC programs. For example, in general SC programs document only sketchily PGRs’ folk names, uses, or cultivation practices (Cherfas et al., 1994). This may be because such information is difficult to manage with standard database software or perhaps because it is considered ancillary to SC programs’ primary objectives. Furthermore, the organization of national SC programs may militate against successfully conserving certain data. An extreme example

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would be some national SC programs for Zea, Phaseolus, and various species of Cucurbita L., the dietary triad often grown in a polyculture by traditional Latin American farmers. For various historical and compelling practical managerial reasons, the NPGS manages samples of maize, beans, and squash that were collected from the same campesino’s field and are perhaps the end result of millennia of coevolution, at different sites by different crop-specific curators. Currently, such accessions are not cross-referenced in the GRIN database so that their actual intimate agroecological associations would not be evident therein. A specialized database, such as that assembled for the FLORUTIL (acronym for “useful plant” in Spanish) project (Nabhan et al., I99 I), may be required to optimally manage some of the diverse information that would be useful for guiding DC programs. The DC of traditional agricultural knowledge is extremely important because it is as fluid and in danger of extirpation as are PGRs themselves (Bellon, 1996a,b). Farmers are continuously evaluating and testing PGRs’ utility and transmitting these findings to others. Their practical knowledge of PGRs is invaluable not only for guiding DC programs but also is highly relevant for scientific crop improvement. Perhaps the most effective means of DC for traditional farming knowledge is for the fabric of traditional societies to remain intact. If that is not possible, SC would be required. The SC of traditional crop management systems, innovations, scheduling and organizing of labor, and taxonomies associated with PGRs may best be conducted independently of genebanks by specialized institutions, such as the Center for Indigenous Knowledge for Agriculture and Rural Development (CIKARD), located at Iowa State University, Ames (McKiernan, 1990). The goals of CIKARDcollecting, conserving, and disseminating traditional agricultural knowledgestrongly parallel those of various SC genebanks, and its efforts have spawned regional centers for SC of traditional knowledge located worldwide.

E. STRATEGIC PJANNINGAND PROGRAMMATIC MANAGEMENT As Ingram (1996) has noted, an integrated long-term program of monitoring and inventorying abiotic, biotic, and human cultural factors is required for optimally planning and implementing DC of PGRs. The preceding program should also include a research component that enables hypotheses regarding optimal management practices to be tested. The qualitative and quantitative properties of genes, plants, plant communities, traditional cultures, and those cultures’ knowledge of PGRs, when assembled into databases described in the preceding section, will provide baseline data for strategic planning of DC programs. For instance, McDonald and Hamrick’s ( I 996) populational genetic profiles of endemic wild plants of Florida suggested that, perhaps because of its relative recency, habitat fragmentation has not yet tangibly reduced those plants’ genetic diversity. In addition to this

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information’s current value to planning DC, it could serve as an invaluable baseline for monitoring changes in these plants’ genetic diversity through time and consequently estimating the risks of extirpation or genetic impoverishment. Whenever the magnitude of the preceding risks can be estimated, such information would be key for planning DC programs and for assessing their progress. In the context of DC of PGRs, risk is generally gauged as a function or index of the probability of losing particular PGRs, weighted or scaled by some measure of their value. Probability of loss may be difficult to assess directly; therefore, some estimates have used rates of human population growth and intensity of economic activity as indirect indices for risk because those factors apparently may be statistically if not causally associated with probability of wide-scale loss of PGRs. For instance, an “overall risk to ecosystem index,” calculated for each state of the United States, combines estimates for the probability of biota loss (“overall development pressure”-essentially the rate by which natural habitat is destroyed) with measures of ecological-evolutionary value for the endangered biota (number of “most endangered ecosystems” and “percentage of imperiled species”; Noss and Peters, 1995). A Danish interagency governmental program selected tree and shrub PGRs for DC based partially on their value. i.e., their actual or potential human use (Graudal et al., 1995), then used value as a criterion for setting priorities and making decisions. However, estimating the true value of PGRs may be an extremely difficult task, and additional research by teams of economists and biologists is required to develop theoretical and practical tools for more accurate and practical estimates (Bower Kux, 1991). Risk alone should not set priorities for DC programs. In the words of Bower Kux (199 I ) , “local priorities and decisions may be the most important ruling factor in maintaining living resources” (p. 309). Without the support of local traditional people, a DC program for crop PGRs may be doomed to failure; therefore, ideally, they would serve as comanagers of PGR programs (Ingram, 1996). Local factors will determine the feasibility of proposed PGRC programs, so they must be considered whenever setting priorities or constructing a strategic plan (Noss and Peters, 1995). For instance, a superior strategic plan for PGRC, such as that developed for Danish tree and shrub PGRs (Graudal et al., 1995), will consider not only risk but also programmatic objectives, their justification, and optimal means for attaining them. Graudal et al. (1995) recognized that, because of the central dilemma of PGRC (see Section II,A), the scientific knowledge of the PGRs to be conserved is never perfect and often rather sketchy. In the words of Ingram (1996; p. 469), “our networks of reserves are only as effective as our knowledge bases or at least our abilities to translate the second-guessing of our ignorance into prudent decision-making.” Accordingly, strategic planning for DC must be flexible to adjust to the ramifications of new knowledge and ideally will even contain a mechanism for

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generating new knowledge (Ingram, 1996). Empirical experimentation with various DC strategies is highly desirable, and “caution should therefore be taken not to mistake ‘preliminary findings’ for ‘final truths”’ (Graudal et al., 1995, p. 131). Weighing the diverse managerial objectives of a DC program simultaneously with the disparate demands of numerous program participants and constituents, PGR users, and DC managers represents very complicated “conservation frameworks for choice and compromise” (Ingram, 1996, p. 47 1). Mechanisms for optimally managing change are required to successfully plan and manage PGRC programs. This is manifest in the annual report for one IARC, which pleads for “a respite and a period of tranquility to digest the meaning and significance of recent developments. This is not to argue against change but to plea for its proper management, primarily through the control of its pace” (International Center for Agricultural Research in the Dry Areas, 1995, p. v). If the struggles of modern organizations to adapt to rapid change are any indication, the pressures now exerted on traditional cultures by rapid population growth, urbanization, and cultural/spatial integration (Brush, 1995) must be indeed inexorable. Ideally, mechanisms for forecasting which traditional cultures will change rapidly and when they will do so would be incorporated into strategic planning for DC programs (Oldfield and Alcorn, 1987). An enumeration of the optimal qualities for managers of DC programs may be inherently subjective, biased according to personal experience, and certainly will provoke vigorous debate. Notwithstanding theses caveats, we have noted from our personal experience that effective managers of DC programs often are broadly educated in the natural sciences (especially in economic botany, ethnobotany, agriculture, horticulture, pharmacology, ecology, genetics, and/or biostatistics) and in the social sciences (especially in anthropology, linguistics, and/or economics). Individuals with this broad education may be able to facilitate the interdisciplinary research projects required to generate information required for managing and improving DC programs (Brush, 1995). Skill in interpersonal interaction is important because PGR managers “need not only to establish the scientific base for action, but above all to promote dialogue between many different social groups, and organize them” (Chauvet, 1994, p. 147). For instance, Cherfas et al. (1994) questioned whether traditional farmers or enthusiasts can be trained to regenerate, characterize, and evaluate germpiasm successfully, and Brush (1 99 1) had concluded that “The means of involving farmers in conservation has so far been an intractable obstacle” (p. 155). We think that any relatively bright person can be trained if they want to learn. The keys to successful training are effective teachers and/or managers, access to key technical tools, some reward (monetary or spiritual) for such training, and some evidence that their educational efforts are successful. Finally, a practical, decision-making orientation may be valuable for a DC manager, especially if one agrees with Chau-

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vet (1994) that “the job of researchers is to find new questions, whereas the job of managers is to obtain better answers” (p. 145). Individuals possessing many of the preceding competences and qualities do exist but, unfortunately, they are too rare (Gallagher and Straws, 1995). Consequently, the ability to lead multidisciplinary teams resembling those sometimes devoted to scientific crop improvement (Shands, 1991) may aid managers with successfully incorporating personnel (traditional people and scientists/managers) with divergent skills into DC programs (see Katzenbach and Smith, 1993,for a review of team dynamics). Interdisciplinary “comanaged” (Ingram, 1996) teams may direct most of the DC programs of the future (Cohen et al., 1991). Martin ( 1995)notes that unfortunately teamwork may be the exception rather than the rule in current DC programs, many of which are spearheaded by one or a few often charismatic persons-the so-called “champions” or “heroes (heroines)” who may have founded the program. Optimal management of teams, in contrast, will require what Keegan ( 1987) has termed “post-heroic leadership” (p. 347), characterized by prudent and rational thinking. Such managers must be capable of juggling “multiple and sometimes conflicting sets of management objectives for particular sites and populations” (Ingram, 1996, p. 469). The organizational models and structures for DC programs are almost as diverse as the PGRs that they seek to conserve. Since humans evolved, the foremost organizations for PGRC have been traditional hunting-and-gathering groups or farming cultures, which are today generally restricted to marginal areas, in both an economic sense and in the sense of land quality (Dalla Ragione and Perrino, 1994; Brush, 1995). Their highly diverse organizational structures are vital mechanisms of human adaptation to environmental challenges (Bennett, 1976; Moran, 1979; Worede, 1993). Individuals, either members of traditional cultures or members of modern cultures (often termed “enthusiasts;” Cherfas, 1994), have by their individual action conducted or promoted DC programs. A variety of NGOs for DC of wild flora have emerged worldwide, but NGOs for DC of crops are relatively rarer, although some do exist in the United States, Europe (Begemann, 1994; Cherfas, 1994), and developing countries (Cooper et al., 1992). Farmer cooperatives and associations seemingly play a very important role in Italian DC programs (Dalla Ragione and Perrino, 1994).All the preceding types of organizations have been categorized by some as the informal sector of PGRC, although Dalla Ragione and Perrino (1994) noted wryly that this sector’s heterogeneity seemingly suggests that its constituency has been defined solely by being “not official.” The so-called formal sector may include corporations and associated nonprofit foundations that support DC presumably because of benevolence and/or enlightened self-interest. A prominent example of the preceding type of organization is the Healing Forest Conservancy, a charitable trust supported by Shaman Pharma-

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ceuticals, Inc. that seeks to foster DC of traditional PGRs and associated ethnobotanical knowledge (King and Tempesta, 1994). However, private-sector-supported DC programs are the rarity. Most “formal” DC programs are sustained by governments or other political groups (local, regional, or national), international agencies (UNESCO, FAODPGRI, and World Bank), educational institutions-including botanical gardens (Plucknett et al., 1987), some of whose exhibits now incorporate a more lively ethnobotanical and evolutionary perspective-and a miscellany of organizations fostering a diversity of agendas, including world or regional peace (e.g., gene parks in Galilee; Porceddu, 1995). Finally, certain DC programs are network/team/collaborative efforts among a variety of organizations. For instance, REDARFIT (Andean Network for Plant Genetic Resources) aims to develop national programs for managing and conserving Andean PGRs that are not duplicative (Castillo, 1995). Martin (1995) describes the “Plants and People Initiative,” a consortium of an intergovernmental organization (UNESCO), a nongovernmental conservation organization (World Wildlife Fund), and a botanical garden (Royal Botanical Garden at Kew, England) partially financed by the governments of the United States and the United Kingdom. To attain its main goal of enhancing local communities’ capacity to conduct DC of plants, it has initiated demonstration education projects and prepared several “how-to” manuals for DC, including one by Martin (1995).

F. DCRESERVES Following initial surveys, monitoring, data analysis, and strategic planning, a DC program for PGRs may be established. Dynamic conservation programs are generally conducted either in reserves or “on-farm,’’ approaches that differ primarily according to the objectives of the DC program, the type of PGR conserved, who (traditional people or PGRC professionals or both) manages human activity at the DC site, and specific managerial methods. Many DC reserves focus on conserving wild biota and natural evolutionary and ecological processes. Management of the reserves may be controlled centrally (e.g., by a national agency). The reserves often have well-defined boundaries, within which managers may have partial to nearly complete control over human activity that affects PGRs. Designing DC reserves for wild biota is a rapidly emerging science (Stolzenburg, 1996; Szaro and Johnston, 1996), but the following generalizations may be currently valid. Superior reserves comprise multiple sites and approaches that mimic the metapopulations (Namkoong, 1986; Henry et al., 1991) often found in nature, with respect to the number of sites, their size, the demographic and genetic profiles of specific PGRs (Horovitz and Feldman, 1991), and the reserves’ constituent flora (Graudal et ul., 1995). Ingram (1996, p. 468) has listed five “functional categories” of land management zones for a DC reserve: (i) natural cores,

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where human activity is strictly regulated; (ii) naturally or culturally modified buffers, where a broader spectrum of human activities occurs; (iii) transitional areas of cultural landscapes involving gradients of modem and traditional social and technological impacts; (iv) corridors for gene flow among the metapopulations mentioned previously; and (v) barriers for regulating gene flow from, and the migration of, “alien” biota. Reserves such as those outlined in the preceding sentences seek to conserve the dynamic processes of evolution (Browning, 1991) whereby “the genetic composition of target species is allowed to adapt to the prevailing environmental conditions and their changes with time” (Graudal et al., 1995, p. 126). Browning ( 199 1, p. 79) would accept that under certain conditions, DC reserves might be managed with “benign neglect as the main conservation philosophy.” However, in our experience, superior reserves are actively managed (Ingram, 1996), e.g., they institute effective steps to minimize habitat conversion, unrestricted human activities, and genetic contamination via the introduction of alien germplasm (Murphy, 1996) or genes (Graudal et al., 1995). Such steps include removing invading forest species and thereby conserving grasslands, controlled burning of prairies, restricting the spectrum of human activities by zoning according to use (Goerke and Erdmann, 1994), restricting access of modem cultures to traditional PGRs andor cultures, and, if particular traditional cultures desire it, maintaining their geographical isolation and limited communication with the outside world. For instance, some of the traditional Amerindian cultures of contemporary Costa Rica (Torres, 1987), Panama (Clay, 1991; Gregg, 1991), and the Coordinating Body for Indigenous Peoples’ Organizations of the Amazon Basin (Martin, 1995) seek to regulate the effects of external contacts and modernization on traditional people as a means of DC of traditional cultures and their PGRs. Russia and other states of the former Soviet Union have implemented an extensive system of more than 100 DC reserves for the PGRs of crops and their wild/weedy relatives (Dinerstein et al., 1994). Currently, some of these sites, such as the wild apple (Malus L. spp.) forests of Kazakhstan, are endangered by economic development, political unrest, and habitat deterioration (via animal grazing; Hokanson et al., 1996). Israel contains a much smaller but better documented system of similar reserves (Browning, l991), including the well-studied Ammiad site and other reserves (Anikster, 1995). Arecently initiated program in Turkey is planning to establish a series of gene management zones for DC of useful woody plants and wild crop relatives (Strauss and Gallagher, 1995).Ideally, DC reserves for wild relatives of crops incorporate traditional or local people into the initial planning of the reserve. For instance, local Israeli farmers helped with the early planning and retained ownership of the land comprising the Ammiad Site of Special Scientific Interest for studying and conserving a wild relative of wheat (Hawkes, 1991). Information provided by traditional people, and by botanical surveys, indicated that the chiltepin [C. annuurn L. var. aviculare (Dierb.) D’Arcy and Eshb.], a wild

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relative of chiles, was rare in the southwestern United States because of overharvesting and habitat deterioration (Nabhan, 1990a). Certain populations were first declared “protected” in land managed by the United States Department of Agriculture’s Forest Service (USDAFS), and an enclosure to exclude grazing animals was erected. Under a memorandum of understanding with the USDABS, Native SeeddSEARCH is gathering demographic and ecogeographical distribution data for the chiltepin and associated vegetation and assembling them into a GIs. Preliminary results indicate that at least 15 other wild crop relatives occur at this site, which consequently may be declared a “Zoological/Botanical .4rea”-a designation that would provide additional protection from unrestricted grazing and other activities that may endanger these PGRs (J. Donovan, Native SeeddSEARCH, personal communication). Nabhan et ul. (1991) build on the infrastructure provided by extant reservations-regions devoted to the DC of traditional Native American cultures-in the southwestern United States and adjacent northwestern Mexico to initiate the FLORUTIL Conservation Project. This project sought to (i) develop a bilingual Spanish-English database for information regarding threatened wild or semidomesticated PGRs, (ii) promote DC programs that incorporate traditional people as full participants, (iii) conserve traditional knowledge regarding PGRs, and (iv) investigate the effects of various land use practices on PGRs. During the initial stages of this project, the region was surveyed for endangered useful wild or semidomesticated plants and the effects of various land use regimens on the biological status of the species were assessed. A group of rare plants was selected for more intensive evaluation over time, i.e., to assemble a time series documenting trends and changes. The preliminary results of the project suggested that destruction of habitat and overharvest for medicinal use or for private SC collections were the two most serious threats to these PGRs (Nabhan et al., 1991). The concept of DC reserves for crop PGRs is not new, having been described decades ago [see Browning (1991) and Wilkes (199 I ) for documentation of various early, unpublished information]. In general, the craft of managing DC reserves for crop PGRs is less advanced than is the science of managing wildland reserves primarily because much less practical experience has accumulated for the former. Accordingly, it may be beneficial to closely ally nascent DC programs devoted primarily to crop PGRs with those emphasizing wild biota [e.g., UNESCO’s Man and the Biosphere (MAB) Biosphere Reserve Program; Gregg, 1991;Goerke and Erdmann, 19941 as a means of sharing logistical support and of gaining practical experience in certain PGRC methods. For such a collaboration to be successful, there must be mechanisms whereby DC programs for wild biota also encourage DC and utilization of crop PGRs (Cherfas et ul., 1994),e.g., European MAB programs with demonstrated commitments to collaborating in crop PGRC (Goerke and Erdmann, 1994). Apparently, MAB reserves and programs elsewhere have not always successfully incorporated DC of PGRs and traditional agriculture into their total con-

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servation programs (Bower Kux, 1991 ). The PGRs included in many biosphere reserves are still poorly known scientifically, and managerial objectives of the reserves may stress priorities other than DC of crops and their wild relatives (Ingram, 1996). In the future, DC of entire traditional agricultural landscapes deserves close scrutiny (Zamanis et al., 1994; Goerke and Erdmann, 1994). We are aware of few large-scale (i.e., hundreds of km2) DC reserves for agricultural landscapes or reserves that, although not seeking to replicate traditional agricultural landscapes completely, attempt to conserve the essence of the latter’s key functions and processes. One such large reserve is the Sierra de Manantlan Biosphere Reserve in Mexico (Benz et al., 1996), a several-hundred km2 protected area originally founded for DC of a rare teosinte and associated biota. This reserve has evolved over time into a regional program for DC of traditional agroecosystems and for promoting “sustainable” rural development. Most extant DC programs for traditional agricultural landscapes manage much smaller areas than in the preceding example. Neot Kedumim Biblical Landscape Reserve comprises ca. 250 ha2 (Neot Kedumim, 1995) in Israel devoted to recreating the agricultural landscape characteristic of that region during Biblical times. “Living history farms” and agricultural museums (see discussion of the Association for Living Historical Farms and Agricultural Museums in Woods, 1987) also altempt to recreate on a small scale the essence of bygone agricultural landscapes. For instance, Living History Farms near Des Moines, Iowa, depicts the traditional agricultural landscape of the midwestern United States of 1840-1900. Although this organization and others (Woods, 1987) emphasize educational tourism and conservation of traditional folk culture rather than crop DC, they do cultivate traditional maize PGRs, seeds of which were originally provided by the NPGS. The preceding examples demonstrate that collaboration between crop SC and DC programs is feasible, and leads logically to the concept of “on-farm conservation,” discussed in the next section.

G. ON-FARM DC, BREEDING,AND RURALDEVELOPMENT Compared to DC reserves, on-farm DC programs generally focus on preserving crop rather than wild PGRs and on evolutionary and ecological processes mediated by both human and natural selection. Relatively less control may be exerted over human activity, and a relatively broader diversity of people (traditional farmers, amateur enthusiasts, breeders, etc.) may participate in programmatic planning, implementation, and management. Interfarmer exchange of PGRs, farmer selection and breeding of specific varieties, and PGR selection and storage by farmers are particularly important components of on-farm DC. Consequently, on-farm DC programs often seek to preserve traditional networks of PGR exchange and to un-

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derstand (i) traditional farmers’ selection criteria (often agroecological adaptation, human use, and role in the agroecosystem) for deciding whether to maintain PGRs; (ii) how traditional farmers adapt PGRs to particular agroecological niches; and (iii) how traditional farmers store PGRs and maintain the germplasm’s health vigor and purity (Bellon, 1996b). On-farm DC programs may be implemented throughout a broader ecogeographical region, with less sharply defined boundaries than are DC reserves, because programmatic focus may be the DC of specific crop PGRs rather than DC of entire natural ecosystems. Often, the ecogeographical focus for such a program is the agroecosystem where the crop or a particular cultivar originated (Bellon, 1996b). Enlisting traditional farmers to mitigate genetic erosion due to adoption of improved varieties has been discussed extensively, but the specific mechanisms for successfully implementing this strategy (Dissuading farmers from growing only elite varieties? Subsidizing the cultivation of economically inferior landraces?) have been controversial (Cherfas et al., 1994). It has not been clear whether technological conservatism must be encouraged, if traditional landscapes must be reconstructed, and/or if markets for products derived from traditional PGRs must be developed to ensure successful DC on-farm by traditional farmers. It is clear that approaches that encourage PGR management by traditional cultures should form the foundation of on-farm DC (Bellon, 1996b). Studies of crop PGRs managed by traditional farmers on different continents [sesame (Sesamum indicurn L.) in the Sudan (Bedigian, 1991); maize in Mexico, potatoes (species of Solanum L.) in Peru, and wheat (Triticum aestivum L.) in Turkey (Brush, 1995)] suggest that DC of traditional PGRs is not inextricably connected to retention of traditional farming methods. Instead, fragmentation of land holdings into small plots, marginal local agronomic conditions, economic isolation (often by mountains), and cultural preferences apparently were more closely associated with the retention of traditional PGRs at those four locations than were traditional agricultural practices. It would be unacceptable for PGRC programs to seek to preserve rural poverty and certain other undesirable conditions that may favor DC of traditional PGRs. Nonetheless, such programs may seek to influence cultural preferences of traditional and modern people (see Section K H ) , perhaps by on-farm DC programs. Cherfas et al. (1994) noted that on-farm DC programs could (i) regenerate accessions for preservation in SC genebanks, (ii) conserve PGRs by helping conserve the traditional agricultural cultures, and (iii) conduct on-farm breeding or varietal selection efforts. Both the first and the third activities could be conducted for a fee-an economic incentive (see Section II,H) that apparently is contemplated for “on-woodlot conservation” of woody species on private land in Denmark (Graudal et al., 1995). Similarly, traditional Nepalese farmers will be paid to regenerate and maintain genebank accessions of chayote, Sechium edule Sw., for a new SC genebank in Nepal (Sharma et al., 1995), and farmers in the European

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Community are paid a premium to grow endangered PGRs (Dessylas, 1994), although it is uncertain how long this funding will be available. On-farm or “participatory” breeding or varietal selection (Witcombe and Joshi, 1996) involves scientists, primarily from SC institutions or scientific breeding programs, in collaboration(s) with traditional people to conserve and enhance traditional PGRs and agricultural systems (Hardon and de Boef, 1993; Cherfas et al., 1994; Sperling and Loevinsohn, 1995). In participatory varietal selection, traditional farmers choose “finished” varieties for incorporation into their traditional agriculture, whereas in participatory plant breeding they are involved with actually producing an adapted, improved variety (Witcombe and Joshi, 1996). Participatory varietal selection may not enhance intracultivar genetic diversity nor change traditional crop improvement strategies. It may encourage the adoption of fewer new cultivars than would participatory plant breeding, and its influence on traditional crop improvement strategies may be fairly uniform over a relatively large region. In contrast, participatory plant breeding may greatly increase not only intracultivar genetic diversity but also the number of constituent cultivars in a particular local agriculture. Its effects on traditional breeding strategies may be quite variable throughout particular regions, and it may alter the latter in a manner that encourages PGRC (Witcombe and Joshi, 1996). Ideally, participatory varietal selection programs would precede participatory plant breeding efforts, perhaps with the former serving as “pilot projects” for evaluating the feasibility of the latter. Berg and Hardon and collaborators (Hardon and de Boef, 1993; Hardon, 1995; Berg, 1996) critically assessed the challenge of integrating the approaches of contemporary scientific breeders with those of traditional farmers to maximize both gains in agronomic productivity and the amount of PGRs conserved. Generally, the traditional and scientific breeding approaches have focused on different, but not necessarily mutually exclusive, plant breeding objectives. For instance, traditional Nepalese farmers incorporated different selective criteria to rank rice cultivars’ agronomic merit but the rankings were highly congruent with those of Nepalese agricultural researchers (Sthapit er al., 1996). Scientific breeding generally seeks to maximize yields from application of external inputs and to improve the plant’s resistance to biotic and abiotic stresses encountered over a relatively large region, whereas breeding PGRs for contemporary traditional agriculture involves enhancing yield and “yield stability” while avoiding the risk of total crop failure when the PGRs are cultivated with minimal external inputs in marginal environments (Hardon, 1995). Optimal approaches for improving traditional plant breeding methods have not yet been refined, but it is evident that genetically heterogeneous PGRs, with “high evolutionary potential” (Berg, 1996, p. I 18), should be incorporated into breeding programs for traditional agriculture, that they should be exposed to selective factors resembling those on-farm, and that their genetic diversity must be preserved

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in order to maintain yield stability and evolutionary potential (Berg, 1996).To successfully integrate the traditional and scientific approaches to breeding, traditional farmers must participate in developing programmatic objectives, the most important of which will be survival of the traditional culture and DC of its PGRs (Hardon, 1995). Their participation may be superficial if the scientific breeders conduct most of the project. The organizational structure for on-farm varietal selection or breeding programs must reflect the nature of PGRs to be managed and traditional forms of social organization, decision making, risk-taking, etc. (Berg, 1996).The farmers, scientific breeders, and the extension workers participating in these projects must be chosen very carefully not only for their technical skill and acuity as plant selectors but also for their leadership potential and ability to work cooperatively in formal partnerships between traditional communities and external institutions (Weltzien et al., 1996). It is likely that both farmer and breeder participants will require various types of “cultural sensitivity” training before the project begins (Hardon, 1995). On-farm participatory varietal selection or breeding programs are under way in several countries. As part of the initial phase of a DC program, traditional Rwandan farmers who were renowned as skilled plant selectors were invited to field stations to evaluate diverse Phaseolus vulgaris L. germplasm for their own use. They identified introduced cultivars that proved to be high yielding on their farms, although not necessarily at the field stations. Perhaps because of their early participation in this DC program and their acuity as varietal selectors, these farmers retained this introduced PGR longer than did farmers involved with earlier plant introduction and DC programs (Sperling et al., 1993). Leaders of traditional farming communities in Ethiopia diagnosed poor seed quality as the cause for poor agricultural productivity. Community seed banks were started and skilled local seed selectors identified “superior” seeds for the banks, which then distributed the seeds to farmers. Although the stimulus for establishing the seed banks was poor seed quality, the banks have also conserved genetic diversity (Berg, 1996). Traditional farming people in New Guinea are collaborating with scientists from an IARC and a national agricultural research program (NAR) to conserve and breed traditional varieties of sweet potato (Ipomoea batatas L.) in a pilot project originally inspired by a tribal leader’s concern regarding genetic erosion in this crop (Anonymous, 1995). The leader feared that the genetic erosion of local sweet potato varieties might also cause “cultural erosion” because this crop plays a central, pervasive role in this people’s culture, subsistence system, religion, etc. An extensive “on-farm breeding” project is under way in traditional farming communities of Ethiopia (Worede, 1993). Sorghum [Sorghum bicolor (L.) Moench] germplasm is collected and distributed via cooperatives to farming families who, with the advice of scientists from Ethiopia’s national Plant Genetic Resources Center (PGRCE), cultivate the sorghum by traditional methods and concurrently con-

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duct simple mass selection to retain desirable genotypes, cull inferior genotypes, and advance the improved but still diverse germplasm to the next season. In a similar program, elite germplasm of durum wheat (Triticum durum Desf.) developed by the PGRCE is regenerated, evaluated, and selected, together with traditional varieties of durum wheat, on traditional farms. In this manner, traditional farmers serve as “genetic enhancers” of PGRs in this relatively sophisticated scheme (Worede, 1993). CONSERVE, the Community-Based Native Seeds Research Center, is devoted to collecting, conserving, and enhancing rice and maize PGRs in Mindanao, The Philippines (Magnifico, 1996). Farmers play a key role in this program, which considers DC of PGRs on-farm to be a foundation for developing rural farming communities in a manner that reduces use of chemical farm inputs. “Farmer curators,” identified with the help of local NGOs, not only grew PGRs but also circulated germplasm widely within traditional communities. Notably, farmer curators discarded about a third of the rice varieties received from CONSERVE because of the latter’s poor agronomic performance. Nevertheless, these varieties were not lost because CONSERVE maintains a SC backup collection at its farm headquarters as a shield against that eventuality. CONSERVE’S farm also characterizes and evaluates PGRs. CONSERVE’Sactivities have caused a decrease in the number of modern rice cultivars grown and in the amount of agrichemicals applied but have increased the frequency that traditional rice PGR is cultivated (Magnifico, 1996). For DC of fruit tree or timber tree PGRs, especially in the tropics, the “tending” long practiced in European forestry (e.g., Denmark, Graudal et al., 1995) might effectively enhance PGRs and ameliorate the sad state of crop improvement efforts for many locally or regionally important tropical perennial crops (Hardon and de Boef, 1993; Simmonds, 1995). In tending, the forester thins stands, removes poorly performing plants or trees, and, by relatively light selection pressure often applied at the juvenile stage, enhances the PGR’s value without necessarily diminishing its overall genetic diversity. For instance, the Huichol, Mexican traditional people, have conducted an ongoing tending program linked with producing wood for carpentry (Clay, 199 I). The Mixe, another Mexican traditional culture, have tangibly improved the quality of Leucaena esculenta (Moc. et SessC ex A. DC.) Benth., an outcrossing leguminous tree, as a source of forage and pot herbs via tending practices (Casas and Caballero, 1996). Through on-farm varietal selection, breeding, and other DC programs, not only are crop PGRs maintained but also scientists are garnering new knowledge about crop physiology and genetics by learning how the traditional farmers actually manage the crop. This knowledge could generate new theories and practices for scientific breeding programs and for DC and SC efforts. It may help breeders improve yields of crops cultivated under marginal conditions in the poor lands often inhabited by the world’s poorest people (Hardon and de Boef, 1993). Furthermore, on-farm DC programs may provide data helpful for determining the effects on

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PGRC of the often dramatic reductions in population sizes of traditional PGRs maintained in isolated patches by traditional cultures (Brush, 1995). By monitoring the genetic status of PGRs on-farm with some of the techniques noted under Sections II,A and ILB, potentially dangerous changes in their evolutionary trajectories and stability might be detected.

H. INCENTIVES FOR DC Enhancing or altering PGRs’ economic value involves complicated logistic and ethical issues (see G. Nabhan’s guidelines on p. 182 of Martin, 1995). Furthermore, Brush (1991) does not consider subsidies for DC of traditional PGRs a “viable option” (p. 163), and Oldfield and Alcorn (1987) warn that subsidies may “build unreasonable expectations and hasten socioeconomic change” (p. 50). As a result of on-farm breeding and DC programs, the economic value of PGRs may be increased, which may be one of the more effective incentives for PGRC. At least part of the economic benefits accruing from this increased value should flow to the traditional cultures and communities participating in the DC program (Ingram, 1996). This increased revenue may encourage DC-Bellon (1 996a) has cited economic factors (value of grain and cost of labor and inputs), along with adaptation to risks associated with abiotic and biotic stresses, as important criteria by which traditional Mexican farmers assign a relative value to maize PGRs. Brush ( 1991) has advocated removing disincentives (often imposed by national governments) to growing traditional crops and enhancing market incentives for the latter as fundamental cornerstones for encouraging DC of PGRs. Recognizing that ethnic cuisine and unusual variations of everyday foods are stylish today, Cherfas et al. ( I 994) wondered whether clearly labeled “traditional produce” can promote DC of regional traditional crops by enhancing market demand and hence economic value. Apparently, at least one U.S. specialty food company, Frieda’s, Inc., has done exactly that by marketing traditional Native American crops in the United States under the trademark “Lost Crops of the Americas” (Frieda’s, Inc., 1994).Furthermore, several NGOs are helping traditional Costa Rican people market their cacao and banana harvests as “organically” grown to increase their commercial value (McEnany, 1996).The preceding program seeks to both increase income of this people and to encourage DC on its land, which is very rich in genetic diversity. “Bioprospecting” (Reid et ul., 1993) (with plants, essentially synonymous with the time-honored endeavors “economic botany” or “pharmocognosy”) may potentially enhance the value of, and thereby sustain DC programs for, wild biota. Conversely, unregulated bioprospecting can lead to PGR’s destruction. Bioprospecting has focused on identifying novel, highly effective human medicines from essentially wild flora, often in tropical forests. In the future, bioprospecting

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programs will seek not only pharmaceuticals but also novel “environmentfriendly” pesticides (Schubert and Chippendale, 199 1 ), herbicides, and other compounds (Reid et al., 1993). Programs for linking DC of forests with tending, bioprospecting, and other types of non-timber harvesting should develop optimal methods for exploiting these PGRs economically without depleting their genetic diversity. Peters ( 1994) describes techniques for measuring the effects of non-timber harvesting on the genetic diversity of tropical forests and for judging an optimal harvest level for sustainable economic gain. Economic value is not the sole incentive for PGRC. Alcorn (1991) has argued that economic incentives, especially those provided by subsidies, furnish only ephemeral support for DC of PGRs. According to Alcorn, the strongest incentive for DC of traditional farming cultures and their PGRs is a vibrant local, traditional conservation ethic. Programs for DC should foster the latter while encouraging the evolution of “a new, modem conservation ethic appropriate for the emerging global capitalist economy” (Alcorn, I99 1, p. 3 17). Externally imposed DC programs could play a vital role in facilitating a smooth transition from the traditional ethic to a new ethic “appropriate to large rural populations, regional economic relationships, local economies, and local, subcultural variations of global culture” (Alcorn, I99 I , p. 3 17). Religious or ritual significance (Hawkes, 1983; Bellon, 1996a) may be an important incentive for PGRC, as with sacred groves of trees maintained via DC by several ethnic groups in India (Hajra, 199 I ) . For instance, the religious faith of the Vishnoi of India has inspired them to protect biota actively, even to the point of sacrificing their lives (Tiwari and Damania, 1995). Specific PGRs are grown for culinary rituals associated with livestock management in the Andes (Holle and Risi, 1993). Dioscorea esculenfa (Lour.) Burkill and other yams are grown in Papua New Guinea not only for food but also because their seeds are exchanged as gifts during feasts and are associated with rituals (Ingram, 1996). Heiser (1985) has hypothesized that some plants may have been cultivated initially for their roles in religious rituals. In other cases, although their conservation may not be directly connected to religious practice, PGRs have endured by their association with religious sites (church yards, monasteries, cemeteries, etc.) that themselves have been preserved like museums. For example, monasteries and convents in highland Italy have been instrumental in DC of traditional fruit varieties (Dalla Ragione and Perrino, 1994). Ornamental PGRs are conserved in botanic gardens because of their economic and aesthetic value (Watson e f al., 1993). Wilson (1984) has argued that biodiversity should be conserved for its aesthetic value alone because humans apparently possess an inherent affinity for it. Brush (1995) has noted PGRs’ role in arts and crafts, a use that bridges the gap between aesthetic and economic value. The value of some PGRs may emanate from their association with historical or archaeological sites and their potential for enhancing our understanding of prehistoric peo-

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ple, e g , wild pecan stands associated with archaeological sites (Grauke et al., 1995).

I. ACCESSTO PGRs AND THEIR INTERRELATIONSHIP WITH DC The level(s) of international, national, regional, and/or local political control over PGRs may affect their access by users (Shands, 1995). The PGRs in SC genebanks at IARCs, e.g., rice at the International Rice Research Institute (IRRI), maize at the Centro Internacional de Mejoramiento de Maiz y Trig0 (CIMMyT), etc., are under the nominal political control of the international community and, as far as we are aware, are distributed to recipients of every nation. Usually, the level of current political control over access to PGRs is national (see Lacy, 1993, which may result in restricted access (Barton, 1995). Despite the national sovereignty over PGR access that is common elsewhere, some European nations have established highly integrated bilateral or multilateral SC programs for specific crops. For instance, genebanks in Germany and the United Kingdom duplicate accessions in Dutch genebanks as a risk avoidance strategy. The degree of integration among these national SC programs is so great that a scientist from the Dutch national germplasm system has been stationed at a German germplasm bank (Houseal et al., 1985). The national SC programs for the Scandinavian nations are also very highly integrated (Blixt, 1994b), to the extent that they share a common SC facility-the Nordic Gene Bank. In contrast to the preceding examples, we know of no DC programs wherein access to crop PGRs is under international political control. This is not surprising because DC may require regulating access and/or regulating human activities within certain regions, and very few nations, provinces, or locales would willingly permit such political control by external organizations. Consequently, political control of PGRs conserved via DC is usually exerted by the traditional cultivators (e.g., the Kuna people of PanamB; Clay, 1991), the external organization(s) implementing the DC program, local or national governments, or a multijurisdictional combination of these parties (Shands, 199I). Intellectual property rights associated with PGRs and issues linked to the interpretation of the concepts of farmers’ rights and traditional people’s rights may become increasingly important determinants of access to PGRs maintained by traditional people due to the activities of some traditional people, ethnobotanical researchers (reviewed in Martin, 1995), international organizations (e.g., FA0 and UNESCO), national and regional governments (Shands, 1995), and, perhaps most important, NGO advocates who participate in the CBD and other international conventions. Nonetheless, Duvick ( 1993) found no indication that intellectual property rights (IPRs) have been directly implicated in the loss of PGRs from centers of genetic diversity.

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The effects of IPRs on DC programs that, especially in the developing world (Juma, 1993), may be difficult to partition from the effects of political factors (Houseal et al., 1985; Crucible Group, 1994), are potentially profound and currently poorly understood (Barton, 1995). For example, consider a hypothetical onfarm sorghum breeding DC program in India that includes traditional farmers and scientists from India’s NAR, from an IARC [e.g., International Center for Research in the Semi-Arid Tropics, (ICRISAT)], from a NAR of a developed country, and from commercial sorghum breeding companies. Suppose this program produces a unique, highly divergent sorghum population that yields twice as much grain as does current elite germplasm but requires half the water. Who owns and thus controls access to the PGR? What is the nature of the nation’s IPRs system, and does it apply in this case? Who benefits economically from this breakthrough? All the program’s participants, equally? Some of them? None of them? How do they benefit? For how long? The preceding hypothetical case demonstrates that the IPRs associated with PGRs, or which may be associated with IPRs in the future, should be clarified early in on-farm breeding programs to avoid any potential disputes regarding this issue. An early establishment of commercial terms and the commercial goals of a program, along with formal clarification of IPRs, perhaps via material transfer agreements (Barton, 1995), are consistent with provisions of the CBD, with standard international business practices, and with the General Agreement on Trade and Tariffs enforced by the World Trade Organization. International and national regulations may also restrict access to PGRs. For instance, European regulations designed to reduce fraud in the seed trade complicate SC programs and consequently may reduce the economic benefit a farmer could realize through DC of traditional PGRs (Cherfas et al., 1994).According to Cherfas er al., laws governing plant variety commerce in Europe could be greatly simplified via mandatory deposit of voucher specimens in a SC-another example of how SC and DC programs could act synergistically to safeguard PGRs. Although phytosanitary regulations may protect traditional PGRs from alien genes, pathogens, and pests, these same regulations may also impede DC programs by reducing the potential market profitability of traditional PGRs (Cherfas et al., 1994).

J. EDUCATION,PUBLICITY, AND POLITICAL SUPPORT FOR

PGRC

Martin ( 1995) describes the role of ethnobotanical education in implementing DC programs. This education may include classes, exhibits, books, and newsletters for facilitating not only DC (Browning, 1991) but also the intergenerational transmission of local knowledge regarding plants (McKiernan, 1990). Education is considered a vital component of DC programs in Ethiopia (Worede, 1993), Colombia (Clay, 1991), and elsewhere. Education in support of PGRC may take

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the form of ecotourism (Janzen, 1986), which not only educates the tourists but also adds economic value to the conserved PGRs. Botanical gardens also play an important role in educating the populace regarding DC and PGRC in general (Watson et al., 1993). All the authors cited in this section recognize the importance of public support, especially at the local level, that Brush (1991) has identified as a key element for sustaining DC for PGRs. Educational campaigns can be integrated with efforts to establish economic incentives for DC of PGRs and to monitor the progress of DC projects. Dalla Ragione and Perrino (1994)have conducted two integrated projects for DC and reintroduction of traditional Italian fruit varieties. An NGO entitled “Archeologia Arborea” (Tree Archaeology) was established to promote DC of PGRs and associated folk knowledge, and “Archeologia Agricola” (Farmer Archaeology) was established to encourage commerce of local-traditional fruit PGRs and to facilitate education and communication between growers and potential consumers, especially those involved in “rural tourism.” Three specialized conservation orchards for demonstrating traditional management techniques were also initiated. The locations of old varieties will be mapped for monitoring and use in commerce. A similar program for the DC of fruit trees is under way in Provence, France (Barret and Crossa-Reynaud, 1995) under the auspices of a local NGO. Primarily through publicity, it has increased the market demand for traditional varieties to such an extent that local nurseries are being provided with traditional PGRs for commercial multiplication and sale. Publicity, a specialized form of education, often uses standard educational media and approaches. Publicity is one key component of a recently initiated DC program in Turkey (Strauss and Gallagher, 1995). Various NGOs have commissioned extensive reports that aim not only to educate the populace regarding threats to PGRs but also to gain financial supporters by publicizing the need for PGRC (Noss and Peters, 1995). Indeed, one index for the success of specific PGRC programs is the diversity of their supporters and the breadth of their constituency. In the future, transnational communications, either via the Internet or television, must play an increasingly important role in mobilizing public support for PGRC because “no [one] funding source will be enough to meet the multifaceted challenges of conservation . . . on a long-term basis, no strategy will prove viable if we don’t reach the support of public opinion and mainstream society” (Chauvet, 1994, p. 145). International agencies such as UNESCO exert “moral suasion” by designating certain wildlands (often well-established regional or national parks) as “World Heritage Sites” based on the intrinsic biological value of the site and on the quality of its managerial program (Gregg, 1991). These designations may be widely publicized and, when they bolster ecotourism (e.g., Costa Rica’s national parks), moral suasion may be subtly transformed into increased economic value and hence political leverage for supporting DC and broad access to PGRs. We wonder

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whether DC of traditional agricultural landscapes, human cultures, and PGRs can be encouraged through an analogous ranking system by value, i.e., “World Agricultural Heritage Sites.” Perhaps pilot programs associated with current MAB sites (Gregg, 1991) could be initiated to test this concept’s utility. For international political considerations, it might be best to begin within the developed countries, e.g., the traditional Amish communities of Pennsylvania and Ohio, the Hopi communities of Arizona, etc. Success of such programs might contribute significantly to solving some of the political barriers clouding the future prospects for DC programs, which is the topic of the following section.

In. DC’S FUTURE PROSPECTS Section I11 appraises the future prospects for DC in light of the issues discussed under Section 11. The PGRs that might be accorded highest priority for DC programs are discussed, together with some high-priority goals for DC programs and mechanisms for assessing the ability of such programs to address priorities successfully. Complementary DC and SC programs are advocated for optimal progress with PGRC, and the importance of designing DC programs that mesh optimally with international, national, regional, and local abiotic, biotic, and human cultural contexts is stressed.

As noted under Section II,D, priorities for DC of PGRs should be set with reference to the risk of losing particular PGRs and their perceived value to humanity. In Section II,G, the establishment of DC wildland reserves was listed as an action that would reduce the risk that wild biota would be extirpated. Also in Section II,G, fragmentation of land holdings into small plots, marginal local agronomic conditions, economic isolation, and cultural preferences were cited as factors favoring DC of crop PGRs by traditional societies, whereas human populational growth and “spatial integration” (i.e., better transportation and communications) were cited as forces that, if not actually endangering traditional PGRs’ immediate survival, would not reduce the risk that PGRs would be extirpated (Brush, 1995). Given these factors and their interrelationships, we concur with Brush’s (1995) forecast that “traditional high-yielding cultivars” adapted to optimal local agronomic conditions are probably the crop PGRs that are most at risk of future loss from traditional societies through habitat destruction or by replacement by introduced elite germplasm.

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Although extrapolating the future for DC of PGRs in particular regions from agricultural history elsewhere may be risky (Brush, 1991), it may provide a useful forecasting tool. Traditional high-yielding cultivars in crops such as maize disappeared relatively rapidly from the most productive lands in Europe and North America following the advent of scientific crop improvement (Wallace and Brown, 1988). Similarly, barley (Hordeum vulgare L.) and finger millet [Eleusine coruc a m (L.) Gaertn.] traditional varieties have been replaced by wheat in the lowlands of Nepal, but the former persists in the highlands (Riley, 1996). Moreover, the wild flora covering the highly productive lowland alluvia in the topics, e.g., Jamaican riparian lowland forests (Thompson et al., 1986), and at higher latitudes, e.g., riparian forests in the Mississippi River Basin of the United States (Grauke et ul., 1999, have clearly suffered more from genetic erosion via land conversion than have montane flora covering marginal agricultural lands. Relatively few wildland DC reserves have been established in agronomically superior landscapes, such as Jamaican riparian alluvia (Thompson et al., 1986). Traditional high-yielding PGRs may be quite valuable if they incorporate genetic systems for maximizing yields that are highly divergent from those predominating in current elite PGRs. Through history, the melding of highly divergent PGRs was responsible for many dramatic advances in crop productivity, such as the evolution of the highly productive maize landrace Corn Belt Dent via the hybridization of two divergent traditional varieties (Wallace and Brown, 1988). The identification of just one novel “heterotic group” in traditional maize PGRs would likely result in productivity gains worth several times the total financial support allocated annually to all maize PGRC programs worldwide. Therefore, considering their actual or potential risk of loss and inherent value, traditional high-yielding crop varieties should be ranked as high-priority targets for crop DC, but we are unaware of any DC reserves or on-farm conservation programs currently devoted specifically to their conservation. As a first step, the ecogeographical locales wherein traditional people still practice traditional agriculture should be identified. This effort may require an international, interdisciplinary survey incorporating both crop germplasm experts and ethnobotanists and anthropologists. Once identified, these sites should be mapped onto a GIS system. Whenever this high-yielding germplasm is located, it would be imperative to at least collect propagules immediately for SC and possible later reintroduction. Establishing on-farm DC programs for these PGRs may be a short- to medium-term goal that could unite the resources of traditional societies, agricultural scientists, national and international governmental agencies, NGOs, and commercial companies into a joint DC program. Once DC programs for high-yielding crop varieties are well established, DC efforts could expand to address ecogeographically or culturally “marginal” PGRs that are in less immediate danger of loss. Another priority task for DC programs that might unite the resources of disparate

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traditional cultures, NARs, IARCs, and corporations is to sustain and enhance “indigenous” (Riley, 1966, p. 152) breeding programs for regional or locally important crop PGRs, especially the indigenous crops of the tropics. Santhakumar (1996) has described how the agricultural research establishment has been unable to breed high-yielding rice varieties that were acceptable to traditional farmers of Kerala, India, because of the agroecological diversity of this region and the failure to incorporate traditional farmers into the breeding program. Simmonds (1995) has excoriated the agricultural research establishment as a whole for essentially ignoring tropical tree crops as subjects for crop improvement. For example, there is a wealth of locally or regionally important fruits from the Andes (National Research Council, 1989; Holle and Risi, 1993; Castillo, 1995) that, with the proper crop improvement effort, could become key elements of that region’s export trade. By enhancing the horticultural or agricultural merit of these crops via local breeding programs comanaged by traditional farmers and local scientists, the inherent value of both PGRC and plant breeding per se might be compellingly demonstrated to scientists, politicians, and decision makers in developing countries. Furthermore, incorporating a DC component into successful local breeding programs might conserve valuable PGRs at least for the short term. It may be more beneficial, from the perspective of conserving traditional culture, for traditional people to participate in combined breeding-DC programs that enhance the practical value of PGRs rather than to serve simply as tour guides in ecotourist-oriented “nature parks” for traditional agriculture and crops. Integrated breeding-DC programs that strive to help “the farmer develop indigenous landraces which are maintained using indigenous knowledge” (Riley, 1996, p. 151) may prove to be more durable and to be of greater long-term value than ecotourism because tourists may not receive enough benefit, over time, to continue to visit, i.e., buy the product. As noted under Section IIJ, the apportionment of IPRs and financial benefits that might accrue from developing agronomically or horticulturally superior PGRs must be established early during strategic planning for on-farm breeding and DC programs, and a tangible portion of these benefits must accrue to traditional people. Another priority task for DC programs may be to convince managers of extant agricultural/horticultural field stations located near regions of traditional agriculture to devote a small percentage of their land and operational resources to traditional farmers who would cultivate traditional PGRs with traditional technology (see examples under Section 11,G).Apparently, one IARC (ICRISAT; LennC et al., 1996) may adapt this approach. The pattern of land use at the stations would then mimic that of some traditional farmers who maintain small populations of ancient varieties as garden curiosities, for religious reasons, etc., whereas they plant most of their land to scientifically improved, higher yielding PGRs (Bellon, 1996b). Also, it would take advantage of the knack for experimentation with PGRs mani-

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fested by many traditional people (Alcorn, 1995). Nonetheless, we have no illusions regarding the difficulty of implementing the preceding scheme. If field stations with a dual crop improvement-DC mission could be developed in regions of high genetic diversity of PGRs, they might serve as “evolutionary gardens” (Wilkes, 1991, pp. 94-95) where crop PGRs, challenged by a variety of important abiotic and biotic stresses, interbreeding with wild and weedy relatives, would evolve dynamically under natural and human selection. The preceding types of programs, if properly designed, would serve as the long-term “base-broadening” efforts for regional gene pools championed by Duvick (1990) and Simmonds ( 1993). The base-broadening programs could link traditional and scientific crop improvement and DC practices and philosophies and link breeding PGRs for commercial farmers with breeding for traditional local farmers (Hardon and de Boef, 1993). An associated extension-outreach effort (see Section II,J) for convincing commercial farmers, “scientific” breeders, traditional farmers, and rural dwellers that DC of PGRs and scientific and traditional breeding are complementary activities (Hardon and de Boef, 1993) would enhance the probability of a DC program’s success (Wilkes, 1991). The “dual-mission” field stations described previously include many of the essential characteristics of some extant PGR management sites of some IARCs (LennC et al., 1996) and of national germplasm systems, e.g., the North Central Regional Plant Introduction Station (NCRPIS), which is part of the NPGS. At the aforementioned joint U.S. government-university facility, PGRs are conserved via SC in cold rooms, freezers, and long-term field plantings, but DC is promoted by distributing worldwide, free of costs and restrictions, a wide variety of PGRs. Other activities include extensive genetic characterization programs, long-term evaluations of local adaptation and host-plant resistance, and small-scale crop improvement programs to adapt introduced germplasm to local conditions, to make genes or gene blocks from wild or traditional crop PGRs more easily accessible to breeders, and to accumulate host-plant resistance genes into genetically broadly based populations through long-term natural and human-directed recurrent selection (NCRPIS, 1996). These disparate activities are conducted by a professional staff who uses both modem technology and time-honored, labor-intensive methods of scientific crop improvement and PGRC. Organizations such as the NCRPIS have much to learn from counterparts conducting DC of PGRs in traditional agroecosystems, who in turn may find aspects of NCRPIS’s organizational structure, managerial philosophy, and integrated operational approach to PGRC relevant for strategic planning for DC programs. Interchange of divergent institutional perspectives might tangibly improve programs for the DC and SC phases of conserving PGRs and their associated ecological, evolutionary, and traditional cultural processes and knowledge. Consequently, strengthening communication links among divergent PGRC organizations of different sectors (governmental and NGO) and countries must be viewed as a high priority.

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B. HALLMARKSFOR ASSESSING DC PROGRAMS Various PGRC institutions, such as the NCRPIS, the IPK genebank at Gatersleben, Germany, or the VIR genebanks in Russia, may be 40 or more years old, but most DC programs are much younger, thus complicating efforts to assess their efficacy or to forecast their fate and that of the PGRs they seek to conserve. In addition to these organizations’ youth, the relatively few details that are readily available regarding institutional or programmatic operations, capabilities, etc. impede such assessments. For instance, because of the lack of data regarding “policy/institutional feasibility,” and an inability to analyze the extant data in a standard way, a recent assessment of DC priorities for the biota of Latin America and the Caribbean simply omitted policy/institutional feasibility as a criterion for priority setting (Biodiversity Support Program et al., 1995). Thus, the following hallmarks for assessing DC programs are based on the experience of several authors (see the following paragraph), general principles of organizational management, anecdotal evidence, personal observations and experiences, and the paucity of available data that were examined. We agree that commitment, competence, and accountability are fundamental to successful PGRC programs (Shands, 199 1 ), and that “without a monitoring/accounting system to substitute for profit measurement, the impacts of conservation investment decisions are not being measured, and there is no feedback system to trigger decisions that do lead to successful conservation” (Alcom, 1991, p. 322). We agree that the complementarity of DC programs with SC efforts is an important hallmark of programmatic quality (Brush, 199I ) ; consequently, Section III,C is devoted to that topic. We also agree that minimizing bureaucracy, reinforcing extant institutions and incentives, choosing appropriate goals for rural development, and international collaboration may be fruitful approaches for implementing a successful DC program (Brush, 1991). In this section, we will suggest additional criteria for assessing DC programs’ current impact and future potential. These criteria and those listed previously might be considered as hypotheses to be tested, once sufficient data regarding DC programs accumulate. They may also serve as a starting point for choosing the most meritorious recipients of the increased funding that may be available for DC (see Section 1,E).We agree that such assessments will require “a tireless commitment to evaluate what works and what doesn’t work-an evaluation that must give equal weight to the assessments of local people and outside experts” (Alcorn, 199 I , p. 344), and we underscore Alcom’s warning that the extant systems for assessing DC programs’ success have “failed to monitor biodiversity through indicators important to either the global capitalist economy or domestic economies” (Alcorn, 1991, p. 336). The numbers of genes, species, biomes, or human cultures addressed by a DC program may provide hallmarks for programmatic strength, success, or potential,

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as may the diversity and amount of economic resources available to the program. The preceding criteria may be best weighed in conjunction with other factors such as the breadth of programmatic objectives. For instance, the strategic plan of the PGRC program for Danish trees and shrubs mentioned previously includes “only” 75 species (Graudal et al., 1995); however, the breadth of objectives addressed by the plan and the financial resources potentially available for attaining programmatic goals engender optimism for this PGRC program’s success. Furthermore, the relative demand that traditional people or financial supporters exhibit for funding or participating in these programs (Clay, 1991) and the number and kind of “offshoot organizations” derived from particular DC programs may gauge their efficacy. For instance, the staff of the prominent NGO, Native SeeddSEARCH, devoted to conserving the traditional PGRs and agriculture of the southwestern United States and northwestern Mexico, has been instrumental in founding other programs and organizations for conserving the native pollinators of U.S. crops and for preserving knowledge of traditional farming methods (Joaquin, 1995). A superior DC program will have established a coherent and clear focus, as evidenced by a record of sustained achievement of objectives (see Section 11,E). Ideally, sustained achievement would be demonstrated by tangible positive changes between baseline and current measures of the number of traditional PGRs cultivated or conserved, their economic value, etc. Ratios or indices of various measures, e.g., increases in the hectares planted to a traditional crop per dollar spent per site, might be especially useful measures of achievement and could test the hypothesis that DC might be more cost-effective than SC for attaining certain PGRC objectives (Brush, 199 1). As mentioned previously, unfortunately such baseline data are often absent, and an indexed file of the few baseline data currently available (Horovitz and Feldman, 1991) is badly needed for this criterion to be practical. Apparently, the FA0 has established a “World Information System and Early Warning System” to monitor genetic erosion in landraces (K. Williams, personal communication). This system may generate some of the baseline data needed for quantitative analyses. Furthermore, these baseline data should be generated from studies of a variety of “model cropshaxa” because the biotic, abiotic, and human cultural factors bearing, for example, on DC of autogamous annual wild wheat relatives in Israel (Horovitz and Feldman, 1991), will likely be highly divergent from those affecting DC of allogamous, wild perennial maize relatives in Mexico (Sinchez G. and Ordaz S., 1987). The superior DC program will have a diversity of resources, especially economic, but also land, communication networks, etc., currently committed to its operation and also in reserve. We consider the diversity of resources to be more important than the absolute amount because diversity provides a buffer against rapid change in donor priorities, in governmental policies, etc. A diversity of resources will help lend the breadth and stability needed for programmatic achievement, which in the context of PGRC is equated to sustained success over years or gen-

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erations. From our experience, we consider a stable cadre of scientific staff and/or farmer participants to be especially vital for sustained programmatic achievement with PGRC. Programmatic stability should not result in organizational ossification. Mechanisms for encouraging innovation, flexibility, and organizational evolution will characterize superior DC programs. In particular, active, committed, and broadbased (incorporating traditional people whenever possible) boards of directors (Drucker, 1992) or other external advisory groups (Shands, 1991) are vital for sustaining growing and evolving programs. The organizational structure should encourage the program’s staff and/or farmer participants to be innovative. For example, the Instituto Nacional de Biodiversidad (INBio), Costa Rica’s leading NGO for DC of wild biota, has established an innovative program for training parataxonomists (graduates of high school or undergraduate college) for inventorying, identifying, and monitoring wild biota and for serving as local naturalists and advocates in rural communities for DC of wild biota (Janzen, 1986). This staff has itself developed innovative means of pooling and managing its personal financial resources in a manner that maximizes mutual benefit (J. LCon, personal communication). Notably, INBio seeks to promote not only the economic but also the intellectual rewards of PGRs (Gamez, 1991). Another instructive example of innovative organizational structure is The Plants and People Initiative (see Section KD), an interorganizational DC partnership whose network-like structure resembles those of the boundary-less, “virtual corporations” that may soon dominate the commercial world (Davidow and Malone, 1992). The organizations constituting this DC partnership comprise temporary, focused, interorganizational teams-an organizational structure widely touted as optimal for achievement (Katzenbach and Smith, 1993). In the future, DC reserves or on-farm DC programs may be implemented by teams composed of specialists and other resources allocated from divergent “home” organizations (e.g., NGOs and IARCs) to address a portfolio of short- and long-term DC projects for predetermined periods. Ideally, these teams would be strongly linked to the local organizations of traditional people whose support is a vital prerequisite to successful DC of traditional culture and PGRs (Clay, 1991).After the completion of the project segment, which involves “external” expertise, local organizations of traditional people would assume full responsibility for sustaining the DC program. Finally, a superior DC program, like a durable traditional farming culture, will develop mechanisms for continuity. Although a DC program may be initiated by the zeal of “enlightened individuals” (champions), it will not endure unless its leadership can be transferred in a well-understood, orderly way by its founders to managers, ideally characterized by the qualities noted under Section II,D, who will enhance and sustain it subsequently.The successors, if not the founders, should include the “local [traditional] promoters” who are often key to the success of various rural development projects (Chapin, 1991). Thus, many organizational fea-

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tures of superior DC programs for PGRs may mimic the well-established, resilient networks of seed exchange and DC in durable traditional farming cultures (e.g., Ethiopia; Worede, 1993). Consequently, the organizational culture of superior DC programs may be well adapted to augmenting the DC capabilities of traditional people, without distorting the essential features of traditional societies.

C. COMPLEMENTARY DC AND SC PROGRAMS According to Brush (1991), from their inception DC programs should be designed to be complementary to extant SC efforts. Complementary links with national or international SC genebanks that could serve as long-term archives for baseline data, traditional knowledge regarding PGRs, and storage sites for PGRs could help ensure the long-term success of governmental or NGO DC programs (Czembor et al., 1994; Hardon and van Hintum, 1994).To date, relatively few such links have been established, in some cases possibly because of the “curious phenomenon that while both the government and NGO programmes have a shared concern to maintain genetic diversity, their actions are often carried out in an atmosphere of distrust and competition” (Hardon and van Hintum, 1994, p. 180). Some DC programs (e.g., the NGOs Native SeeddSEARCH, Seed Savers’ Exchange, and The Henry Doubleday Trust) have established their own “in-house” genebanks to fulfill SC functions, perhaps because of the former curious phenomenon or because of the greatly divergent organizations, policies, cultures, and objectives of some DC and SC programs. For the benefit of PGRC worldwide, cooperation and coordination between SC and DC programs must be enhanced (Engels, 1995). Traditional people usually recognize the importance of integrating SC and DC methods for ensuring the survival of traditional PGRs. Native Americans in the southwestern United States and northwestern Mexico conserve PGRs via SC by transplanting certain endangered wild cacti, which have various traditional uses, from nature to houseyard gardens, and by conserving seeds of other useful plants in hermetically sealed jars kept in caves or storerooms (Nabhan e f al., 1991). Similarly, traditional farmers in Ethiopia seal seeds in clay pots or stone mortars to preserve them via SC (Worede, 1993), and traditional farmers in Zimbabwe secreted PGRs in hidden granaries to protect them against drought and invaders (van Oosterhuit, 1996). Complementary PGRC efforts may benefit scientific users of PGRs (Shands, 1991), such as Revilla and Tracy ( 1 995a,b), who acquired North American sweet corn (Zea mays L.) PGRs for their research from both the NPGS and from Seed Savers Exchange, a heritage seed NGO. Cooperation and collaboration could be enhanced by SC genebanks recognizing traditional farmers and farming communities as bona tide PGR managers and users (Berg, 1996) and taking other steps, such as inviting traditional farmers to

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field displays, demonstrations, etc., to make the PGRs and associated information conserved by genebanks more accessible to traditional people or to personnel of DC programs. This would provide additional opportunities for SC genebank personnel to communicate clearly to traditional farmers and staff of DC programs that scientific breeders and PGR managers also esteem certain traditional crop PGRs. Such cooperation may magnify the effectiveness of PGRC as a whole, as may occur under the memorandum of agreement between Agriculture and Agri-Food Canada and the Canadian Heritage Seed Program whereby amateur enthusiasts can regenerate seed accessions for incorporation into the Canadian national SC genebank (Cherfas, 1994). Similarly, a SC institution (the NPGS’s National Seed Storage Laboratory) has already collaborated with the Center for Plant Conservation (CPC), an NGO focused on PGRC of wild flora, by maintaining seeds of the CPC’s wild PGR collection in long-term storage vaults (McMahan and Falk, 1989). These PGRs will now be accessible over the long-term for DC programs to reestablish or bolster endangered flora in nature. Collaboration should be expected among PGRC programs that, on close examination, actually share highly congruent missions. According to Cherfas ( 1994), informal-sector DC programs are united by their commitment to PGRC through utilization, a commitment shared with governmental PGRC programs that recognize that utilization is “the very ruison d’ctre of genetic conservation” (Simmonds, 1979, p. 327). For instance, The Henry Doubleday Research Association (a British NGO devoted to PGRC) Genetic Resource Department’s mission statement [“to conserve as much crop biodiversity as possible and to make as many varieties available as possible” (Cherfas, 1994)] is nearly identical to that of the NCRPIS [“to conserve a broad diversity of crop germplasm and to encourage its utilization” (NCRPIS, 1993)]. Closer collaboration between SC and DC programs with complementary weaknesses and strengths might be forged through mutual advisory or consulting missions focused on particular ecogeographical sites, PGRs, or PGRC components. The concept for such collaborative efforts is not new (Congdon, 1987), but its implementation has been problematic. Personnel from DC organizations eventually might be seconded to SC genebanks-which would provide logistical support (communications, computers, and transportation) and field assistance-to help plan and initiate DC programs for wildlweedy or traditional crop PGRs located nearby the genebank. Personnel from the genebank could then maintain the DC effort with periodic help from personnel of the DC program. Similarly, SC genebank personnel or breeders could be seconded to DC programs to learn more about traditional agricultural practices and agroecological processes that determine the evolutionary trajectory of traditional PGRs. Moreover, the dual-mission field stations discussed previously could be established and staffed jointly by a consortium of disparate DC and SC institutions.

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D. CONCLUDING REMARKS We recommend that decisions to implement particular phases of PGRC be considered carefully relative to the attributes of PGRs listed under Section I,A and by Brush (1991) and Engels (1995). The importance of maize, rice, and the other annual grains considered the “staples of life” to human survival worldwide may never wane. Their annual or herbaceous perennial wildlweedy relatives must be protected in well-conceived DC reserves linked somehow to internationaMntergovernmental agencies (Brush, 1991), and genetically representative samples should be incorporated into SC genebanks. These DC reserves should also be connected in an administratively flexible way with a network of scientific breeding programs and traditional farmers’ organizations that would collaborate at carefully sited dual-mission field stations to implement DC and genetic enhancement of locally/regionally important traditional varieties of these staple crops. The precise organizational nature of the preceding networks should be determined by abiotic, biotic, and human cultural factors intrinsic to specific taxa and/or their traditional cultivators, but the DC program itself should be implemented according to certain internationally established minimum technical guidelines. Locally important traditional crops other than the previously mentioned worldwide staples may be vital to the long-term health of regional economies (especially in the developing world) and to the survival of particular traditional cultures (Prescott-Allen and Prescott-Allen, 1990). Many of these crops are tropical perennials (root crops and trees) that perpetuate clonally or by short-lived seeds. As such, they often cannot be stored as seeds or in vitro, but rather must be conserved in orchards or glasshouse plantings. Some of these crops may become the future new crops of international commerce (e.g., the kiwifruit, Actinidia chinensis Planchon). Their wild/weedy relatives could be conserved in reserves established for DC of wild biota as a whole and their status monitored periodically by national, regional, or local DC organizations or designated staff of relevant SC institutions. As long as traditional cultures and their local economies retain their essential features, these crops and their wild/weedy relatives may endure via local DC activities implemented by traditional people without any external intervention. In contrast to the staples of life, these local/regional traditional crops may progress through a cycle of waxing and waning human interest and interdependence-”garden curiosity-minor crop-major cropminor cropgarden curiosity”-at least at a local level if not on a broader ecogeographical scope. The archaeobotanical and historical record suggests that this occurred in Europe and North America for some crops ( e g , flax, Linum usitatissimum L.; Zohary and Hopf, 1988) and for some traditional varieties (squash, Cucurbita p e p L; Smith, 1992). Human interest in other local or regional crops (e.g., large-achened vanants of sumpweed, Iva annua L.) apparently waned to the extent that they may now be extinct (Heiser, 1985).

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According to Simmonds (1979) and Frankel e t a / . (1 995b), only SC can prevent the extirpation of severely waning but potentially useful crop PGRs that, because of waning human interest, essentially resemble the “living dead,” symbolized by the solitary dominant rain forest tree standing in a sea of exotic pasture grass (Janzen, 1986). Given the biological features of the tropical perennial crops described previously, maintenance of these locally/regionally important PGRs at dual DC-on-farm breeding stations should be assessed critically as a practical alternative to SC, but we recognize that “absolute integrity in perpetuity can never be guaranteed. What can be done is to adopt the most conservative methods that are technologically feasible, replicate collections over diverse well-chosen sites and exercise great practical care” (Simmonds, 1979, p. 331).

ACKNOWLEDGMENTS We thank R. Clark (USDA/ARS), P. Forsline (USDA/ARS). E. Garvey (USDNARS), L. J. Grauke (USDA/ARS), G. Seiler (USDNARS), H. L. Shands (USDNARS), N. W. Simmonds (Edinburgh), J. S. C. Smith (Pioneer Hi-Bred International), and M. P. Widrlechner (USDNARS) for their advice and critiques of the manuscript, and M. Bellon (IRRI), M. L. Frankland (Plantlife), L. J. Grauke (IJSDAIARS),J . Hardon (CPRO-DLO-CGEN), M. Holle (CIP), K. Hummer (USDNARS), J. Sawhill (The Nature Conservancy), and K. Williams (USDA/ARS) for providing information regarding various ongoing DC efforts and organizations. We dedicate this paper to the memory of our esteemed colleague Dr. Calvin R. Sperling, 1957-1995. Journal Paper J- I7253 ofthe Iowa Agriculture and Home Economics Experiment Station, Ames, Iowa, Project 1018.

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