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Edgar Anderson: Interdisciplinary authority on what was not known about corn
Edgar Anderson: interdisciplinary authority on what was not known about corn Kim Kleinman While Edgar Anderson made significant contributions to the Mangelsdorf and Reeves ‘tripartite hypothesis’ on the origin of maize and added to the development of hybrid corn, his interests ranged widely over many aspects of the plant. Ultimately, he captured this approach by stating that his goal was ‘To study the plain old-fashioned Botany of Corn with the greatest possible precision.’ His work shows the power of an interdisciplinary research program that combined genetics, morphology and taxonomy while drawing on agronomy, archaeology and anthropology.
Summarizing his career between 1941 and 1954, Edgar Anderson (1897-1969) of the Missouri Botanical Garden commented: During the years when research on corn and its relatives was my main interest, I was often introduced as ‘An authority on corn,’ to which I usually responded that I was NOT an authority on corn, but an authority on what was not known about it.1 Anderson listed, among others, R.A. Emerson, L.J. Stadler, Donald F. Jones, E.G. Anderson and Paul Mangelsdorf, as the real authorities on maize*. With the exception of Emerson’s pupil, E.G. Anderson, they were all students of E.M. East at Harvard’s Bussey Institution. Anderson, too, studied with East but his doctoral dissertation concerned
*In 1969 (Ref. 3), Edgar Anderson wrote ‘I am using this [term, ‘corn’] in its common American sense and not as in England where an ‘ear of corn’ refers to what Americans would call a spike of wheat, and a ‘corn field’ is the common name for a wheat field.’ While I have generally used the terms ‘maize’ or ‘22~ muys’ in this paper, I still frequently directly quote or paraphrase Anderson using the term ‘corn’ in the above sense. Readers should be guided by Anderson’s admonition throughout this paper. Kim Kleinman is a research associate at the Missouri Botanical Garden and currently teaches at Webster University for the Philosophy Department and General Studies Program. He presented a version of this paper as part of a panel called, ‘Why Corn?: Studies of a Model Oraanism at the Crossroads of 20th Century Science, Technology, and Agriculture’, at the 1998 History of Science Society Meeting in Kansas City, Missouri, USA. Kleinman’s work on Edgar Anderson grows out of research conducted at the Missouri Botanical Garden, which culminated in The Museum in the Garden: Research, Display, and Education at the Missouri Botanical Garden (PhD Dissertation, The Union Institute, 1997).
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flowering tobacco plants, Nicotiana. East, Anderson explained, was ‘one of the two men [G.H. Shull was the other] who discovered the inbred-hybrid breeding method and the one who continued analyzing heterosis (hybrid vigor) in corn-breeding plots.‘2 (See Figure 1 for more on both the inbred-hybrid breeding method and heterosis.) Heterosis and hybridization were of vital interest to Anderson throughout his career. But more than the fact that his dissertation concerned a different plant lies behind Anderson’s quip about his expertise on maize. Anderson came to Zea mays via a different route than the authorities, ‘men who spent their lives studying it”, and asked different questions of it. After Harvard, whereas Emerson and Mangelsdorf, for example, were employed by universities with strong agricultural programs (Cornell and Texas A&M, respectively), Anderson came to the Missouri Botanical Garden and Washington University. At that great center of systematic botany: the main interests of my colleagues and students were in taxonomy, morphology, and physiology. I was keenly interested in natural history and the then little known Ozarks were at our back door. I taught genetics, but I explored the Ozarks with my students. They learned about genetics from me and they convinced me that I should take a serious interest in taxonomy. With them and with other colleagues and students I have studied it ever since. We really explored together much more than the Ozarks; we explored the wide field between genetics and taxonomy, then a terra incognita. I began to study the species problem. I began to think about the importance of back-crossing in wildflowers and ornamental shrubs. I took a keen interest in the effects of heterosis outside of corn-breeding plots. With my students, I helped originate what is now called ‘biosystematics’r.
0160-9327/99/$-see
With
innovative
studies
of
Iris
and
Tradescantia (spiderworts) Anderson began
to illustrate the power of ‘biosystematics,’ the ‘hybrid’ of genetics and taxonomy. On the basis of this work, he was invited to give the 1941 Jesup Lectures at Columbia University with Ernst Mayr on ‘Systematics and the Origin of Species’. Of course, Mayr converted his lectures into one of the hallmark works of what has come to be known as the Evolutionary Synthesis, Systenatics and the Origin of Species: From the Mewpoint ofa Zoologisti. That subtitle reflected
the expectation that Anderson, too, would fashion a book ‘from the viewpoint of a botanist’ that would take its place in defining the emerging Synthesis. Anderson never delivered a manuscript despite having contracted to do so. It was not until G. Ledyard Stebbins’s Variation and Evolution in Plants5 was published in 1950 (based on the 1946 Jesup Lectures) that the Synthesis had a central botanical text. I have discussed elsewhere6 my contention that Anderson pursued his own synthesis (one of genetics, taxonomy, agronomy, history, archaeology, geography and anthropology, for starters) through his work on Zea mays. That project drew him away from the mainstream of the Evolutionary Synthesis as we know it today. Here, I take up Anderson’s maize project on its own terms. Looking at Anderson in this way (and not as a potential but failed architect of the Evolutionary Synthesis) provides the chance to study the interdisciplinary power of Anderson’s own ‘biosystematic’ approach and to examine institutional and geographic influences - in Anderson’s case the Missouri Botanical Garden, the Ozarks, and the Midwest farm belt itself - on science. That Anderson occasionally framed his maize project is negative terms, ‘What We do not Know About Zea mays’l, reflects his refreshing, innovative approach. By asking unconventional questions, by coming to Zea as a biosystematist and not as an agriculturebased geneticist, and by bringing so many
front matter 0 1999 Elsevier Science Ltd. All rights reserved. PII: SO160-9327(99)01202-S
The Anderson-Mangelsdorf collaboration Of all the other major authorities on corn, Paul Mangelsdorf was the one with whom Anderson collaborated most closely. They were roommates during graduate school at Harvard, beginning a fruitful, if occasionally strained, relationship that lasted throughout Anderson’s active years of Zea research. On July 16, 1937, just as Mangelsdorf was assessing the data that would lead to the tripartite hypothesis, he wrote Anderson:
Figure 1
The results of E.M. East’s and G.H. Shull’s inbred-hybrid corn breeding method. In the first stage, the pure bred lines A and B as well as C and D are crossed. Then the results themselves are crossed yielding (A x B) and (C x D). Note the relative greater size and kernel regularity of the first crosses A x B and C x D compared with their respective parents. This illustrates hybrid vigor or heterosis. (Photograph from Donald F. Jones and W. Ralph Singleton, Crossed Sweet Corn, New Haven: Connecticut Agric. Exper. Stat. Bull. 361 (1934) p. 531. Courtesy of the Connecticut Agricultural Experiment Station.)
diverse disciplines to bear, Anderson was in fact able to learn much about maize precisely because he worked at the intersections of so many disciplines. Claiming authority on what was not known about corn is a typical Anderson quip, but its serious side is his recognition that his contribution was to look at the maize problem from his interdisciplinary perspective leading to new questions and applications. Anderson’s contributions to maize research includes his acknowledged suggestion to Mangelsdorf and R.G. Reeves that led to their tripartite hypothesis that the wild grass Teosinte is an artifact, not an ancestor, of Zea mays-“. As Anderson put it ‘Teosinte might have come from corn crossed with Tripsacum [a third related grass], but it could never have been its chief ancestor’3. Further, Anderson himself offered four summary statements of the significance of his maize research~.~.~‘&~~.
You may recall that last spring when you visited here you asked me if I had developed any new theories on the origin of corn. I told you . that I not only had no new theories, but that I had purposely avoided even thinking about the matter until a certain amount of underbrush could be cleared away by careful, time-consuming research. You then asked whether there was any possibility that Teosinte had originated from a cross of corn and Tripsacum. I said that there wasn’t because such a cross could never have occurred in nature. So far as I know this thought never occurred to me again until three or four days ago, when some recent developments in our work here quite suddenly led me to the conclusion that Teosinte may have resulted from a cross of corn and Tripsacum. Then I remembered that you made exactly this suggestion months ago. Now what 1 want to know is this: was there any basis for your suggestion or did you merely mention it as a possibility? In other words, has your experience with Tradescantia combined with your familiarity with the corn work, given you any reason to believe that we should expect to find such a situation, or were you merely throwing it out as a possibility that hadn’t properly been considered? Any information on this point will be greatly appreciated’?. Anderson and his far-ranging biosystematic work had generated a fruitful hypothesis for his more maize-focused colleague. This debt was freely acknowledged as Mangelsdorf and Reeves began to publish their conclusions. In ‘The Origin of Maize’7 they note that they ‘began to consider seriously for the first time an unpublished suggestion made by Dr. Edgar Anderson, that Euchlaena [Teosinte] might be the product of the natural hybridization of Zea and Tripsacum’. Similarly in 1939 (Ref. 8), they wrote ‘we are especially indebted to Dr. Edgar Anderson who has followed our investigations for many years and has made numerous critical and stimulating suggestions.’ In 1940 (Ref. 9) Mangelsdorf pointed to the significance of Anderson’s work with Leslie Hubricht on introgressive hybridization in Tradescantia” and how his own maize work reinforced those insights.
What Anderson found out about the corn plant In 1941, Anderson shifted his attention almost completely to the maize project. The Missouri Botanical Garden Director’s report included a section summarizing Anderson’s professional and research activities for the year. Besides the Jesup Lectures, which were mentioned only in passing, the report lists the results of collecting in Central America by Hugh Cutler; experimental plots in St Louis, Cuba, and Texas supervised by Anderson, Mangelsdorf and Reeves, respectively; and the help of Carl Sauer and Ralph Beals of the University of California-Berkeley. Anderson himself was working on updating the maize herbarium bequeathed to the Missouri Botanical Garden by E. Lewis Sturtevant nearly 50 years earlier ‘making it possible to work out a rough grouping indicating the relationships in somewhat the same way that anthropologists divide mankind into races and sub-races’lJ. This perspective - at once taxonomic, genetic, agronomic, and anthropological was to define Anderson’s maize research for several years. On four occasions in different contexts and for different purposes’~‘~‘0~~~,Anderson summarized the meaning of his maize research invoking elements of this initial perspective. Three of these came near the end of his life in the late 196Os, but in 1945 he wrote ‘What is Zea mays?: A Report of Progress’i” as a ‘short summary [which] will serve to sketch the problem as a whole and to summarize the published results.’ In this article, Anderson identifies three related questions that his enquiry is addressing: ‘what is Zea Mays .?’ , ‘what is the origin of Zea Mays ?’ and ‘what is the agronomic importance of understanding Zea Mays as a whole?’ The first question concerned the results of the taxonomic projections made in the 1942 Missouri Botanical Garden Director’s Report. Anderson was acutely aware that ‘this specific name [Zea mays] covers a multitude of races and varieties’ 1”.ln addition to his own general surveys with Cutlerl5xlh. Anderson pointed to and provided bibliographic citations for ‘a few of these [races and varieties of Zeu mays which] have now been fairly accurately described.’ While Anderson’s contribution to Mangelsdorf and Reeves’s work helped stimulate research into the origin of Zeu ma?s, in answer to his second question he explained that: The whole problem outlined above was undertaken in protest against discussion of a virtually unknown plant. It seemed to me that one should acquire at least a rough notion of what Zea mays as a whole was lie before wasting any serious thought on how such a group of plants might have originatedlil. Anderson commented further that ‘1 still feel the time is not yet ripe for a serious study of the problem’ of Zea origins, but
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‘What We do not Know About Corn’ - 1968 Anderson’s most technical summary of his corn work was presented at the 100th bnual Meeting of the Kansas Academy of Science, University of Kansas, May 3, 1968 (Ref. 1). Here he noted that biosystematics was a hybrid from the cross of Missouri Botanical Garden systematic taxonomy with Harvard genetics. From this perspective then, Anderson commented:
Figure 2 Edgar Anderson at the Missouri Botanical Garden Arboretum in Gray Summit, Missouri, in 1967. Throughout his career, Anderson’s thinking was stimulated by the variation in natural populations that he observed at the Arboretum. These observations contributed to his development of ‘biosystematics’ and his conclusions about introgressive hybridization as an evolutionary mechanism. (Photograph courtesy of the Archives of the Missouri Botanical Garden.)
also he could not resist listing 11 bits of
‘rather trivial’ yet ‘most suggestive’ evidence for a possible east Asian origin for maize, in part to stimulate collections of Asian maize. In posing the third question, ‘the agronomic importance of understanding Zea Mays as a whole,’ he recognized that he was part of the transition to using hybrid corn that reshaped agriculture in the first half of the twentieth centuryIT. His own work on gene recombination and linkage’* touched on this question. Briefly, if: genes which went into modem maize together, might tend to stay together, even in corn-belt varieties . . . [then] knowledge of the general morphology of Mexican and South American races may be very helpful in practical breedinglo. Thus, for Anderson taxonomy, morphology and genetics were literally organically connected and, furthermore, that knowledge, had profound practical implications. ‘The Importance of my work to corn breeding’ - 1967 In Anderson’s papers at the Archives of the Missouri Botanical Garden is a very rough, two-page typescript dated February 1967 entitled ‘The Importance of my work to corn breeding’. It probably served as an internal memo at the Garden. In any case, this short document serves as a retrospective summary of the answers Anderson generated by posing in 1945 the possible ‘agronomic importance of understanding Zea Mays as a whole’. Anderson saw this work based on ‘my most important and best written technical paper [which] has won over every mathematical geneticist who set out to disprove my conclusions’ll. The upshot of the 1939
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paper was ‘that the total cohesive effect of linkage [of genes on the same chromosome] in the germplasm comes out to figures of interstellar magnitude when you try to estimate them’. Thus, as he suggested in 1945, examining the sources of genetic variation throughout Zea mays could identify the possibilities and limits with which plant breeders were working. Further, Anderson asserted that he ‘originated the hypothesis that much of the hybrid vigor of the Corn Belt Corn came from soft white dents [maize with white dented kernels on many rowed ears] and the long, hard yellow flint corns [maize with yellow, even red, flinty kernels in S-10 rows on narrow ears] of the Eastern US’l9JO. This work grew out of his collaboration with William H. Brown of Pioneer Hi-Bred Corn. The significance of this hypothesis is that Anderson persuaded corn breeders that such crosses could be a source of ‘still more heterosis’. He added by hand an emphatic ‘They got it!’ His taxonomic studies had particular implications for ‘the importance of my corn work to World agriculture and tofeeding the world’ [again, handwritten]. Only by recognizing the varieties and races could one identify potentially successful crosses. As Anderson stressed, ‘UP TO THAT DISCOVERY HYBRID CORN HAD BEEN A FAILURE OUTSIDE THE US CORN BELT.’ Thus, the aim of Anderson’s maize research was not directed at the origin of maize so much as ‘how best to classify the corns of the world, how best to measure their differences morphologically as a guide and check to measuring chemically these same differences’. Brown and others were using these insights to improve southern US and Caribbean corn ‘by mixing US inbreds and Latin American varieties’.
I became interested in such unexplored fields as: (1) The history of popcorn, including its long usage by primitive man. (2) The morphology of the corn tassel. (3) The incredible hidden structures which back up the corn kernel from underneath. (4) The history of the old, marvellously productive open-pollinated varieties of the corn belt’. In this context, to his audience of professional colleagues, Anderson characterized his maize research this way: Looking back at these studies, the one central theme seems to have been heterosis, hybrid vigor. In maize, its distribution is far from random, therefore I still distrust corn-breeding theories based on randomness, such as thosB advanced by Dobzhansky and other Drosophila geneticists at the Ames Conference on Heterosis ( 1952)*J9. In his famous 1928 paper on the Northern blue flags21, Anderson was led to ‘deny the slow accumulation of individual differences an important role in species building’ and thus set himself against the ‘general theory . . . held by many of the Drosophila workers who see in the gene mutation the unit of process which, compounded a thousand-fold, results in specific differences.’ The fullest statement of Anderson’s views on evolutionary mechanisms is Introgressive Hybridization22. As it pertained to maize, genetic linkage explained that variation was not random and any useful corn-breeding theory needed to take that into account. Thus, backcrossing as a source of genetic variation (introgressive hybridization) was a more fruitful model. Further, the aim of corn breeders was to maximize the vigor of their crosses. Hence, heterosis deserved serious study and Anderson saw his own research as a contribution to that effort. ‘What I Found Out About the Corn Plant’ - 1969 In this final summary statement, Anderson suggested his whole program aimed ‘To study the plain old-fashioned Botany of Corn with the greatest possible precision’3. To study maize as a plant in its entirety he drew on genetics, morphology and taxonomy, and relied on finely-tuned observations from natural history, archaeology and anthropology.
Figure 3 Edgar Anderson measuring maize ears and kernels in 1948. Anderson’s close morphological observations of specimens from around the world were an important basis for his conclusions about the genetics, taxonomy and origins of Zea mays. Using the Missouri Botanical Garden’s herbarium holdings donated by E. Lewis Sturtevant and adding to them with the irreplaceable help of colleagues including Hugh Cutler, Paul Mangelsdorf and Carl Sauer, Anderson was able to draw on a collection that represented varieties, races and subraces of maize from many continents. (Photograph courtesy of the Archives of the Missouri Botanical Garden.)
Its conclusions pointed back to the origins of maize and yet had implications for the future of corn breeding. Here in a popular format, Anderson reiterated his agronomic conclusionsr9Ja that the maize of the US combelt ‘is not the kind of corn we got from the Indians but a legacy from hard-pressed pioneers of the early and mid-eighteen hundreds’. ‘Corn belt dents’ were produced from repeated crosses over decades between ‘northern flints’ and ‘southern dents’. This mixture has great hybrid vigor, indeed it ‘is the world’s most important source’ of it for maize.
Conclusions Despite Anderson’s contribution to the Mangelsdorf and Reeves ‘tripartite hypothesis’ on the origins of maize, Anderson liked to point out that he was not one of the real authorities on corn. Those authorities, the
geneticists, agronomists, and corn breeders, were the ones who knew corn. Instead, Anderson characterized himself as ‘an authority on what was NOT known about corn.’ Anderson’s quip on the nature of his authority is in part his attempt to be judged on his own terms and not within the confines of a particular discipline. Geneticists like Mangelsdorf and Barbara McClintock were able to make lasting contributions with sustained focused work on maize. Anderson’s unique contributions were of a different character. He chose instead to explore the parameters of what was known through various disciplinary approaches and then synthesize from them. No one perspective could have fully answered his questions about maize, so he forged one of his own. ‘To study the plain old-fashioned Botany of Corn with the greatest possible precision,’ Anderson drew on genetics, morphology and taxonomy (while collaborating with archaeologists, anthropologists and agronomists). His 1939 work on the strong effect of linkage on gene recombination dovetailed with what he learned from E.M. East about heterosis. Careful study of plant structures, particularly by someone with the kind of keen naturalist’s eye that could develop biosystematics at the point where genetics and taxonomy met, helped him recognize signs of hybrid vigor as he walked among the plots of maize he examined. Then, a thorough knowledge of the many varieties and races that made up the species Zeu mays provided a catalogue of sources for heterosis with important implications for corn breeding. Anderson suggested, in his final comment on this aspect of his career: In conclusion, it has become apparent that I have learned more from the best of the corn breeders I associated with, than they have learned from me. Aristotle said that every science began as an art and ended as a philosophy. The most important aspect of these studies on corn is that they are carrying the art of corn-breeding farther along the path to the science of corn-breeding’. The path from art to science requires someone willing to explore what is NOT known. For maize in the mid-Twentieth century, that individual was Edgar Anderson.
Acknowledgments Many thanks to Nathaniel Comfort, Deborah Fitzgerald and Mark Lesney for their support and helpful comments on this paper and our joint panel, ‘Why Corn?: Studies of a Model Organism at the Crossroads of 20th Century Science, Technology, and Agriculture,’ at the 1998 History of Science Society Meeting in Kansas City, Missouri, USA. Similar thanks are also due to Gar Allen, Jane Cocalis, Barbara Kimmelman, Betty Smocovitis and Alan Wbittemore. Doug Holland and Chandra Oleksiewicz of the Missouri Botanical Garden staff provided irreplaceable archival and technical assistance.
References
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12
13 14 15 16 17
18 19
20 21 22
Anderson, E. (1969)Missouri Botan. Gard. Bull. 57 (September/October), 6-9 Anderson, E. (1968) Trans. Kansas Acad. Sci. 7 I, 373-378 Anderson, E. ( 1940) Proc. Amer. .4cad. Arts 74, 117-118 Mayr. E. (1942) S.ystematics and the Origin qf‘Species, Columbia University Press Stebbins, G.L. ( 1950) Variation and Evolution in Plants, Columbia University Press Kleinman, K. ( 1999) Joum. Hist. Biol. 32, [forthcoming] Mangelsdorf, P.C. and Reeves. R.G. ( 1938) Proc. Natl. Acad. Sci. 24, 303-3 12 Mangelsdorf, P.C. and Reeves, R.G. (1939) Texas Agric. Exp. Stat. Bull. 574, l-3 15 Mangelsdorf, P.C. (1940) 8th Ames Sci. Coy. Proc. 3,261-274 Anderson, E. ( 1945) Chron. Botun. 9. 88-92 Anderson, E. ( 1967) typescript in Edgar Anderson Papers, Missouri Botanical Garden Archives Mangelsdorf, P.C. to Edgar Anderson, July 16, 1937 in the Edgar Anderson Papers. Missouri Botanical Garden Archives Anderson, E. and Hubricht. L. (1938) Amen J. Botan. 25, 396-402 in Missouri Botan. Gard. Bull. 30, l-29 Anderson, E. and Cutler, H. (1942) Ann. Missouri Botan. Gard. 29, 69-88 Anderson, E. (1943) Acta AmrK I, 58-68 Fitzgerald, D. (1990) The Business of Breeding: Hybrid Corn in Illinois, 1890-1940, Cornell University Press Anderson, E. ( 1939) Genetics 24,668-698 Anderson, E. and Brown, W. (1952) in Heterosis: (Gowen, J.W., ed.). pp. 124-148. Iowa State College Press Anderson. E. and Brown. W. (1952) Agric. Hist. 26, 2-R Anderson (1928) Ann. Missouri Botan. Gard. 15. 241-322 Anderson (1949) Intro~ressive Hybridi:ation. John Wiley and Sons
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Summarizing his career between 1941 and 1954, Edgar Anderson (1897-1969) of the Missouri Botanical Garden commented: During the years when research on corn and its relatives was my main interest, I was often introduced as ‘An authority on corn,’ to which I usually responded that I was NOT an authority on corn, but an authority on what was not known about it.1 Anderson listed, among others, R.A. Emerson, L.J. Stadler, Donald F. Jones, E.G. Anderson and Paul Mangelsdorf, as the real authorities on maize*. With the exception of Emerson’s pupil, E.G. Anderson, they were all students of E.M. East at Harvard’s Bussey Institution. Anderson, too, studied with East but his doctoral dissertation concerned
*In 1969 (Ref. 3), Edgar Anderson wrote ‘I am using this [term, ‘corn’] in its common American sense and not as in England where an ‘ear of corn’ refers to what Americans would call a spike of wheat, and a ‘corn field’ is the common name for a wheat field.’ While I have generally used the terms ‘maize’ or ‘22~ muys’ in this paper, I still frequently directly quote or paraphrase Anderson using the term ‘corn’ in the above sense. Readers should be guided by Anderson’s admonition throughout this paper. Kim Kleinman is a research associate at the Missouri Botanical Garden and currently teaches at Webster University for the Philosophy Department and General Studies Program. He presented a version of this paper as part of a panel called, ‘Why Corn?: Studies of a Model Oraanism at the Crossroads of 20th Century Science, Technology, and Agriculture’, at the 1998 History of Science Society Meeting in Kansas City, Missouri, USA. Kleinman’s work on Edgar Anderson grows out of research conducted at the Missouri Botanical Garden, which culminated in The Museum in the Garden: Research, Display, and Education at the Missouri Botanical Garden (PhD Dissertation, The Union Institute, 1997).
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flowering tobacco plants, Nicotiana. East, Anderson explained, was ‘one of the two men [G.H. Shull was the other] who discovered the inbred-hybrid breeding method and the one who continued analyzing heterosis (hybrid vigor) in corn-breeding plots.‘2 (See Figure 1 for more on both the inbred-hybrid breeding method and heterosis.) Heterosis and hybridization were of vital interest to Anderson throughout his career. But more than the fact that his dissertation concerned a different plant lies behind Anderson’s quip about his expertise on maize. Anderson came to Zea mays via a different route than the authorities, ‘men who spent their lives studying it”, and asked different questions of it. After Harvard, whereas Emerson and Mangelsdorf, for example, were employed by universities with strong agricultural programs (Cornell and Texas A&M, respectively), Anderson came to the Missouri Botanical Garden and Washington University. At that great center of systematic botany: the main interests of my colleagues and students were in taxonomy, morphology, and physiology. I was keenly interested in natural history and the then little known Ozarks were at our back door. I taught genetics, but I explored the Ozarks with my students. They learned about genetics from me and they convinced me that I should take a serious interest in taxonomy. With them and with other colleagues and students I have studied it ever since. We really explored together much more than the Ozarks; we explored the wide field between genetics and taxonomy, then a terra incognita. I began to study the species problem. I began to think about the importance of back-crossing in wildflowers and ornamental shrubs. I took a keen interest in the effects of heterosis outside of corn-breeding plots. With my students, I helped originate what is now called ‘biosystematics’r.
0160-9327/99/$-see
With
innovative
studies
of
Iris
and
Tradescantia (spiderworts) Anderson began
to illustrate the power of ‘biosystematics,’ the ‘hybrid’ of genetics and taxonomy. On the basis of this work, he was invited to give the 1941 Jesup Lectures at Columbia University with Ernst Mayr on ‘Systematics and the Origin of Species’. Of course, Mayr converted his lectures into one of the hallmark works of what has come to be known as the Evolutionary Synthesis, Systenatics and the Origin of Species: From the Mewpoint ofa Zoologisti. That subtitle reflected
the expectation that Anderson, too, would fashion a book ‘from the viewpoint of a botanist’ that would take its place in defining the emerging Synthesis. Anderson never delivered a manuscript despite having contracted to do so. It was not until G. Ledyard Stebbins’s Variation and Evolution in Plants5 was published in 1950 (based on the 1946 Jesup Lectures) that the Synthesis had a central botanical text. I have discussed elsewhere6 my contention that Anderson pursued his own synthesis (one of genetics, taxonomy, agronomy, history, archaeology, geography and anthropology, for starters) through his work on Zea mays. That project drew him away from the mainstream of the Evolutionary Synthesis as we know it today. Here, I take up Anderson’s maize project on its own terms. Looking at Anderson in this way (and not as a potential but failed architect of the Evolutionary Synthesis) provides the chance to study the interdisciplinary power of Anderson’s own ‘biosystematic’ approach and to examine institutional and geographic influences - in Anderson’s case the Missouri Botanical Garden, the Ozarks, and the Midwest farm belt itself - on science. That Anderson occasionally framed his maize project is negative terms, ‘What We do not Know About Zea mays’l, reflects his refreshing, innovative approach. By asking unconventional questions, by coming to Zea as a biosystematist and not as an agriculturebased geneticist, and by bringing so many
front matter 0 1999 Elsevier Science Ltd. All rights reserved. PII: SO160-9327(99)01202-S
The Anderson-Mangelsdorf collaboration Of all the other major authorities on corn, Paul Mangelsdorf was the one with whom Anderson collaborated most closely. They were roommates during graduate school at Harvard, beginning a fruitful, if occasionally strained, relationship that lasted throughout Anderson’s active years of Zea research. On July 16, 1937, just as Mangelsdorf was assessing the data that would lead to the tripartite hypothesis, he wrote Anderson:
Figure 1
The results of E.M. East’s and G.H. Shull’s inbred-hybrid corn breeding method. In the first stage, the pure bred lines A and B as well as C and D are crossed. Then the results themselves are crossed yielding (A x B) and (C x D). Note the relative greater size and kernel regularity of the first crosses A x B and C x D compared with their respective parents. This illustrates hybrid vigor or heterosis. (Photograph from Donald F. Jones and W. Ralph Singleton, Crossed Sweet Corn, New Haven: Connecticut Agric. Exper. Stat. Bull. 361 (1934) p. 531. Courtesy of the Connecticut Agricultural Experiment Station.)
diverse disciplines to bear, Anderson was in fact able to learn much about maize precisely because he worked at the intersections of so many disciplines. Claiming authority on what was not known about corn is a typical Anderson quip, but its serious side is his recognition that his contribution was to look at the maize problem from his interdisciplinary perspective leading to new questions and applications. Anderson’s contributions to maize research includes his acknowledged suggestion to Mangelsdorf and R.G. Reeves that led to their tripartite hypothesis that the wild grass Teosinte is an artifact, not an ancestor, of Zea mays-“. As Anderson put it ‘Teosinte might have come from corn crossed with Tripsacum [a third related grass], but it could never have been its chief ancestor’3. Further, Anderson himself offered four summary statements of the significance of his maize research~.~.~‘&~~.
You may recall that last spring when you visited here you asked me if I had developed any new theories on the origin of corn. I told you . that I not only had no new theories, but that I had purposely avoided even thinking about the matter until a certain amount of underbrush could be cleared away by careful, time-consuming research. You then asked whether there was any possibility that Teosinte had originated from a cross of corn and Tripsacum. I said that there wasn’t because such a cross could never have occurred in nature. So far as I know this thought never occurred to me again until three or four days ago, when some recent developments in our work here quite suddenly led me to the conclusion that Teosinte may have resulted from a cross of corn and Tripsacum. Then I remembered that you made exactly this suggestion months ago. Now what 1 want to know is this: was there any basis for your suggestion or did you merely mention it as a possibility? In other words, has your experience with Tradescantia combined with your familiarity with the corn work, given you any reason to believe that we should expect to find such a situation, or were you merely throwing it out as a possibility that hadn’t properly been considered? Any information on this point will be greatly appreciated’?. Anderson and his far-ranging biosystematic work had generated a fruitful hypothesis for his more maize-focused colleague. This debt was freely acknowledged as Mangelsdorf and Reeves began to publish their conclusions. In ‘The Origin of Maize’7 they note that they ‘began to consider seriously for the first time an unpublished suggestion made by Dr. Edgar Anderson, that Euchlaena [Teosinte] might be the product of the natural hybridization of Zea and Tripsacum’. Similarly in 1939 (Ref. 8), they wrote ‘we are especially indebted to Dr. Edgar Anderson who has followed our investigations for many years and has made numerous critical and stimulating suggestions.’ In 1940 (Ref. 9) Mangelsdorf pointed to the significance of Anderson’s work with Leslie Hubricht on introgressive hybridization in Tradescantia” and how his own maize work reinforced those insights.
What Anderson found out about the corn plant In 1941, Anderson shifted his attention almost completely to the maize project. The Missouri Botanical Garden Director’s report included a section summarizing Anderson’s professional and research activities for the year. Besides the Jesup Lectures, which were mentioned only in passing, the report lists the results of collecting in Central America by Hugh Cutler; experimental plots in St Louis, Cuba, and Texas supervised by Anderson, Mangelsdorf and Reeves, respectively; and the help of Carl Sauer and Ralph Beals of the University of California-Berkeley. Anderson himself was working on updating the maize herbarium bequeathed to the Missouri Botanical Garden by E. Lewis Sturtevant nearly 50 years earlier ‘making it possible to work out a rough grouping indicating the relationships in somewhat the same way that anthropologists divide mankind into races and sub-races’lJ. This perspective - at once taxonomic, genetic, agronomic, and anthropological was to define Anderson’s maize research for several years. On four occasions in different contexts and for different purposes’~‘~‘0~~~,Anderson summarized the meaning of his maize research invoking elements of this initial perspective. Three of these came near the end of his life in the late 196Os, but in 1945 he wrote ‘What is Zea mays?: A Report of Progress’i” as a ‘short summary [which] will serve to sketch the problem as a whole and to summarize the published results.’ In this article, Anderson identifies three related questions that his enquiry is addressing: ‘what is Zea Mays .?’ , ‘what is the origin of Zea Mays ?’ and ‘what is the agronomic importance of understanding Zea Mays as a whole?’ The first question concerned the results of the taxonomic projections made in the 1942 Missouri Botanical Garden Director’s Report. Anderson was acutely aware that ‘this specific name [Zea mays] covers a multitude of races and varieties’ 1”.ln addition to his own general surveys with Cutlerl5xlh. Anderson pointed to and provided bibliographic citations for ‘a few of these [races and varieties of Zeu mays which] have now been fairly accurately described.’ While Anderson’s contribution to Mangelsdorf and Reeves’s work helped stimulate research into the origin of Zeu ma?s, in answer to his second question he explained that: The whole problem outlined above was undertaken in protest against discussion of a virtually unknown plant. It seemed to me that one should acquire at least a rough notion of what Zea mays as a whole was lie before wasting any serious thought on how such a group of plants might have originatedlil. Anderson commented further that ‘1 still feel the time is not yet ripe for a serious study of the problem’ of Zea origins, but
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‘What We do not Know About Corn’ - 1968 Anderson’s most technical summary of his corn work was presented at the 100th bnual Meeting of the Kansas Academy of Science, University of Kansas, May 3, 1968 (Ref. 1). Here he noted that biosystematics was a hybrid from the cross of Missouri Botanical Garden systematic taxonomy with Harvard genetics. From this perspective then, Anderson commented:
Figure 2 Edgar Anderson at the Missouri Botanical Garden Arboretum in Gray Summit, Missouri, in 1967. Throughout his career, Anderson’s thinking was stimulated by the variation in natural populations that he observed at the Arboretum. These observations contributed to his development of ‘biosystematics’ and his conclusions about introgressive hybridization as an evolutionary mechanism. (Photograph courtesy of the Archives of the Missouri Botanical Garden.)
also he could not resist listing 11 bits of
‘rather trivial’ yet ‘most suggestive’ evidence for a possible east Asian origin for maize, in part to stimulate collections of Asian maize. In posing the third question, ‘the agronomic importance of understanding Zea Mays as a whole,’ he recognized that he was part of the transition to using hybrid corn that reshaped agriculture in the first half of the twentieth centuryIT. His own work on gene recombination and linkage’* touched on this question. Briefly, if: genes which went into modem maize together, might tend to stay together, even in corn-belt varieties . . . [then] knowledge of the general morphology of Mexican and South American races may be very helpful in practical breedinglo. Thus, for Anderson taxonomy, morphology and genetics were literally organically connected and, furthermore, that knowledge, had profound practical implications. ‘The Importance of my work to corn breeding’ - 1967 In Anderson’s papers at the Archives of the Missouri Botanical Garden is a very rough, two-page typescript dated February 1967 entitled ‘The Importance of my work to corn breeding’. It probably served as an internal memo at the Garden. In any case, this short document serves as a retrospective summary of the answers Anderson generated by posing in 1945 the possible ‘agronomic importance of understanding Zea Mays as a whole’. Anderson saw this work based on ‘my most important and best written technical paper [which] has won over every mathematical geneticist who set out to disprove my conclusions’ll. The upshot of the 1939
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paper was ‘that the total cohesive effect of linkage [of genes on the same chromosome] in the germplasm comes out to figures of interstellar magnitude when you try to estimate them’. Thus, as he suggested in 1945, examining the sources of genetic variation throughout Zea mays could identify the possibilities and limits with which plant breeders were working. Further, Anderson asserted that he ‘originated the hypothesis that much of the hybrid vigor of the Corn Belt Corn came from soft white dents [maize with white dented kernels on many rowed ears] and the long, hard yellow flint corns [maize with yellow, even red, flinty kernels in S-10 rows on narrow ears] of the Eastern US’l9JO. This work grew out of his collaboration with William H. Brown of Pioneer Hi-Bred Corn. The significance of this hypothesis is that Anderson persuaded corn breeders that such crosses could be a source of ‘still more heterosis’. He added by hand an emphatic ‘They got it!’ His taxonomic studies had particular implications for ‘the importance of my corn work to World agriculture and tofeeding the world’ [again, handwritten]. Only by recognizing the varieties and races could one identify potentially successful crosses. As Anderson stressed, ‘UP TO THAT DISCOVERY HYBRID CORN HAD BEEN A FAILURE OUTSIDE THE US CORN BELT.’ Thus, the aim of Anderson’s maize research was not directed at the origin of maize so much as ‘how best to classify the corns of the world, how best to measure their differences morphologically as a guide and check to measuring chemically these same differences’. Brown and others were using these insights to improve southern US and Caribbean corn ‘by mixing US inbreds and Latin American varieties’.
I became interested in such unexplored fields as: (1) The history of popcorn, including its long usage by primitive man. (2) The morphology of the corn tassel. (3) The incredible hidden structures which back up the corn kernel from underneath. (4) The history of the old, marvellously productive open-pollinated varieties of the corn belt’. In this context, to his audience of professional colleagues, Anderson characterized his maize research this way: Looking back at these studies, the one central theme seems to have been heterosis, hybrid vigor. In maize, its distribution is far from random, therefore I still distrust corn-breeding theories based on randomness, such as thosB advanced by Dobzhansky and other Drosophila geneticists at the Ames Conference on Heterosis ( 1952)*J9. In his famous 1928 paper on the Northern blue flags21, Anderson was led to ‘deny the slow accumulation of individual differences an important role in species building’ and thus set himself against the ‘general theory . . . held by many of the Drosophila workers who see in the gene mutation the unit of process which, compounded a thousand-fold, results in specific differences.’ The fullest statement of Anderson’s views on evolutionary mechanisms is Introgressive Hybridization22. As it pertained to maize, genetic linkage explained that variation was not random and any useful corn-breeding theory needed to take that into account. Thus, backcrossing as a source of genetic variation (introgressive hybridization) was a more fruitful model. Further, the aim of corn breeders was to maximize the vigor of their crosses. Hence, heterosis deserved serious study and Anderson saw his own research as a contribution to that effort. ‘What I Found Out About the Corn Plant’ - 1969 In this final summary statement, Anderson suggested his whole program aimed ‘To study the plain old-fashioned Botany of Corn with the greatest possible precision’3. To study maize as a plant in its entirety he drew on genetics, morphology and taxonomy, and relied on finely-tuned observations from natural history, archaeology and anthropology.
Figure 3 Edgar Anderson measuring maize ears and kernels in 1948. Anderson’s close morphological observations of specimens from around the world were an important basis for his conclusions about the genetics, taxonomy and origins of Zea mays. Using the Missouri Botanical Garden’s herbarium holdings donated by E. Lewis Sturtevant and adding to them with the irreplaceable help of colleagues including Hugh Cutler, Paul Mangelsdorf and Carl Sauer, Anderson was able to draw on a collection that represented varieties, races and subraces of maize from many continents. (Photograph courtesy of the Archives of the Missouri Botanical Garden.)
Its conclusions pointed back to the origins of maize and yet had implications for the future of corn breeding. Here in a popular format, Anderson reiterated his agronomic conclusionsr9Ja that the maize of the US combelt ‘is not the kind of corn we got from the Indians but a legacy from hard-pressed pioneers of the early and mid-eighteen hundreds’. ‘Corn belt dents’ were produced from repeated crosses over decades between ‘northern flints’ and ‘southern dents’. This mixture has great hybrid vigor, indeed it ‘is the world’s most important source’ of it for maize.
Conclusions Despite Anderson’s contribution to the Mangelsdorf and Reeves ‘tripartite hypothesis’ on the origins of maize, Anderson liked to point out that he was not one of the real authorities on corn. Those authorities, the
geneticists, agronomists, and corn breeders, were the ones who knew corn. Instead, Anderson characterized himself as ‘an authority on what was NOT known about corn.’ Anderson’s quip on the nature of his authority is in part his attempt to be judged on his own terms and not within the confines of a particular discipline. Geneticists like Mangelsdorf and Barbara McClintock were able to make lasting contributions with sustained focused work on maize. Anderson’s unique contributions were of a different character. He chose instead to explore the parameters of what was known through various disciplinary approaches and then synthesize from them. No one perspective could have fully answered his questions about maize, so he forged one of his own. ‘To study the plain old-fashioned Botany of Corn with the greatest possible precision,’ Anderson drew on genetics, morphology and taxonomy (while collaborating with archaeologists, anthropologists and agronomists). His 1939 work on the strong effect of linkage on gene recombination dovetailed with what he learned from E.M. East about heterosis. Careful study of plant structures, particularly by someone with the kind of keen naturalist’s eye that could develop biosystematics at the point where genetics and taxonomy met, helped him recognize signs of hybrid vigor as he walked among the plots of maize he examined. Then, a thorough knowledge of the many varieties and races that made up the species Zeu mays provided a catalogue of sources for heterosis with important implications for corn breeding. Anderson suggested, in his final comment on this aspect of his career: In conclusion, it has become apparent that I have learned more from the best of the corn breeders I associated with, than they have learned from me. Aristotle said that every science began as an art and ended as a philosophy. The most important aspect of these studies on corn is that they are carrying the art of corn-breeding farther along the path to the science of corn-breeding’. The path from art to science requires someone willing to explore what is NOT known. For maize in the mid-Twentieth century, that individual was Edgar Anderson.
Acknowledgments Many thanks to Nathaniel Comfort, Deborah Fitzgerald and Mark Lesney for their support and helpful comments on this paper and our joint panel, ‘Why Corn?: Studies of a Model Organism at the Crossroads of 20th Century Science, Technology, and Agriculture,’ at the 1998 History of Science Society Meeting in Kansas City, Missouri, USA. Similar thanks are also due to Gar Allen, Jane Cocalis, Barbara Kimmelman, Betty Smocovitis and Alan Wbittemore. Doug Holland and Chandra Oleksiewicz of the Missouri Botanical Garden staff provided irreplaceable archival and technical assistance.
References
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13 14 15 16 17
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Anderson, E. (1969)Missouri Botan. Gard. Bull. 57 (September/October), 6-9 Anderson, E. (1968) Trans. Kansas Acad. Sci. 7 I, 373-378 Anderson, E. ( 1940) Proc. Amer. .4cad. Arts 74, 117-118 Mayr. E. (1942) S.ystematics and the Origin qf‘Species, Columbia University Press Stebbins, G.L. ( 1950) Variation and Evolution in Plants, Columbia University Press Kleinman, K. ( 1999) Joum. Hist. Biol. 32, [forthcoming] Mangelsdorf, P.C. and Reeves. R.G. ( 1938) Proc. Natl. Acad. Sci. 24, 303-3 12 Mangelsdorf, P.C. and Reeves, R.G. (1939) Texas Agric. Exp. Stat. Bull. 574, l-3 15 Mangelsdorf, P.C. (1940) 8th Ames Sci. Coy. Proc. 3,261-274 Anderson, E. ( 1945) Chron. Botun. 9. 88-92 Anderson, E. ( 1967) typescript in Edgar Anderson Papers, Missouri Botanical Garden Archives Mangelsdorf, P.C. to Edgar Anderson, July 16, 1937 in the Edgar Anderson Papers. Missouri Botanical Garden Archives Anderson, E. and Hubricht. L. (1938) Amen J. Botan. 25, 396-402 in Missouri Botan. Gard. Bull. 30, l-29 Anderson, E. and Cutler, H. (1942) Ann. Missouri Botan. Gard. 29, 69-88 Anderson, E. (1943) Acta AmrK I, 58-68 Fitzgerald, D. (1990) The Business of Breeding: Hybrid Corn in Illinois, 1890-1940, Cornell University Press Anderson, E. ( 1939) Genetics 24,668-698 Anderson, E. and Brown, W. (1952) in Heterosis: (Gowen, J.W., ed.). pp. 124-148. Iowa State College Press Anderson. E. and Brown. W. (1952) Agric. Hist. 26, 2-R Anderson (1928) Ann. Missouri Botan. Gard. 15. 241-322 Anderson (1949) Intro~ressive Hybridi:ation. John Wiley and Sons
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