Banana

TROPICAL AGRICULTURE

Contents Banana Oil Palm Plantation Crops and Plantations Rubber Rubber Production Tea, Coffee, and Cocoa The Coconut Palm Tropical Fruits Yam (Dioscorea spp.)

Banana Y Israeli, Regional Center for Agricultural Research, Zemach, Israel E Lahav, Regional Experiment Station, Acre, Israel Ó 2017 Elsevier Ltd. All rights reserved.

Center of Origin, Taxonomy, Domestication, and World Distribution

before replanting; hence corms served as food for hunter– gatherers and fishermen and were also used as propagules (Figure 1).

Background A member of the Zingiberales order, Musaceae originated in the wet tropics of South-East Asia (SEA). Since then, the giant monocotyledonous perennial herb banana (Musa spp., Musaceae) is now grown all over the tropics and in many subtropical regions. Musa and Ensete are the only Musaceae genera. The latter monocarpic species is native to tropical and subtropical regions in Africa and South Asia. It lacks rhizomes and produces inedible fruit packed with seeds. Of these, Ensete ventricosum is cultivated in South Ethiopia highlands for the starch stored in its pseudostem and corm.

Banana Center of Distribution and Utilization The banana originated in the humid rainforests of Melanesia and the monsoon regions from South China to NE India. Malaysia and Indonesia are currently the center of diversity of wild seeded banana diploids. From the inhabitants of Papua New Guinea (PNG) and the Pacific Islands we learn that roots, corm, inner leaf sheaths, true stem, and the male bud of wild bananas were consumed as commonly done with yam and taro, long before domestication. Even today, banana leaves and pseudostems are still used for the fibers, and the other organs are used for their medicinal values and for ritual ceremonies. Banana corms can be uprooted, dried, and stored for months

Encyclopedia of Applied Plant Sciences, 2nd edition, Volume 3

Musa Taxonomy Musa taxonomy is not fully resolved due to difficulties in distinguishing between true wild and edible diploid or polyploid varieties. In the mid-twentieth century, a classification based on chromosome number and morphological traits helped identify four sections: Eumusa (currently Musa) and Rhodochlamys with 11 pairs, and Callimusa and Australimusa with 10 pairs of chromosomes. Bract color and seed morphology served for distinguishing between sections having equal chromosome number. Modern molecular phylogenetic studies resulted in taxonomy revision where this genus is divided into two sections according to their basic chromosome number, namely Musa and Callimusa consisting of 33 and 35 species, respectively. It is estimated that some other Musa spp. grow wild, waiting for identification and classification (Figure 2). Being the ancient parents of most edible bananas, M. acuminata and M. balbisiana are of special importance. The former includes seven subspecies that vary in morphology and geographical distribution (Figure 3). There is also interest in some species of the Callimusa section, from the Pacific Islands, PNG, and Northern Australia. M. textilis is used for fiber production in the Philippines and Micronesia, and most probably, some others were ancestors of the edible Fe’i banana: M. peekelii (10 m tall), M. maclayi, and M. jackeyi. The latter grows on a very limited scale in North Queensland,

http://dx.doi.org/10.1016/B978-0-12-394807-6.00072-1

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(a)

(b)

(d)

(c)

(e)

(f)

Figure 1 Variety of banana uses: (a) Fibers extracted from pseudostems; (b) Beer made of East Africa highland bananas; (c) Foliage midribs used for baskets or mat weaving; (d) Male buds prepared for cooking; (e) Leaf lamina used as table plate, for wrapping, and more; (f) Corms used for propagation and for consumption as cooked food.

(a)

(b)

(c)

Figure 2

Seed and seed propagated wild Musa spp.: (a) M. balbisiana; (b) M. laterita; (c) M. balbisiana seeds.

and like Fe’i banana produces upright inflorescence, relatively short colored fruit, and large greenish bell.

Banana Domestication and Ancient World Distribution In addition to other uses, wild Musa of SEA served for selections of plants that produce fruit with edible pulp and only few seeds. Vegetative propagation facilitated the progress of

domestication as demonstrated in PNG where parthenocarpic diploids are grown in many backyards at the rainforest boundaries, whereas semiwild inedible cultivars (¼cultiwild) grow only in the transition zone and seeded wild types grow in the rainforests solely. The earliest evidence of banana cultivation, about 10 000 years ago, was found in the Kuk swamps in the PNG Highlands. Mounding cultivation system started about 6450–

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M. balbisiana

Errans Burmannica /siamea

Malaccensis Truncata

Microcarpa Banksii

Zebrina

Figure 3 Geographical distribution of Musa acuminata subspecies and M. balbisiana. The area of the seven M. acuminata ssp. is indicated in orange (except the truncata that got a brighter color since it overlaps the malaccensis) and M. balbisiana is in yellow. After de Langhe (1996), Perrier et al. (2009), and Perrier, X., De Langhe, E., Donohue, M., et al., 2011. Multidisciplinary perspectives on banana (Musa spp.) domestication. PNAS 108 (28), 11311–11318.

6950 years ago, and about 2000 years later, these plants were adapted to cultivation in the ditches. Hence, together with wheat, rice, and alliums, banana is one of the earliest domesticated plants. Domestication continued with migration to regions where M. acuminata ssp. hybridized with other Musa sub-species with the consequent development of sterile, parthenocarpic monospecific diploid with edible fruit. Interspecific hybridization between M. balbisiana and M. acuminata resulted in new bispecific cultivars. Moreover, the crosses also formed triploids (and some tetraploids) of mono- or bispecific origin (see below) which gave rise to some additional variation. Secondary centers of banana diversity developed in India and in the Pacific Islands and a tertiary center in Africa. Based on linguistic and archeobotanical evidences, it was concluded that bananas were imported from SEA to East Africa about 3500 years ago (Figure 4), with the consequent presence of edible diploids in Africa, long after their disappearance and replacement by advanced genotypes in Asia. Other early introductions include M. acuminata triploids from SEA to East Africa and plantain (a triploid of bispecific M. acuminata–M. balbisiana) from Celebes Sea zone to Central-West Africa.

of the names plantain and platano for the starchy bananas is not clear. Both banana and plantain were cultivated in the west coast of Africa in the fifteenth century, concomitant with the introduction of the former to the Canary Islands by Portuguese sailors and to Santo Domingo and Panama by the Spaniards. The need for food in the growing colonies enhanced the spread of banana over the New World tropics and subtropics. Hence, by the end of the eighteenth century bananas were widespread in the Americas, the Caribbean, and Pacific Islands. Two most important banana dessert cultivars are triploids (AAA) of M. acuminata genome: imported from South Asia to Martinique, the ‘Gros Michel’ produces fruit excelling in color, taste, storage, and yields. It was the first and most popular internationally traded banana until its destruction by Panama disease in the late 1950s. Its successor, cv. ‘Cavendish’ from South China, was imported in 1826 to Mauritius and in 1829 purchased by Duke Cavendish of Devonshire, England. Suckers were introduced successfully to Samoa and Fiji in 1838 and since then have become the most popular banana accounting for 50% of the world’s production.

Economics and Importance Banana Nomenclature and Global Distribution Banana is mentioned in old (500 BC) Sanskrit scripts and is carved on the walls of Buddhist temples in India. ‘Kan-Chiao’ and other banana cultivars were described by Chi Han (304 AD) in South China and South Vietnam. Europeans were first introduced to banana (named Moca) in 327 BC when Alexander of Macedon’s army invaded North India. Arab traders introduced banana to Persia, Iraq, the Mediterranean, and North Africa under the name Moza, Mouz, or Moz. This name was adopted by the Romans as Musa. The source

Bananas grow well in various conditions, recover quickly after weather catastrophes, and adapt to intercropping and mixed farming. Time from planting to harvest is short, and planting material is easily available and relatively cheap (Figure 5). Hence, production is common in 120 countries over most tropical and subtropical regions. Plantains are mostly consumed as local staple food year round, while dessert bananas are grown for both local consumption and international trade. In 2013, banana (plantain, cooking, and dessert bananas) ranked globally first in fruit production totaling 144.5 million

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Figure 4 World’s banana migration routes. Early migration (BC): 1. About 5000–6000 years ago, a possible transfer of M. balbisiana by the Austronesian migration from South China via Taiwan to the Philippines and further to PNG may have occurred. 2. >3000 years ago plantains were brought by seafarers (probably Austronesians) to Africa. 3. About 2000 years ago ‘Mlali’ (AA diploid) reached Africa, South Asia, and North India. Hybridization with local AA diploids in SA generated ‘Gros Michel’ and AAA Cavendish subgroups. In India, hybridization of ‘Mlali’ with M. balbisiana generated the AAB ‘Pome’. 4. About 2000 years ago, ‘Mutika’/‘Lujugira’ (AAA triploid) arrived in East Africa, thus creating the basis for EAHB group of cultivars. 5. About. 4500 years ago, migration of AAB bananas (‘Popoulu’/‘Maia Maoli’/‘Iholena’ subgroup) from Melanesia eastward started. The first banana reached Hawaii c.2000 years ago. Late migration (AD). 6. About 650, Muslim traders commenced the move of banana, as described bananas along the Indian Ocean and East Africa coasts. 7. Concomitantly, traders carry bananas via Persia, Syria, Israel, Egypt, and North Africa up to Spain and possibly up to West Africa. 8. 1498, Vasco de Gama established maritime routes from India to Europe. Indian banana cultivars were transferred along African coasts to Canary Islands. 9. 1516, Bananas from the Canaries reached Santo Domingo and shortly later dispersed to Panama, Mexico, and Costa Rica. 10. 1521, Magellan established the Spaniards’ maritime lines thus new opportunities for banana transfer to the New World opened. 11. About 1600–1800 the need for cheap food in the growing colonies leads to a rapid spread of bananas in Central and SouthAmerica and the Caribbean Islands. 12, 14:. About 1800–1870 Chinese immigrants brought bananas to Carnarvon, West and then to East Australia. 13. 1866, First banana export shipment from Panama to New York.

Figure 5 Production systems – from backyard grove to commercial plantation: (a, b) Backyard bananas; (c, d) Small holder plantations; (e) Intercropping banana and pepper (courtsey: Hadi Leghari, Pakistan); (f) Highland commercial plantation; (g) Lowland large plantation.

Tropical Agriculture j Banana Banana, total 106.7 T*106 LaƟn Amer+ Caribb 25%

LaƟn Amer+ Caribb 23%

Oceania 2%

Banana+Plantain, total 144.6 T*106

LaƟn Amer+ Caribb 25%

Asia 4%

Asia 56%

Africa 16%

Figure 6 2014.

Plantain, total 37.9 T*106

Africa 73%

Oceania 1% Asia 43%

Africa 31%

Distribution of yearly production by geographic region for banana, plantain, and banana þ plantain, 2013. Reproduced from FAOSTAT

tonnes annually and as the third fresh food produce after potatoes and tomatoes. It is a highly important staple food in Africa, Asia, Central America, and the Pacific Islands, second only to Cassava and Taro. Of the world’s banana product, 25% and 56% are produced in the Americas and in Asia, respectively. Africa leads in plantain production (Figure 6) and India is the world’s largest banana producer, followed by China (Figure 7). All Asian countries grow banana for domestic consumption only, but the Philippines and Taiwan grow banana also for export. Production of 28 countries in Asia, Africa, and Latin America in 2013 exceeded 1 million tonnes of banana and plantain each (Figure 8).

Economic Importance to Producing Countries Climate variation enhances diversification, hence a wide range of banana genomic groups (AA, AAA, AB, AAB, and ABB) grow in India where some of the most important banana cultivars were bred (Table 1; Figure 9). They grow there in backyards, small plots, and in large plantations for both domestic consumption and the Indian internal markets. Ripe fruit and

cooked male buds are consumed as food, and leaves serve for padding, cover, wrapping, as disposable food plates, and in decoration. Consumers’ preference for Cavendish fruit is on the rise reaching a 60% share of the total production in Asian countries and about 90% in China. This monoculture exposes the crop to serious risks by both biotic and abiotic stress. In the Great Lakes area of East Africa, the AAA subgroup of the starchy Highland Bananas (EAHB) plays an important economy role, as well as an important source of staple food and for flour and beer production. Up to 30% of calories intake in that area are supplied by bananas (Table 2). In Central and West Africa, the true plantain (AAB) was developed. More than 100 clones were selected for domestic consumption at about 100 kg capita1 y1. Additionally, export of ‘Cavendish’ bananas is of paramount importance in the economies of Cameroon, Ghana, and Ivory Coast. FAO figures for 2013 show that the world’s average yields are 21 and 6.9 t ha1 for banana and plantain, respectively. The highest yields obtained in subtropical climates, in Central America and SEA, and the lowest in Africa. From 2000 to 2013, world

Top ten banana producing countries, 2013

Top ten plantain producing countries, 2013

Burundi

Myanmar

Tanzania, U.R.

Congo, D.R.

Angola

Cote d'Ivoire

Guatemala

Peru

Indonesia

Nigeria

Ecuador

Rwanda

Brazil

Colombia

Philippines

Ghana

China

Cameroon

India

Uganda 0

5

10

15

20

25

30

0

Million tonnes Figure 7

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World’s top 10 banana and plantain producers, 2013. Reproduced from FAOSTAT 2014.

2

4

6

Million tonnes

8

10

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Figure 8 Banana þ plantain world production map. The circles represent production of each country in million tonnes in accordance with the legend. Please consider that the smallest unit is 1 million; smaller production values cannot be distinguished. (FAOSTAT 2014).

Table 1 Distribution and prevalence of banana genotypes across geographic areas in India Banana cultivar

Genome

Geographic area

Cavendish Silk, Pome French plantain Horn plantain Ney Poovana

AAA AAB

North of India Center and South of India

round, mainly from Central and South America, the Philippines, and West Africa (Table 4), where it provides employment and serves as a major component of national economies.

Breeding and Genetic Improvement AB

South of India

a

One of the few bispecific edible cultivars.

banana and plantain production increased by 62% and 25%, respectively, the fastest growth occur in India and China and lowest in Africa. Bananas, the most important imported fresh fruit in USA, EEC, Russia, and Japan (Table 3), are available there the year

About 1200 banana cultivars are known worldwide, almost all are assigned to either one of the five (AA, AB, AAA, AAB, and ABB) genomic groups (Table 5).

Hybridization, Ploidy, and Development of Important Cultivar Groups Spontaneous mutations for sterility and parthenocarpy in M. acuminata are maintained by vegetative propagation, and

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(a)

(c)

(b) (d)

Figure 9 Variation in Asian banana’s fruits: (a) ‘Horn plantain’ (AAB); (b) ‘Red’ banana (AAA); (c, d) Philippines typical bananas. From left to right: ‘Cardaba’ (ABB); ‘Lakatan’ (AA); ‘Latundan’ (AAB); ‘Senorita’ (AA).

Table 2

Banana consumption worldwide (2013)

Region/Country Uganda, Ruanda, Burundi, Tanzania Central America, Caribbean Islands

Table 3

Consumption kg capita1

Region/ country

Consumption kg capita1

Region

240

World average Developed Countries

20

World Europe

60

World banana import 2012 (in 103 tonnes) Country

EC (27) Russia Fed. Others

10–15 North America and Canada

spontaneous hybridization between cultiwilds of M. acuminata ssp. further increased variation within the AA diploids thus producing seedless edible fruit. Seldom, none reduced ovuli (2n gametes) may produce a triploid when fertilized with normal (1n) gamete. Intercrossing within the species, or outcrossing with M. balbisiana, resulted in the production of both AA and AB diploids and of triploid groups AAA, AAB, ABB to which most modern edible banana cultivars belong. A few exceptions are intercrosses between M. acuminata and Australimusa (T genome) or with M. schizocarpa (S genome). Most primary AA cultivars in SEA are endemic to this region except for the ‘Mlali’ subgroup, a product of hybridization between M. acuminata ssp. zebrina and ssp. Banksii. This group served as the basis of c.120 EAHB, triploid AAA cultivars. The ‘Mlali’ introduction to North India resulted in crossfertilization between unreduced ‘Mlali’ ovules with haploid pollen from M. acuminata ‘Pisang Pipit’ thus giving rise to the monospecific triploid ‘Cavendish’ subgroups. Similarly, a cross fertilization with wild Thai M. acuminata ‘Kai nai’ brought about the triploid ‘Gros Michel’ group. Another North Indian

USA Canada Asia Japan China Iran Korea Rep. Others Latin America and Caribbean Argentina Others Africa

Oceania

Algeria Others New Zealand

T  103

%

16 252 6 390 4 488 1 254 649 4 877 4 350 527 3 822 1 087 716 356 368 1 295 668 377 291 414 231 183 81

100 39.3 27.6 7.7 4.0 30 26.8 3.2 23.5 6.7 4.4 2.2 2.3 8.0 4.1 2.3 1.8 2.5 1.4 1.1 0.5

Reproduced from FAO (2014).

offspring of an interspecific cross between ‘Mlali’ unreduced ovule and M. balbisiana haploid pollen resulted in the development of the Pome subgroup (AAB). Diversity within subgroups increased by selection of somaclonal mutants, hence about eight Cavendish cultivars are

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Table 4

World banana export 2012 (in 103 tonnes)

Region

Country

World Central America Costa Rica Guatemala Honduras Mexico Others S. America Ecuador Colombia Peru Caribbean Dominican Republic Others Asia Philippines Others Africa Ivory coast Cameroon Others

T  103

%

16 495 5 764 2 028 1 921 901 306 608 6 941 4 982 1 835 124 323 297 26 2818 2646 172 649 339 247 63

100 34.7 12.3 11.6 5.5 1.9 3.7 42.1 30 11.1 0.8 2 1.8 0.2 17.1 16 1.1 3.9 2 1.5 0.4

Reproduced from FAO (2014).

Table 5

distinguished by stature, fruit shape, and size and many other traits, from the tall ‘Lacatan’ to the very short ‘Extra Dwarf’ (see Table 5). Similarly, over 100 modern plantain cultivars (AAB) resulted from selections of mutations within the few genotypes brought to West Africa at least 2500 years ago. Intraspecific triploid bananas are more robust, grow faster, and produce bigger bunches of sterile flowers and big parthenocarpic fruits than their diploid ancestors. In the interspecific triploid hybrids, sterility, parthenocarpy, and some disease resistances originated from M. acuminata while M. balbisiana contributed to plant hardiness, fruit starchiness, and some degree of drought and low temperature tolerance.

Genetic Improvement Controlled Hybridization and Breeding Currently, banana breeding programs are run in about 15 research institutions. It all started in 1922 in Trinidad and in Jamaica in 1924 where hybridization led to a better understanding of Musa cytogenetics, and the establishment of valuable Musa germplasm collections. In 1960 the United Fruit Company launched a breeding program in Honduras (presently under FIHA) aiming at the development of ‘Gros Michel’ type cultivar resistant to Panama disease Race 1. Later, the short stature,

Genomic nomenclature for major banana groups and subgroups, with examples of well-known cultivars

Genome group

Subgroup

Cultivars

AA

Sucrier Lakatana Pisang Lilin Ney Poovan Cavendish

‘Sucrier’ (¼‘Pisang Mas’) ‘Lakatan’ (¼‘Pisang Berangan Merah/Kuning’) ‘Pisang Lilin’ (¼‘Lidi’) ‘Ney Poovan’ (¼‘Safet Velchi’) ‘Pisang Masak Hijau’ (¼‘Lacatan’) Giant Cavendish cultivars: ‘Valery’, ‘Robusta’, ‘Poyo’, ‘Williams’ ‘Grand Nain’ ‘Dwarf Cavendish’ (¼‘Pisang Serenda’) ‘Extra dwarf Cavendish’ (¼‘Dwarf parfit’) ‘Gros Michel’ (¼‘Pisang Ambon’) ‘Highgate’ (¼‘Cocos’), ‘Lowgate’ ‘Yangambi Km5’ The East Africa highland bananas. About up to 200 cultivars, which groups into five sets: ‘Beer’, ‘Musakala’, ‘Nakabululu’, ‘Nakitembe’, ‘Nfuuka’ ‘Red’, ‘Pisang Raja Udang’ ‘Green Red’, ‘Pisang Mundam’ (¼‘Pisang Berangan’) Pacific typical; much diversified. Called in general ‘Pacific plantains’ Pacific Islands’ groups of typical clones that form also intermediate types Much diversified subgroup. The ‘Horn’ type has few very big fruits on a bunch and degenerated or absent male axis. The ‘French plantain’ type has a fully developed bunch and normal male axis. Both types are of great importance in West Africa, Latin America, and some Asian countries. (¼‘Pisang Kelling’, ‘Lal Velchi’, ‘Poovan’) ‘Pome’, ‘Pisang Kelat Jambi’, ‘Prata Ana’, ‘Pacovan’ ‘Manzana’, ‘Silk Fig’, ‘Pisang Rastali’ ‘Klue Nam wa’, ‘Pisang Klotok’, ‘Ducasse’ ‘Bluggoe’, ‘Pisang Abu Kelling’, ‘Silver Bluggoe’ ‘Monthan’, ‘Pisang Abu Bujal’, ‘Maduranga’ ‘Ney Mannan’, ‘Ice Cream’, ‘Blue Java’ ‘Pelipita’ ‘Saba’, ‘Cardaba’, ‘Pisang Kepok’

AB AAA

Gros Michel Ibota Mutika/Lujugira Red

AAB

ABB

Lakatana Iholena Maoli-Popoulu Plantain

Mysore Pome Silk Pisang Awak Bluggoe Monthan Ney Mannan Pelipita Saba

Ploidy of the Philippines ‘Lakatan’ not yet clarified. Source: Reproduced from Stover, R.H., Simmonds, N.W., 1987. Bananas, third ed. Longman, Singapore; Ploetz et al. (2007).

a

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high-yielding ‘Grand Nain’ became the industry standard thus dwarfism, superior fruit qualities, better agronomic performance, resistances to leaf diseases (especially black leaf streak (BLS)), Panama disease Race 4, and nematodes became its main objectives. Crosses between rare triploid ovuli of ‘Gros Michel’ or with its shorter mutant ‘Highgate,’ and haploid pollen from a wild diploid were initiated with the consequent production of tetraploids progenies. Later ‘Prata’ (ABB) served for breeding of clones suitable for smallholders and plantain growers. Some of the tetraploid interspecific hybrids are being cultivated on a limited scale, but the long-term goal has not yet been achieved.

International Cooperation in Musa Germplasm Collection, Preservation, and Utilization During the last 30 years, comprehensive international efforts were promoted and coordinated by MUSANET with the aim of identifying, collecting, preserving, and disseminating of Musa germplasm. Additionally, an in vitro collection of c.1400 accessions was established at the Bioversity International Transit Centre in Leuven University, Belgium. Bioversity International manages the International Musa Testing Program for characterization of agronomic traits; response to major threats (Fusarium Wilt, BLS, Sigatoka, and nematodes); and postharvest performance of synthetic cultivars under diverse conditions worldwide (see Recent Developments and Future Challenges).

Figure 10 Morphology of a fruiting banana plant with suckers. After Champion (1963).

Mutation Breeding The 1–5% rate of somaclonal mutations, obtained during in vitro propagation, generated additional genetic variation, in Musa. Application of physical (gamma irradiation) or chemical (EMS) mutagens is used to further increase variation for crop improvements. In Taiwan, a mutant of ‘Pei Chiao’ (‘Giant Cavendish’ type cultivar) tolerant to Fusarium Wilt Tropical Race 4 (TR4), was selected. However, this mutant produces fruit with inferior quality thus limiting its use to local markets. In another case, a random mutation excelling in agronomic performance and fruit quality was released as cv. ‘Formosana.’ This plant exhibits a good tolerance to Fusarium Wilt TR4 in the Philippine highland and midland.

Developmental Morphology and Life Cycle

structure of the soil, the fleshy roots can reach a depth of 60–80 cm and spread horizontally to a distance of 3–5 m. Primary roots (¼‘cord roots’) are 5–8 mm in diameter. They arise in groups of three to four per leaf; hence during its life cycle each plant produces 150–200 of them. A system of hairy secondary and tertiary roots develops at the distal part of the primary roots and plays an important role in water and mineral uptake. Close to floral differentiation, emergence of primary roots from the parent rhizome ceases, and new sucker roots become dominant. After harvest, the pseudostem dries out followed by the gradual death of its root system. Soil compaction, lack of aeration, excess or lack of water, and nematodes or soil-borne diseases may lead to early root death.

Banana Morphology – General Description

Rhizome (¼Corm)

The giant herbaceous monocarpic plant produces a branched underground rhizome (¼‘corm’) with roots and vegetative buds, and above ground canopy. The canopy consists of a pseudostem made of circular tighten leaf sheaths and leaves’ laminae. The corm produces new shoots (¼‘suckers’) that eventually form new plants. Together with their mother plant, the suckers form a perennial ‘mat’ (¼‘stool,’ ‘clump’). Each plant flowers once in its life cycle and dies. The terminal inflorescence (¼‘bunch’) emerges from the center of the leaves’ crown at the top of the pseudostem (Figure 10).

Roots Due to the nature of vegetative propagation, all roots of the banana plants are adventitious. Depending on the physical

A typical spherical rhizome of mature ‘Cavendish’ banana is about 30 cm in diameter, and closely packed leaf scars envelop its extremely short internodes. Internally, it consists of a central cylinder and cortex. Roots develop from the outer surface of the central cylinder and grow outward through the cortex and the epidermis. The starchy parenchyma of the ground tissue is an important energy storage that supports growth of the bunch and the developing suckers. The rhizome’s meristem is a flattened dome situated in a depression at its top. Leaves are formed at the central growing point in a spiral succession and develop sequentially from the center outward. During leaf production, a vegetative bud is initiated, opposite the axil of each leaf, on the outer surface of the central cylinder, but only few grow, emerge, and develop into suckers.

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Following a certain period of vegetative growth, the apex differentiates into an inflorescence.

Suckers Apical dominance is common at the early stage of vegetative development. Later, when a certain mass is obtained, the apical dominance weakens and suckers sprout. At the early stages of development suckers’ growth depends on supply from the mother plant, thus competing for nutrients and energy with the developing inflorescence. Under adequate conditions, suckers produce a couple of broad leaves and may have a small ‘peeper’ during its own mother plant inflorescence emergence (‘shooting’). After harvest, reserves from the stump are translocated to the developing new plants. In commercial plantation, only one sucker is used for regeneration. Selection is based on agronomic considerations (Figure 11). Two types of suckers are distinguished (Figure 12). Sword suckers develop from auxiliary buds at the bottom of the corm. First, they produce scale leaves with no lamina, then narrow, pointed leaves with rudimental lamina, and gradually broader laminate leaves develop. Their growth is controlled by apical dominance of the mother plant that provide support to the development of the sucker’s rhizome and root system till blooming. Sword suckers are preferred as followers and for propagation. Water suckers develop from shallow buds or old rhizome parts. These weakly attached suckers produce broad leaves and thin pseudostems that get no supply from a mother plant and hence poor vigor and lower yields than those grown from sword suckers.

Leaves and Pseudostem Banana leaves consists of a long, cylindrical sheath, a stout petiole, and a lamina blade. The first three to five scale leaves

(d)

are followed by five to eight sword leaves and finally broad lamina leaves develop gradually increasing in size. A new furled (‘cigar’) leaf emerges vertically from the center of the pseudostem, due to the growth of its sheath. Initially, the circular sheaths are tightly packed around the meristem thus forming the fleshy yet sturdy pseudostem. Later their margins are forced open by the successive leaves that emerge at 5–14-day intervals. Emergence rate of leaves is genetically controlled and is affected by temperature, day length, age, plants density, and supply of water and nutrients. Total leaf number from the first scale leaf to shooting is 26–50, but due to aging, at each time point only 10–14 leaves are actually functional. It takes 10–12 weeks from leaf initiation to complete emergence. Life span of a leaf lasts 3 months, and total leaf surface (c.25 m2) increases continuously till shooting when leaf emergence ceases and total leaf surface gradually decreases. The pseudostem elongates with the emergence of each new leaf reaching its final length of 2 or 5 m at shooting, for ‘Dwarf Cavendish’ and ‘Lacatan,’ respectively.

Developmental Stages Banana development is characterized by three distinct stages. (1) Vegetative stage: from the beginning of the initial lateral bud growth to floral differentiation. This stage can be further divided into juvenile and the late vegetative phase depending (complete to partial) on the need for supply from the mother plant; (2) Reproductive stage: from floral differentiation to anthesis; (3) Fruiting stage: from anthesis to fruit maturity. Floral differentiation of the mother plant enhances suckers’ development into the late vegetative stage. The life cycle of Cavendish banana under optimal conditions takes about 12 months, then the follower plant enters the late vegetative stage. Practically, cycles of 1.5–1.6 bunches per mat a year are obtained in the lowland tropics.

(c)

(b) (a) (e)

Figure 11 Banana rhizome generation sequence (¼mat): (a) Great grandmother corm; (b) Grandmother corm and base of pseudostem; (c) Fruiting mother; (d) Vegetative stage follower; (e) Emerging fifth generation.

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Figure 12

373

Water and sword suckers.

Leaf Physiology Under humid conditions, each top megaphyll of ‘Grand Nain’ has a surface area of 1.8–2.0 m2, with high photosyntheticactive radiation (PAR) interception. Substantial leaf at night and early morning guttation indicates a positive root pressure and optimal water supply. Here, the horizontal posture of the lamina thus maximizes light harvest, with c.45 and 4.5 kg of fresh and dry matter m2 year2, respectively. At 26–34  C and 1800 mmol Quanta m2 s1 PAR, bananas assimilate 30 mmol CO2 m2 s1, a very high rate for C3 plant, but temperatures above 36  C may result in partial stomata closure with the consequent increase in lamina temperature and reduction in photosynthesis rate. The third to the seventh leaves from the top are the most active in carbon fixation. The negative effects of leaf temperatures above 38 or below 24  C on AAA bananas’ photosynthetic capacity provides yet additional evidence for its adaptation to the humid lowland tropics. Reduced water uptake and/or xylem transport results in low leaf turgor with the consequent downfolding of the lamina halves by the pulvinar bands, reduction in energy load, and in rise of leaf temperature. Lamina tearing by winds reduces the boundary leaf layer and increases transpiration thus facilitating leaf cooling but photosynthesis is reduced.

formation, it takes 1–2 days compared with 10 days, respectively. Another significant change is the dramatic elongation of internodes between the top six to seven leaf nodes and the formation of the true stem, with the peduncle at its top. It takes about 3 months for the inflorescence to grow inside the pseudostem until emergence of the two transition leaves and the complete inflorescence. The immediate contact between the top six to seven leaves and the peduncle facilitates the translocation of photosynthates to the growing fruits. The signal for floral differentiation is not clear. An empirical factor ‘Ts’ that sums the leaf area during the lifetime of the plant multiplied by hours of daylight and mean temperature and by the area of the last leaf is well correlated with the actual observed transition time. It was also found that transition occurs only in postjuvenile plants that accumulated a certain mass, and later it was stipulated that bananas and plantains are facultative long photoperiod plants, where autonomous meristem transition occurs but long photoperiod promotes flowering. The number of female flower hands and fingers is affected by genetic factors and by plant vigor, crop cycle, temperature, competition with neighbors, and agrotechnology. The number of hands is determined in the early stage of differentiation, while the number of fingers depends on environment prevailing prior to shooting.

Banana Inflorescence (Bunch)

Fruit Development and Postharvest Physiology From Floral Differentiation to Anthesis Floral Differentiation The transition from the late vegetative to the reproductive stage commences at the rhizomic central meristematic zone, with no morphological modifications. Thereafter, significant anatomic and histological changes in the stem axis and in the activity of the meristematic tissue occur. The meristem produces two transitional leaves, then due to intensive mitotic activity; bracts that subtend axillary meristematic cushions are formed from which flower buds differentiate. In comparison to leaf

The banana inflorescence is a compound spike, consisting of a peduncle on which flowers are arranged in clusters (‘hands’). The 5–18 proximal nodes bear female flowers, followed by one to two neuter flower hands and thereafter c.150 nodes of male flowers. The ‘male bud’ (‘Bell’) located at the distal nodes is made of tightly enclosed bracts with subtended male flowers and functioning apical meristem. The inflorescence emerges vertically but bends quickly due to geotropic response. The inflorescence bud is initially enclosed inside a purple spathe leaf and bracts. It grows in volume until anthesis when female flowers (‘fingers’) show a negative geotropic response. During anthesis, they partially lift aside thus allowing for nectar accumulation. In most

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Musa AAA cultivars, the bracts roll back, dry out, and drop off during the early stages of bunch development. The female hands open sequentially basipetally along the bunch. Thereafter, fruit ripening follows the same order as above.

Flower Banana flowers have an inferior ovary and the zygomorphic perianth at the top divides to adaxial compound tepals and abaxial-free tepal (Figure 13). Apart from position, male and female flowers are morphologically indistinguishable until the inflorescence is about half way upward inside the pseudostem. Then the ovary grows fast in female flowers but remains rudimentary in male flowers. The almost sterile androecium consists of five anthers in the male flower while female flowers contain staminodes. All flowers are nectiferous as bananas are adapted to bat pollination. The unfertilized ovules shrivel within 9–14 days after anthesis but remain visible as brown specks inside the ripe fruit. An autonomous auxin production in the ovary induces the development of the parthenocarpic fruit’s pulp. Most edible dessert bananas develop an abscission layer at the base of the perianth shortly after anthesis, and frequently also at the base of the male flowers.

Fruit Growth A period of intensive fruit growth starts about 14 days before inflorescence emergence. The peel grows first followed by postanthesis pulp development. Peak growth is reached on peeping and slows down about 30 days later (at about a fortnight after anthesis) (Figure 14). This is also a period of intensive cell division; hence any stress at this time is bound to affect the size of the finger. Fruit elongation slows down at about 40 days after emergence, but linear slow increase in fruit diameter continues until harvest. Hence, fruit volume and weight grow exponentially. Accumulation of dry matter is much reduced toward maturation, thus from this stage onwards, water absorption contributes to increase in fruit weight.

Variations in Bunch Weight and Finger Size Bunch weight is affected by number of hands, number of fingers, and size. Each of these is differently affected by the genome and environment. In ‘Cavendish,’ the number of hands can vary from 5 to 16, and number of fingers from 16

Figure 13

Mature female and male flowers (‘Grand Nain’ (AAA)).

to 22 per hand. Stress may result in smaller fruit than those grown under standard conditions, e.g., 100 vs 200 g, respectively, and bunch weight thus ranges between 9 and 70 kg. Inherently, the size of the fingers is largest at the top (basal) and smaller at the bottom (proximal), while fingers on the same hand are of similar size. Commercially, the last two or three hands are pruned at anthesis to increase fruit uniformity (Figure 15).

Harvest and Postharvest Physiology In backyards spontaneous and gradual ripening occur from top to bottom within a week. Commercially, fruit are harvested green, and shelf-life extension is attained by controlled temperatures, high relative humidity, and reduced ethylene. Banana fruit can be harvested and ripened already 9–10 weeks after anthesis. The 100–120 g ripened fruit is edible. An additional 3–4 weeks of growth allows for optimal maturity, regularity, and increase in weight to 180–200 g. From anthesis 90–110 days are required for maturation in the tropics but ranging between 80 and 210 days in the subtropics, depending on temperature. In commercial plantations, fruit age, finger’s caliper, and angularity are used to determine readiness for harvest. ‘Cavendish’ banana peel is highly sensitive to mechanical damage with the consequent scarring, bruising, and latex staining. Quality fruit is expected to be free from blemishes; hence care is taken to reduce damages, including protecting from immediate contact with objects using polyethylene ‘hand bagging’ and whole bunch cover sleeves. Thorough fruit selection is performed in the packinghouse, and rejections of up to 25% are not uncommon. The fruits are washed in aqueous alum sulfate for >20 min to stop latex bleeding. The fresh cuts of the hands are treated with fungicide (to prevent development of crown rot) and packed in carton box laminated with polyethylene. Thereafter fruit temperature is cooled to 13  C and placed in ventilated storage rooms or containers to remove ethylene, yet relative humidity must be kept above 75% to avoid desiccation. Fruit exposed to lower temperatures in the field or in storage is prone to suffer chilling injury, caused by coagulation of latex in the subepidermal latex ducts (‘under-peel discoloration’) with the consequent unacceptable dull yellow color of the ripe fruit. Edible traits, however, are not affected. Exposure to temperature below 5  C may cause further damage.

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Figure 14 From inflorescence emergence to anthesis: (a) Emergence at top of the leaves crown; (b) Bent inflorescence; (c) The two basal hands are partly lifted; (d) The three basal hands at anthesis. Bracts curled upward and nectar secreted. (1) Spade leaf. (2) Spathe; (e) Female flower with a drop of nectar. The free tepal is full of nectar; (f) More female hands open; (g) Seven female hands are at post or full-anthesis; bracts start to abscise; (h) All female hands opened. The terminals are at anthesis. Perianth of the top hands dries out; (i) All female hands are at postanthesis. Basal hands start to bend upward.

Figure 15 From anthesis to harvest: (a) Last proximal female hand at anthesis; (b) Male hands opened. Fruits curve upward; (c–f) Stages of fruit growth. Male bud removed, some bottom female hands are trimmed, perianth remnants are sometimes cleaned and plastic bags inserted between hands to minimize bruising; (g) Fruit ‘three quarters full,’ ready for harvest; (h) Demonstrating the ‘grade’ (caliper) of a full fruit.

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For long-distance transport, young fruits are packed in big polyethylene bags with reduced air pressure. Use of modified atmosphere, vacuum storage, and ethylene absorbents were successfully tested but not adopted by the industry. When pulp temperature rises to 16–21  C and ambient RH to 90–95%, banana fruit ripens spontaneously in a few days. The climacteric fruit responds well to ethylene (500–1000 ppm for 24–48 h) application in ripening rooms and is ready for marketing in 4–6 days. Other than chlorophyll degradation and yellowing, ripening processes include starch conversion to sugars with the consequent increase in total soluble solids and in total titratable acidity; movement of water from the peel to the pulp; increase in pulp/peel ratio; and pulp softening. In recent years, promotion of organic bananas and sustainability by conforming to ‘Fair Trade’ and ‘Rainforest Alliance’ organizations are being made.

to suffer injury upon sudden insulation, but adapts easily to gradual changes, by modification of leaf characteristics.

Water Shortage and Salinity Stress Water shortage is the most common environmental stress affecting banana, even in the tropics. Therefore, watering is mandatory in the subtropics and beneficial in tropical dry periods. Mediated by ABA and hydraulic signals, the isohydric banana closes its stomata with increased soil water shortage and increased leaf to air vapor pressure difference. Leaf water potential is thus maintained, but photosynthesis is much reduced, yet recovery occurs when water becomes available (Figure 16). Banana is extremely susceptible to salinity in general and to sodium in particular. Increase in ground water osmotic pressure reduces water availability with the consequences detailed earlier. This situation, however, can be remedied by increase in water application.

Ecological and Physiological Adaptations Climatic Requirements

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Originated in the humid tropical lowlands (latitude N to 20 S and low altitudes), with daily 20–30  C  3–4  C temperature fluctuation, and a weekly rainfall of 50–70 mm, the banana flourishes in quite variable ecological conditions and survives occasional droughts and floods. It is now cultivated in the subtropics as north as Antalya (Turkey, 36.9 N), in the very hot climate of Sindh, Pakistan, and Maharashtra, India where temperatures rise to 50  C, and at 1000 m elevation in the Philippines, East Africa, and Caribbean, where cool weather and cloudiness prevail. In the latter, rate of leaf emergence is slow, yet the ‘Grand Nain’ (AAA, Cavendish subgroup) plants grow tall, with large leaves and thick pseudostems producing 70–80 kg bunch once in 15 months whereas in the warm lowlands, the same cultivar produces 30–40 kg bunches/plant once every 9 months. Banana grows well in warm climates if frequently irrigated and grow densely for mutual shading. Survival during droughts is achieved by reduced leaf area and transpiration. Frequent chilling poses an ecological limit for banana spread. The B genome confers some low temperature and drought tolerance, but does not survive frost.

Edaphic Demands Banana grows successfully on variable soils, from organic peat soils, mineral soils, calcareous soils (with high pH), and tropical low pH soils to sandy soils and limitations are efficiently overcome by appropriate nutrition program. The only edaphic requirement is good aeration and efficient drainage system. Hence, heavy compacted soils are not suitable for banana production.

Abiotic and Biotic Constraints Effect of Light Regime The banana efficiently utilizes high irradiation fluxes, and yet accommodates to shaded environment by changing anatomical and physiological traits: increase in leaf area and chlorophyll content and decrease in lamina thickness. These plants are prone

Winds tear lamina and reduce boundary layer resistance with the consequent increased transpiration that can be compensated by increased water supply, as increased transpiration facilitates stabilization of leaf energy balance. More frequently, however, heavy leaf tearing negatively affects photosynthesis with the consequent decrease in bunch weight. Use of wind breaks or growing in screen houses lowers wind velocity and leaf tearing.

Biotic Constraints Bananas and plantains are susceptible to a wide range of pests and diseases, especially in the tropics. Some are devastating, e.g., Panama disease caused by Fusarium oxysporum f. sp. cubense. Others, like BLS (‘Black Sigatoka’) caused by Mycosphaerella fijiensis is controllable but with great efforts and expenses. Some pests and diseases such as nematodes and BLS are specifically harmful to smallholder growers of plantain in West Africa; Xanthomonas bacterial wilt and corm weevil are common in EAHB; and Bunchy Top virus or the Moko bacterial disease infect banana smallholders in SEA. Less detrimental banana pests and diseases are found in the subtropics since the environment there is less favorable for major pests and diseases.

Soil-Borne Diseases Panama disease, the most destructive biotic stress, had spread widely between 1900 and 1960 in Latin America when c.40 000 ha of ‘Gros Michel’ were destroyed and replaced by ‘Cavendish’ subgroup cultivars. The most aggressive race of F. oxysporum f. sp. cubense is the TR4 VCG 01213 that infects even the Cavendish subgroup in the tropics. Its spores survive in the soil for over 40 years, and germinate in the presence of banana roots exudates with the consequent wilting of leaves and death (Figure 17). Spread by root to root contact is fast and spread by infected suckers, soil, and water, especially by floods, is common. Currently, all commercial plantations use only tested TC plants, but these succumb easily to the disease if inoculum exists in the soil. The tolerant GCTCV selected in

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Figure 16 Abiotic stress: (a) Drought: discoloration and splitting of fruit tip; (b) Frost damage; (c) Sunburn; (d) Flood; (e) Wind damage – leaf shredding.

Taiwan provides a temporary relief but not a long-term solution. Originated in Latin America, the soil-borne Pseudomonas solanacearum Race 2 bacterial (Moko) disease reached the Philippines with infected propagules in the 1960s. Symptoms are quite similar to FW but Moko affects mother plants and the suckers simultaneously. Infested tools, soil, and water serve also for spread of the disease. The bacteria does not sustain in the soil for more than 9 months. Therefore, after 1 year of proper fallow, replanting is possible.

Leaf Diseases Black Leaf Streak (BLS) (¼Black Sigatoka Disease) caused by Mycosphaerella fijiensis is the most important banana foliar disease. Up to 50 annual air-spray cycles are needed to control BLS, thus costing 15–27% of the total annual production costs. Infected plants suffer leaf streaks that expand and become necrotic lesions and spots that later coalesce to cause leaf death. The reduced photosynthetic capacity and the forced early harvest result is small bunch and fruits size. Additionally, the fungal toxin moves to the fruit with the consequent shorter green-life (Figure 18).

Viral Diseases Bananas are susceptible to cucumber mosaic virus, banana mild mosaic virus, banana bract mosaic virus, and the banana bunchy top virus (BBTV). BBTV is by far the most virulent and aggressive pathogen with destructive potential of the entire crop. It is currently endemic to the eastern hemisphere, but not reported in Latin America or the Caribbean Islands. The typical symptoms are ‘Bunchy’ appearance: short, pointing upright, and chocking top leaves with dark green flecks along the leaf midrib. Infected plants rarely produce a bunch. Control requires early detection and destruction of diseased mats along with efficient control of the vector banana aphid, Pentalonia nigronervosa.

Pests Significant number of insects attack banana and plantain. Common all over the world, the weevil borer, Cosmopolites sordidus, is the main pest of banana’s rhizome. Burrowing nematodes are important destructive root and rhizome parasites of banana in most tropical and subtropical plantations. Infected plants tend to uproot or topple and suffer low water and mineral uptake, slow plant growth, and reduced yields. Control

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Figure 17 Biotic stress caused by Fusarium Wilt Tropical Race 4: (a) Early stage of Fusarium infected ‘Williams’ plant; (b) Infected plant at fruiting; (c) Collapse of infected plant; (d) Newly FOC-infected plantation after floods; (e) Commercial plantation of ‘Grand Nain’ destroyed by FOC; (f) Early FOC infection symptoms on ‘Lakatan’, Philippines; (g) Internal symptoms of FOC infection.

Figure 18 Biotic stress–Black Leaf Streak (Black Sigatoka leaf spots disease): (a–d) Developmental stages of BLS on ‘Grand Nain’ leaves; (e) Highly infected ‘Lakatan’ plantation (Philippines); (f) Minimal leaf surface after trimming of infected tissues; (g, h) Bunches supported by less than three full size functional leaves are chopped down.

Tropical Agriculture j Banana methods include planting plants from in vitro culture on nematocides treated virgin or on fallow soil.

important limiting factor for practical use of such propagation despite the fact that rates of mutations are less than 5%. Off-type plants may differ permanently or temporarily from the source plants. For ‘Cavendish’ the most common off-types are ‘dwarfs’ and ‘Masada’ (uneuploids). These may be partially roughed out already in the nursery. Some off-types, however, can hardly be recognized at the vegetative stage but at fruiting.

Micropropagation – Achievements and Limitations Conventional propagation of bananas and plantains is common with smallholders (Figure 1(f)) while in vitro propagation is dominant with commercial growers, thus reducing the risks of pests and disease transmission by propagules. Micropropagation begins with shoot tip culture, and takes 6–10 months for 1:1000 to 1:10 000 multiplication rate. Then, plantlets are transferred to a rooting medium for 3–4 weeks followed by 4 weeks septic hardening and 6 weeks in the nursery (Figure 19). The uniform propagules are free from pests and diseases; are available year round; transplanting is easy and efficient; and dense stand for heavy production and fast return is plausible (Figure 20). In vitro techniques are also used for germplasm conservation and exchange, genetic improvement by somaclonal variation, molecular analyses, and genomic research (see Recent Developments and Future Challenges). Important limitations are increase in propagation costs and extra care at planting and establishment; need for specific knowhow especially on pruning at the first cycle; ex vitro plants are susceptible to pests and diseases at the early stage of growth, and occurrence of somaclonal variation which varies with genotype; source and type of explants, type of budding, medium composition, and duration in culture. Somaclonal variation is by far the most

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Recent Developments and Future Challenges Formerly, banana research and development was performed mainly by the multinational exporters, the producers of about 10% of the world crop, focusing on agronomy, applied physiology, basic genetics, plant protection, and postharvest physiology. Little was done, however, for the producers of the 90% world crop of staple food bananas. The introduction of in vitro propagation in the 1970s initiated a change due to mass supply of selected, pathogen-free propagules, and for safe movement of germplasm worldwide, making Musa available universally, thus paving the way for advanced research. Traditionally, banana served for studying postharvest behavior of a climacteric fruit, and currently in addition to Arabidopsis and Oryza as a model plant in genomics and proteomics research. Benefitting smallholders in developing countries, globalization of banana research commenced with the establishment in 1985 of an International Network for the Improvement

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Figure 19 Controlled vegetative propagation from tissue culture to nursery: (a) Proliferating explants; (b) Proliferating culture; (c) Rooting: last stage under septic conditions; (d) Hardening and acclimatization to aseptic conditions; (e) Early protected nursery stage; (f) Advanced nursery stage; (g) Well-rooted TC plantlets.

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Figure 20 Postnursery TC plants’ performance: (a) Ready to plant rooted plantlet; (b) High-density plantation 1 month after planting in a screenhouse; (c) Two months old TC plantation; (d) Highly uniform about to flower 5 months old plantation; (e–g) Uniform fruiting.

of Banana and Plantain. Under the new framework of the Bioversity International, it is supporting various global banana research, conservation, and bioinformatics functions (Figure 21 and see also: International Cooperation in Musa Germplasm Collection, Preservation and Utilization). The ‘DH-Pahang’ M. acuminata ssp. malaccensis was fully sequenced, as well as that of the B genome of a wild diploid M. balbisiana, and genetic maps developed. The ‘DH’ (doubled-haploid) was generated using anthers’ culture of

Figure 21

the wild Malaysian ‘Pahang’ accession. Some haploids underwent spontaneous chromosome doubling to produce the diploid homozygote ‘DH-Pahang’ at CIRAD (Guadeloupe). The results of these and other efforts will contribute to further breeding of banana and plantain. The dominance of the clonal propagation of cv. ‘Cavendish’ and the fast spread of pathogens such as FW-TR4, poses the risk of mega destruction similar to the great famine in Ireland, the southern corn leaf blight epidemics in the US, and

The structure of Bioversity International Global Banana-related Networks. Each of the activities is freely web-accessible.

Tropical Agriculture j Banana the sugarcane grassy shoot disease epidemic in the 1990s. A repetition of the destruction of ‘Gros Michel’ is possible. Hence, the urgent need for increased variability, maintaining its biodiversity sustainability, and identification of sources for resistances. Biotechnology facilitates breeding, making it faster and more efficient than classical breeding solely. Technically, the production of transgenic banana is feasible and researchers worldwide attempt to make use of advancements in Musa genomics and proteomics into practical uses. Since 1995, however, just a few works reached field testing. Moreover, acceptance of transgenes by the public is not clear. It is hoped that molecular tools can be used inside the Musa species to the benefit of the hundreds of millions of people who depend on banana as a major food and to facilitate availability to the rapidly growing population and to withstand hazardous climatic changes.

Acknowledgment The technical assistance of Anna Lubin Arbiti, Idan Elingold, Adi Schlank and David Sapir is greatly appreciated.

See also: Arable Crops: The Domestication of Crop Plants. Crop Diseases and Pests: Genomic Selection in Crop Plants. Plant Breeding and Genetics: Plant Breeding, Practice. Postharvest Biology: Ripening; Storage; Transport of Fresh Produce.

Further Reading Bakry, F., Careel, F., Jenny, C., Horry, J.P., 2009. Genetic improvement of banana. In: Jain, S.M., Priyadarshan, P.M. (Eds.), Breeding Plantation Tree Crops: Tropical Species. Springer ScienceþBusiness media, LLC, pp. 3–50.

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De Langhe, E., Vrydaghs, L., de Maret, P., Perriere, X., Denham, T., 2009. Why banana matter: an introduction to the history of banana domestication. Ethnobot. Res. Appl. 7, 179–197. Denham, T.P., Haberle, S.G., Lentfer, C., Fullagar, R., Field, J., 2003. Origins of agriculture at Kuk Swamp in the Highlands of New Guinea. Science 301, 189–193. D’Hont, A., Denoeud, F., Aury, J.M., et al., 2012. The banana (Musa acuminata) genome and the evolution of monocotyledonous plants. Nature 1–7. Fortescue, J.A., Turner, D.W., 2011. Reproductive biology. In: Pillay, M., Tenkouano, A. (Eds.), Banana Breeding: Progress and Challenges. CRC Press, Boca Raton, FL, pp. 145–180. Hakkinen, M., 2013. Reappraisal of sectional taxonomy in Musa (Musaceae). Taxon 62, 809–813. Heslop-Harrison, J.S., Schwarzacher, T., 2007. Domestication, genomics and the future for banana. Ann. Bot. 100, 1073–1084. Hippolyte, I., Jenny, C., Gardes, L., et al., 2012. Foundation characteristics of edible Musa triploids revealed from allelic distribution of SSR markers. Ann. Bot. 109, 937–951. Israeli, Y., Lahav, E., Reuveni, O., 1995. In vitro culture of bananas. In: Gowen, S. (Ed.), Bananas and Plantains. Chapman & Hall, London, pp. 147–178. Jones, D.R., 2000. Diseases of Banana, Abaca and Enset. CABI Publishing, Worcestershire, UK. Ortiz, R., Swennen, R., 2014. From crossbreeding to biotechnology-facilitated improvement of banana and plantain. Biotechnol. Adv. 32, 158–169. Perrier, X., De Langhe, E., Donohue, M., et al., 2011. Multidisciplinary perspectives on banana (Musa spp.) domestication. PNAS 108 (28), 11311–11318. Robinson, J.C., Galan Sauco, V., 2011. Bananas and Plantains, second ed. CABI. 311. Stover, R.H., Simmonds, N.W., 1987. Bananas, third ed. Longman, Singapore. Turner, D.W., Fortescue, J.A., Thomas, D.S., 2007. Environmental physiology of the bananas (Musa spp.). Plant Physiol. Biochem. 19, 463–484.

Relevant Websites http://www.promusa.org – Banana Cultivars Checklist. http://www.promusa.org – Banana Wild Species Portal. http://faostat3.fao.org – FAOSTAT 2013, 2014, 2015. http://www.musagenomics.org/ – Global Musa Genomic Consortium. https://sites.google.com/a/cgxchange.org/musanet/home – Musa Genetic Resources. http://www.promusa.org – Promusa Home Page.