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Chapter 5 - Yams
- Edited by Dominic Fuccillo, University of Arkansas, Linda Sears, International Plant Genetic Resources Institute, Rome, Paul Stapleton, International Plant Genetic Resources Institute, Rome
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- Biodiversity in Trust
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- 22 September 2009
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- 28 August 1997, pp 57-66
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Summary
BOTANY AND DISTRIBUTION
Several sections have been described under the genus Dioscorea of family Dioscoreaceae. The main food yams have been grouped as follows:
Section Enantiophyllum
This is the largest section with respect to number of species and food importance (Degras 1993). Members may be further grouped in terms of geography as: Asian - Oceanian species, e.g. D. alata L. (water yam, greater yam, white yam), D. glabra Roxb., D. nummularia Lam., D. transversa Br.; Sino-Japanese species (or species complex), e.g. D. japonica Thumb, (igname de Chine, Chinese yam), D. opposita Thumb., and African species or species complex, e.g. D. cayenensis Lam. (yellow yam), D. rotundata Poir. (white Guinea yam, white yam).
Section Lasiophyton
D. pentaphylla L., D. hispida Dennsdest, D. dumetorum (Knuth) Pax (bitter yam)
Section Opsophyton
D. bulbifera L. (aerial yam)
Section Combilium
D. esculenta (Lour.) Burk. (Chinese yam, lesser yam)
Section Macrogynodium
D. trifida L. (cush-cush yam)
The many species of yams (Dioscorea sp.) have various unique or peculiar characteristics that distinguish them from each other. The principal food species have been described in a series of monographs (Martin 1974a, 1974b, 1976; Martin and Degras 1978a, 1978b; Martin and Sadik 1977). Generally the yam plant comprises a shoot portion made up of a vine with branches, leaves and sometimes bulbils in the axils of the leaves, fibrous roots and an underground storage organ, the tuber. The vine twines clockwise or anticlockwise depending on the species.
Chapter 19 - Rice
- Edited by Dominic Fuccillo, University of Arkansas, Linda Sears, International Plant Genetic Resources Institute, Rome, Paul Stapleton, International Plant Genetic Resources Institute, Rome
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- Biodiversity in Trust
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- 22 September 2009
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- 28 August 1997, pp 273-291
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Rice feeds half the world's people, mainly in Asia. Their food security and crop biodiversity depend upon continued access to seed developed from thousands of locally adapted varieties of Oryza sativa and O. glaberrima that Asian and African farmers have grown for generations, the more than 20 species of wild rice native to Asia, Africa, Latin America and Oceania, and the related genera in the tribe Oryzeae. Worldwide, about 80 million ha of rice are grown under irrigated conditions, the most important rice production system, with average yields of 3-9 t/ha. Athough four CGIAR centres (IRRI, WARDA, CIAT and IITA) hold and use rice germplasm, only IRRI has a global mandate to conserve and improve germplasm. Other centres have regional or continental mandates in Africa and Latin America.
The aggregate population of the less-developed countries grew from 2.3 billion in 1965 to 4.1 billion in 1991. Asia accounted for 59% of the global population, about 92% of the world's rice production and 90% of global rice consumption. Bangladesh, China, India, Indonesia, Myanmar, Thailand and Vietnam are the world's largest rice producers, accounting for about 78% of world production (IRRI 1995). Even with rice providing 35–80% of total calories consumed in Asia and with a slowing of growth in total planted area, production has so far kept up with demand. The world's annual rough rice production, however, will have to increase by almost 70% over the next 35 years to keep up with population growth and income-induced demand for food.
Chapter 1 - Cassava
- Edited by Dominic Fuccillo, University of Arkansas, Linda Sears, International Plant Genetic Resources Institute, Rome, Paul Stapleton, International Plant Genetic Resources Institute, Rome
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- Biodiversity in Trust
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- 22 September 2009
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- 28 August 1997, pp 1-20
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Cassava (Manihot esculenta Crantz) is a major food source for more than 500 million people in Africa, Latin America and Asia. Cultivated for its starchy roots, this New World native species claims a world production of 152 million t (FAO 1995), ranking seventh in yield production among all crops and fourth as an important source of calories in the tropics (Cock 1985; Balogapalan et al. 1988). The storage roots form the basic carbohydrate component of the diet and the leaves are consumed as a preferred green vegetable in many parts of Africa, providing protein, mineral and vitamins (Hahn 1989). Two CGIAR Centres, CIAT and IITA, share the mandate for cassava. Genetic diversity of the Manihot genus is eroding in the face of expansion of agriculture in the American tropical lowlands, while in important cassava-growing regions of Africa, hundreds of traditional varieties have been abandoned during the 20th century (Nweke and Polson 1990; Nweke et al. 1994), and newer production regions in Asia tend to rely on single-cultivar plantations.
BOTANY AND DISTRIBUTION
Cassava is a member of the Euphorbiaceae, subfamily Crotonoideae and tribe Manihotae. The genus Manihot contains nearly 100 species of herbs, shrubs and trees among which the production of latex and cyanogenic glucosides is common (Rogers and Fleming 1973; Bailey 1976) and these are grouped into 19 taxonomic sections (Rogers and Appan 1973).
Chapter 7 - Cowpea
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- By N.Q. Ng, B.B. Singh
- Edited by Dominic Fuccillo, University of Arkansas, Linda Sears, International Plant Genetic Resources Institute, Rome, Paul Stapleton, International Plant Genetic Resources Institute, Rome
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- Biodiversity in Trust
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- 22 September 2009
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- 28 August 1997, pp 82-99
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The major cowpea-growing countries are Nigeria, Niger, Mali, Burkina Faso, Senegal, Togo, Benin, Ghana, Chad and Cameroon in West and Central Africa; Tanzania, Somalia, Kenya, Zambia, Zimbabwe, Botswana and Mozambique in East and Southern Africa; India, Pakistan, Sri Lanka, the Philippines, Bangladesh, Indonesia and China in Asia; and Brazil, the West Indies, Cuba and southern USA in the Western hemisphere. The estimated area under cowpea cultivation in the world is over 10 million hectares with about 70% in West and Central Africa and 12% in Brazil (Singh et al. 1996).
BOTANY AND DISTRIBUTION
Taxonomy
Cowpea belongs to the family Leguminosae, subfamily Papilionoideae, tribe Phaseoleae and genus Vigna.
Vigna is a large and immensely variable genus consisting of more than 85 species, divided into seven subgenera: Vigna, Sigmoidotropis, Plectotropis, Macrorhyncha, Ceratotropis, Haydonia and Lasiocarpa (Marechal et al. 1978). Seven species are cultivated. Five Asiatic domesticated species – V. radiata (L.) R.Wilczek, V. mungo (L.) Hepper, V. umbellata (Thumb.) Ohwi & Ohashi, V. angularis (Wild.) Ohwi & Ohashi and V. aconitifolias (L). (Jacq.) M. M. & S. – falling under the subgenus Ceratotropis are genetically highly isolated from cowpea. Bambara groundnut (V. subterranea L.), like cowpea, is also an African domesticated species. It is classified under the same subgenus Vigna with cowpea, but in a different section Vigna. It has very little in common with cowpea.
According to Marechal et al. (1978), cultivated cowpea and their closely related wild species are classified under a single botanical species V. unguiculata (L.) Walp.