Genetic enhancement of pearl millet and sorghum for the semi-arid tropics of Asia and Africa

Sorghum (Sorghum bicolor (L.) Moench) and pearl millet (Pennisetum glaucum (L.) R. Br.), ranking fifth and sixth in global cereal hectarage, respectiv ely, are the most important coarse-grain cereals in the semi-arid tropical regions of Asia and Africa. Pearl millet displays better adaptation to and is grown in relatively more marginal environments than sorghum. Under subsi stence farming conditions, both crops have low grain yields (0.5-0.7 t.ha(- 1) for pearl millet and 0.7-0.9 t.ha(-1) for sorghum), although improved hy brid cultivars give 3-4 t.ha(-1) of realizable grain yields in better-endow ed environments. African germplasm, especially Zera Zera sorghums from the Sudan-Ethiopian border in eastern Africa and Iniari pearl millets from the Togo - Ghana - Benin - Burkina Faso region of western Africa, has proved mo st useful for the genetic improvement of these crops. The greatest impact o f improved cultivars (mostly hybrids) has occurred in India, where the area under high-yielding varieties (HYVs) increased from 6% for pearl millet an d 3% for sorghum in the triennium 1968-1970 to 53% for pearl millet and 54% for sorghum in the triennium 1992-1994. During the same period, productivi ty of both crops increased by 59%, which is attributable to both genetic im provement and management factors. HYVs have now started to be adopted in so me of the African countries as well (e.g., Chad, Cameroon, Botswana, and Zi mbabwe for sorghum; Chad, Namibia, Zambia, and Zimbabwe for pearl millet). The availability of vast untapped genetic resources and continuing yield ga ins indicate that there are good prospects for future genetic improvement i n the productivity of these crops, which can be accelerated with the applic ation of biotechnological tools. Sorghum and pearl millet will continue to be important food crops in their traditional semi-arid tropical areas. Sorg hum is already an important feed crop in the developed world and pearl mill et has the potential to become an even better feed crop, as it has higher p rotein content and a better amino acid profile than sorghum. The nutritiona l value of both crops for food and feed use can be further improved by bree ding. Also, through genetic enhancement, there exist opportunities for the development of sorghum and pearl millet cultivars suitable for alternative uses in the bakery and beverage industries.