Effect of yield potential, drought escape and drought tolerance on yield of pearl millet (Pennisetum glaucum) in different stress environments

An experiment was conducted during the rainy season of 1988 and 1989 and the dry season of 1989 and 1990 to study the effect of yield potential, drought escape and tolerance on the grain yield of pearl millet [Pennisetum glaucum (L.) R. Br. emend. Stuntz] under stress. Different types of drought and heat stress occurred, viz moderate and severe post-flowering drought and sevcrepre-flowecing drought, combined with either high or low temperature during grain filling. Yield potential was only related to yield under stress when pre-flowering drought was combined with low temperatures. Escape was the predominant factor if temperature was high, except if combined with pre-flowering drought, in which case tolerance became more important. These results show that for stressed environments, selection for yield potential is of limited use. The importance of escape and tolerance, however, depends on the timing and intensity of stress occurrence. If pearl millet-growing regions can be charaoterized based on occurrence of abiotic stress, breeders can select more efficiently for plant traits that enhance stress adaptation in specific target environments.