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 a nd the dry season of 1989 and 1990 to study the effect of yield potent ial, 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 pos t-flowering drought and severe pre-flowering drought, combined with ei ther high dr low temperature during grain filling. Yield potential was only related to yield under stress when pre-flowering drought was com bined with low temperatures. Escape was the predominant factor if temp erature was high, except if combined with pre-flowering drought, in wh ich 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 timi ng and intensity of stress occurrence. If pearl miller-growing regions can be characterized based on occurrence of abiotic stress, breeders can select more efficiently for plant traits that enhance stress adapt ation in specific target environments.