Comparative performance of sorghum hybrids and their parents under extreme water stress

Sorghum hybrids are generally considered to be drought tolerant based on their yield performance in multi-locational trials. The present study was undertaken to test this hypothesis. A short duration hybrid, CSH-6, a long duration hybrid, CSH-9, their common male parent and both female parents were evaluated in the field in India under both rainfed and irrigated conditions during the rainy seasons of 1986 and 1987. Due to the low rainfall received in these years, the unirrigated treatments experienced severe water stress during the vegetative and post-anthesis periods. The hybrids produced more leaf area and dry matter than their parents even under water stress. The values for the physiological traits examined either resembled those of one of their parents or were intermediate between them. The hybrid CSH-6 produced more grain than its female parent under rainfed conditions but, due to the severe water stress, neither CSH-9 nor its parents exhibited panicle emergence. The results suggest that crop phenology is very important for the production of grain yield under severe water stress. Given knowledge of rainfall characteristics and probable periods of drought within specific regions, it should be possible to breed phenologically and physiologically adapted hybrids for specific environments