Genotypic response of sorghum (Sorghum bicolor L. Moench) to drought stress

This study aimed at assessing the genotypic variability for drought tolerance in sorghum (Sorghum bicolor L. Moench). Eight genotypes were selected out of a set of 96 which had already been analysed by SSRs. Three field experiments were conducted in Sudan at two locations (Medani and El Rahad) in two seasons (2002-2003) under two water regimes, and a pot experiment was carried out at Giessen, Germany. In field tests drought was imposed naturally, while under pot conditions drought was imposed at 40 % and 70 % water hold capacity. In the pot trial and field experiments, genotypes differed significantly in most of the traits measured. In the pot experiment grain yield under drought stress ranged from 28 - 61 g plant-1 and relative yield ranged from 30 - 56 % with an average of 47 %, while in the field, the yield varied from 26 - 53 g plant-1, with an average of 41 g plant-1, and the relative yield ranged from 59 - 85 % with a mean of 75 %. The yield under field stress condition was moderately but significantly correlated with yield under pot stress condition (r = 0.52*). Based on yield, genotypes ?Wad Ahmed?, ?ICSR91030? and ?SAR 41? turned out to be the best under both stress conditions, and based on the relative yield the best genotypes were 'Arfa Gadamak' (85 %), 'Wad Ahmed' (84 %) and 'Gadamballia' (81 %) under field conditions, and ?SAR 41? (56 %), 'Wad Ahmed' (55 %) and 'Red Mugud' (53 %) in the pot experiment.