Parental Drought and Defoliation Effect on Yield, Grains Biochemical Aspects and Drought Performance of Sorghum Progeny

This study was designed to evaluate the effect of drought stress and drought with defoliation on yield parameters of three sorghum varieties (Giza 15, Dorado and Hybrid 113). Also, the effect of these parental stress treatments on drought performance of progeny of the most drought tolerant variety was investigated. Application of drought stress in the vegetative stage non significantly affected panicles number, grain yield and harvest index of all cultivars. Drought stress in the reproductive stage of Giza 15 and Hybrid 113 cultivars caused a two fold increase in length of lateral branch and panicles number. However, grain yield and total panicles weight were significantly reduced in all cultivars due to this stress. Application of drought with defoliation in the vegetative stage reduced shoot and straw weights, and grain yield in sorghum in comparison with drought stress only. Protein-N and polysaccharides content were decreased in parent grains in response to water stress. The stress intensity index (SII) of progeny from drought- subjected parents was about 30-fold greater than SII of progeny from control parents. Further, SII of progeny from parents exposed to drought stress in the reproductive stage was higher than the SII of progeny from parents subjected to drought stress in the vegetative stage . A strong negative correlation appeared between the stress intensity index of the progeny and polysaccharides content of parent grains. Based on our research parental defoliation did not improve the drought resistance of sorghum progeny.