Effect of Soil Water Deficit on Grain Yield in Synthetic Bread Wheat Derivatives

This study aimed to analyze drought tolerance in bread wheat by examining the effect of soil water deficit on yield performance of synthetic bread wheat derivatives. Thirteen genotypes of synthetic bread wheat derivatives selected from a backcross (Cham 6 ///Haurani / Ae. tauschii ICAG400709 //Cham 6) were used for field evaluation in two experimental sites for two consecutive years. In addition, three synthetic wheat genotypes grown under different planting dates were compared for yield performance. Grain yield was highly correlated with harvest index under all of four cropping environments. No significant contribution of biomass to the grain yield was found in these plant materials. Late planting generated plant growth under the drier soil conditions after the heading time than under normal planting conditions, which resulted in considerable grain yield reduction. A synthetic wheat genotype selected from the materials showed significantly higher grain yield under late planting condition than the check variety, Cham 6. These results suggest that higher grain yield in a synthetic bread wheat genotype is associated with rapid translocation of photosynthetic carbohydrates to the grains after heading time.