Yield components and yield stability of bread wheat in water limited environments

Grain yield and its components of four local wheat cultivars ( Sakha 92, Sakha 69, Giza 69 and Giza 163)and twelve wheat genotypes introduced from ICARDA, were evaluated under a combination of 5 water regimes and 3 locations, representing the traditional Egyptian farming system (Om El-Zain Sharkia) during 1991/1992 and 1992/1993 growing seasons, and during one cropping season (1992/1993) in the newly reclaimed lands of El-Arish, Sinai). The results revealed that the genotype x environment interaction component accounted for the most part of the total variation for grain yield and its components, i.e. number of spikes/m(2), number of grains/spike and 1000-grain weight. Regression coefficient (b) values varied among the studied genotypes from 0.68 to 1.9 for grain yield, 0.67 to 1.29 for spikes/m(2), 0.74 to 1.22 for grains/spike and 0.46 to 1.48 for 1000 grain weight. Wheat genotypes Nos 5, 7 and 12 showed a consistent performance over environments and could be considered as stable ones. Significant correlation coefficient between mean value and b was detected for grain yield and spikes/m2, indicating that the performance of genotypes could be predicted from its mean value. However, nonsignificant correlations were observed for grains/spike and 1000 grain weight, showing the independence of genes controlling the inheritance of these characters and the possibility of breeding new stable wheat recombinants across different environments, with high yield potential.