The present investigation was carried out to estimate the genetic variability of agro-physiologicalcharacters using biometrical genetic techniques in bread wheat genotypes under rainfed condition. The results of variance analysis (ANOVA) showed significant differences for stress yield (Ys), relative water content (RWC), evapotranspiration efficiency (ETE) and water use efficiency (WUE) under rainfed conditions indicating the presence of a considerable genotypic variation and possible selection

more »

... f drought tolerant genotypes under rainfed conditions. Comparison of means showed that the genotype D-79-15 (G8) had the highest, WUE, relative chlorophyll content (RCC), stomatal conductance (SC), the ratio of chlrophyll a/ chlorophyll b (a/b) and Ys. Cluster analysis based on grain yield and physiological criteria classified the genotypes in three groups. Group 1 (drought tolerance) consisted of genotypes G3, G4 and G8, group 2 (semi-resistance) included genotypes G7 and group 3 (drought sensitive) discriminated genotypes G1, G2, G5 and G6. High heritability and genetic gain was observed for Ys, RWC, ETE, WUE and a/b. The results of phenotypic and genetic correlation coefficient (Table 4 ) displayed that RCC, ETE, SC and a/b contributed significantly towards Ys. High coheritability was observed between relative water loss (RWL) and Ys (5.042), RWL and WUE (5.317). Positive coheritability estimate was observed between Ys and all other physiological traits suggesting that selection of either of the characters would simultaneously affect the others positively.