Genotypic variation for agro-physiological traits and their utilization as screening indices for drought tolerance in wheat

Abstract

Plants of 56 genotypes of bread wheat (Triticum aestivum L.) were grown under irrigated and droughted conditions under field conditions at CCS Haryana Agricultural University, Hisar, India. Leaf water status, canopy temperature depression and gas exchange were measured in the flag leaf at anthesis and yield-attributes and yield were recorded at harvest. The results revealed that there was a significant genotypic variation for all traits. Seed yield was positively correlated with yield attributes but a stronger relationship was observed with biomass. Drought susceptibility index (DSI) of genotypes matched for biomass and seed yield. Significant correlations were found among agro-physiological traits. Genotypes with higher soil moisture use from deeper layers (90-180 mm) maintained higher leaf relative water content (RWC), transpiration rate (E), photosynthetic rate (PN) and cooler canopy (higher canopy temperature depression, CTD). Agro-physiological traits such as soil moisture use (90- 180 mm), RWC, PN and CTD were strongly correlated with seed yield. Since CTD is easier to measure than other characters, therefore, CTD measured at midday at the anthesis stage could be used as selection indices to screen large number of germplasm lines of wheat for drought tolerance under field conditions.