Effect of water stress on leaf level gas exchange capacity and water-use efficiency of wheat cultivars

Water stress constitutes one of the most important environmental constraints limiting wheat productivity worldwide. In an open pot experiments six spring wheat cultivars, viz., Barigom-23, Barigom-24, Barigom-25, Barigom-26, Barigom-27, and Barigom-28 were grown under control and water stress conditions to evaluate their genetic variations for gas exchange parameters and water-use efficiency. Results showed that genotypic variations for the gas exchange parameters and water-use efficiency were very prominent among wheat cultivars under control and water stress conditions. Water stress adversely affected net photosynthesis, stomatal conductance, internal CO 2 concentration, transpiration rate, carboxylation efficiency, instantaneous and intrinsic water-use efficiencies compared to control condition. Wheat cultivars Barigom-23 showed best performances for most of the characters. Cultivars Barigom-26 and Barigom-27 showed medium performances, whereas Barigom-24 showed lowest performance for most of the characters under water stress condition. A clear significant positive linear relationship was observed between net photosynthesis and stomatal conductance which indicated that increase in stomatal conductance improves net photosynthesis.