Photosynthetic attributes and biological yield of wheat genotypes as influenced by exogenous trehalose and cytokinins under field drought stress

Present investigation was aimed at studying the effect of exogenous application of cytokinins like kinetin (Kn) and benzyl adenine (BA) in combination with osmoprotectant like trehalose (Tre) at two stages i.e vegetative stage (VS) and flag leaf stage (FLS) on photosynthetic parameters and biological yield of drought stressed wheat genotypes. Under drought stress, significant decrease in leaf net photosynthetic rate (Pn), stomatal conductance (gs), transpiration rate, sub-stomatal CO₂ concentration and decrease in photosynthetic water use efficiency has been observed. Foliar application of both cytokinins and trehalose had ameliorative effect on photosynthetic rate, stomatal conductance, transpiration rate, substomatal conductance of carbon dioxide. Significant increase was recorded in chlorophyll a, b, total chlorophyll content and carotenoid content of wheat genotypes with exogenous application of cytokinins and trehalose. Exogenous application of Tre @ 1.5mM along with Kn @ 40mg/L, was observed more effective in mitigation of adverse effect of drought stress in wheat genotypes.