Association of yield and flag leaf photosynthesis among wheat recombinant inbred lines (RILs) under drought condition

Drought stress is one of the major limitations to crop productivity. To develop crop plants with enhanced tolerance of drought stress, a basic understanding of physiology is essential. The objective of this study was to investigate the possible physiological basis of high yield of the wheat recombinant inbred lines (RILs). We thus compared photosynthetic capacity of flag leaves and tolerance to drought stress between the wheat RILs and their parents. Agronomic and physiological traits were measured on young flag leaves of full grown plants of both stressed and non-stressed treatments at an early (EGF) and late (LGF) grain-filling stage. The responses of net photosynthesis (An), stomatal conductance (gs) and intercellular CO2 concentration (Ci) in this study make clear that drought stress significantly decreases photosynthesis rate. Compared with Ci, An and gs was found to be more sensitive to the drought stress.