W heat is an imperative grain crop and a staple food of many countries around the globe. Water scarcity during the anthesis stage of wheat reduces the grain production. Due to low rainfall and ever rising temperature, the risk of drought at anthesis or post anthesis stages of wheat is alarming in semi arid areas of the world. Drought stress at anthesis stage causes the abortion of wheat grains (Rajala et al., 2009) and also affects the process of grain filling. It results in grain shrinkage (dried-up) and responsible for reduction in grain yield (Dias de Oliverira et al., 2013;Mitchell et al., 2013). Water is the key element in determining the wheat yield when it is used at anthesis or post anthesis stage (Manschadi et al., 2006).
Threats of drought for agricultural production areAbstract | Water shortage is the main limitation for agricultural production in many parts of the world. Drought or unavailability of water may seriously limit plant growth as well as yield. A pot experiment was carried out to evaluate the effects of various irrigation strategies i.e. Full (FI), deficit (DI) and partial rootzone drying (PRD) on physiological, water relations, water use efficiency (WUE), and yield related attributes of wheat. These irrigation treatments were started at anthesis stage and maintained for 30 days. For FI and DI, 100 and 50% of evapotranspiration (ET) was replaced by irrigating the entire pot surface every 4-5 days. For PRD, root system was split into two equal halves and during each irrigation event, only one-half of the root system was irrigated with the same amount of water as applied to DI, and subsequently, irrigation was switched to the second half. PRD irrigation significantly improved WUE (both photosynthetic and intrinsic) and instantaneous carboxylation efficiency of Rubisco than FI and DI. Higher Abscisic acid (ABA) production under PRD reduced stomatal conductance, net photosynthesis and transpiration rate. Magnitude of osmotic adjustment (i.e. leaf water, osmotic and tugor potential) was lowest and highest under FI, DI and PRD, respectively. However, PRD had lower shoot biomass and grain yield per plant as compared to FI but higher than the DI. Despite improving the WUE, PRD tended to compromise the yield of wheat crop but PRD is recommended instead of DI. Results imply that PRD treatment can be an option under water shortage; however, its suitability and efficacy should further be tested under field conditions.