Drought Priming Enhanced Grain Yield of Wheat Against Salinity Stress

Climate change-induced drought and salinity stress pose major threats to global food security. These stresses adversely affect plant growth, development, and productivity, leading to reduced crop yields. Developing sustainable and economically viable solutions to enhance crop stability and productivity is imperative through improving water management practices and promote the development of drought and/or salinity-resistant crops against abiotic stresses. Drought priming, a cost-efficient strategy, has emerged as a promising approach to increase plant tolerance to subsequent abiotic stresses. However, it is still unknown whether and how drought priming at the early growth stage reduces the drought and/or salinity stress at the later growth stage and enhances plants' water use efficiency (WUEp). To investigate the effect of the drought priming on the morphological and yield responses of wheat plants to salinity stress, a pot experiment was carried out under the rain shelter from November, 2021 to March, 2022 at Sylhet Agricultural University, Bangladesh. Two leading wheat cultivars (BARI Gom-28 and WMRI Gom-3) were subjected to two drought priming levels at the fourth and sixth leaf stage and subsequent moderate salinity stress at 100 mmol NaCl applied at the later growth stage. The plant morphological attributes like plant height, tiller length, tillers number, spike length, spikes number, spikelets number per spike, kernel number per spike, dry biomass, and WUEp as well as the yield and yield components were investigated. The results showed that the non-primed plants reduced yield parameters including tiller number, spike number, spike length, kernel number, and biomass by 13, 1, 15, 12, and 14% in BARI Gom-28 and 8, 1, 14, 11, and 13% in WMRI Gom-3, respectively, with increasing salinity levels, whereas the drought primed plants improved grain yield by 21% in BARI Gom-28 and 19% in WMRI Gom-3 through increased kernel number and grain weight. Maximal dry matter at maturity and the highest grain yield were observed in drought-primed plants under salinity stress compared to control plants. The increased number of tillers, particularly secondary tillers, under salinity stress for primed plants contributed to overall grain production. The interaction between drought priming and salinity significantly affected kernel number and grain yield in both wheat cultivars. This research will be helpful for crop physiologists to design agronomically relevant strategies for the development of broad-spectrum stress-tolerant crops.