Impact of water stress on physiological traits and yields of different varieties of spring wheat

【Background】 Wheat is the second largest cereal crop after rice in China and is largely grown in arid and semiarid regions in the North. Understanding the impact of water stress on its growth and final yield is important to improve its water use efficiency and safeguard wheat production. We studied this in a field experiment. 【Method】 The experiment was conducted at Wuwei of Gansu province, using the varieties Longchun 41 and Yongliang No.4 as the model plants. This paper aimed to elucidate how water stress imposed in the jointing and grain-filling stages influence growth, physiology and yields of the crops. The control was sufficient irrigation (CK). There were four deficit irrigation treatments: irrigating 65% of water in the CK during both jointing and grain-filling stages (W1), 80% during the joint stage and 65% during the grouting stage (W2), 65% during the jointing stage and 80% during the grain-filling stage (W3), 80% during both jointing and grain-filling stages (W4). In each treatment, we measured growth indexes, grain yield, leaf photosynthetic traits and chlorophyll fluorescence kinetic traits. 【Result】 Water stress during the jointing and grain-filling stages significantly reduced plant height, leaf area index, dry matter accumulation, net photosynthetic rate, transpiration rate, and photosynthetic electron transport rate. Sufficient irrigation during the tasseling stage can restore the leaf area index (LAI) of the Longchun 41 variety, positively influencing SPAD values, photosynthetic electron transfer, and transpiration. Increasing water deficit led to a reduction in grain yield. On average, the yield of Longchun No.41 was higher than that of Yongliang No.4. The yield of Longchun No.41 in W4 was not significantly different from that in CK. 【Conclusion】 Considering water saving and grain yield, the optimal irrigation and cultivation for spring wheat in the studied region is to grow the Longchun No.41 variety and irrigate 80% of water used in sufficient irrigation during both the jointing and grain-filling stages.