Abstract:
Abstract: Frequent occurrence of waterlogging has posed a great threat to the production of the crops in the middle and late stages of winter wheat growth in the Jianghan Plain, even the middle and lower reaches of the Yangtze River in China. However, the impact of waterlogging on the grain filling process is still unclear during this time. Taking Zhengmai 9023 (tolerant genotype) and Yangmai 20 (sensitive genotype) as research objects, this study aims to explore the effects of water logging after anthesis on grain filling of winter wheat under different tolerances. A systematic experiment was conducted under 5, 9, 13, and 17 d of waterlogging duration after anthesis of winter wheat in the test-pit with a controllable irrigation and drainage system. The soil moisture was kept at 90% field capacity in the waterlogging treatments. Meanwhile, the treatment with soil moisture at 70%-80% field capacity was used as a control. The grain filling was firstly simulated for two varieties of wheat under waterlogging environment stress using the Richard model. Subsequently, the yield component parameters were quantitatively analyzed the dynamic influence on grain filling, further to explore the influence process after anthesis waterlogging on winter wheat yield. The results showed that the waterlogging for 5, 9, 13, and 17 d after anthesis reduced the yield of Zhengmai 9023 (tolerant genotype) by 10.84%, 19.51%, 25.93%, 36.52% and Yangmai 20 (sensitive genotype) by 14.25%, 25.84%, 37.26%, 47.84%, respectively. The main reason was attributed to the decrease of thousand-grain mass. When waterlogging increased by 1 d after anthesis, the thousand-grain mass of Zhengmai 9023 (tolerance genotype) and Yangmai 20 (sensitive genotype) decreased by 0.961 and 0.996 g, respectively. The Richards equation presented better to simulate the grain filling of waterlogged winter wheat after anthesis. Specifically, the determination coefficients of the fitting equation were all above 0.99. Furthermore, there was a different influence mechanism of waterlogging after anthesis on the grain filling of wheat under different waterlogging tolerance. In waterlogging-tolerant wheat, the waterlogging was greatly contributed to shortening significantly the active days of the grain filling after anthesis, and specially shortened significantly the duration days in grain-filling fast increase period and grain-filling slowly increase period. In the waterlogging-sensitive wheat, the waterlogging after anthesis was mainly contributed to significantly reducing the filling rate in three periods of grain filling. Specifically, the waterlogging increased by 1 d after anthesis, and the grain filling active days of Zhengmai 9023 was shortened by 0.827 d, among which the duration days in grain-filling fast increase period and grain-filling slowly increase period was shortened by 0.492 and 0.963 d, respectively. Correspondingly, waterlogging increased by 1 d after anthesis, the maximum grain-filling rate per kernel of Yangmai 20 decreased by 0.046 mg/d, and the mean grain-filling rate per kernel decreased by 0.032 mg/d, the grain-filling rate per kernel in grain-filling pyramid period, grain-filling fast increase period and grain-filling slowly increase the period of winter wheat decreased by 0.011, 0.040 and 0.010 mg/d, respectively. The finding can provide strong theoretical support for the prevention and control of waterlogging disasters in winter wheat.