花后渍水对不同耐渍型冬小麦籽粒灌浆特性的影响

江汉平原冬小麦中后期常遭受涝渍灾害，为明确花后渍水对冬小麦籽粒灌浆进程的影响，以郑麦9023（耐渍型）和扬麦20（敏感型）2个小麦品种为研究对象，利用灌排可控的测坑模拟冬小麦花后不同天数（5、9、13和17 d）的渍水胁迫，应用Richards模型对冬小麦籽粒灌浆进程进行了模拟，在此基础上分析各籽粒灌浆参数与渍水天数的关系。结果表明：花后渍水5、9、13和17 d，郑麦9023（耐渍型）分别减产10.84%、19.51%、25.93%和36.52%，扬麦20（敏感型）分别减产14.25%、25.84%、37.26%和47.84%。导致冬小麦减产的主要原因是千粒质量降低，花后渍水天数每增加1 d，冬小麦郑麦9023和扬麦20千粒质量分别降低0.961和0.996 g。Richards方程能极显著模拟花后渍水冬小麦籽粒灌浆过程，拟合方程决定系数均在0.99以上。对耐渍型冬小麦，花后渍水主要显著缩短活跃灌浆期，且主要是显著缩短籽粒灌浆快增期和缓增期的持续天数；对敏感型冬小麦，花后渍水主要显著降低籽粒灌浆三阶段的灌浆速率。花后渍水增加1 d，郑麦9023籽粒活跃灌浆期缩短0.827 d，籽粒灌浆快增期、缓增期灌浆持续天数分别缩短0.492、0.963 d，扬麦20单粒最大灌浆速率降低0.046 mg/d、单粒平均灌浆速率降低0.032 mg/d，籽粒灌浆渐增期、快增期和缓增期单粒灌浆速率分别降低0.011、0.040和0.010 mg/d。研究可揭示花后渍水致使冬小麦减产的影响过程，为冬小麦涝渍灾害防控提供理论支撑。

Effects of waterlogging after anthesis on the grain filling characteristics of winter wheat with different waterlogging tolerances

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.