Alternate wetting and drying irrigation is a widely used irrigation method for water-savings and high-yielding in rice (Oryza sativa L.) production; however, its effect on grain yield (GY) in the main and ratoon crops is unclear. With two rice cultivars as materials, the effects on GY in the main and ratoon crop of three irrigation regimes, that is, conventional flooding irrigation (CI), alternate wetting and moderate soil drying irrigation (WMD), and alternate wetting and severe soil drying irrigation (WSD), during grain filling of the main crop were investigated. Compared with CI, WMD increased GY by 6.0∼6.5% in the main crop by increasing the 1,000-grain weight and filled grain rate, whereas the ratoon crop GY increased by 13.3∼14.6% via increased panicle number. The WSD had no significant effects on the main crop GY, but significantly decreased ratoon crop GY by decreasing panicle number. A higher leaf photosynthetic rate, leaf area index, root oxidation activity, dry matter accumulation and nonstructural carbohydrate (NSC) translocation under WMD primarily drove the increased 1,000-grain weight and filled grain rate in the main crop. Under WMD, higher soluble sugar contents catalysed by high amylase activity and higher zeatin + zeatin riboside in stems of the main crop promoted the growth of regenerated buds and increased the ratoon crop panicle number. In conclusion, WMD during grain filling of the main crop improved the growth and development of the main crop and promote the germination of regenerated buds, thereby increasing the GY of both main and ratoon crops.

中文翻译：

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交替润湿和适度土壤干燥可以提高主稻和宿根稻作物的粮食产量

干湿交替灌溉是一种广泛应用的水稻节水高产灌溉方式（Oryza sativaL.) 生产; 然而，它对主要作物和宿根作物的谷物产量 (GY) 的影响尚不清楚。以2个水稻品种为材料，常规漫灌（CI）、干湿交替灌溉（WMD）、干湿交替灌溉3种灌溉方式对主季和宿根作物GY的影响灌溉（WSD），在主要作物的灌浆期进行了调查。与CI相比，WMD通过提高千粒重和饱粒率，使主要作物的GY增加6.0～6.5%，而宿根作物GY通过增加穗数增加13.3～14.6%。WSD对主要作物GY没有显着影响，但通过减少穗数显着降低宿根作物GY。较高的叶片光合速率、叶面积指数、根系氧化活性，WMD 下的干物质积累和非结构性碳水化合物 (NSC) 转运主要推动了主要作物千粒重和饱粒率的增加。WMD作用下，高淀粉酶活性催化可溶性糖含量升高，主要作物茎部玉米素+玉米素核苷含量升高，促进再生芽生长，增加宿根穗数。综上所述，WMD在主粮灌浆期促进主粮生长发育，促进再生芽萌发，从而提高主粮和宿根作物的GY。高淀粉酶活性催化可溶性糖含量升高，主作物茎部玉米素+玉米素核苷含量增加，促进再生芽生长，增加宿根穗数。综上所述，WMD在主粮灌浆期促进主粮生长发育，促进再生芽萌发，从而提高主粮和宿根作物的GY。高淀粉酶活性催化可溶性糖含量升高，主作物茎部玉米素+玉米素核苷含量增加，促进再生芽生长，增加宿根穗数。综上所述，WMD在主粮灌浆期促进主粮生长发育，促进再生芽萌发，从而提高主粮和宿根作物的GY。