Objective  The stress of wheat waterlogging is the main abiotic stress factor in wheat production in the middle and lower reaches of the Yangtze River. To study the effects of different duration of waterlogging on physiological characteristics and yield of wheat at booting stage provides a theoretical basis for the research on the mechanism of wheat waterlogging resistance at booting stage and production.

  Method  The effects of waterlogging duration on wheat growth and yield at booting stage were studied by pot pot water control method with wheat varieties Yangmai 16 and Zhongmai 895 as experimental materials.

  Result  (1) Under the stress of waterlogging, the chlorophyll content of wheat leaves decreased significantly. The longer the waterlogging lasted, the greater the decline of SPAD value was. The SPAD value of the more heavily injured leaves decreased more, and the more severely injured the inverted two leaves than the flag leaves. (2) The activity of antioxidant enzymes such as CAT, SOD and POD in wheat showed a trend of type "∧" during the waterlogging period, while the content of reactive oxygen species (ROS) decreased or increased slowly in the early stage of waterlogging, while increased sharply in the late stage. (3) In the booting period, the effective number of ears, grain number of ears, 1000-grain weight and other yield factors increased slightly, which may be caused by the stress response of wheat. (4) The stress of waterlogging at the stage of heading had no significant effect on the height of wheat plant. Long-term waterlogging resulted in a significant decrease in wheat yield. The decrease of effective panicle number, grain number per panicle and 1000-grain weight was the main factor causing wheat yield reduction. After 15 d of waterlogging stress, the yield per plant of zhongmai 895 and yangmai 16 decreased by 51.47% and 43.99%, respectively, compared with CK.

  Conclusion  Booting stage waterlogging stress significantly reduced the wheat leaf chlorophyll content, destroyed the plant active oxygen metabolism in the body and the balance between antioxidant enzyme system, excessive accumulation of reactive oxygen species causes cells to peroxide lipid membrane, causing cell structure and function is impaired, affect plant photosynthesis and nutrient transfer and accumulation, increase the biomass of wheat is reduced, resulting in lack of grain-filling, caused empty grain, grain and invalid number of flat significantly increased, resulting in wheat production. In addition, during the whole process of waterlogging stress, the resistance of the two wheat varieties tested was as follows: yangmai 16＞zhongmai 895.