Effect of Waterlogging Stress on Dry Matter Accumulation, Photosynthesis Characteristics, Yield, and Yield Components in Three Different Ecotypes of Peanut (Arachis hypogaea L.)

Waterlogging has a negative effect on peanut production, but few studies have focused on the relationship between the geographical origin and waterlogging tolerance of peanut varieties. To explore this problem, three different peanut ecotypes (Zhanhong 2, Zhongkaihua 1, and Huayu 39) were waterlogged for 5, 10, and 15 days at seedling stage (S), flowering and pegging stage (F), and pod-filling stage (P), respectively. The relationship between the ecotype and waterlogging tolerance was determined by analyzing the effects of waterlogging on dry matter accumulation, photosynthetic characteristics, yield, and the yield components of peanut. The soil and plant analysis development (SPAD), net photosynthetic rate (Pn), stomatal conductance (Gs), transpiration rate (Tr), and intercellular CO2 concentration (Ci) values in leaves decreased under waterlogging stress, which led to a significant decrease in yield and yield components. The most noticeable effect of waterlogging stress appeared at the P stage and deleterious effects increased with an extension of the duration of waterlogging, where the yield loss was mainly attributed to the decrease in the number of total pods (TP) and the number of full pods (FP). Significant relationships were found between total dry weight (TDW), leaf dry weight (LDW), pod dry weight (PDW), TP, and FP, and the waterlogging stress tolerance index (WTI). Additionally, the waterlogging tolerance of peanut ecotypes is closely related to their geographic origin, where the most waterlogging-resistant ecotype was Zhanhong 2, followed by Zhongkaihua 1 and Huayu 39. Finally, breeding backgrounds and screening indices (SPAD, Pn, dry matter accumulation, and pod characteristics) beneficial to waterlogging tolerance breeding are suggested.