Abstract:

To provide references for the waterlogging-tolerance and yield-stability cultivation of wheat,the experiment was conducted to study the effects of different degrees of waterlogging on root dry weight and vigor in different soil layers,shoot growth,grain yield,and its components using Yangmai 25 and Ningmai 13 as experimental materials.The treatments included short-term mild(SL,10 cm water layer under the soil surface for 3 days),short-term severe(SS,2 cm water layer above the soil surface for 3 days),long-term mild(LL,10 cm water layer under the soil surface for 12 days),long-term severe(LS,2 cm water layer above the soil surface for 12 days)waterlogging treatments at stem-elongation stage,and control treatment(CK,maintaining the relative soil water content of 70%—75%).The results showed that Yangmai 25 showed significantly higher grain yield,1000-grain weight,root dry weight,root activity in the 0—40 cm soil layer,and ratio of root to shoot than Ningmai 13.Compared with CK,SL and SS reduced grain yield by 13.44%—22.45%,while LL and LS reduced grain yield significantly by 28.76%—37.26%.There was no significant difference in grain yield between SL and SS,LL and LS.Under the short-term waterlogging,the biomass of root and shoot were slightly reduced,the root in 0—20 cm soil layer maintained high vigor,and the vigor of root in 20—60 cm soil layer could recover.However,long-term waterlogging significantly decreased root dry weight resulting in growth imbalance of root and shoot.In addition,root activity was low and difficult to recover under long-term waterlogging,and the top-three leaves was prone to premature senescence with the top 3rd leaf showing most obvious.The results suggested that lowering water levels as soon as possible after waterlogging could help the surface roots maintain growth and physiological activity,and reduced the risk of premature leaf senescence,satisfying the photosynthetic needs for grain filling.

Key words: Wheat, Waterlogging, Degree of stress, Root system, Grain yield