Effect of water-limited deficit stress in different growth stages on winter wheat grain yields and their yield constituents

Using pot experimert with or without N fertilizer supply,the effects of water limited deficit stress in different stages on wheat grain yields and their constituents were studied.The results showed that water limited deficit stress in seedling stage,jointing stage and filling stage significantly affected grain yield,biomass,the effective numbers of ears,the grain numbers of each ear and the 1000 grain weight.The seedling stage and filling stage were not so sensitive to water limit deficit stress,but the jointing stage was very sensitive to the stress.The grain numbers of each ear and the 1000 grain weight significantly decreased by water stress in jointing stage with N fertilizer supply before sowing.On the other hand,the seedling stage was water effective compensation period of biomass;the jointing stage was highly effective water compensations period of biomass and also the effective compensation period of grain yield.Affected by the water status in seedling stage and filling stage,water supply in jointing stage have different compensation effects to 3 yield kind of factors.With N fertilizer applicated before sowing,water supply in filling stage had no compensation effect to grain yield but lowered the 1000 grain weight.