Effects On Growth And Grain Yield Of Winter Wheat Under Water Stress In North China

Lack of rainfall and its uneven distribution are the current situation in north China, and Water has become the main cause of reduction of yield in this area. In different growing stage, water shortage feedback will be different. According to above research findings, based on limited irrigation, optimized limited water distribution based on susceptible index, and adjusted the water stress degree artificially to influence the process in which crop physiology, biochemical and yield was informed, regulated deficit irrigation increases the using of biology and achieved high water utilization ratio ultimately.A pot experiment with four water stress treatments and one CK (full irrigation during whole growth period) designed according to deficit degree (mild 60% FC and severe 40% FC) and stress duration (5d and 10d) for each variety, was conducted to study the effects of water stress -rewatering at jointing and filling stage on growth, dry matter accumulation, allocation, yield and WUE of winter wheat with the representative triticum cultivars Shijiazhuang 8 and YM20 in north China. The main results are as follows:(1)The results showed that, the growth of two triticum cultivars, include plant height, leaf area, stem diameter and tiller number, was limited and less than CK, the greater the stress level the greater negative effects on growth. In comparison, the effects of water stress to wheat growth at filing stage were less. The two triticum cultivars'growth recovered limited after rewatering. Judging from the harvest index, mild stress is conducive to grain transport and accumulation from other organs'dry matter.(2)The dry matter of root,stem,leaf and the dry weight per plant were decreased under water stress at jointing and filling stage, and dry matter accumulation of all the water stress treatments were less than CK, but the mild was better than the severe. That early appropriate mild water stress could control the distribution of dry matter and increase root/shoot ration, could produce compensatory growth at certain level. However, that water stress at filling stage was against vegetative and reproductive growth.(3)This experiment also proved that different stress level corresponds to different canopy temperature: the greater water stress the higher canopy temperature. Therefore, field water conditions can be determined according to the field canopy temperature.(4)Two varieties of wheat to water stress jointing stage and filling stage, reflected in grouting process different. Shijiazhuang 8 is by delaying the start time of grain filling and YM20 is by the maximum accelerated grouting rate of arrival time, which affected yield.(5)CK had the highest yield, which showed water stress at jointing stage and filling stage would affect the yield if winter wheat. Water stress at jointing stage and filling stage mainly reduced grain number and grain weight separately under this test condition.(6)The best stress degree at jointing stage and filling stage on WUE was 60% of field capacity, and the best stress duration at jointing stage and filling stage were 5 days and 10 days respectively. The WUE treatment SB60%-5 was even higher than CK. The effects of water stress at jointing stage was worse than at filling stage, and more sensitivity to water stress. Therefore try to avoid water deficit at jointing stage, and can not surpass 5d under water stress.This experiment indicated that, jointing stage and filling stage is sensitive to water stress, so water stress should be avoid during the two stages. However, it can be appropriately regulated deficit exercises, not beyond the 60% FC.