The Mechanism And Effect Of Different Water-controlled Measures On Yield And Quality Of Winter Wheat

In order to provide appropriate irrigation index of high quality wheat for high yield efficiency in Huang-Huai Area, different treatments of water stress and stress period at jointing and grain-filling stage were designed to investigate effects of different water conditions on yield and quality of winter wheat grown in the pots and barrels, using many detection methods in indoor and outdoor to monitor and analyze growth and development, physiology and biochemistry, yield factors and grain quality and other indexes. Results indicated that water sensitivity stage was middle jointing stage. Water stress at this period had important effects on various indexes of physiology and biochemistry and yield, but effcts on grain quality were relative small. Water stress at middle and late season of grain-filling stage was beneficial to nutrient translcation to grain, and increase amino acid and protein content in grains, but effcts on grain tield were relative small. Basic principle of water regulation for winter wheat with high yield and quality was to fully ensure water use at jointing stage and appropriately decrease water supply at late grain-filling stage.It was conclued from studying on effects of water stress on physiological and biochemical indexes that photosynthetic rate, transpiration rate and stomatal conductance of leaves were decreased with increasing water stress at joinging stage. Drought at jointing and grain-filling stage was beneficial to increase free amino acid content in leaves after anthesis of winter wheat, and the serious stress treatment made the greater increasing extent of free amino acid. Drought at elarly grain-filling stage had a little effect on amino acid content. On 7 and 14 days after anthesis, amnio acid content in leaves for each treatment was increased with increasing water stress at grain-filling stage. On 7, 14 and 21 days after anthesis, amino acid content of leaves increased first and then decreased with increasing water stress at jointing stage. On 7 and 14days after anthesis, soluble protein content was increased with increasing water stress at jointing stage. On 28 days after anthesis, soluble protein content was increased with increasing water stress at jointing stage, but decreased with increasing water stress at grain-filling stage. Results conclued from studying on effects of water regulation on wheat yield and yield factors were as follows. Any water stress at jointing and grain-filling stage could result in yield loss. Drought at jointing stage significantly affected effective panicle number and grain number per spike. Yield was more sensitve to drought at middle jointing stage, and 1000-grain weight was more sensitive to drought at middle grain-filling stage. Yield and WUE (Water Use Efficientcy) were increased with increasing irrigation amount at jointing stage, and they increased first and then decreased with increasing irrigation amount at grain-filling stage. WUE of CK treatment was higher than that of all treatments at jointing stage,but lower than that of treatments with soil relative water content more than 45% at grain-filling stage. Results conclued from studying on effects of water regulation on wheat nutritional qiality were as follows. Water stress at jointing stage and grain-filling stage was favorable to increase amino acid and protein content in grains and water stress at grain-filling stage had more obviously increase of that. High soil moisture at grain-filling stage caused a decrease of grain quality. Moderate drought stress was beneficial to increase amino acid and protein content, but serious drought had disadvantageous influence on amino acid and protein content.After comprehensive evaluation, harmony and unification of high yield, high quality and water-saving would be achieved with full irrigation at jonting stage and 45%-55%of soil relative water conten at grain-filling stage,or full irrigation at jonting stage and early grain-filling stage, and 55%-70% of soil relative water conten at later grain-filling stage.