The effect on yield, WUE in three genotypes of spring wheat(Triticum aestinum L.) to limited water supply

The study is a plot experiment under movable rainproof shelter. The objective was to compare the response on yield and water use efficiency( WUE) to limited water supply at different growth stages and genotypes of spring wheat, access the lowest and suitable points of soil water content for coupling grain yield and WUE, and analyzed the related eco-physiological mechanism. It was used three genotypes of spring wheat, Hongwangmai(dryland variety), Dingxi 8139 (2) (Irri. -dryland) and Yongliang 12 (Irrigation land) as the experimental materials, and made five treatments of supplying water 55 similar to 60mm at growth stage jointing, booting, grain-filling, drought, and well watered in all stages as control. The result showed that the genotypes sequence on grain yield and WUE of spring wheat to total limited water was Irri. -dryland genotype > irrigation land genotype > dryland genotype. To supply water at different growth stages, the order of yield effect was jointing > booting > grain filling to the Irrigation load genotype and Irri. -dryland genotype, grain filling and jointing > booting to the dryland genotype. Using a ratio between net photosynthesis rate(Pn) and Tr to express WUE on leaf level, the JVUE of the genotypes was a peak at 8 - 10 a.m., and a big different at 2 p.m., which was determined by non-symmetry and contrary characteristics of Pn and Tr.