Study On The Physiological Basis Of High-yield And Super-high-yield Spring Wheat

The photosynthesis proper,dry matter accumulation, dynamic of tiller and young ear,absorption and accumulation of N,P K and character of grain-filling,yield formation of two tested spring wheat varieties yongliang4 and mengmai28 were systematically studied. The result show that the spring wheat yield over 7500kg/ha, the maximum leaf area index (LAI) should be over 6 at booting stage and decreased slowly during late growing and developing period , remaining about 3 at milk stage.The total leaf area duration (LAD) of whole growth stage is 150000-160000 m2d.The group photosynthesis rate is 18-22 p mol C02/m2.s.The N application at late growth stage can increase grain-rate of young spike and young flower, increase the number of grain. Comparing to high-yield cultivation, absorption of N,P,K of super high-yield cultivation increased obviously. The amount of increasing K>N>P.The absorptive ratio of N,P205,K20 of yongliang4 is 2.61:1:3.11,mengmai28 is 2.46:1:3.11, the absorptive amount per hundred kilogram of yongliang4 is N 3.58kg,P2051.34kg K204.Olkg, mengmai28isN3.6Skg,P2051.38kg, K20 4.0 lkg.Under super-high yield cultivation, the process of grain-wheat increasing can be divided three stages ,the second stage is most important for grain wheat.In yield formation , more main-stem spike or middle main-stern spike and less tiller spike all can get super-high yield (7500kg/ha).