Effects On Yield And Inheritance Of Canopy Structure Of Super-High-Yielding Winter Wheat Cultivars

This paper studied the yield structure patterns, effect on yield and inheritance of canopy structure of super-high-yielding winter wheat cultivars in Huang-Huai winter wheat region. The results showed that: (1)for many-ears variety the number of ears per hectare, the number of kernels per ear and 1000-kernels weight should be harmonized to achieve super high yield; Under enough number of ears per hectare, the number of kernels per ear and 1000-kernels weight should be increased. The optimum yield structure was 680.6 ears/m2, 38. 16 kernels/ear, 40.34g/1000-kemels. For big-ears variety, key was increasing the number of kernels per ear and 1000-kernels weight to achieve super high yield. The optimum yield structure was 467.6 ears/m2, 49.73 kernels/ear, 49. 38g/1000-kemels.(2)Compared with general varieties, super-high-yielding varieties had more bio-yield per plant, grain weight per plant, harvest index, number of ears per plant, and their leaf laminas were narrower and their dropiness were smaller, and their stem walls were thicker and their ears were longer.(3) Double stepwise regression results indicated that48there were 16 major characters to influence yield and its components. According data mentioned, super regressive equations were established. Ideal canopy structure of super -high-yielding wheat varieties with different yield levels were simulated with Monte-Carlo method.(4)The correlation between the canopy characters and yield with its components were studied by the canonical correlation analysis . Results showed that yield was significantly correlated with its components and the plant characteristics; The number of kernels/ear, the number of ears/plant and population exited bigger effects on yield. The weight of dry substance and the plant height in plant characterstics exited bigger effect on yield. The length of leaf was signifficantly correlated with yield; The effect of length of top 3rd leaf was the bigest on the plot yield; The effects of 3 leaves on the grain yield per plant were similar ; The yield components were signifficantly canonical correlated with canopy characteristics. The stem diameter was signifficantly correlated with stem wall thickness and length between knots. In canony leaf characters, every two groups exited signifficant correlation.(5)Using K.Mather's genetic model , six sets of winter wheat genetic materials with P1, P2, B1, B2, F1 and F2were used to estimate the gene effects of stem and leaf of canopy in common wheat. The results indicated there were 1~3 types49of epistasis for all characters of stem and leaf of canopy and many gene models. Their genetic mechanisms were more complicated.(6)Heritability of all characters of stem and leaf of canopy were stronger. With dropping of the leaf position , genetic variation coeffients decreased.