[Dynamic characteristics of leaf area index and allocation characters of ecological resources for different yielding spring maize populations].

By using 3-year field experimental results and related meteorological observation data, the dynamic characteristics of leaf area index (LAI) and the allocation characters of ecological resources for different yielding spring maize (Zea Mays L.) population in Huadian of Jilin Province were studied. The results showed that the dynamic characteristics of relative LAI, with the relative growth days of test population, relative effective accumulated temperature, relative sunshine hours and relative rainfall as independent variables, fitted rational formula y = (a + bx) /(1 + cx + dx2), and the regression equation of maize yield with the ratios of growth days before and after silking (x1), effective accumulated temperature before and after silking (x2), rainfall before and after silking (x3), and sunshine hours before and after silking (x4) was y = 5465.19 + 17810.64x(1) - 23236.14x(2) + 4093.41x(3) + 6287.37x(4) (R2 = 0. 8187, P < 0.01), with the effects of these ecological factors on yield being in the sequence of x1 > x2 > x3 > x4 according to the absolute values of partial regression coefficients. In super high yielding (15499.86 kg x hm(-2)) spring maize population, the allocation ratios of x1, x2, x3, and x4 were 1.43, 1.41, 1.44, and 1.40, respectively. Therefore, in Northeast China, appropriate early sowing of spring maize to prolong its growth days with more rainfall and sunshine hours before silking could attain high yielding, and high or super high yield could be achieved when the allocation ratios of x1, x2, x3, and x4 were all about 1.4.