群体密度对提型杂种小麦产量性状及其杂种优势的影响

The Effects of Population Density on the Yield Characters and Their Heterosis in Hybrid Wheat with TIMOPHEEVI Cytoplasmic Male Sterility

本文研究了群体密度对提型杂种小麦产量性状及其杂种优势的影响.结果表明:各性状在密度间都存在着显著差异.单株穗数、穗粒数和千粒重随密度增加而下降,籽粒产量与密度呈二次抛物线关系.平均穗粒数和单株穗数的杂种优势在产量杂种优势形成中的直接作用是低密度高于高密度;千粒重的杂种优势在产量杂种优势形成中的直接作用是低密度低于高密度;通过对杂种小麦产量及杂种优势标准化联立方程组求解和对产量回归方程求导的方法,确定了杂种小麦的适宜密度范围为每亩8.5～13万株,最后提出了适当降低杂种小麦密度应采取的栽培措施.

The effects of the population density on the yield characters and their heterosis in four T-type hybrid wheats were studied. The results indicated that all characters existed significant differences among densities. The number of ears per plant, the number of kernels per ear and 1000-kernel weight decreased as density increased. Grain yield and density showed a quadratic parabola relationship. The direct effects of heterosis of average number of kernels per ear and number of ears per plant were higher in the lower density than in the higher density, while that of 1000-kernel weight was lower in the lower density than in the higher density in the formation of heterosis of yield. The aptimum range of population density in hybrid wheat is found to be 85-130 thousands plants/mu, which was determined by solving the simultaneous standardized equations of the yield and its heterosis and also by finding the derivative of the yield regression equations. Adopted cultivating measures were suggested when the population density of hybrid wheat was decreased appropriately.