滇Ⅰ型不育系繁殖父本花粉密度与母本异交结实的关系*

 在父母本花期相遇良好的不育系繁殖田，通过每平方毫米内父本花粉量和母本异交结实粒数的调查，利用回归分析，回归方程为Y=16.254+4.189 x，相关系数r=0.719，决定系数r²=0.517，︱r︱=0.719＞r_0.01，13=0.641。结果表明：父本花粉量与母本异交结实粒数呈极显著正相关关系，当1 mm²内父本花粉量每增加一粒，母本异交结实粒数增加4.189粒，母本结实粒数有51.70%由父本花粉量决定，随着父本花粉量减少，母本异交结实粒数也随之减少。田间温度28.0～34.4 ℃，相对湿度62%～78%范围内，父母本花时差较小，分别在10～23 min之间，对异交授粉较为有利。

Correlation between Cross Pollination and Pollen Density in CMS-D1 Multiplying Field

The correlation between the seed set of cytoplasmic male sterile (CMS) line cross pollination of Dian one (D1) type and the pollen density of male parent in multiplying field under the synchronization of two parents' heading date was investigated. The result indicated that the seed set on MS line largely depended on the pollen size of male parent in multiplying field. For that, a regressive formula, Y=16.254+4.189 x, was built, which meant that another 4.189 MS seeds were obtained with every pollen increasing in an area of 1 mm². The obviously positive relationship was also detected between the seed set rate of cross pollination and pollen density (r=0.719).In addition, some factors were also of great importance for increasing the outcrossing seed set, which included the temperature of 28~34.4 ℃, the relative humidity of 62%~78% and the blooming time difference of both parents between 10 min and 23 min.