玉米两个同源种质群体主要经济性状的遗传组成分析

用TTC法研究了玉米两个同源种质群体单株产量等十个经济性状的遗传组成,结果表明在大部分经济性状中,都有上位性效应存在。在总的遗传变异中,加性遗传分量(D)作用最大,显性遗传分量(H)次之,上位性遗传分量(I)除抽丝天数、株高、穗长外一般较小。基础群体ACO的株高、穗长、穗粗、穗行数、行粒数、单株籽粒重等以可固定的D为主,而抽丝天数、穗位高、出籽率、百粒重除D重要外,H和I的效应也有显著作用。通过三轮改良穗行选择和一轮交互轮回选择形成的衍生群体AC_4各性状的D效应继续得到积累;穗长、穗粗、穗行数、行粒数、百粒重、出粒率、单株粒重的H和I方差,在总变异中发挥重要的作用,因此,AC_4在遗传组成的总体上优于AC。

GENETIC CONSTITUTION OF MAJOR ECONOMIC CHARACTERS IN TWO HOMOGENETIC POPULATIONS OF MAIZE

The genetic constitution of 10 economic characters, such as kernel yield/plant, plant height and so on in 2 homogenetic populaions of maize, was analyzed by the TTC method. The results indicate that the epistatic effect was considerable in most of the characters; amony the overall genetic variation, that additive component (19) was the largest, that the following was dominance component (H)and that epistatic component (I)was usually small except for days to silking, plant height and ear length, in the basis population AC_0, plaint height, ear length, ear diameter, rows/ear, kernels/row and kernel weight/plant were mainly controlled by the fixable D, but H and I were also significant for days to silking, ear height, kernel productivity and 100—kernel weight except for D. In the population AC_4 derived from AC_0 through 3 cycles of improved ear—line selection and 1 cycle of reciprocal recurrent selection, the D effect was continuously accumulated for all the characters, but H and I variances still had important roles in the overall varitions for ear length, ear diameter, rows/ear, kernels/row, 100—kernel weight, kernel productivity, and kernel weight/plant. Therefore, AC_4 was generally better than AC_0 in genetic constitution.