玉米雄穗主轴长度和分枝数的主基因+多基因遗传分析

GENETIC ANALYSIS OF BRANCH NUMBER AND SPINDLE LENGTH OF MAIZE TASSEL BY MAJOR GENES PLUS POLYGENES MODEL

以PH4CV/昌7-2(组合Ⅰ)和PH6WC/7873(组合Ⅱ)的P1、P2、F1、F2、B1和B2六世代群体为材料,用主基因+多基因六世代联合分离分析方法,研究了春播和夏播环境下雄穗主轴长度和雄穗分枝数的遗传规律。结果表明:2个组合雄穗主轴长在春播环境下均符合E-1模型。夏播环境下,组合Ⅰ雄穗主轴长符合C-0模型,组合Ⅱ雄穗主轴长符合E-3模型。在2个环境下,组合Ⅰ的雄穗分支数符合D-2模型,组合Ⅱ的雄穗分支数符合D-3模型。春播环境下,组合Ⅰ雄穗分支数表现为主基因遗传或以主基因遗传为主,主基因和多基因对2个组合雄穗主轴长的影响相当,可以采用单交重组或简单回交转育进行改良。夏播环境下,2个组合雄穗主轴长和组合Ⅱ雄穗分支数表现为多基因遗传或以多基因遗传为主,可以采用聚合回交或轮回选择累积增效基因的方法,以提高育种效率。

The joint segregation analysis of major genes plus polygenes mixed inheritance model was conducted to study the genetics of branch number and spindle length of maize tassel. The 6 generations （P1, P2, F1, B1, B2, and F2） of 2 crosses, PH4CV/Chang 7 -2 （cross Ⅰ） and PH6WC/7873 （cross Ⅱ）, were grown in spring and summer seasons. Results suggested that in spring sowing environment, the branch number of tassel could be explained by genetic model E-l in both 2 crosses. In summer season, the optimal model was C-0 for cross Ⅰ, and E-3 for cross Ⅱ. In both environments, the spindle length of tassel was governed by model D-2 in cross Ⅰ, but by model D-3 in cross Ⅱ. In spring season, branch number of tassel in two crosses were controlled or mainly controlled by major genes. The effect of major genes on spindle length of tassel was equal to that of polygenes. In order to improve the efficiency of maize breeding, single cross or simple backcross could be adopted. In summer season, spindle length of tassel in two crosses and branch number of tassel in cross Ⅱ were controlled or mainly controlled by major genes. In order to improve the efficiency of maize breeding, repeated backcross or recurrent selection to cumulate positive alleles could be adopted.