梨杂种后代株型和株高的遗传分析

THE ANALYSIS OF THE HEREDITY OF TREE TYPE AND TREE HEIGHM OF PEAR SELECTIONS

从锦香梨(南果×巴梨)的自然实生后代中选出具有紧凑、矮壮等特点的紧凑型品系S_2、S_3、S_4、S_5、用它们作母本与祖代亲本巴梨回交。S_2×巴梨与S_4×巴梨的杂种后代株型(普通型、紧凑型)的实际分离符合1:1的理论分离值,S_3×巴梨与S_5×巴梨的杂种后代株型实际分离符合3:1的理论分离值,表明株型的遗传方式属于质量性状遗传。S系与巴梨杂种后代株高的遗传变异幅度大,大部分实生苗株高低于低亲和介于双亲之间,属于连续性变异,株高的遗传力小,后代株高基因占表现型的比重小,容易受环境因子的影响,表明株高的遗传方式属于数量性状遗传。

The heredity of tree type and tree height of compact pear selections, S_2, S_3, S_4 and S_5, which is the seedlings of Jin-xiang-li, was analysed. In the testcross of these selections with Bartlett the hybrid progeny sepregated into vigorous and compact trees. The sepregation ratio of these two type trees was fit to the theoretical sepregation ratio of 1:1 in the hybrid seedlings of S_2×Bartlett. and S_4×Bartlett, and the sepregation ratio in the hybrid seedlings of S_3×Bartlett and S_5×Bartlett was fit to the theoretical sepregation ratio of 3:1. It is concluded that tree type acts qualitative character inheritance and compact habit is controlled by two recessive genes.The heredity of tree height was also studied. In the hybrid progeny tre^e height expressed a highly variable region and the variation was continuous. And the proportion of genotype square-error in pytotype square-error of tree height was rather small, indicating that this character is very easily affected by environment. It is estimated that tree height acts quantative character inheretane. It is also obserrved that tree height had a tendency of getting dwarf in hybrid progenies.