甘蓝型油菜含油量的主基因+多基因遗传分析

Major Gene Plus Polygene Inheritance of Oil Content in Brassica napus L.

应用植物数量性状主基因＋多基因混合遗传模型多世代联合分析方法，研究了甘蓝型油菜1064—3×H105（组合I）和1064-4×H134（组合Ⅱ）的P1、P2、F1、B2、B2和F2 6个世代含油量的遗传。含油量次数分布显示2个组合的B1、B2和F2群体均呈连续分布且显示多峰，呈明显的主基因＋多基因遗传的特征。遗传分析结果表明：2个组合的最佳遗传模型均为D-2模型，即一对加性主基因＋加一显性多基因混合模型。2个组合中，广义遗传率为47．87％～65．13％，平均为53．70％；而环境变异占表型变异的34．87％-52．13％，平均为46．30％，可见油菜含油量性状受基因型和环境双重影响。2个组合中，多基因遗传率为15．22％-60．41％，平均为45．32％；而主基因遗传率为2．26％一33．10％，平均为8．38％，表明含油量的遗传体系中，微效多基因的遗传贡献占主要部分，高含油量育种应在高世代进行选择。

The joint segregation analysis of a mixed genetic model of major gene plus polygene was used to study the inheritance of oil content in Brassica napus L.. Six generations populations, i. e P1, P2, F1, B1, B2 and F2, from each of the two crosses of 1064-3 × H105 （ cross Ⅰ ） and 1064-4 × H134 （ cross Ⅱ ） were investigated. The frequency distributions of oil content in B1, B2 and F2 populations showed characteristics of a mixed normal distribution, which indicated that the inheritance of oil content followed a major gene plus polygene model. The results of joint segregation analysis showed that oil content in oilseed rape was controlled by one additive major gene plus additive and dominance polygenes （D-2 model） in the two crosses. The environmental variance and the genetic variance accounted for 46. 30% and 53.70% of the phenotypic variance in two crosses,respectively. It indicated that the environmental factors have a great effect on lodging in B. napus 2 L.. On average ,the hereditability of major gene （ hmg^2 ） and polygenes （ hpg^2 ） in all population of two crosses were 8.38% and 45.32% ,respectively. The heritability of the polygene was higher than that of major gene. It indicated that the oil con- tent in B. napus L. was dominated by polygenes, so it would be more efficient to conduct selection in high generation for high oil content breeding.