辣椒单果种子数的遗传分析

摘要

Selection of two capsicum hybridization combinations to build each six-generation populations,name-ly,F1 ,F2 ,backcrosses B1 and B2 and their parents P1 and P2 ,whose seed number per fruit of Simudou were counted to study its genetic law. The results showed that seed number per fruit of isolated populations of two crosses dis-played quantitatively genetic characteristics with multimodal or unimodal skewed distribution. Multigenerational joint segregation analysis indicated the heritance of seed number per fruit fitted the pattern of two additive-dominance-e-pitasis major genes(B-1 model). Genetic analysis of the 1st-order parameters showed that in two crosses there were almost the opposite performance in effects of additive,dominant,and additive × additive,exception of some similarity of epistatic interaction between the two loci in effects of additive × dominant,dominant × dominant. In addition,po-tential ratio comparison showed that the 1st and 2nd main genes were each expressed as negative,positive overdomi-nant effect in the performance in crossⅠ,and positive and negative overdominance in crossⅡ,and integrated domi-nant effects partially offset between two loci. Genetic analysis of the 2nd-order parameters showed that in crossⅠtwo major gene QTLs determining seed number per fruit of capsicum were concentrated in parent 1110B,but in crossⅡwere distributed in both parents,furthermore,the major gene heritability of F2 populations was 61. 84% in crossⅠand 37. 30% in crossⅡ,which indicated the seed number per fruit was dissimilar in different pepper germplasms, and suggested artificial selection of seed number per fruit should be performed at higher separated generations.%选用2个辣椒杂交组合构建6世代群体( P1、P2、F1、B1、B2和F2),对各世代四母斗果实的单果种子数进行计数,研究其遗传规律,结果表明：2个杂交组合的分离群体单果种子数表现多峰或单峰偏态分布,呈现数量遗传特征；多世代联合分离分析表明,辣椒单果种子数遗传模式符合2对加性-显性-上位性主基因遗传模型(B-1模型)。一阶遗传参数分析表明,2个组合中除了两基因间加性×显性、显性×显性互作等上位效应相似外,其加性、显性、加性×加性效应表现几乎相反；势能比值比较表明,组合Ⅰ中第1、2对主基因分别表现为负、正向超显作用,组合Ⅱ中则表现为正、负向超显作用；同一组合中2基因座间综合显性效应有部分抵消。二阶遗传参数分析表明,组合Ⅰ中控制辣椒单果种子数的2对主基因QTL比较集中在1110B材料中,组合Ⅱ则在2个亲本材料中都有分布。同时组合Ⅰ、Ⅱ的F2群体主基因遗传率分别为61.84%和37.30%,说明辣椒单果种子数因种质材料不同有差异,育种中对单果种子数的遗传选择应在分离的较高世代进行。