基于QTL定位分析策略的一般配合力遗传基础研究

Study on the Genetic Basis of General Combining Ability with QTL Mapping Strategy

【目的】一般配合力(GCA)是评价亲本利用价值的重要指标。研究GCA的遗传基础及GCA相关QTL(QTLGCA)定位的可行性,为杂交育种提供技术参考。【方法】以双亲杂交衍生的重组自交系(RIL)为被测系、若干个随机选择的纯系为测验系的NCII交配设计以及QTL定位策略,系统研究GCA的遗传组成、影响QTLGCA定位的因素以及QTLGCA与性状本身QTL之间的关系。【结果】若性状受1对等位基因控制,RIL的GCA以及QTLGCA定位均与控制性状本身基因位点的加性效应、显性效应以及测验系等位基因的频率有关;若性状受2对加/显性的等位基因控制,则GCA估计及QTLGCA定位均与基因间是否连锁无关,其影响因素与性状受一个基因控制时相同;若性状受2对互作基因控制,GCA及QTLGCA定位均与测验系等位基因频率和性状本身QTL的主效应以及基因间互作效应有关,此外,GCA效应估计还与基因间是否连锁有关。【结论】无论是GCA效应估计还是QTLGCA定位,测验系等位基因频率和性状本身QTL效应大小都是重要的影响因素。此外,QTLGCA与性状本身QTL的差异还取决于性状的遗传结构以及QTL定位方法的选择。

【Objective】 General combining ability （GCA） is an important indicator for assessing parents. Studying the genetic basis of GCA and the feasibility of mapping QTL related with GCA （QTL GCA ） may provide a foundation in breeding. 【Method】 A NCII mating design, where a set of recombinant inbred lines （RIL） derived from two pure lines was used as the tested lines and several randomly selected pure lines were used as testers, and QTL mapping strategy was applied to investigate the genetic component of GCA, the impact factors for QTL GCA mapping and the relationship between QTL GCA and QTL controlling trait per se. 【Result】 Results indicated that when a trait was controlled by one pair of alleles, the GCA effect estimate of RIL and QTL GCA mapping were all associated with additive effect, dominant effect of QTL controlling trait per se and the alleles frequency in testers. When a trait was controlled by two pairs of additive/dominance alleles, the GCA effect estimate of RIL and QTL GCA mapping did not associate with whether the linkage between genes or not, and the impact factors of GCA estimate and QTL GCA mapping were the same as that in one pair of alleles. When a trait was controlled by two pairs of interactive alleles, both GCA estimate and QTL GCA mapping were all associated with the alleles frequency in testers, the major effect of QTL controlling trait and interactive effect between QTL. In addition, GCA estimate was also influenced by the recombination rate between loci. 【Conclusion】 The allele frequency in testers and relative size of effects of QTL controlling trait per se were important factors not only to GCA estimation but also to QTL GCA mapping, and the difference between QTL GCA mapping and QTL mapping also depended on the genetic architecture of quantitative traits and analyzsis method of mapping QTL.