烟草青枯病抗性突变体486-K和117-K的遗传分析

烟草青枯病是一种典型的维管束细菌性病害，严重影响我国烟叶生产。为了解烟草青枯病抗性突变体的遗传规律和开发抗性相关分子标记，本研究选用EMS诱变烤烟品种翠碧一号获得的烟草青枯病抗性突变体486-K和117-K为研究对象，以翠碧一号和2个突变体为亲本，构建了两个不同的杂交组合，采用卡方检验和植物数量性状"主基因+多基因"混合遗传模型分析方法，进行群体遗传效应分析。结果表明，卡方检验显示突变体486-K和117-K的F2代各病级株数呈正态分布，存在一定性状分离。"主基因+多基因"混合模型分析发现突变体117-K的最优抗性遗传模型为2MG-A，即2对主基因为加性效应控制遗传，无显性效应和上位性效应，主基因的遗传效率为78.57%；突变体486-K的最优抗性遗传模型为2MG-ADI，即2对加性-显性-上位性主基因模型，上位性效应中以显性×显性互作和显性×加性互作效应较大，主基因遗传效率为88.34%。表明烟草青枯病抗性突变体的遗传方式以主基因效应为主，受环境影响较小。

Genetic Analysis of Bacterial Wilt Resistance Mutants 486-K and 117-K in Tobacco

Tobacco bacterial wilt is a typical vascular bundle bacterial disease that seriously affects tobacco production in China.In order to understand the genetic basis of tobacco bacterial wilt resistance mutants and develop molecular markers related to resistance,and to provide theoretical basis for breeding high quality resistant varieties,in this study,tobacco bacterial wilt resistance mutants 486-K and 117-K obtained by EMS mutagenesis of flue-cured tobacco variety Cuibi 1 were selected as research objects,and Cubi 1 and the two mutants were used as parents to construct two different hybrid combinations.The analysis method of population genetic effect was carried out by using the analysis method of Chi-square test and"major-gene+polygene"mixed genetic model of plant quantitative traits.The results showed that,based on the Chi-square test,the number of disease-level strains of F2 generation of mutants 486-K and 117-K showed a normal distribution,and showed some trait separation.Analysis of the"major-gene+polygene"mixed model showed that 2MG-A was the optimal genetic model for resistance in mutant 117-K,with two pairs of major genes showing additive effects without dominant or epistatic effect,and the genetic efficiency of major genes being 78.57%.The optimal resistance genetic model for mutant 486-K was 2MG-ADI,or the two pairs of additive-dominant-epigenetic master gene model.Among the epistatic effects,the dominant×dominant interaction and dominant×additive interaction effects were larger,and the genetic efficiency of the main genes was 88.34%.It was indicated that the inheritance of tobacco bacterial wilt resistance mutants was dominated by main gene effect and less affected by the environment.