Malus asiatica×M.domestica种间杂种苹果斑点落叶病感病性的QTL定位

Mapping quantitative trait loci associated with Alternaria leaf blotch susceptibility in a Malus asiatica×M.domestica interspecific population

为进一步研究苹果斑点落叶病感病性遗传规律,采用1株苹果斑点落叶病菌株对‘紫塞明珠’ב富士’(Malus asiatica×M.domestica)的1 071株杂交实生树的离体叶片进行斑点落叶病的接种鉴定,将表型数据结合本实验室之前构建的遗传连锁图谱及基因型数据,进行QTL区间作图分析。采用Regression和Mixture model 2种算法共得到与苹果斑点落叶病感病性相关的QTL位点18个,分布在LG07、LG08、LG09、LG12和LG17等5个连锁群上。Mixture model算法与Regression算法所得微效QTL位点重叠或完全重合。Regression算法未能定位到主效QTL位点,而Mixture model算法在发病率和严重度2个感病指标均检测到2个主效QTL位点。发病率与病情指数性状的遗传控制基本相同,严重度则表现为相对独立性状。

This paper focused on understanding the susceptibility inheritance rule of Alternarialeaf blotch.One strain of A.mali was inoculated on the detached leaves of 1 071 seedlings of M.asiatica‘Zisai pearl'× M.domestica‘Red Fuji'and then measured the infection rate,disease severity,disease index.Interval mapping of QTL were processed with the phenotypic data,the genetic map of the population and parental genotype data.The 18 QTLs related to the susceptibility of Malus domestica to Alternaria leaf blotch were mapped with both regression algorithm and mixture model algorithm.They were located in LG07LG08LG09LG12 and LG17.The minor QTLs mapped within regression were totally or partially overlapped with those by mixture model.Regression algorithm did not give the major QTLs.However,two major QTLs were mapped with the mixture model algorithm in infection rate and disease severity.There were some similarities and differences between the outcomes of regression algorithm and mixture model algorithm.In general,the mixture model algorithm was more comprehensive and precise than regression algorithm.The genetic control of infection rate was fundamentally same as that of disease index,while disease severity was independent.