甜瓜果实风味相关性状QTL定位分析

QTL Mapping Analysis of Fruit Flavor-related Traits in Melon

为了研究甜瓜风味相关基因的遗传定位,以高糖、哈密瓜风味品种‘皇后’和低糖、清香风味品种‘NS6’为亲本构建F2群体,通过筛选亲本间有多态性的简单重复序列(simple sequence repeats,SSR)标记,检测F2群体的个体基因型并构建甜瓜遗传图谱,对糖度和香味性状的数量性状位点(quantitative trait locus,QTL)进行定位分析。构建的遗传图谱包含8个连锁群,总长度576 cM,标记间的平均遗传距离10.97 cM。通过QTL分析、表型和基因型差异显著性检验,在LG5上发现一个与糖度性状相关的QTL(LOD=2.1),但未发现主效QTL;在LG12上发现一个与香味性状相关的主效QTL(LOD=2.9)。在LG12上设计15对SSR引物,利用7个在亲本间有多态性的标记构建LG12的遗传连锁图,进一步将香味相关基因定位于EMAGN33标记的下方,与染色体末端的物理距离为592.48 kb。本研究为甜瓜风味相关基因的定位克隆及风味品种改良提供理论依据。

In order to study the genetic mapping of melon flavor related genes,this study took the high sugar and cantaloupe flavor cultivar'Queen'and low sugar and fen-flavor cultivar'NS6'as parents to construct in F_2 population,the quantitative trait loci(QTLs)of sugar content and fragrance traits were located by screening polymorphic simple sequence repeats(SSR)markers between the parents,detecting individual genotypes of F_2 populations and constructing a melon genetic map.The constructed genetic map consists of 8 linkage groups with a total length of576 cM and the average genetic distance of 10.97 cM between markers.QTL analysis and phenotypic and genotypic significance tests showed that a QTL related to sugar content traits was found on LG5(LOD=2.1),but not major QTL was found;a major QTL related to fragrance traits was found on LG12(LOD=2.9).We designed fifteen pairs of SSR primers on LG12,and constructed the genetic linkage map of LG12 using 7 polymorphism markers between the parents,the result showed that the gene related to fragrance traits was located below the EMAGN33 marker,with a physical distance of 592.48 kb from the end of the chromosome.This study provides a theoretical basis for locating and cloning of genes related to flavor traits and improvement of melon flavor cultivars.