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甜瓜(Cucumis melo)果实外观性状是重要的农艺性状,发掘影响甜瓜果实性状变异的基因(位点)是对果实外观品质进行遗传改良的基础。为此,本研究利用在甜瓜染色体上均匀分布的104个SSR,对甜瓜核心种质进行基因型鉴定,并对2013~2015年连续3年间的5个果实性状进行全基因组关联分析(genome-wide association study,GWAS)。结果表明,在甜瓜核心种质中共检测到456个等位基因,标记的多态性信息含量(polymorphism information content,PIC)为0.12~0.89,平均PIC为0.51。核心种质的遗传多样性较丰富,5个果实性状的多样性指数(Shannon Wiener index,H′)均高于2.0。基于贝叶斯模型可将核心种质分为2个亚群,亚群的划分与甜瓜亚种分类一致。利用GWAS在3个环境下共检测到42个极显著关联位点(P<0.01),4个位点(HNM36、DM0035、HNM38和DM0767)在3年间重复出现,21个位点在2年间重复出现,一些稳定表达的位点与前人连锁分析结果的一致性较高。与果纵径(fruit length,FL)、果横径(fruit diameter,FD)、果形指数(fruit shape index,FS)、果肉厚度(flesh thickness,FT)和单果鲜重(fruit fresh weight,FW)相关位点数分别有10、5、9、8和10个,具有最大表型解释率的位点分别为HNM36、HNM16、CMCCA145、HNM31和HNM31。研究结果为甜瓜果实性状QTL精细定位、候选基因发掘和分子标记开发提供基础。
Appearance traits of melon (Cucumis melo) are important agronomic traits. To explore the genes (loci) that affect the variation of fruit traits in melon is the basis of genetic improvement of the appearance quality of fruits. In this study, 104 SSRs evenly distributed on Muskmelon chromosomes were used to identify the core collection of Muskmelon, and genome-wide analysis was carried out on 5 fruit traits for three consecutive years from 2013 to 2015 (genome-wide association study, GWAS). The results showed that 456 alleles were detected in core collection of melon, the polymorphism information content (PIC) was 0.12-0.89, and the average PIC was 0.51. The core diversity was rich in genetic diversity, and the Shannon Wiener index (H ’) of all five fruit traits was higher than 2.0. Based on the Bayesian model, the core germplasm can be divided into two subgroups. The subgroups are classified according to the classification of the muskmelon subspecies. Forty-two loci (P <0.01) were detected by GWAS in three environments. Four loci (HNM36, DM0035, HNM38 and DM0767) repeatedly appeared in three years and 21 loci were repeated in two years Appeared, some of the stable expression of the site and the previous analysis of the results of a higher linkage. The fruit length (FL), fruit diameter (FD), fruit shape index (FS), flesh thickness (FT) and fruit fresh weight ) Were 10,5,9,8 and 10, respectively. The loci with the largest phenotypic interpretation rate were HNM36, HNM16, CMCCA145, HNM31 and HNM31, respectively. The results provided the basis for fine QTL mapping of melon fruit traits, development of candidate genes and development of molecular markers.