西瓜种子外观性状遗传多样性及全基因组关联分析

Genetic Diversity and Genome-wide Association Analysis of Appearance Traits of Watermelon Seed

本研究选用144份不同西瓜(Citrullus lanatus L.)种质资源作为材料,调查西瓜种子外观性状,包括种皮颜色、种皮斑块、种皮裂刻、种脐斑和种子喙形状等表型数据,进行遗传多样性及全基因组关联分析。遗传多样性分析结果表明,在144份西瓜种质资源中种皮颜色分为8种类型,分别为绿色、褐色、黑色、红色、棕色、白色、黄色和斑驳,多样性指数为1.66,其中黑色占比最多,为31.25%,绿色占比最少,为0.69%;种皮斑块的多样性指数为0.15,其中无斑块种子占96.53%;种皮裂刻的多样性指数为0.21,表面无裂刻的占94.44%;种脐斑的多样性指数为0.63,其中种子无种脐斑的占67.36%;种子喙形状的多样性指数为0.19,其中圆喙种子占95.14%。通过全基因组关联分析,检测到1个与种皮颜色相关的数量性状基因座(quantitative trait locus,QTL),位于10号染色体上;5个与种皮斑块相关的QTL,分别位于2号、6号、7号、10号和11号染色体上;6个与种皮裂刻相关的QTL,分别位于1号、3号、4号、6号、7号和11号染色体上。研究结果为进一步开展西瓜种子外观性状相关基因克隆、功能分析及调控机理的研究提供理论基础。

In this study,144 watermelon germplasms were selected to be used as materials to investigate the appearance traits of watermelon seed,including the phenotypic data of seed coat color,seed coat spots,seed with crack,patches at hilum and shape of seed beak,then to perform genetic diversity and genome-wide association analysis.The genetic diversity analysis results showed that the seed coat color was divided into 8 types,including green,tan,black,red,tan,white,yellow,and mottled,the diversity index was 1.66,the black seed was the most common,accounting for 31.25%,and the green seed was the least,accounting for 0.69%;the diversity index of seed coat spots was 0.15,the seed without spots accounted for 96.53%;the diversity index of seed with crack was 0.21,the seed without crack accounted for 94.44%;the diversity index of patches at hilum was 0.63,the seed without patches at hilum accounted for 67.36%;the diversity index of shape of seed beak was 0.19,the seed with round seed beak accounted for 95.14%.According to the genome-wide association analysis,1 QTL(quantitative trait locus)related to the seed coat color was detected,located on chromosome 10;5 QTL related to seed coat spots,located on chromosomes 2,6,7,10 and 11,respectively;and 6 QTL related to seed with crack were located on chromosomes 1,3,4,6,7 and 11,respectively.The results will lay a theoretical foundation for further study on cloning,functional analysis and regulation mechanism of watermelon seed appearance related genes.