基于SRAP分子标记的51份西瓜抗、感病毒病种质资源遗传多样性分析

Genetic diversity analysis of 51 antivirus and susceptible germplasm resources of watermelon by SRAP molecular markers

  • 摘要: 【目的】利用SRAP分子标记对51份西瓜抗、感病毒病种质资源遗传多样性分析,为加速西瓜抗病毒病新品种的选育进程提供理论参考。【方法】利用筛选出的多态性引物对51份抗、感病毒病西瓜种质进行多态性扩增,利用NTsys-pc 2.1e中的非加权组平均法(UPGMA)计算获得遗传相似系数,利用PopGene Version 3.2计算不同类型西瓜的遗传多样性参数。【结果】从500对SRAP引物组合中筛选出18对扩增条带清晰稳定且多态性较高的引物,共扩增出402条清晰可辨的条带,其中多态性条带271条;平均每对引物可扩增出稳定清晰的条带22.33条,其中多态性条带15.06条,平均多态性比率达67.41%。观测等位基因数(Na)为1.6766、有效等位基因数(Ne)为1.3033、Nei’s基因多样性指数(H)为0.1878、Shannon’s信息指数(I)为0.2931,除感病毒型西瓜种质的Na高于抗病毒型西瓜种质外,感病毒型西瓜种质的其他遗传多样性指数均低于抗病毒型西瓜种质,表明抗病毒型西瓜种质的遗传多样性较感病毒型西瓜种质丰富。抗病毒型与感病毒型西瓜种质的遗传一致度为0.8924,遗传距离为0.1138。供试西瓜种质的遗传相似系数为0.62~0.95。在遗传相似系数0.78处,可将51份供试西瓜种质划分为四大类群,抗病毒型西瓜种质分布在Ⅰ和Ⅱ类群中,感病型种质均集中在第Ⅲ、Ⅳ类群中,野生西瓜种质与其他西瓜种质的亲缘关系最远。遗传相似系数矩阵和UPGMA聚类矩阵之间的相关性明显(r=0.914),可准确地体现供试西瓜种质之间的遗传关系。【结论】筛选出的SRAP引物组合具有较好的品种鉴别能力,可用于西瓜种质的遗传多样性分析。抗病毒型与感病毒型西瓜种质的亲缘关系较近,遗传多样性丰富度不高,应加大发掘优良抗病种质资源力度,以拓宽西瓜的遗传基础。

     

    Abstract: 【Objective】To provide theoretical referencefor acceleratingthe breeding process of antivirus varieties of watermelon, the genetic diversity of 51 germplasm resources of antivirus watermelon were analyzed by SRAP molecular markers.【Method】The polymorphic primers were selected to amplify 51 antivirus and susceptible germplasm resources of watermelon.The genetic similarity coefficients were calculated by unweighted pair group method with arithmetic average(UPGMA) by NTsys-pc 2.1e. Genetic diversity parameters of different types of watermelon were calculated by PopGene Version 3.2.【Result】Eighteenpairs of primers with clear and stable bands and high amplified polymorphism were selected from 500 pairs of SRAP primers, and a total of 402 clearly identifiable bands were amplified, among which 271 were polymorphic bands. And 22.33 stable and clear bands were amplified on average with each pair of primers, including 15.06 polymorphic bands, with an average polymorphism rate of 67.41%. The observed number of alleles(Na) was 1.6766, the effective number of alleles(Ne) was 1.3033, the diversity index of Nei's gene(H) was 0.1878, and the Shannon's information index(I) was 0.2931. Except the Na of susceptible watermelon germplasmswas higher than that of antivirus watermelon germplasms, the other genetic diversity indexes of antivirus watermelon germplasms was higher than that of susceptible watermelon germplasms. The results showed that the genetic diversity of antivirus watermelon germplasms was higher than that of virus susceptible watermelon germplasms. The genetic consistency and genetic distance of the virus resistant and susceptible watermelon germplasms were 0.8924 and 0.1138 respectively. The genetic similarity coefficients of the experimental watermelon germplasms were between 0.62-0.95. With the genetic similarity coefficient of 0.78 as the boundary, 51 watermelon germplasms were divided into four groups. Antiviral type of watermelon germplasms were in groupsⅠ and Ⅱ, and virus susceptible type of watermelon germplasms were concentrated in groups Ⅲ and Ⅳ, and wild watermelon materials and other watermelon varieties showed the most distantly related.The correlation between the genetic similarity coefficient matrix and the UPGMA clustering matrix was obvious(r=0.914), which accurately reflected the genetic relationship among the watermelon germplasms.【Conclusion】The selected SRAP primer combinations have good ability of variety identification and can be used for the analysis of watermelon germplasm genetic diversity. The germplasm of antivirus and virus susceptible type are closely related, so the genetic diversity is not high. Excellent disease-resistant germplasms should be explored to broaden the genetic base of watermelon.

     

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