砧用茄子种质遗传多样性分析及抗病性鉴定

Genetic Diversity Analysis and Resistance Identification of Eggplant Germplasm for Rootstock

对70份砧用茄子种质资源的19个植物学性状进行调查,通过遗传多样性分析、主成分分析和聚类分析,及青枯病、根结线虫病、黄萎病等茄子生产中3种主要土传性病害的抗性鉴定,对现有砧用茄子种质进行评价,以期为茄子砧木育种提供理论和实践依据。遗传多样性分析结果表明:19个植物学性状的变异系数介于15.90%~73.05%,平均为46.11%,遗传多样性指数介于0.325~2.008,平均为1.155,其中,单果重变异系数最高(73.05%),主茎粗的遗传多样性最丰富,指数为2.0083。主成分分析结果显示:特征值大于1的主成分有7个,累计贡献率76.55%,其中,第4主成分(植株刺因子)、第5主成分(茎粗因子)与嫁接操作便利度和植株生长势相关。聚类分析将参试种质分为3个类群:第Ⅰ类群和第Ⅲ类群全是栽培种,但主茎色、叶缘、果色、果实大小等性状差异明显;第Ⅱ类群包含4份栽培种和20份野生近缘种,主茎粗最高(20.42 mm),果实最小(平均果长3.79 cm、果粗4.60 cm、单果重73.38 g)。抗病性鉴定筛选出高抗青枯病种质22份、高抗根结线虫病种质11份、高抗黄萎病种质7份,其中,高抗青枯病和根结线虫病的种质3份(BW9、LJ-7、Ng1-052),高抗根结线虫病和黄萎病的种质4份(Ng1-003、喀西茄、蒜芥茄、水茄),这些种质可为茄子抗病育种提供抗源。最后,根据植物学性状和抗病性鉴定结果,筛选出生长旺盛、嫁接操作方便的多抗栽培种种质3份(LJ-18、Ng1-015和Ng1-013),为培育优质、多抗茄子砧木奠定基础。

To provide theoretical and practical guidance for rootstock breeding,19 botanical traits of 70 eggplant germplasm resources for rootstock were investigated in this study,followed by the genetic diversity,principal component and cluster analysis.Moreover,tests for resistance to three soil-borne diseases(bacterial wilt,root-knot nematode and Verticillium wilt)were conducted.The coefficient of variation was variable from 15.90%-73.05%with an average of 46.11%.The genetic diversity index ranged from 0.325-2.008 with an average of 1.155.The coefficient of variation of weight per fruit was the highest(73.05%),and the genetic diversity of main stem diameter was the richest with an index of 2.0083.The component analysis revealed seven principal components(eigenvalues>1)with a cumulative rate of 76.55%.The 4th and 5th principal components were related to the convenience of grafting and the growth of grafted plant.The cluster analysis suggested three groups in this collection,including GroupⅠand GroupⅢwere cultivated species,which showed obvious differences in main stem color,leaf margin,fruit color and fruit size;GroupⅡcontained four cultivated species and 20 wild germplasms,with the highest main stem diameter(20.42 mm)and the smallest fruit(the average length of 3.79 cm and diameter of 4.60 cm and weight of 73.38 g).22 eggplant germplasms were detected with high resistance to bacterial wilt,11 eggplant germplasms with high resistance to root-knot nematode and 7 eggplant germplasms with high resistance to Verticillium wilt.Three eggplant germplasms(BW9,LJ-7,Ng1-052)were highly resistant against bacterial wilt and root-knot nematode,and four eggplant germplasms(Ng1-003,Solanum khasianum C.B.Clarke,Solanum sisymbriifolium Lam.,Solanum torvum Sw.)were highly resistant against rootknot nematode and Verticillium wilt.These eggplant germplasms can be used as resistance sources for disease resistance breeding.Based on the identification of botanical traits and disease resistance,three cultivars(LJ-18,Ng1-015 and Ng1-013)showing resistant against multiple diseases and vigorous growth and convenient graft were obtained,which laid a foundation for excellent multi-resistant eggplant rootstock breeding.