太空搭载膜荚黄芪SP_(2)代2年生群体遗传变异分析

Genetic Variation of SP_(2) Biennial Population from Astragalus membranaceus Seeds Carried in Space

目的:探寻创造多年生膜荚黄芪优异种质的途径,筛选新品种选育的优异变异群体。方法:将其种子搭载“神舟十一号”和“长征七号”,在太空分别历时33 d和22 h,统计分析SP_(2)代2年生群体表型性状,用简单重复序列(SSR)分子标记技术对其遗传多样性进行分析。结果:33 d、22 h和对照(CK)群体表型性状的平均变异系数分别为29.37%、26.17%和26.10%,平均遗传多样性指数分别为1.27、1.22和1.24,在欧氏距离5处,33 d有5类群、22 h有6类群、CK有3类群。SSR标记的8对有效引物扩增显示,33 d、22 h和CK群体平均每对引物的多态信息值分别为0.320、0.427和0.333,遗传距离变幅分别为0~0.8959、0.0270~0.9435和0~0.8959,遗传相似系数分别为0.4000~1.0000、0.3846~0.9730和0.4000~1.0000,在遗传相似系数为0.68时,33 d和CK群体均归为4类群,22 h归为5类群。尽管表型和分子聚类结果有一定差异,但各群体均以株高、株幅、茎粗、复叶数、茎色和花色为主要类群性状。结论:以太空搭载膜荚黄芪种子为研究对象所建立的SP_(2)代2年生群体后代遗传多样性丰富,是新品种选育的优异变异群体。

Objective:To explore the premium germplasm of perennial Astragalus membranaceus and screen the population with genetic variation for the breeding of new varieties.Methods:The seeds of A.membranaceus were carried on"Shenzhou 11"and"Long March-7"for 33 days and 22 hours respectively.The phenotypic traits of its SP_(2)biennial population were statistically analyzed,and the genetic diversity was analyzed by SSR technology.Results:The mean coefficients of variation(CV)of phenotypic traits of 33 d,22 h,and CK populations were 29.37%,26.17%,and 26.10%,respectively,with the mean genetic diversity indexes of 1.27,1.22,and 1.24,respectively.At Euclidean distance of 5,there were five taxa at 33 d,six taxa at 22 h,and three taxa at CK.The amplification of SSR-marked eight pairs of effective primers showed that the average polymorphism information content(PIC)value of each primer pair was 0.320,0.427,and0.333 in 33 d,22 h,and CK populations,and the genetic distance variances ranged from 0-0.8959,0.0270-0.9435,and 0-0.8959,respectively.Additionally,the genetic similarity coefficients ranged from 0.4000-1.0000,0.3846-0.9730,and0.4000-1.0000,respectively.Both 33 d and CK populations were classified into four taxa and 22 h into five taxa when the similarity coefficient was 0.68.In spite of some differences between phenotypic and molecular clustering results,plant height,plant width,stem thickness,number of compound leaves,stem color,and flower color were considered as the main group traits of all populations.Conclusion:The offspring of SP_(2)biennial population of A.membranaceus seeds carried in space is rich in genetic diversity,which is a premium population with genetic variation for the breeding of new varieties.