以多叶苜蓿为轮回亲本、以淮阴苜蓿为父本,构建回交群体,通过回交育种获得符合需求的育种材料.对回交一代(BC1)群体的农艺性状与杂交F1群体进行农艺性状遗传多样性分析,并从分子水平进行遗传多样性和群体结构分析.结果表明:BC1群体的农艺性状较F1群体更接近亲本性状,且性状多样性丰富.25对SSR分子标记共检测到148个等位变异,25对引物的平均多态性比率是82.16％.群体结构分析表明,当K=4时 ΔK最大,将BC1群体分为4个类群,其中84.27％的单株遗传组分相对比较单一,而15.73％的单株遗传背景比较复杂.多叶苜蓿BC1群体遗传多样性丰富,群体结构的划分与亲缘关系不完全相关.%To provide materials for breeding multifoliolate alfalfa varieties that are suitable for Jiang-huai area and has higher yields and improved quality,the backcross population was constructed,multi-fo-liate alfalfa (PL34HQ)was used as recurrent parent and Huaiyin alfalfa as non-recurrent parent,and breeding materials to meet the requirements for backcross breeding were obtained.The agronomic traits of BC1 population were compared with F1 population,the genetic diversity of agronomic traits were analyzed, and genetic diversity and population structure were analyzed from the molecular level.The results showed that agronomic traits of BC1 population were closer to ones of parents than F1 population,and traits diver-sity of BC1 population were rich.A total of 148 alleles variations were detected by 25 pairs of SSR mark-ers,and average 5.92 per primer,the average ratio of polymorphism was 82.16％.Analysis of population structure showed that K had a maximum value when K =4,the BC1 could be divided into 4 groups,of which 84.27％ of individual plants were with single genetic components,the rest 15.73％ were with mixed genetic component.The genetic diversity of BC1 population were abundant,and the division of population structure were not completely related to genetic relationship.
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