本研究利用SSR分子标记对2个多花黑麦草杂交组合5轮改良群体进行遗传变异分析。20对SSR 引物在12个育种群体中共扩增出217个条带，多态性条带比率为92．2％。2个杂交群体的不同选择世代中，分别有72．3％和75．2％的遗传变异存在于群体内，27．7％和24．8％的遗传变异存在于各群体间，群体内的遗传变异大于群体间的遗传变异。从带型分析来看，杂交改良群体中双亲共有的条带比例增多，同时缺失双亲特异性条带的比例减少。随着混合选择世代的增加，多态性条带百分率、Shannon遗传多样性指数及Nei’s基因多态性都呈递减趋势，表明群体内的遗传差异随着选择世代的增加呈下降趋势。研究结果将为多花黑麦草杂交选择育种提供基本信息。%SSR markers were used to evaluate the genetic diversity in two crossbreeding groups of annual ryegrass after 5 cycles mass selection.With the 20 primer pairs selected,a total of 217 bands were detected in the two populations and the percentage of polymorphic bands was 92.2%.In the two crossbreeding groups, 72.3% or 75.2% of the genetic diversities were estimated intra-populations and 27.7% or 24.8%,respective-ly,were estimated inter-populations.The genetic diversity of the inter-population was much more than that of the intra-population.After analysis of the bands,it was found from the amplified results that the crossbreeding groups had more bands shared by parents and progeny but fewer non parental specific bands.As mass selection proceeded in the crossbreeding groups,the percentage of polymorphic bands in populations declined as did the Shannon index and Nei’s gene diversity.It is shown that genetic diversity of each population declined under mass selection.The results of this study will provide some basic information for ryegrass crossbreeding.
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