1950年以来山东省主推小麦品种的遗传多样性演变

利用24对SSR引物对62个山东省1950年以来大面积推广小麦品种遗传多样性的演变情况进行了分析。结果表明24对引物均有较好的多态性,共扩增到100个等位变异片段(等位基因),平均每个标记获得4.167个等位基因,多态性信息量(PIC)值平均为0.527,变幅0.200～0.723,基因多样性指数变幅0.225～0.761,平均0.582。三个基因组的位点多态性存在明显差异,平均等位变异丰富度D>B>A,基因多样性指数和多态性信息指数B、D基因组接近,并明显高于A基因组。山东省小麦品种平均遗传丰富度、遗传多样性指数和平均遗传距离均以50年代较高(分别为3.042,0.531和0.596),然后缓慢下降,1980年代回升到顶峰(分别为3.250,0.560和0.616),然后迅速下降。62个品种遗传相似系数变幅为0.580～0.940,平均为0.723。按非加权类平均法(UPGMA)、在遗传相似系数0.719处将不同品种聚类成7类,基本与山东省不同时期育种骨干亲本及其衍生品种一致,说明山东省近60年来小麦育种与全国一样,围绕骨干亲本展开。由于特有种质资源的创造和应用,山东省小麦品种遗传多样性高于全国和其他麦区,尤其是1980年代,但之后迅速下降,必须引起足够重视。

The Evolution of Genetic Diversity of Wheat Varieties Released in Shandong Province since 1950

The evolution of 62 wheat varieties cultivated widely in Shandong province since 1950 was evaluated by 24 pairs of SSR markers.The results revealed that all 24 pairs of SSR markers were highly polymorphic,and 100 alleles were amplified with the average of 4.167 per marker.The mean polymorphism information content(PIC) is 0.527 with a range from 0.200 to 0.723.The genetic diversity indexesrange from 0.225 to 0.761 with the average of 0.582.There were significant differences in site polymorphism among these three genomes,and the average richness of allelic variation in each genome is D>B>A.The genetic diversity index and the polymorphism information content index of genome B are similar to that of genome D,but higher obviously than that of genome A.The average genetic richness,genetic diversity index and genetic distance in 1950s are all higher,and each of them is 3.042,0.531 and 0.596 respectively.Then they decreased slowly untilthey rebounded in 1980s and reached the highest of 3.250,0.560 and 0.616 respectively.After that they decreased sharply again.The genetic similarity coefficients of 62 wheat cultivars vary from 0.580 to 0.940,and the mean is 0.723.All wheat cultivars could cluster into 7 groups at 0.719 with the method of UPGMA.The clustering result is mostly consistent with the main parental lines and their derivatives for wheat breeding on different period in Shandong province.It shows that the wheat breeding in Shandong province,as well as throughout China,has been based on core parental lines since 1950.Because of the creation and application of the endemic germplasm,genetic diversity of wheat cultivars released in Shandong province had even been the highest in all the wheat regions of China,especially in 1980s.But it declined sharply after 1980s.Therefore more effort needs to be made to broaden the wheat breeding base and conserve wheat germplasm.