大麦遗传多样性及连锁不平衡分析

为了合理评价引进种质资源，为大麦基因发掘及育种组合配置提供依据，选用分布于全基因组的64个SSR标记，对221份大麦材料进行了基因型分析。共检测到192个等位变异，变幅为2~7个；基因频率变异范围为0.0090~0.9729，平均0.3333；全部位点的基因多样性变化范围在0.0528~0.7807，平均0.4813；多态性信息含量(PIC)变异范围在0.0514~0.7464，平均0.4113。供试材料间遗传相似系数变幅为0.4844~0.9792，平均0.7023。221份材料被划分成两大群7个亚群，国内地方品种与1份北京品种为一大群，国内育种品种与所有国外引进品种为另一群。遗传结构分析与聚类结果基本一致，两大类群间的遗传距离为0.3358，且第二大群多样性比第一大群丰富。2016个SSR位点成对组合中，不论共线性组合还是非共线性组合，都存在一定程度的连锁不平衡(LD)。D′统计概率(P<0.01)支持的LD成对位点830个，占全部位点组合的41.2%，D′平均值为0.4，整体LD水平较高。栽培品种的LD水平高于地方品种，且现代遗传改良的目标性状集中于2H、4H、6H和7H染色体。

Genetic Diversity and Linkage Disequilibrium Analysis in Barley

The objective of this study was to provide a suitable evaluation for introduced germplasm resources and useful information for associate analysis and parental combinations in barley (Hordeum valgare L.). A total of 192 alleles were detected by 64 SSR markers on chromosomes 1H to 7H in 221 barley accessions with 2–7 alleles per locus. The allelic frequency ranged from 0.0090 to 0.9729, with the mean of 0.3333. The gene diversity was from 0.0528 to 0.7807, averagely 0.4813. The polymorphism information content (PIC) value ranged from 0.0514 to 0.7464 with the mean of 0.4113. The genetic similarity of the 221 accessions ranged from 0.4844 to 0.9792 with the mean of 0.7023. All accessions were clustered into two major groups and seven subgroups. Most landraces or developed varieties fell into the same major group. Genetic structure analysis revealed two subpopulations of these accessions, with consistence to the clustering analysis. Genetic distance between the two subpopulations was 0.3358, and the second subpopulation had richer diversity than the first one. There was linkage disequilibrium (LD) among linked loci and unlinked loci pairs, and 830 out of 2016 loci pairs (41.2%) had significant LD (P < 0.01) with D′ average value of 0.4. The LD level of developed variety was higher than that of landraces. Target traits of developed varieties were mainly distributed on chromosomes 2H, 4H, 6H, and 7H.