“青藏高原六棱大麦地方品种群体结构和连锁不平衡”一文在Crop Science上发表

　　王蕾,徐金青,夏腾飞,张怀刚,刘登才^*, 沈裕虎^*(Lei Wang, Jinqing Xu, Tengfei Xia, Huaigang Zhang, Dengcai Liu,^* Yuhu Shen^*).Population Structure and Linkage Disequilibriumin Six-Rowed Barley Landraces from the Qinghai-Tibetan Plateau. Crop science.2014,54(5):2011-2022.IF=1.478 

　　论文利用1264个DArT多态性标记对来自青藏高原的255份六棱大麦（其中251份为六棱裸大麦即青稞）地方品种进行了遗传多样性、群体结构和基因组连锁不平衡性检测。发现青稞地方品种内存在显著的群体结构分化，可划分为5个亚类群，其结构分层同材料的地理来源间关系密切；参试材料基因组内连锁不平衡性随遗传距离的增加呈下降趋势，整个基因组的LD衰减距离为3.32cM（r²=0.22）。该项研究为进一步开展青藏高原青稞关联作图和分子育种研究提供了良好的前期基础。 

　　Abstract: The genetic diversity, population structure, and extent of linkage disequilibrium (LD) were investigated at a genome-wide level in 255 six-rowed barley (Hordeum vulgare L. ssp. Vulgare) landraces from the Qinghai-Tibetan Plateau using 1264 polymorphic diversity array technology (DArT) markers. The mean polymorphism information content (PIC) of the DArT markers ranged between 0.008 and 0.500 with an average of 0.213. Bayesian, principal coordinate analysis, and phylogenetic analysis supported that six-rowed barley landraces from this region are divided into five distinct subpopulations centered on the regions of origin of the germplasm. The genetic distances calculated for all the individual pairs were geographically dependent, as revealed by Mantel tests (r = 0.35, P < 0.001) and spatial autocorrelation analysis. The LD values, expressed as r2, declined with increasing genetic distance, and the same tendency occurred on each chromosome. In general, LD values were low (9.1% of adjacent markers; P < 0.001), and mean LD values across the whole genome decayed to below the critical r2 of 0.22 after 3.32 cM. Approximately 19.0% of marker pairs (mean r2 = 0.586) located on the same chromosome and 4.9% of pairs (mean r2 = 0.318) located on different chromosomes were in LD (r2 ≥ 0.22). Our results discerned relevant patterns of genetic diversity, population structure, and LD among members of a Qinghai-Tibet Plateau barley landraces panel proposed to be ‘typical’ of a target region or environment and have important implications for further studies on association mapping and practical breeding in high-altitude naked barley.