应用微卫星标记研究西藏野生大麦的遗传多样性

以西藏不同地区的106份野生大麦为材料，其中包括50份野生二棱大麦（HS），27份野生瓶形大麦（HL）和29份野生六棱大麦（HA），用Liu等（1996）发表的SSR连锁图的每个连锁群的两个臂的不同位置上选取3～5个共30个SSR标记，研究了西藏3类野生大麦的遗传多样性。结果表明，这3类野生大麦在遗传组成及等位变异频率分布上存在着明显的遗传分化。在总样本中，共检测到229个等位变异，平均每个SSR位点检测到7．6个等位变异，其中70个为这3类野生大麦间共同的等位变异，等位变异数在这3类野生大麦间有明显的差异，亚种问的遗传多样性明显高于亚种内的遗传多样性。其遗传多样性大小顺序为HS〉HL〉HA。聚类分析表明，野生二棱大麦、野生六棱大麦分别聚在不同的两类，而野生瓶形大麦中各有约50％的材料分别聚在这两类。根据本研究及前人研究结果，我们认为中国栽培大麦是从野生二棱大麦经野生瓶形大麦向野生六棱大麦进化的。该结果支持了栽培大麦起源的“野生二棱大麦单系起源论”的观点。

Genetic Diversity Analysis of Tibetan Wild Barley Using SSR Markers

One hundred and six accessions of wild barley collected from Tibet, China, including 50 entries of the two-rowed wild barley Hordeum vulgare ssp. spontaneum (HS), 29 entries of the six-rowed wild barley Hordeum vulgare ssp. agriocrithon (HA), and 27 entries of the six-rowed wild barley Hordeum vulgare ssp. agriocrithon var. lagunculiforme (HL), were analyzed using 30 SSR markers selected from the seven barley linkage groups for studying genetic diversity and evolutionary relationship of the three subspecies of Tibetan wild barley to cultivated barley in China. Over the 30 genetic loci that were studied, 229 alleles were identified among the 106 accessions, of which 70 were common alleles. H. vulgare ssp. spontaneum possesses about thrice more private alleles (2.83 alleles/locus) than HS (0.93 alleles/locus), whereas almost no private alleles were detected in HL. The genetic diversity among-subspecies is much higher than that within-subspecies. Generally, the genetic diversity among the three subspecies is of the order HS > HL > HA. Phylogenetic analysis of the 106 accessions showed that all the accessions of HS and HA was clustered in their own groups, whereas the 27 accessions of HL were separated into two groups (14 entries with group HS and the rest with group HA). This indicated that HL was an intermediate form between HS and HA. Based on this study and previous works, we suggested that Chinese cultivated barley might evolve from HS via HL to HA.