| Abstrakt: |
Cultivated hexaploid oat is one of the most important cereal crops in the word, clearing its hexaploid ancestor would substantially improve the utilization efficiency of the genetic resources of oat, and therefore provide theoretical reference for oat germplasm conservation. In this study, 27 naked oats originated from China were sequenced by using GBS (genotyping by sequencing). SNPs were calling by combining the previously published GBS data of another 66 hexaploid oats including six species using UNEAK pipeline. A total of 8902 SNPs with MAF > 0.5, call rate > 0.95 were obtained. Four taxa with missing value greater than 15% were excluded for further analyses. Finally, 89 oat taxa meeting the requirement were used for PCA, STRUCTURE and UPGMA clustering analyses. All three analyses revealed some consistent results as follows: most wild hexap- loid oats with the exception of A. sterilis showed strong genetic differentiations among each other, resulting in a grouping by species. Clustering analysis divided all the taxa into two clusters representing wild species and cultivated species, respectively, indicating some significant genetic differences existed between this two types of hexaploids. Within cultivated hexaploid oats, A. byzantina showed a high degree of genetic homogeneity with A. sativa, while naked oats differed from the others and formed an independent subcluster with close relationships with A. sativa. The taxa from the wild hexaploid species A. sterilis were mainly subdivided into two groups. Notably, these accessions of A. sterilis originated from western Asia (Iran-Iraq-Turkey region) were clustered with the cultivated oats A. sativa and A. byzantina, suggesting that A. sativa and A. byzantina might be derived from progenitor germplasm from Iran-Iraq-Turkey region. Another wild hexaploid species A. hybrida showed high degree of genetic homogeneity with A. fatua, is better to consider as a subspecies of A. fatua. This research contributes to clarifying the hexaploid origin of cultivated hexaploid oats. [ABSTRACT FROM AUTHOR] |
