Ploidy Detection and Genetic Analysis of SSR Markers of 15 Populus Cultivars in North China

In this study, in order to enrich genetic information of Populus cultivars, 15 cultivars widely used in North China were collected to detect their ploidy levels and to conduct genetic analysis based on SSR markers. It was found that the cultivars P. × 'Heilin 1' and P. × 'Bailin 3' were triploids, suggesting that triploids were existed in Populus cultivars planted in North China. A total of 106 allelic variations were found from screened 12 pairs of SSR primers, including 105 polymorphic allelic variations and 46 specific variations, which accounted for 99.06% and 43.40% of total, respectively. According to characteristics of allelic variations for each pair of primer, the 15 cultivars could be effective distinguished by primer pairs LG1926 and LG1937. The SSR fingerprints were established for each cultivar. Clustering analysis with UPGMA (unweighted pair group method arithmetic averages) showed that the genetic similarities among cultivars ranged from 0.622 6 to 0.886 8, with average of 0.733 7.