Fingerprint identification of white clover cultivars based on SSR molecular markers.

White clover (Trifolium repens L.) is an important perennial legume forage with high productivity and quality. To strengthen the basic research on the genetic characteristics, fingerprint identification and adaptability of white clover germplasm resources, Simple sequence repeat (SSR) molecular markers were applied to 10 white clover cultivars to assess the genetic diversity and related lines of white clover at the molecular level in order to lay a theoretical foundation for the selection of high-quality seeds and cultivars of white clover. A total of 120 different bands were amplified by 29 pairs of SSR primers with good polymorphism, of which 103 (89.5%) were polymorphic. Meanwhile, the PIC of each primer was 0.181-0.588, with an average of 0.329. Analysis of molecular variance revealed that 57% of the genetic variation occurred within cultivars and 43% occurred among cultivars. The results of cluster analysis and the principal coordinate analysis revealed that the parental relationships of the 10 cultivars, with the 'Purple' cultivar very distantly related to the other 9 cultivars and the closest parental relationship between 'Ladino' and 'Sulky'. The fingerprints constructed by three representative primers (gtrs679, gtrs319, and gtrs678) have a strong identification ability. In summary, the SSR markers had good polymorphism and could be used for DNA fingerprint analysis of white clover cultivars.