Genetic variation of white clover (Trifolium repens L.) collections from China detected by morphological traits, RAPD and SSR.

Abstract

White clover is an important legume naturalized in China. But genetic variation of Chinese local white clover germplasm has not been reported. There is no information for parents’ selection and genetic resource conservation. The objective of this study was to investigate and characterize genetic variation of ten local white clover germplasms collected from different geographical regions of China. Morphological data analysis of white clover populations was coupled with molecular markers of random amplified polymorphic DNA (RAPD) and simple sequence repeat (SSR) to investigate the genetic relationships among white clover germplasms of China, and four commercial cultivars were included for a comparison. The results revealed that the populations showed diverse morphological traits, RAPD and SSR patterns. Despite the certain similarities among the dendrograms of particular populations, the overall correlations among the distance matrices appeared to be rather low. In the present study, cluster analysis only slightly reflected the geographical origins of populations, and the dendrogram employing SSR data showed the closest agreement with collections’ geographical origins. The analysis of molecular variance (AMOVA) analysis based on both RAPD and SSR markers revealed higher levels of intra-population variation than inter-population variation. Neither RAPD nor SSR based grouping showed obvious agreement with variation of leaf sizes and other morphological traits. Our results suggest that the combination of morphological traits and SSR analysis could be a useful method for assessing genetic variation in white clover, and could be helpful for breeders to plan crosses for positive traits.