DNA fingerprinting and genetic relationships among white clover cultivars

Abstract

Genetic diversity provides the raw material for plant improvement programmes. The assessment of genetic diversity is commonly based on plant morphology; however, this indirect measure of genetic diversity is often confounded by environmental effects. Microsatellite (SSR) markers are a powerful tool that directly measures variation among plants at the DNA level. We assayed the pattern of relatedness among 32 white clover (Trifolium repens L.) cultivars using 39 SSR markers that are evenly distributed within the white clover genome. The 390 alleles detected were used to quantify the 496 pairwise genetic similarity estimates among the cultivars, detecting a mean value of 0.56 (range 0.44 - 0.68). Cluster analysis assigned the 32 cultivars to 14 clusters based on their genetic similar ity. The resulting clusters revealed strong correlation with known genetic relationships based on pedigree and the geographic origin of the parental germplasm. The development of a DNA fingerprinting technique based on high-throughput SSR markers has potential applications in plant variety rights, seed certification and variety identification in grazed pastures. Keywords: cluster analysis, DNA fingerpr inting, genetic diversity, microsatellite , molecular markers, Trifolium repens L