Microsatellite Markers to Complement Distinctness, Uniformity, Stability Testing of Brassica chinensis (Xiao Baicai) Varieties

Brassica chinensis varieties are mostly consumed as vegetables. In order to assess utility of microsatellite markers for testing distinctness, uniformity and stability of B. chinensis varieties, we used nine polymorphic microsatellite marker loci (with a total of 131 alleles) to evaluate four open pollinated and four hybrid varieties of B. chinensis. Each variety was represented by 48 randomly sampled individuals from a population of 150. Morphological evaluations were also conducted to the same samples. Compared with morphological evaluations, the microsatellite analysis provided a higher degree of separation and reflected greater uniformity for the three hybrid varieties by cluster analysis, Principal Coordinates Analysis (PCA) and assignment test. Average pair-wise Jaccard similarities and statistical tests by AMOVA (analysis of molecular variance) also suggested higher levels of intra-variety uniformity. It was also noted that there was no significant correlation between the genetic and morphological distance matrices (Mantel test). We conclude that microsatellite genotyping can be a valuable tool to complement morphological assessment of Brassica vegetable varieties for distinctiveness and uniformity.