2019 ASHS Annual Conference

Muscadine grape (Vitis rotundifolia) was the first native North American grape to be domesticated. Over the last century breeding programs have created a large collection of muscadine cultivars. In this study, simple sequence repeat (SSR) markers were used to access the genetic diversity of muscadines. With 20 SSR markers, a total of 161 alleles were amplified for 71 muscadine cultivars producing an average of 8.1 alleles per marker. The analysis of genetic diversity was conducted at four levels: all muscadine cultivars, historical muscadine cultivars, current muscadine cultivars and wild relative accessions. While sharing the similar average Ho (observed heterozygosity), both the average alleles per marker and the number of private alleles (alleles detected only in the group) for wild muscadines (8.4 and 65) were higher than that for cultivated muscadines (8.1 and 58). It indicated that eight wild muscadines convey a higher level of genetic diversity than 71 cultivated muscadines. Although elite cultivars tend to be used excessively in recent muscadine breeding programs, the data proved the set of current cultivars also has substantial diversity and there is no inbreeding depression observed. The Principle Coordinate Analysis (PCoA) shows clear separation among wild accessions, Vitis cultivars, and cultivated muscadines with PCoA1 and PCoA2 explaining 11.1% and 9.3% of the total variation respectively.