GENETIC DIVERSITY IN MUSCADINE AND AMERICAN BUNCH GRAPES BASED ON RANDOMLY AMPLIFIED POLYMORPHIC DNA (RAPD) ANALYSIS

Two morphologically distinct types of grapes belonging to the subgener a Euvitis and Muscadinia in the genus Vitis are cultivated in the Unit ed States. The former is commonly called bunch grapes while the latter is usually called muscadine. Genetic diversity among these grapes was investigated using RAPD markers. Sixteen grape cultivars, with parent age including V. rotundifolia Michx., V. vinifera L., and several Amer ican Vitis species, were used for the RAPD analysis. A total of 156 RA PD markers was produced from 19 random primers, over 90% of which was polymorphic among the muscadine and the bunch grapes. Polymorphisms we re lower within each subgenus. Relationships between these two subgene ra were estimated based on band-sharing and cluster analysis. The aver age genetic distance between the bunch and the muscadine grape cultiva rs was 0.45. The results based on DNA analysis agree with isozyme data obtained from a separate study, which demonstrated that muscadine gra pes share very few common alleles with American bunch grapes and Europ ean grapes.