2017 ASHS Annual Conference

Muscadines (Vitis rotundifolia Michx.) are a diploid (2n=40) fruit-bearing vine indigenous to the southeastern United States. The grape-like berries are considered a local delicacy for fresh consumption and for making wines, jams, and jellies. While limited genetic information is available for muscadines, they are closely related to the European winegrape, Vitis vinifera L., (2n=38), for which a reference genome is available. We have created a high-density linkage map of a F₁ muscadine population (‘Black Beauty’ x ‘Nesbitt’) segregating for fruit color (bronze and black) and flower type (female and hermaphroditic) using genotyping-by-sequencing (GBS). Over 1200 single nucleotide polymorphism (SNP) markers were placed in 20 linkage groups on the genetic map. Synteny was strongly conserved between the muscadine linkage map and the V. vinifera reference genome. The splitting of V. vinifera chromosome 7 into two independently segregating linkage groups accounted for the higher chromosome number in muscadine. The locus controlling flower type in muscadine was mapped to chromosome 2, the same location as the previously described sex locus in V. vinifera. Interestingly, the candidate gene for fruit color in V. vinifera is located on chromosome 2, but the muscadine fruit color locus was placed on chromosome 4. This dense linkage map lays the groundwork for the implementation of marker-assisted breeding in muscadine.