Inbreeding Among Muscadine Cultivars

Abstract

Pedigrees were used to identify inbreeding among named muscadine ( Vitis rotundifoliaMichx., syn. Muscadinia rotundifolia(Michx.) Small) cultivars for the purpose of improving decision making by breeding programs. Public muscadine breeding programs in the United States operate in hopes to improve the quality of muscadine grapes and expand their consumption. Major quality goals of muscadine breeding programs are to achieve more productive, bigger berry, self-fertile cultivars with more sugar content. While the hybridization of bunch grape (Vitis sp.) and muscadine germplasm has the potential to reduce inbreeding, most current muscadine cultivars are based on a narrow genetic background. We examined 153 muscadine cultivars and selections to determine their parentage and then subjected the reported parentage of every cultivar to statistical analysis to identify inbreeding coefficients for each cultivar. This list was compiled by examining sources dating as far back as 1909. Inbreeding coefficients ranged from 0 to 0.369, higher than what was previously found in other studies. Inbreeding coefficients of 57 out of 153 cultivars were greater than 0, with ‘Redgate’, ‘Tara’, ‘Scarlett’, and ‘African Queen’ having the highest coefficients of inbreeding. Newer released cultivars showed higher inbreeding coefficients than older releases. While many cultivars with higher inbreeding coefficients have been commercially successful, breeders should be cautious of using germplasm with high levels of inbreeding when considering new crosses in a muscadine breeding program.