Muscadine Grape Breeding

Abstract

The transition of muscadine grapes ( Vitis rotundifolia Michx.) from a wild fruiting plant to a domesticated crop has taken place in the last 150 years. Muscadine grapes are one of only two species in the Muscadinia subgenera of the Vitis genus. The Muscadinia differ substantially genetically and morphologically from the other Vitis species (subgenus Vitis ). Chromosomal differences between Muscadinia (2 x = 2 n = 40) and Vitis (2 x = 2 n = 38) have generally, although not completely, prevented the movement of genes between the subgenera. Partly due to this genetic isolation, muscadine grapes have been domesticated into a unique fruit crop with many differences from other grape cultivars. Muscadine grapes are grown throughout the southeastern United States and are one of the few fruit crops well suited to this hot and humid growing environment. Muscadines are prized in this region for their unique flavor and aroma and are grown as juice and wine grapes as well as for fresh consumption. Muscadine grapes are also gaining recognition for their high levels of beneficial phytochemicals. Despite these advantages, muscadines are not well known outside of the southeast United States. This is due in part to difficulties in long-term storage of the crop and also to the inherent difficulties in marketing an unfamiliar product. Several long-term breeding programs have transformed this crop from a functionally dioecious species bearing small berries with a tough skin and soft pulp to a hermaphroditic vine with large berries having a firm flesh and crisp skin. Recent success in intersubgeneric hybridization has resulted in the successful incorporation of stenospermocarpic seedlessness into muscadine. These breeding advances have opened exciting possibilities and positioned muscadine to transform from a niche to a mainstream crop.