Vitis rotundifolia, or muscadine, is a grapevine species native to the southeastern and south-central United States. The growth range extends from Florida to New Jersey coast, and west to eastern Texas and Oklahoma. It has been extensively cultivated since the 16th century. The plants are well-adapted to their native warm and humid climate; they need fewer chilling hours than better known varieties, and thrive in summer heat. Muscadine berries may be bronze or dark purple or black when ripe. Wild varieties may stay green through maturity. Muscadines have thick, tough skin, making eating raw fruit similar to eating a plum. Muscadines are typically used in making artisan wines, juice, and jelly. They are rich sources of polyphenols. In a natural setting, muscadines provide wildlife habitat as shelter, browse, and food for many birds and animals. It is a larval host for the Nessus Sphinx Moth and the Mournful Sphinx Moth.
Taxonomy and pathology
Although in the same genus Vitis with the other grapevine species, muscadines belong to a separate subgenus, Muscadinia, and some have suggested giving it standing as a genus of its own. Some taxonomists have also suggested splitting two additional species off from Vitis rotundifolia, Vitis munsoniana and Vitis popenoei. All have 40 chromosomes, rather than 38, are generally not cross-compatible with Euvitis species, and most hybrids between the subgenera are sterile. A few are moderately fertile, and have been used in breeding. A commercially available Euvitis x Muscadinia hybrid is the Southern Homecultivar. Although muscadines are hearty grapes with tough skin that protects them from many plant diseases, these grapes appear to be susceptible to parasitic nematodes.
Cultivars
There are about 152 muscadine cultivars grown in the Southern states. These include bronze, black and red varieties and consist of common grapes and patented grapes. Unlike most cultivated grapevines, many muscadine cultivars are pistillate, requiring a pollenizer to set fruit. A few, such as 'Carlos' and 'Noble', are perfect-flowered, produce fruit with their own pollen, and may also pollinate pistillate cultivars. Muscadine grape cultivars may have low or inconsistent yields, small berries, flavor and thick skin unsuitable to consumer acceptance, and disease susceptibility. Cultivars tend to be developed either for a limited fresh market or for winemaking. For consumer acceptance, fresh market grapes need to be large, sweet, and with relatively thin skin, whereas those for wine, juice or jelly need high yields of high-sugar, color-stable berries. Fresh-market cultivars include Black Beauty, Carlos, Cowart, Flowers, Fry, Granny Val, Ison, James, Jumbo, Magnolia, Memory, Mish, Nesbitt, Noble, Scuppernong, Summit, Supreme, and Thomas. Produced by the University of Florida, the cultivar, 'Southern Home', contains both muscadine and subgenus Vitis in its background. Crops can be started in 3–5 years. Commercial yields of 20–45 tonnes per hectare are possible. Muscadines grow best in fertile sandy loam and alluvial soils. They grow wild in well-drained bottom lands that are not subject to extended drought or waterlogging. They are also resistant to pests and diseases, including Pierce's disease, which can destroy other grape species. Muscadine is one of the grape species most resistant to Phylloxera, an insect that can kill roots of grapevines.
indicates that the thick skins and variable in-season quality of fresh muscadine grapes are significant deterrents to retail acceptance.
Resveratrol and other polyphenols
As muscadine grapes are notable for their highly pigmented, thick skins in which the content of polyphenols is known to be high, there is active research interest to define these phytochemicals. One report indicated that muscadine grapes contained high concentrations of resveratrol, but subsequent studies have found no or little resveratrol in muscadine grapes. Other muscadine polyphenols include:
