`Star' Southern Highbush Blueberry

Abstract

Southern highbush blueberry cultivars are hybrids bred from a gene pool developed by crossing northern highbush cultivars (largely V. corymbosum L.) with one or more low-chill blueberry species native to the southeastern United States. Vaccinium darrowi Camp has been the most widely used source of climatic adaptation to warm areas. Vaccinium darrowi is a low-growing, late-ripening species with small fruit, and several generations of backcrossing, intercrossing, and selection are normally needed to produce upright-growing cultivars with berries large enough for commercial exploitation. The principal value of southern highbush blueberry cultivars is that they can be cultivated where the mean temperature of the three coldest months is as high as 15 °C, whereas northern highbush blueberry cultivars are not consistently productive where mean temperatures for these months exceed 10 °C. The wide range of northern highbush cultivars and the wide geographic range over which they are cultivated allows fresh fruit harvest from midMay through the end of September in the northern hemisphere and from mid-November through the end of March in the southern hemisphere. The remaining gaps in the harvest year can be filled by growing southern highbush cultivars in areas where temperatures are warm in late winter and early spring. Lowchill southern highbush cultivars are needed in these areas, because climates that are warm enough to promote early berry development in late winter and early spring do not provide sufficient chill units during winter to break dormancy in high-chill cultivars. Southern highbush cultivars can provide fresh blueberries in April and early May in the northern hemisphere and in October and early November in the southern hemisphere. They also make it possible for millions of people living in subtropical and warm-temperate areas to produce blueberries in home gardens or for local markets. ‘Sharpblue’ and ‘Flordablue’, the first southern highbush blueberry cultivars, were released by the Univ. of Florida in 1975 (Sharpe and Sherman, 1976), and other low-chill blueberry cultivars have subsequently been re