THE INFLUENCE OF SELF- AND CROSS-POLLINATION ON FRUITING IN SOUTHERN HIGHBUSH BLUEBERRIES
Southern highbush (“low chill tetraploid”) blueberries are an earlier-ripening, self pollen-compatible alternative to rabbiteye blueberries. `Sharpblue', the first southern highbush cultivar planted on a commercial scale, has been shown to require cross-pollination for optimal fruit size and earliness of ripening. `Gulfcoast', a recently released cultivar for Gulf states growers of about latitude 30 to 32 N, differs in heritage from `Sharpblue', incorporating about 50% more self-compatible northern highbush germplasm. `Gulfcoast' fruit development after honey bee-mediated self- or cross-pollination with `Sharpblue' was similar in terms of set (85.5 vs. 82.2%), weight (1.26 vs. 1.18g), and seed number (32.8 vs. 33.6), respectively. Cross-pollination did not result in significantly earlier ripening. Thus, `Gulfcoast' appears to be more self-fertile than `Sharpblue'. Other closely-related cultivars are being examined to determine the genetic influence on potential for self-fruitfulness.