Evaluations of Parthenocarpy in Vaccinium VirgatumAiton (Rabbiteye) Blueberry Cultivars

Abstract

Under greenhouse conditions, several rabbiteye ( V. virgatumAiton) blueberry cultivars regularly set fruit that develop to maturity without pollination. Since self-fruitfulness (or lack of) is a critical issue for rabbiteye blueberry, we undertook a study of the propensity of 48 rabbiteye cultivars to set fruit under greenhouse conditions. For this we measured both fruit set and fruit size, and compiled ranking values across 2 years. A few cultivars stood out as having distinct expressions of parthenocarpy. Several cultivars, ‘Suwanee’, ‘Early May’, ‘Florida Rose’ and ‘Ira’ had extremely low or no fruit-set, either year, without pollination. Several cultivars had relatively large fruit at maturity (10-12 mm), but modest fruit-set overall, and ‘Chaucer’, a modern Florida cultivar, had extremely high fruit-set, but its mature fruit were relatively small, typically ~8 mm. Greenhouse rankings were compared to field evaluations (of 20 cultivars common to both studies) that evaluated fruit size and seed number, as indicators of parthenocarpic tendencies. No significant correlations were observed between any of the greenhouse rankings of parthenocarpy (fruit set or fruit size) with any of the field values (fruit weight or seed/g fruit ratios) for either year. The cultivar ‘Premier’, however, was a superior performer in both studies, and thus may represent a desirable parent to enhance parthenocarpic tendencies and fruit size.