Submitted to: HortScience
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/10/2016
Publication Date: 1/2/2018
Citation: Ehlenfeldt, M.K., Stringer, S.J. 2018. Investigations of parthenocarpy in rabbiteye blueberry. HortScience. 72:2-11.
Interpretive Summary: Blueberry plants typically require pollination in order to produce fruit. We observed several varieties of rabbiteye blueberry that produce fruit without pollination and undertook a survey to determine how commonly this may occur in rabbiteye blueberry. Fourty-eight rabbiteye varieties were grown in the greenhouse under conditions that prevented insect pollination and evaluated over two years for fruit size and number of fruit. Fruit production varied among the varieties, ranging from varieties that produce little or no fruit to those that produced many fruit without pollination. Under these conditions, the rabbiteye variety named Premier had superior fruit yield in comparison to all of the varieties evaluated. These research results are valuable for blueberry growers and researchers for developing production management practices for rabbiteye blueberry, and for researchers developing new more productive varieties.
Technical Abstract: Under greenhouse conditions, several rabbiteye blueberry cultivars regularly set fruit and develop it 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 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.