Evaluation of Midwinter Cold Hardiness among 25 Rabbiteye Blueberry Cultivars

Abstract

The midwinter cold hardiness of 25 rabbiteye (V. ashei) blueberry cultivars was assayed across 2 years using a shoot freezing assay. LT50values (i.e. temperature at which 50% of buds are damaged) for the cultivars ranged from –24.9 °C for `Pearl River' (a 50% V. ashei derivative) to –13.7 °C for `Chaucer'. Under New Jersey conditions, numerous cultivars were observed to exhibit dimorphism for dormant floral bud size. Comparisons of bud dimorphism with LT50 values, found dimorphism more common in cultivars with lower floral bud hardiness. LT50 values generally supported empirical observations of winter hardiness, but exceptions suggest that additional factors contribute to observed winter hardiness under field conditions.