Low-temperature survival of blackberry cultivars grown in the midwestern United States

M.R. Warmund
Commonly grown blackberry cultivars are susceptible to low-temperature injury throughout their dormant period. A study was conducted to evaluate the temperature at which 50% of the flower buds of nine blackberry cultivars were killed (T50) following exposure to low temperatures. Blackberry cultivars evaluated included ‘Apache’, ‘Arapaho’, ‘Caddo’, ‘Osage’, ‘Ouachita’, ‘Navaho’, ‘Natchez’, ‘Ponca’, and ‘Von’. Tissue for artificial freezing tests was collected from a research planting near New Franklin, Missouri, USA on January 17, February 28, and November 21, 2022 and January 11, 2023. Immediately after each collection, canes were prepared for low-temperature exposure at a cooling rate of 3°C h‑1. Primary flower bud hardiness among all cultivars varied by 7.2, 13.6, and 6.8°C in January, February, and November 2022, respectively. Due to a naturally occurring low-temperature event in December 2022 (-22°C), primary flower bud survival was evaluated on January 11 and February 28 in 2023. At all test dates, ‘Ouachita’ primary buds had consistently low T50 values and high percent survival. In contrast, ‘Natchez’ primary buds had the highest T50 values and low percent survival among the cultivars. Secondary buds of ‘Natchez’ had 34% survival on both dates in 2023. Based on the results of this study, ‘Ouachita’ flower buds had superior cold tolerance among the cultivars tested in mid-winter and just before budbreak in late winter.
Warmund, M.R. (2024). Low-temperature survival of blackberry cultivars grown in the midwestern United States. Acta Hortic. 1388, 287-294
DOI: 10.17660/ActaHortic.2024.1388.42
Rubus, bud injury, cold hardiness, dormancy, freezing stress

Acta Horticulturae