Submitted to: Canadian Journal of Plant Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/9/2014
Publication Date: 5/1/2015
Publication URL: http://handle.nal.usda.gov/10113/61480
Citation: Ehlenfeldt, M.K., Rowland, L.J., Ogden, E.L., Vinyard, B.T. 2015. LT25, LT50, and LT75 determinations for a diverse selection of vaccinium genotypes. Canadian Journal of Plant Science. 95(3):491-494.
Interpretive Summary: Only limited evaluations have been done on relative cold hardiness in blueberry, even though it is an important part of flower bud survival and fruiting success. In this study, cold hardiness tests were used to determine temperatures causing 25% and 75% flower bud death, respectively, for a diverse group of blueberry plants which had been previously analyzed to determine the temperature causing 50% bud death. The 25% bud death temperature was approximately 1.6 ºC (2.9 ºF) higher than the 50% bud death temperature, and the 75% bud death temperature was approximately 1.6 ºC (2.9 ºF) lower than the 50% damage temperature. This is the first time this information has been determined for such a wide range of selections. This information is useful to researchers trying to develop more cold hardy varieties, and to growers and researchers interested in understanding the cold hardiness of currently available varieties.
Technical Abstract: Freeze-bath cold hardiness results were used to calculate LT25 and LT75 values (temperatures causing 25% and 75% lethality, respectively) for a diverse selection of Vaccinium genotypes which had been previously analyzed for LT50 values. Overall, LT25 and LT75 values paralleled the LT50 values. Across genotypes, the LT25 was approximately 1.6 ºC (2.9 ºF) higher than the LT50, and the LT75 approximately 1.6 ºC (2.9 ºF) lower than the LT50 for any given date. As concerns of climate change increase, knowledge of the ability of breeding germplasm to tolerate greater extremes and greater fluctuations will prove increasingly valuable.