Abstract
Differential thermal analysis (DTA) is a popular semi-automated method for determining the temperature at which plant tissues freeze. It is used to evaluate effects of environmental variables, genotypes, and various agronomic practices on cold hardiness, as well as an Extension tool for cold hardiness monitoring and decision support for growers of many specialty crops. The study presented here evaluated common approaches in sampling and preparation of dormant grapevine compound buds for DTA, to provide a reference point as to which adjustments might be cause for excessive variation in subsequent data. We found that common adjustments in sample preparation, whether using foil packets, moistened tissue paper, or bud orientation, resulted in little consistent consequence in observed DTA values, typically resulting in a variation of less than 1°C. The same was true for storage (or shipping conditions) of 24 h or less, provided samples were maintained at low, but above-freezing temperatures (1.6 to 4°C). Finally, influence of bud position along the length of the cane was also not found to be consistent. Taken together, these findings demonstrate that the robust nature of DTA for estimating grapevine cold hardiness offsets the potential impact of variation introduced from different sample preparation methods. These results can be used to help those wishing to develop DTA protocols, or expand their capacity to conduct DTA analysis, to better design their laboratory protocols to best suit their individual program needs. Consistency in DTA approach is likely more important than the specific methods used, especially when comparing relative differences in observed lethal temperatures.
- Received February 2022.
- Revision received June 2022.
- Revision received July 2022.
- Accepted July 2022.
This is an open access article distributed under the CC BY license (https://creativecommons.org/licenses/by/4.0/).
