Hava Delavar, Harlene Hatterman-Valenti,* Ozkan Kaya, and Summaira Riaz
*North Dakota State University, 1360 Albrecht BLVD. Loftsgard, Fargo, ND, 58105 (h.hatterman.valenti@ndsu.edu)

Cold hardiness is an economically important trait that can significantly affect grape production and quality. Until now, there have been no reports identifying effective quantitative trait loci (QTL) for cold hardiness in grapevines. The bottleneck for QTL mapping of cold hardiness in grapes and other fruit trees is field evaluation, because plants vulnerable to cold often die in their first year of planting. To address this, our study focuses on developing a method that involves acclimating the entire mapping population in the greenhouse with controlled photoperiod and temperature, allowing comprehensive assessment of both cold-susceptible and cold-hardy genotypes using differential thermal analysis. Our primary objective is to establish a method that ensures results obtained from cold evaluation of accessions acclimated in the greenhouse have the same ranking as cold evaluation results from the same accessions under field conditions. For this purpose, a mapping population resulting from a cross between Vitis riparia and Vitis vinifera underwent cold hardiness evaluations under three distinct environments: 1) acclimated in a cold region of North Dakota that experiences temperatures as low as -35°C during winter; 2) acclimated in a greenhouse, where photoperiod and temperature were controlled; and 3) acclimated in the temperate climate of California, devoid of any cold stress. Hardiness monitoring was conducted using the widely accepted analysis method of differential thermal analysis. This research can speed up the breeding processes, as evaluation in the greenhouse can be done at any time of year and is not limited to winter. Data analysis for the study is ongoing, so the findings have not been disclosed at this stage. We anticipate completing the requisite analyses and presenting the results by the time of the Conference.

Funding Support: North Dakota Department of Agriculture Specialty Crop Block Grant