Ramesh Pilli,* Venkateswararao Kadium, Harlene Hattermanvalenti, Andrej Svyntek, and Xuhuei Li
*North Dakota State University, 1053 17th Ave N, University Village unit #152, Fargo, ND, 58102 (ramesh.pilli@ndsu.edu)

Cold tolerance of grapevines (Vitis spp.) varies significantly over the dormant season, especially in response to temperature fluctuations. Extreme temperature fluctuations are ubiquitous in North Dakota, negatively affecting grapevine cold hardiness. Therefore, identifying genes/genomic regions involved in cold hardiness is needed to aid grapevine cultivar development. An incomplete diallel population of 1064 F1 individuals was developed to estimate cold tolerance through differential thermal analysis (DTA). In December and February 2020 to 2023, dormant canes were collected from the field on consecutive days until all individuals were sampled. Buds were removed from the canes, placed in thermoelectric modules with sensors, and placed in a programmed freezer. When a grapevine bud freezes quickly under freezing conditions, we can determine the freezing point or low-temperature exotherm (LTE). LTE obtained from DTA was used as phenotypic data. In addition, we used rhamseq markers (2100) as genotypic data. This study aims to identify the genomic regions associated with complex traits such as acclimation and cold hardiness through a genome-wide association study using this phenotypic and genotypic data. The results have identified significant SNPs on different chromosomes that could be linked to cold hardiness in our population.

Funding Support: Specialty crop