John Stenger* and Harlene Hatterman-Valenti 
*North Dakota State University, PO Box 6050, Dept. 7670,
Fargo, ND 58108-6050 (john.stenger@ndsu.edu)

The lack of mediating water bodies in the continental United States allows for more rapid climactic shifts and subsequent year-to-year unpredictability. The effects of climate change include increased frequency of climactic extremes, increasing effects on the physiological ecology of vines. Moving forward, efforts to breed or identify suitable cultivars based on favorable reactions in response to unpredictable climactic shifts are necessary. An experiment was conducted to compare the effects of temperature on the progression of morphological changes related to fall acclimation response and fruit ripening in three commonly-grown cultivars with differing levels of perceived regional predictability (Frontenac Gris, regionally adapted; St. Croix and Marquette, regionally unpredictable). Twelve indicators relating to growth cessation, tissue maturation, berry growth, and fruit quality were monitored as photoperiod decreased from 14.5 to 12.5 hr of daylight in five environments. Data reduction was used to extract latent processes from high-level interactions between temperature and morphological trait data in each environment. Correlation was used to identify commonalities among temperature deviations and plant reactions among environments. St. Croix was highly reactive to temperature decreases as with symptomology of water restriction to stem tissue and fruit. Alternatively, Marquette was highly reactive to temperature increases and easily reverted back to active growth, as indicated by increased water allocation to all sink tissues. Frontenac Gris had a moderated response, not as reactive to temperature increase as Marquette, but similar as temperatures cooled. The defining characteristic of Frontenac Gris leading to its relative success in North Dakota likely stems from its unrelenting progress in bud maturation under varied environmental conditions. Results suggest that breeding for favorable temperature reactionary types in addition to early acclimation induction may improve the year-to-year stability in production of future cultivars.

Funding Support: North Dakota Specialty Block Grant North Dakota Grape and Wine Research Grant