Freezing Tolerance in Frontenac and Seyval blanc Grapevines

Grape cultivars that are grown in cold climates must be able to tolerate low winter temperatures that typically occur in a given region. Cold hardiness of grapevines is based on primary bud survival, however, many interspecific cultivars can produce a crop on secondary buds if primary buds are injured. Moreover, cane tissues, which are necessary for secondary crop production, can be as susceptible to freezing injury as secondary buds. There is relatively little information concerning the freezing tolerance of cane tissues during the overwintering period, although high freezing tolerance of cane tissues is important where severe freezing events can be anticipated. The objective of this investigation was to characterize differences in freezing tolerance of bark and xylem cane tissues of a very hardy (Frontenac) and a moderately hardy (Seyval blanc) grape cultivar during autumnal acclimation, midwinter period, and vernal deacclimation. A second objective was to identify biochemical markers associated with increased freezing tolerance of grapevine canes (not included in this report)

Protein Expression in Cold Acclimating and Freezing Tolerant Grape Cane Tissues

The continental climate in Iowa is important when selecting grape cultivars that are tolerant of low-temperature stresses. Many coldregulated (COR) proteins respond to freezing stress, and are able to protect cellular membranes from cold-induced dehydration damage. It is unknown which proteins are important for cultivars to withstand extreme temperature fluctuations and low temperatures that can injure over-wintering canes. The objective of this investigation is to observe the ability of two grape cultivars to survive extreme temperature fluctuations during coldacclimation, mid winter, and deacclimation. Experiments will be conducted to determine and compare changes in proteins during cold acclimation and deacclimation in canes for Frontenac and Seyval blanc grape cultivars

2003 Wine Grape Cultivar Trial

Through an Iowa Department of Agriculture and Land Stewardship (IDALS) specialty crops grant awarded to the Iowa Grape Growers Association (now the Iowa Wine Growers Association) and contracted to the ISU Department of Horticulture, a wine grape cultivar trial was established in 2003 to evaluate the adaptability, productivity, and wine-making quality of up to 20 cultivars or advanced selections. Four ISU farms representing different geographic, climatic, and soil conditions were selected for the trial: the Horticulture Station (Hort Station), Ames; the Armstrong Research Farm, Lewis; the Southeast Research Farm, Crawfordsville; and the Northeast Research Farm, Nashua. Cultivars and selections planted in 2003 included Rubiana (GR-7), NY73.136.17, NY84.0101.04, NY70.0809.10, La Crescent, Prairie Star, Cayuga White, Chancellor, DeChaunac, Esprit, Landot 4511, Leon Millot, St. Vincent, and Vidal Blanc. An additional five cultivars (NY76.0844.24, Frontenac Gris, Briana, MN-1211, and MN-1198) were added to the trial in 2004