Location: Horticultural Crops Disease and Pest Management Research Unit
Project Number: 2072-22000-045-024-G
Project Type: Grant
Start Date: May 1, 2022
End Date: Oct 31, 2025
Objective:
This multi-state collaborative proposal will screen novel cold hardy, phylloxera resistant rootstocks from the University of Minnesota (UMN) breeding program. Additional horticultural characterization (grafting capability, winter survival) of stock vines in field trials will be completed at University of Minnesota and Washington State University to evaluate commercialization candidacy of rootstocks for implementation in the Pacific Northwest (PMW). Comprehensive assessment for nematode resistance will be conducted by USDA-ARS Horticulture Crops Research Laboratory (HCRU). It is expected that this collaborative research will result in additional rootstock options for planting in PNW vineyards. Four rootstocks will be evaluated and the results will be presented to nurseries and growers in the PNW as well as in the Midwest at annual conferences or through extension communications. Results of this study may lead to variety release (and in the grape foundation vineyard at the Clean Plant Center Northwest) and associated peer-reviewed manuscripts describing the materials and results of this study.
Objective 1: Stock plant evaluation.
Objective 2: Evaluate potential cold hardy rootstocks for nematode resistance.
Objective 3: Field studies of grafted vines in Washington.
Approach:
Objective 1: Stock plant evaluation. Rootstock will be evaluated at UMN. The field grown stock plants will be assessed for 3 growing seasons in Minnesota to provide sufficient varietal information for potential cultivar release: phenology (budbreak, flowering, fruiting, and véraison, periderm development, and growth cessation), flower sex, internode length and diameter, stem straightness and graft suitability, and counts of units for grafting. Stock plants will be evaluated weekly for seasonal phenology (and any disease or insect pest incidence will be noted). When the vines are pruned, all material will be weighed to assess productivity and bud survival. Internode length and width measurements along with counts of units for grafting will be taken. Data will be analyzed using ANOVA to compare varieties and summarized using R statistical software.
Objective 2: Evaluate potential cold hardy rootstocks for nematode resistance. Dormant cuttings of the rootstock selections will be collected in Winter 2022 and 2023 and rooted at UMN on a mist bench. The rooted cuttings will be sent to HCRU. The rootstocks along with own-rooted V. vinifera ‘Chardonnay’ as a positive nematode control will be evaluated in the greenhouse: genotypes will be replicated 5 times and the experiment arranged in a randomized block design in a greenhouse. Vines will be inoculated with eggs of the southern root-knot nematode (M. incognita) or the northern root-knot nematode (M. hapla); both are maintained at HCRU on tomato. The inclusion of M. incognita in the experimental design will allow for comparison with available literature, and the inclusion of M. hapla has direct application to the species of root-knot nematode found in northern climates. About 5 months after nematode inoculation, pots will be destructively harvested. Nematode eggs will be extracted from roots and collected eggs will be enumerated. Shoot and root dry weights will be determined. Data will be analyzed using ANOVA to detect differences in nematode parasitism and plant growth. This experiment will be conducted twice.
Objective 3: Field studies of grafted vines. Dormant rootstock materials will be collected in Winter 2022 and 2023 at UMN and will be rooted and prepared for grafting experiments. Rootstocks of each selection, approximately 40, will be grafted using the industry standard practice of omega grafting with WSDA certified ‘Chardonnay’ as the scion. Self-grafted controls will also be used in this experiment. The vines will be transferred to WSU Prosser IAREC for healing in and for the field study. A randomized complete block design field trial will be used to evaluate graft compatibly and first season growth. Each winter half of the plant materials will be dissected at the graft union to assess compatibility. The remaining vines will be left in the field for preliminary data collection on the timing of scion bud break the following spring. The first planting will occur in the summer of 2022, and the trial will be repeated with a planting in summer 2023. Data will be analyzed in JPM using GLMM, for the influence of the corresponding rootstock on vine survival characteristics.
