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Evaluation of rootstocks for Concord and Niagara grapes in the Lake Erie production region. © 2003
Objectives: Background and Justification: |
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Many rootstock trials have demonstrated the yield benefit of grafting Concord and Niagara. Experiments at the Fredonia Vineyard Laboratory attributed more than a 20% yield increase in Concord to the use of the phylloxera resistant rootstock 3309 C. Grafted vines are usually larger than own-rooted Concord and larger vines are able to set and ripen greater amounts of fruit. While 3309 C is demonstrated to both increase vine size and yield in Concord, this rootstock is not considered the most invigorating of rootstocks. Determining if more vigorous rootstocks can increase vine capacity and yield is a priority to meet the need for consistently higher yields. The industry target is 8 tons of Concord grapes per acre, although this goal was not met in 2000. Studies in Niagara establishment have demonstrated the benefit of irrigation, a benefit that might be substituted by the use of rootstocks.
Water availability is known to affect Concord and Niagara grape productivity. Some rootstocks are known to improve a vine's resistance to drought; reduced drought sensitivity is one component of increased yields of grafted Concord vines. More vigorous varieties might further reduce the damage due to drought by penetrating deeper into the soil and capturing water unavailable to shallower rooted varieties. Rootstocks need to be evaluated for their potential to enhance drought resistance.
Variation in soil adaptation influences the appropriate choice of rootstock variety. Certain rootstocks are better suited to use on well-drained soils, others on wetter sites. Because of the diversity of soils present in the Lake Erie region, site selection must and will reflect those soil types important commercially.
Rootstock evaluation and breeding have improved the quality of rootstock selections suitable for the Lake Erie region. New information indicates that some rootstocks tested with Concord and Niagara in the past, such as Lenoir and 1202 C, do not have sufficient resistance to phylloxera to be used in areas prone to infestation by this pest. Only rootstocks with demonstrated durable phylloxera resistance will be tested.
European rootstock research continues to result in new varieties that should be tested with Concord and Niagara. Gravesac was developed in France and is recognized for its excellent phylloxera resistance and adaptation to acidic soils, which predominate in many parts of the Lake Erie region. Rootstocks more suited to calcareous soils might perform poorly in acidic sites, regardless of their phylloxera resistance, drought tolerance, and other desirable traits. The performance of this rootstock in the United States is poorly characterized. Examining Gravesac in the Lake Erie region will help establish its adaptation and utility to U.S. viticultural conditions and practices, and will benefit producers of other types of grapes, including other native varieties, Vitis vinifera wine, table, and raisin grapes, and hybrid varieties.
Viticultural practices for Concord and Niagara have changed since many of the rootstock trials for this variety were conducted. New techniques in training, trellising, pruning, floor management, fertilization, and harvest impact the yield, vigor, and capacity of vines. As management approaches change, rootstock evaluations must continue to match current practices in order to remain relevant to growers.
Procedure:
Eight rootstock varieties grafted to Concord and Niagara will be evaluated.
The rootstocks were selected to include varieties commercially available and
to reflect a range of parentage and perceived vigor. Several rootstocks previously
recommended for use with Concord in the Lake Erie production region are included.
Widely commercially available rootstocks included are 101-14 Mgt, 3309 C, 110
R, SO4, 420 A, 44-53 M, and Riparia Gloire. A rootstocks newly introduced to
the United States, Gravesac, will be tested. Own-rooted Concord and Niagara,
which predominate in this production area, will serve as checks.
The experiment will be a randomized complete block design. There will be two locations, representing well-drained, gravelly soils, and heavier, poorly drained soils. At each location, both Concord and Niagara will be planted. Within each variety treatment at each site, there will be eight replicates of the experimental unit. The experimental unit will be a set of six plants on the same rootstock. At an 8 x 9 foot spacing, the 1632 vines of this experiment will occupy 2.7 acres, each of the two sites having about 1.35 acres.
The trial will be established using dormant one-year old benchgrafts or cuttings, using virus-indexed Concord and Niagara source wood. Plants will be obtained from a commercial nursery source. The study is intended for establishment in spring, 2001. The plants will be cultivated in accordance with the standard vineyard practices for the region, including establishment, training, and harvest. Winter pruning will be performed to permit collection of pruning weight data.
Evaluation of horticultural characteristics will begin in the second season. Growth and canopy parameters to be measured will include pruning weight, shoot leaf area, shoot length, lateral growth, internode number and length, fruit exposure, canopy density, and yield/pruning weight ratio. Root pest populations, particularly phylloxera, will be determined. Fruiting characteristics including fruit yield, sugar level, color, bunch disease incidence, cluster numbers, and quality will be assessed. Rootstock variety impact on horticultural characteristics will be compared using analysis of variance. Interactions between rootstock variety, scion variety, and soil types will be calculated.
Outcome and Benefits Expected:
Viticultural performance of Concord and Niagara on eight rootstocks and their
own roots will be measured in the proposed study. The experimental design will
test direct rootstock effects and the interaction of rootstocks with scion variety
and soil type. The results will help guide recommendations for rootstock use
and hopefully enable growers to use rootstocks to increase vine capacity and
vigor, and reduce damage from drought and phylloxera with greater accuracy and
to greater benefit.
The results will be made available to grape growers, nurseries, and other industry participants and the scientific community, including farm advisors and Cooperative Extension specialists. The principle investigators present their research to grape growers at field days and other industry meetings and would include the results of this study in their presentations. Publication of results in grape industry periodicals will be sought. This study addresses both fundamental and applied questions of rootstock impact on Concord and Niagara grapevine capacity and vigor. Study results are expected to be suitable for publication in a peer-reviewed journal such as the American Journal of Enology and Viticulture or the Journal of the American Society for Horticultural Science. Presentation of the results at forums such as the American Society for Enology and Viticulture annual meeting would be appropriate.
