Author
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Pinkerton, John |
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VASCONCELOS, M - OREGON STATE UNIVERSITY |
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Submitted to: American Journal of Enology and Viticulture
Publication Type: Peer Reviewed Journal Publication Acceptance Date: 9/26/2004 Publication Date: 12/1/2005 Citation: Pinkerton, J.N., Vasconcelos, M.C. 2005. Reaction of grape rootstocks to ring nematode Mesocriconema xenoplax. American Journal of Enology and Viticulture. 56:377-385. Interpretive Summary: The ring nematode, Mesocriconema xenoplax¸ is a common plant-parasitic nematode in Pacific Northwest vineyards and has been shown to reduce the growth and fruit yield of young vines. The objective of this research was to identify grape rootstock that are resistant and/or tolerant to this nematode. Population growth of one Oregon population of M. xenoplax differed significantly among 20 rootstock and self-rooted varieties grown in glasshouse trials for 8 months. Three rootstocks, 420A Mgt, 101-14 Mgt, and 110 Richter were resistant, while all other rootstock were susceptible. In another glasshouse experiment, Mgt 420A and Mgt 101-14 also were resistant to four Oregon populations of M. xenoplax and one Washington State population, but both cultivars were susceptible to a California population. Results suggest that the pathotype of M. xenoplax from California was different from the pathotype common in the Pacific Northwest. Nematode population and plant data also were collected 6 and 7 years after planting 16 rootstock cultivars a replicated vineyard trial. Rootstock 420A Mgt produced good vine vigor and yield and showed the highest degree of M. xenoplax resistance. Rootstock 101-14 Mgt, which is widely used in Oregon, was also resistant but produced only average vigor and yield. Other rootstocks popular in Oregon, Riparia Gloire, 3309 Coudrec, and self-rooted Pinot Noir, were highly susceptible to M. xenoplax and were among the least vigorous vines in the vineyard. Planting rootstock cultivars with resistance is recommended on sites infested with the ring nematode, particularly on sites on which vines are subjected to other stresses. Technical Abstract: The reaction of grape rootstocks to the ring nematode, Mesocriconema xenoplax¸ was studied in glasshouse experiments and in a vineyard trial. Growth of one Oregon population of M. xenoplax differed among 20 rootstock and self-rooted cultivars grown in the glasshouse for 8 months. The reproductive factor, Rf, which equals final nematode density divided by initial nematode density, was '0.5 for 420A Mgt rootstock and '2.4 for 101-14 Mgt and 110 Richter rootstocks; Rf values '1 indicate high nematode resistance. Other rootstocks had Rf values between 6.9 and 52.5. Root dry weights of all varieties, except 420A Mgt, were reduced by M. xenoplax. In another glasshouse experiment, 420A Mgt and 101-14 Mgt were found to be resistant to one Washington State and four Oregon populations of M. xenoplax, although both were moderately susceptible to a California population. A rootstock trial was planted in 1997 in a vineyard infested with M. xenoplax. After 6 and 7 years, population densities of M. xenoplax were lowest in vines on 420A Mgt (' 0.08 g-1 soil) and 101-14 Mgt (' 0.24 g-1 soil) rootstocks. Population densities on other rootstocks ranged from 1.25-4.57 g-1 soil. 420A Mgt produced good vine vigor and yield and showed the highest degree of M. xenoplax resistance. Rootstock 101-14 Mgt, which is widely used in Oregon, was also resistant but produced only average vigor and yield. Other common Oregon rootstocks, Riparia Gloire, 3309 Coudrec, and self-rooted Pinot Noir, were highly susceptible to M. xenoplax and were among the least vigorous vines |
