Submitted to: Northwest Center for Small Fruit Research Proceedings
Publication Type: Proceedings
Publication Acceptance Date: 10/24/2008
Publication Date: 12/3/2008
Citation: Schreiner, R.P., Pinkerton, J.N., Bryla, D.R. 2008. Evaluation of nematode resistant grape rootstock for managing Mesocriconema xenoplax. Northwest Center for Small Fruit Research Proceedings. 17:24-26.
Technical Abstract: The objective of this study is to better understand the impact of the ring nematode, Mesocriconema xenoplax, on the productivity and physiology of grapevines grafted onto different rootstocks that showed varying resistance to ring nematodes under greenhouse conditions. Pinot noir grapevines (grafted onto five rootstocks or self-rooted) are in their third year of growth in microplots (25 gallon pot-in-pot). Six vines in each rootstock treatment have been infested or not with ring nematodes. Vines were thinned to eight shoots (four per fruiting cane) with two renewal spurs in late May, and fruit clusters were thinned to one per shoot in early August of 2008. All plots were irrigated as needed to maintain soil moisture above 15% volumetric water content. Nematode populations appear to have reached threshold levels in each of the different rootstock treatments (no increase since July 2007), and all have been consistently affected by rootstocks. The highest ring nematode populations were found in the self-rooted vines, while intermediate levels of nematodes occurred in 1103P and 3309C and the lowest levels occurred in 420A, 101-14 and 110R vines. The first signs of nematode impact on the vines were noticed below-ground (as one might expect) in the summer of 2007, with nematodes reducing fine root growth and percent colonization by arbuscular mycorrhizal fungi and increasing soil respiration in self-rooted vines only. However, there were no effects of the nematodes on above-ground plant growth, gas exchange, or water relations in 2007. Nematodes also did not affect vine nutrient status in 2007, although rootstocks did. So far in 2008, shoot length of vines measured in early July mirrored the effect we observed on roots last year, such that nematodes reduced shoot growth in self-rooted vines only. Our first measurements of gas exchange and soil respiration in 2008 have not shown a similar trend with respect to self-rooted vines, but both measures have been higher in nematode infested plots as compared to non-infested plots (main effect across all rootstocks).