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Submitted to: American Society of Enology and Viticulture Annual Meeting Abstracts
Publication Type: Abstract Only Publication Acceptance Date: 2/11/2001 Publication Date: 6/28/2001 Citation: Baumgartner, K. 2001. Effects of commercially-available arbuscular mycorrhizal fungi on grapevine growth. American Society of Enology and Viticulture Annual Meeting Abstracts. Interpretive Summary: Although soil fumigation is useful for killing plant pathogens, this practice also kills microbes that are beneficial to plants, such as arbuscular mycorrhizal (AM) fungi. AM fungi colonize the roots of plants, enabling more efficient phosphorus uptake which improves plant growth. Past research identified the importance of AM fungi in the survival of grapevines planted into recently-fumigated soil. Delayed colonization of young vines by AM fungi may result in stunted growth and nutrient deficiencies. Inoculation of vines with commercially-available AM fungi (bio-inoculants) at the time of planting may compensate for reductions in AM fungi due to methyl bromide. We compared the effects of two bio-inoculants, MycorMax (JH Biotech, Inc., Ventura, CA) and Bio-Organics Endomycorrhizal Inoculant (Mycorrhizae Inoculants, La Pine, OR), on growth of three grapevine rootstocks, 101-14 Mgt., St. George, and 110R, in the greenhouse. Non-inoculated rootstocks were maintained as controls. Shoots and roots were harvested six months following inoculation. Fresh weights were recorded. Roots were examined for percentage of root length colonized by AM fungal structures. Based on the analysis of these data, inoculation with either bio-inoculant did result in root colonization by AM fungal structures. Inoculated plants were the same size as non-inoculated plants. Higher application rates may result in higher percent root colonization and, possibly, significant growth increases of inoculated vines. Other potential benefits of bio-inoculants that we did not measure, which have been demonstrated for AM fungi on various hosts, include increased nutrient uptake, enhanced resistance to plant pathogens, and stabilization of soil structure. Technical Abstract: Past research on the effects of methyl bromide fumigation on soil-borne propagules of arbuscular mycorrhizal (AM) fungi identified the importance of these beneficial microbes in the survival of grapevines planted into recently-fumigated soil. Delayed colonization of young vines by AM fungi may result in stunted growth and nutrient deficiencies. Inoculation of vines with commercially-available AM fungi (bio-inoculants) at the time of planting may compensate for reductions in AM fungi due to methyl bromide. We compared the effects of two bio-inoculants, MycorMax (JH Biotech, Inc., Ventura, CA) and Bio-Organics Endomycorrhizal Inoculant (Mycorrhizae Inoculants, La Pine, OR), on growth of three grapevine rootstocks, 101-14 Mgt., St. George, and 110R. Rootstocks were propagated from dormant cuttings in the greenhouse in nutrient-poor or nutrient-rich potting mix. Bio-inoculants were applied at recommended rates. Non-inoculated rootstocks were maintained as controls. Shoots and roots were harvested six months following inoculation. Fresh weights were recorded. Roots were examined for percentage of root length colonized by AM fungal structures. Based on the results of an analysis of variance, inoculation with either bio-inoculant resulted in significant root colonization by AM fungal structures. However, neither bio-inoculant had significant effects on growth of inoculated vines, compared to growth of non-inoculated vines. Potting mix, rootstock, and block did have significant effects on percent root colonization by AM fungal structures, shoot weight, and/or root weight. Higher application rates may result in higher percent root colonization and, possibly, significant growth increases of inoculated vines. |
