Taylor Holland,* Carl Bogdanoff, Pat Bowen, Rob Brownlee, and Miranda Hart
*University of British Columbia, Okanagan, #308 2495 Mt. Baldy Dr., Kelowna/BC/v1v 3b4, Canada (taylor.holland@ubc.ca)

Grapevine roots associate with arbuscular mycorrhizal (AM) fungi, symbiotic organisms generally known for the array of benefits they provide host plants such as increased biomass, environmental stress tolerance, and pathogen protection. Although AM fungi likely play an important role in establishing young grapevines, the symbiosis needs to be better understood for AM fungi to be best utilized in grapevine management. For example, what AM fungi are best suited for inoculating grapevines? Because commercial inoculants are produced using only one or a few AM fungal species grown on grass and forb roots in artificial conditions, it may be better to inoculate grapevines with more natural communities containing more diverse mixtures of AM fungi. This study compared the growth effects of natural and commercial AM fungal inoculants on grapevine rootstocks. We inoculated three rootstocks (Riparia gloire, 101-14 Mgt, and SO4) with natural AM communities (isolated from native woody shrubs located adjacent to vineyards) and commercial AM fungal strains. Rootstocks had greater biomass when inoculated with natural AM fungi than with the commercial isolates, both above and below the ground. Due to the nature of the natural inoculant, it is possible that the microbial community as a whole may be responsible for these growth differences, however this is a potential benefit to using whole soil or root communities compared to commercial additives.

Funding Support: Natural Sciences and Engineering Research Council of Canada, Organic Agriculture Centre of Canada Agriculture, and Agri-Foods Canada Killam Laureates Trust