Author
CHENG, XIA0MEI - UC-SAREP | |
Baumgartner, Kendra |
Submitted to: HortScience
Publication Type: Peer Reviewed Journal Publication Acceptance Date: 3/22/2004 Publication Date: 12/1/2004 Citation: Cheng, X., Baumgartner, K. 2004. Survey of arbuscular mycorrhizal fungal communities in Northern California vineyards and mycorrhizal colonization potential of grapevine nursery stock. HortScience. 39: 1702-1706. Interpretive Summary: Grapevines (Vitis spp.) have been reported to naturally form arbuscular mycorrhizal (AM) symbioses with AM fungi in grape-growing regions worldwide. AM fungal species vary in their efficiency of colonizing grapevine roots and improving grapevine growth. Vineyard practices, such as fumigation, likely alter AM fungal community composition. We characterized the indigenous AM fungal community in five fumigated and five non-fumigated vineyards in Northern California. None of the vineyards we surveyed lacked AM fungi, but AM fungal community composition differed among the ten vineyards. Most of the AM fungi we identified were in the genus Glomus. AM fungal diversity was greater in non-fumigated than in fumigated vineyards. We also quantified AM colonization potential of field-propagated grapevine nursery stock. We grew dormant benchgrafts and potted dormant benchgrafts of Cabernet Sauvignon on three rootstocks (101-14, 110R, and St. George) in sterile potting mix in greenhouse. After seven months of growth, new roots initiated from dormant roots of the dormant benchgrafts and potted dormant benchgrafts were colonized by AM fungi. Mycorrhizal colonization of new roots of dormant benchgrafts was significantly higher than that of potted dormant benchgrafts. The higher mycorrhizal colonization of dormant benchgrafts may be due to the fact that they were planted in compact rows where their root systems were in direct contact with each other, unlike potted dormant benchgrafts, which were propagated individually in pots. Our results suggest that field-propagated nursery stock can serve as a source of AM fungi. Dormant benchgrafts, with their higher mycorrhizal colonization than potted dormant benchgrafts, may be better suited for fumigated and/or low phosphorus soils than potted dormant benchgrafts. Technical Abstract: We characterized the indigenous arbuscular mycorrhizal (AM) fungal community in five fumigated and five non-fumigated vineyards in Northern California. None of the vineyards we surveyed lacked AM fungi, but AM fungal community composition differed among the ten vineyards. Most of the AM fungi were in the genus Glomus. Paraglomus occultum Morton & Redecker, G. etunicatum Becker & Gerd., and G. aggregatum Schenck & Smith emend. Koske were the most common species identified. AM fungal diversity was greater in non-fumigated than in fumigated vineyards. We also examined field-propagated grapevine nursery stock as a potential source of AM fungi for fumigated vineyards. We quantified AM fungal colonization of new roots initiated from dormant benchgrafts and potted dormant benchgrafts of Cabernet Sauvignon on three rootstocks (101-14, 110R, and St. George). After seven months of growth in the greenhouse, new roots initiated from dormant roots of the dormant benchgrafts and potted dormant benchgrafts were colonized by AM fungi. Mycorrhizal colonization of new roots of dormant benchgrafts was significantly higher than that of potted dormant benchgrafts. The higher mycorrhizal colonization of dormant benchgrafts may be due to the fact that they were planted in compact rows where their root systems were in direct contact with each other, unlike potted dormant benchgrafts, which were propagated individually in pots. Our results suggest that field-propagated nursery stock can serve as a source of AM fungi. Dormant benchgrafts, with their higher mycorrhizal colonization than potted dormant benchgrafts, may be better suited for fumigated and/or low phosphorus soils than potted dormant benchgrafts. |