ARBUSCULAR MYCORRHIZAL FUNGI INFLUENCE DROUGHT TOLERANCE OF GRAPEVINES UNDER FIELD CONDITIONS

Authors: Schreiner, Roger - Paul

Submitted to: Proceedings of Fourth International Conference on Mycorrhizae
Publication Type: Abstract Only
Publication Acceptance Date: 4/1/2003
Publication Date: 8/10/2003
Citation: ARBUSCULAR MYCORRHIZAL FUNGI INFLUENCE DROUGHT TOLERENCE OF GRAPEVINES UNDER FIELD CONDITIONS. Schreiner, R.P.

Interpretive Summary: The seasonal dynamics of root growth and colonization by arbuscular mycorrhizal fungi (AMF) were studied over two years in a deficit-irrigated Cabernet Sauvignon vineyard on a sandy soil and in a dryland Pinot Noir vineyard on a silty clay loam. Cabernet vines received one of the following irrigation regimes 3 years prior to and during our study; Control vines received 60% Et from fruit set to harvest, Early deficit vines received 30% Et from fruit set to veraison and 60% Et afterwards, and Late deficit vines received 60% Et to veraison and 30% Et from veraison to harvest. Growth of roots expressed on a mass or length basis was greatest between bloom and veraison in the irrigated vineyard. Fine root growth was depressed, however, in both water deficit treatments relative to control vines. Colonization of fine roots by AMF was consistently high (87-97% root length colonized) in all treatments throughout the study. However, the frequency of fine roots with arbuscules was significantly greater in both water deficit treatments throughout most of the year. Whole vines were removed from the dryland vineyard over two years to construct a mineral uptake and allocation budget in addition to monitoring AMF. Results from this study showed that arbuscule frequency in fine roots peaked after the period of maximal N and P uptake, when soil moisture was at a minimum. These studies indicate that AMF enhance the drought tolerance of grapevines in vineyard production systems.

Technical Abstract: The seasonal dynamics of root growth and colonization by arbuscular mycorrhizal fungi (AMF) were studied over two years in a deficit-irrigated Cabernet Sauvignon vineyard on a sandy soil and in a dryland Pinot Noir vineyard on a silty clay loam. Cabernet vines received one of the following irrigation regimes 3 years prior to and during our study; Control vines received 60% Et from fruit set to harvest, Early deficit vines received 30% Et from fruit set to veraison and 60% Et afterwards, and Late deficit vines received 60% Et to veraison and 30% Et from veraison to harvest. Growth of roots expressed on a mass or length basis was greatest between bloom and veraison in the irrigated vineyard. Fine root growth was depressed, however, in both water deficit treatments relative to control vines. Colonization of fine roots by AMF was consistently high (87-97% root length colonized) in all treatments throughout the study. However, the frequency of fine roots with arbuscules was significantly greater in both water deficit treatments throughout most of the year. Whole vines were removed from the dryland vineyard over two years to construct a mineral uptake and allocation budget in addition to monitoring AMF. Results from this study showed that arbuscule frequency in fine roots peaked after the period of maximal N and P uptake, when soil moisture was at a minimum. These studies indicate that AMF enhance the drought tolerance of grapevines in vineyard production systems.