Monday, November 13, 2006 - 3:30 PM

Morphology and Phenology of Hairy Vetch (Vicia villosa) Varieties and Implications for Hardiness as Winter Cover Crops.

Brook J. Wilke, Michigan State Univ, Kellogg Biological Station, 3700 East Gull Lake Dr, Hickory Corners, MI 49060, Sieglinde Snapp, 3700 E. Gull Lake Drive, Michigan State University, Michigan State University, Kellog Biological Station, Hickory Corners, MI 49060, and Kitty O'Neil, Michigan State Univ, Dept of Crop and Soil Sciences, 572 Plant and Soil Science Bldg., East Lansing, MI 48824.

Hairy vetch (Vicia villosa) is a notably cold tolerant winter annual legume. In cool temperate agriculture systems this legume species has a unique role to play as a fall-established cover crop that potentially can fix nitrogen and provide significant living cover after a summer cash crop is harvested. There are significant establishment and management challenges with using this winter annual cover crop, including a deficiency of knowledge about available varieties. The objective of the research was to document the morphological and phenological characteristics of V. villosa varieties under environmentally controlled and cold-treatment conditions and to make correlations between morphology and cold tolerance. Nine varieties, including three from local seed sources, three named cultivars and three accessions were obtained for growth characterization. Early (23 days after planting) and late (84 & 104) destructive harvests showed significant phenotypic variation in specific leaf area, pubescence, height, root to shoot ratio, relative growth rate and total dry mass (P<0.05). Individuals flowering at the time of the late harvests produced significantly less biomass, fewer secondary basal stems, but more secondary axial stems. The number of secondary basal stems was negatively correlated with the number of secondary axial stems (P<0.05). A common variety sold in Michigan, but produced in Oregon, had significantly less pubescence (leaf hairs) than two other U.S. Midwestern ‘common’ varieties at all three harvests (P < 0.01). The degree of pubescence varied with genotype origin and may be positively correlated with winter hardiness. Six varieties were subjected to freezing temperatures in a controlled environment to evaluate pubescence and other characteristics in relationship to cold tolerance. Only three of the six varieties exhibited partial survival at -6 oC, and no plants survived the -12 oC treatment. Understanding the ecology of hairy vetch varieties will aid farmers in effectively choosing genotypes and winter cover management strategies.