Wednesday, November 15, 2006 - 3:55 PM

New, 24-H Seed Vigor Assays for Canola.

Wayne T. Buckley1, R. Byron Irvine1, Katherine E. Buckley1, and Bob Elliott2. (1) Agriculture & Agri-Food Canada, Brandon Research Centre, P.O. Box 1000A, RR 3, 18th St and Grand Valley Rd, Brandon, MB R7A 5Y3, Canada, (2) Agriculture & Agri-Food Canada, 107 Science Pl, Saskatoon, SK S7N 0X2, Canada

Poor canola seed vigor can reduce seedling emergence, crop establishment and oilseed yield.  A functional definition of seed vigor, used herein, is the average seedling biomass produced by a representative sample of seed expressed as a percentage of the biomass of a high-vigor check.  New, 24-h assays have been developed that detect deterioration in canola seed vigor in both treated and untreated seed.  The assays are based on a delayed conversion from anaerobic to aerobic metabolism in poor-vigor seed compared to high-vigor seed during the first 24 h of germination.  As a result of the extended period of anaerobic metabolism, poor-vigor seed generates considerably more ethanol than high-vigor seed.  The ethanol can be readily detected as a gas in an enclosed headspace above seed.  Two versions of the new assays have been developed—a color test and an instrumental test.  The reliability of the assays was evaluated with about 340 treated and untreated seed samples representing current seed treatments and a wide variety of canola genotypes.   Low seed ethanol emissions were found for seed that produced high seedling biomass grown hydroponically.  Below a biomass threshold, ethanol emissions from seed increased in a linear manner.