Vigor tests for evaluating establishment of canola under different growing conditions and tillage practices

Experiments were conducted to develop vigor tests for evaluating the establishment of open-pollinated Argentine canola, Brassica napus L., in conventional tillage (CT), minimum tillage (MT) and zero tillage (ZT). Sixteen seed lots of an open-pollinated cultivar were produced from swathing experiments in 2000 and 2001. Seed lots were assessed in 2003 in the standard germination test (SGT), accelerated aging test (AAT), controlled deterioration test (CDT), pre-chill test (PCT) and electrical conductivity test (ECT). Green seed content and 1000-seed weight were also determined. Establishment of the seed lots was evaluated at three sites with CT, two sites with MT and one site with ZT. The six sites also differed in soil texture and rainfall. Establishment averaged 75-79% in CT, 42-56% in MT and 17% in ZT. Establishment was lowest at sites with reduced tillage, heavy-textured clay and below-average rainfall. Thousand-seed weights, along with germination in the SGT, AAT, CDT and PCT were positively correlated with establishment in CT and MT but not in ZT. Depending on the site, establishment improved by 8-11% with each 1.0 g increase in 1000-seed weight. Germination in the SGT, AAT and CDT provided a better indication of establishment in CT and MT than germination in the PCT. Establishment improved by 1.4-2.4% with each 1.0% increase in germination in the SGT. Green seed content and conductivity were negatively correlated with establishment at all sites. Establishment declined 2-3% with each 1% increase in green seed and 10 microsecond cm(-1) g(-1) increase in conductivity after soaking seeds for 24 h. Conductivity after 4 or 24 h soaking provided the best indication of stand establishment at most field sites. The effects of swathing time on the quality, germination and vigor of canola seed lots are also discussed.