Screening rapeseed/canola for resistance to damping-off and seedling root rot caused byRhizoctonia solani

Abstract
Rapeseed canola (B. napus L. and B. campestris L.) genotypes (300) were evaluated for their resistance to damping-off and seedling root rot caused by R. solani Kuhn. Tests were conducted in a growth chamber programmed to simulate spring soil temperatures in the main canola growing area of east central Saskatchewan [Canada], a low of 7.degree. C. Seeds planted in noninfested soil-free-growth-medium (SFM) were covered with a 1 cm layer of SFM infested with 35 isolates of R. solani with a viable propagule count of 5.7 .times. 103/l mix. the percentages of seedling emergence after 7 days and of survival and healthy plants after 21 days were used as criteria to rank entries. Although none of the genotypes exhibited complete resistance, 5 B. campestris, and 5 B. napus genotypes performed significantly better than either Regent (B. napus) or Candle (B. campestris), the 2 licensed canola cultivars most widely grown at the time of testing. In artificially-infested field plots, the progenies of these genotypes also performed better than the commonly grown cultivars.