科研之友
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摘要
Resting spores of Plasmodiophora brassicae (clubroot) can survive for many years in soil, so crop rotation has not been considered as a major tool for clubroot management. However, it was not known if 2- to 5-year crop rotations would reduce the pathogen inoculum in soil and alleviate disease impact. Two field trials were conducted at a heavily infested site. In 2012, susceptible, moderately susceptible and resistant canola cultivars were seeded to plots with a 0- to 4-year break from susceptible canola. Resting spores in soil were estimated using a quantitative PCR assay. In the second trial on adjacent plots in 2013, three resistant cultivars were evaluated. A break from susceptible canola >= 2 years resulted in a >90% reduction in resting spores relative to continuous canola or a 1-year break, which, however, failed to reduce the clubroot severity substantially on susceptible or moderately susceptible cultivars. Plants of these cultivars died before maturity in plots of continuous canola or a 1-year break, and were stunted in plots of 2- to 4-year breaks. A >= 2-year break increased the yield of all cultivars relative to continuous canola, but the yield was low (<400 kg ha(-1)) for susceptible or moderately susceptible cultivars with all rotation intervals. The yield for resistant cultivar was >1230 kg ha(-1) in continuous canola, and a 2- to 4-year break increased the yield by 32-76%. It was showed here that, for the first time, most P. brassicae resting spores disintegrate within first two years in soil. We also demonstrate that a 2- to 4-year break under heavy infestation alleviate the impact of clubroot on susceptible or moderately susceptible cultivars only marginally, but increase the yield of resistant cultivars substantially. Therefore, a >2-year break from canola is recommended with use of resistant cultivars for clubroot management on canola.
- 出版日期2015-10
