Foster J M, Hausbeck M K
Former Graduate Research Assistant.
Professor, Department of Plant Pathology, Michigan State University, East Lansing 48824.
Plant Dis. 2010 Jan;94(1):24-30. doi: 10.1094/PDIS-94-1-0024.
Greenhouse and laboratory experiments were conducted to determine the virulence of four Phytophthora capsici isolates from Michigan to 31 bell and hot pepper cultivars and breeding lines. Resistance to crown and root rot was assessed following the inoculation of soilless media with P. capsici-infested millet seed. In a detached fruit assay, fruit rot resistance was evaluated following inoculation with zoospore suspensions of 1.75 × 10 zoospores/ml. The four isolates differed in virulence to pepper lines screened for crown and root rot resistance and were considered to be four different physiological races. The pepper lines CM334, NY07-8001, NY07-8006, and NY07-8007 were resistant to the isolates tested. None of the commercial cultivars were resistant to P. capsici isolate 12889, but several cultivars were resistant to the other isolates screened. The isolates varied in their ability to cause infection on the fruits of the different cultivars. Overall, pepper fruit were more susceptible to P. capsici than the roots and crowns. Management of Phytophthora crown and root rot of pepper can be improved through the use of resistant cultivars. However, since isolate virulence affects resistance, cultivar resistance will need to be utilized on a local scale accordingly.
进行了温室和实验室试验，以确定从密歇根州分离出的4种辣椒疫霉菌株对31个甜椒和辣椒品种及育种系的毒力。在无土培养基中接种受辣椒疫霉菌侵染的小米种子后，评估对冠腐病和根腐病的抗性。在离体果实试验中，接种浓度为1.75×10个游动孢子/毫升的游动孢子悬浮液后，评估果实腐烂抗性。这4种菌株对筛选出的抗冠腐病和根腐病的辣椒品系的毒力不同，被认为是4个不同的生理小种。辣椒品系CM334、NY07-8001、NY07-8006和NY07-8007对测试的菌株具有抗性。没有一个商业品种对辣椒疫霉菌株12889具有抗性，但有几个品种对其他筛选出的菌株具有抗性。这些菌株在侵染不同品种果实的能力上存在差异。总体而言，辣椒果实比根和冠更容易受到辣椒疫霉的侵害。通过使用抗性品种可以改善辣椒疫霉冠腐病和根腐病的管理。然而，由于菌株毒力会影响抗性，因此需要在当地相应地利用品种抗性。
