• Research in Plant Disease
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• v.16 no.2
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• pp.141-147
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• 2010

Resistance to Phytophthora blight (Phytophthora capsici Leonian) of commercial cultivars of Capsicum pepper in Korea were evaluated from 2008 to 2010. In 2008 and 2009, the cultivars were tested for resistance to the Pc003 isolate collected in Youngyang, Gyeongbuk province. In 2010, the selected cultivars in the previous years were tested by inoculating with 3 isolates obtained from the pepper plants in Miryang in Gyeongnam province, Youngyang in Gyeongbuk province, and Goesan in Chungbuk province. A continuous variation in resistance from highly resistant to susceptible was observed among the commercial pepper cultivars. It was also noted that some cultivars, although their names were initiating with 'Yeokgang' or 'PR' meaning Phytophthora resistance, were very low in resistance or susceptible. When the resistant cultivars selected in 2008 and 2009 experiment were inoculated with the 3 isolates, all the commercial cultivars except a rootstock, 'Tantan', succumbed to the exceptionally virulent Pc005 (Miryang) isolate. Pc002 (Goesan) was a little more virulent than Pc003 (Youngyang). A few cultivars resistant to Pc003 (Youngyang) were severely infected by Pc002 (Goesan). Significant interaction in analysis of variance suggested the differential interactions between cultivars and pathogen isolates. Strategies to breed cultivars having high level of resistance to the highly variable pathogenic fungus, Phytophthora capsici, were discussed.

• Current Research on Agriculture and Life Sciences
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• v.32 no.3
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• pp.111-117
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• 2014

Phytophthora blight caused by Phytophthora capsici Leonian is a dangerous disease threatening pepper growers worldwide. The efficacy of chemical control is generally low as the pathogen is soil-borne and rapidly spread by zoospores during the rainy season. Thus, based on the demand for resistant varieties, various good resistant sources, such as CM334, AC2258, and PI201234, have been reported and their inheritance of resistance studied by many different authorities. However, the mode of inheritance remains unclear, as 1 or 2 independent dominant genes, 3 genes, or multiple genes have all been reported as responsible for resistance. Recently, QTL mappings of the gene factors for resistance have been reported, and molecular markers for resistance used in breeding programs. With the release of many resistant commercial hybrid cultivars, differentiation of pathotypes of the pathogen is attracting interest among breeders and plant pathologists. Various authorities have already classified the pathogen strains into different races according to the inter-action between resistant host plants, including the source of resistance, such as CM334 and PI201234, and resistant commercial varieties and P. capsici isolates. However, no standard differential host sets have yet been established, so the results are good only for the pathogen strains used in the experiments. Thus, for breeding varieties with durable resist-ance, it is important to introduce resistance from different sources and use diverse local pathogen strains collected in the target area for distribution in a breeding program.