QUANTITATIVE-EVALUATION OF RESISTANCE OF KOREAN TOMATO CULTIVARS TO ISOLATES OF PHYTOPHTHORA-CAPSICI FROM DIFFERENT GEOGRAPHIC AREAS

The resistance of 10 Korean tomato cultivars to seven isolates of Phyt ophthora capsici was evaluated by using stem wounding and foliar spray ing methods under controlled environmental conditions. The response of tomato cultivars tested to Phytophthora blight was quantitative rathe r than qualitative. There were highly significant differences among th e isolates in virulence to the Korean tomato cultivars, indicating som e pathogenic variation in P. capsici. Significant differences were als o observed among cultivar X isolate interactions in the analysis of va riance. When the inoculation was by stem wounding, no symptoms develop ed in the stems of mature tomato plants. Expression of the age-related resistance to Phytophthora blight was more apparent in tomato stems t han in tomato leaves. The foliar spraying inoculation method was effec tive in screening tomato cultivars for resistance to P. capsici, where as the soil drenching and stem wounding inoculation techniques were le ss reliable for evaluating cultivar resistance on old tomato plants.