감자 유전자원의 역병 저항성 평가

Evaluation of Potato Germplasm for Resistance to Late Blight Caused by Phytophthora infestans

This work was carried out to evaluate the resistance of potato germplasm against late blight in Korea. Seven races of Phytophthora infestans were detected from the main potato growing areas. Three races of pathogen were isolated from mono-cropping areas and five races of pathogen were isolated from double cropping areas in Korea. Of 160 isolates collected, 68% of the isolates were identified as race 1.3. Potato clones of CIP 724 and CIP 424 didn’t show the typical symptom of late blight on leaves by the race 1.3. The inoculated area of detached leaves turned brown after inoculation for four days at 20℃. On the other hand, the pathogen actively sporulated and formed the sporangia of pathogen on the detached leaves of 44 potato clones. In field trials, typical symptom of late blight was not developed in four clones of 46 germplams and varieties. However, CIP 424, which is resistance to race 1.3 in inoculation test, showed the susceptible response in the fields. This result indicated that single resistance gene could easily be broken by different races of Phytophthora infestans in fields. Mean area under the disease progress curve(AUDPC) between resistance and susceptible clones have shown the tremendous difference under disease pressure of Daegwallryeong area. It suggest that the potato clone need a horizontal resistance genes against the diversified race in fields.