Evaluation of some potato clones for resistance to Phytophthora infestans.

In this study, a total of 232 clones, derived from 13 different hybrid families were evaluated for resistance to P. infestans in detached leaf tests. One local genotype (Başçiftlikbeyazı) and two commercial cultivar (Agata and Burren) were used as succeptible control. Fully developed leaflets were detached from the middle part of the 6-weekold field-grown potato plants. Three detached leaflets of each clone were inoculated with 5-mm agar plugs of 1-week-old colonies of P. infestans isolate PT-3 grown on tomato juice agar medium. Treated leaflets were placed on moist, sterile filter paper in a 90 mm covered Petri dish. Another leaflets were inoculated as a control with plain agar plugs. Leaflets were incubated in moist chambers at 20±2 ºC for 6 days before measurements were taken. Significant differences were found among families, and within families (P < 0.05). Out of 232 clones, 43 were highly resistant (not show any symptoms of infection). For instance, clones, A3/88, A3/114, A3/147 and A3/193 derived from Serana x TS-9 hybrid family were very suscebtible to P. infestans, while the clones A3/108, A3/169 and A3/142 were found highly resistant to the pathogen. The cultivars used as susceptible control were also found highly susceptible to the pathogen fungus. These results suggest that these potato clones are worthy of use in breeding for late blight resistance