Abstract

Late blight disease caused by Phytophthora infestans (Mont.) de Bary is one of the major diseases of economic importance to potato production in Uganda causing yield losses of 40 to 60%. Use of host resistance is most economical and environmentally feasible solution to control this disease. This study was carried out to identify potato clones with high levels of field resistance to late blight pathogen (P. infestans) andhigh yields so that well adapted and tolerant clones could be developed and released as varieties. Sixteen potato clones of population B3C2 were accessed from International Potato Centre (CIP) in Lima Peru and evaluated for field resistance to late blight pathogen population in Uganda. Six potato clones (396027.205, 396034.103, 396026.103, 393280.82, 396038.107, and 395015.6) out of 16 clones were identified to posses high field resistance to late blight and high yields. The mean late blight disease severity measured as relative area under disease progress curve (rAUDPC) ranged between 15 to 38% for no sprayed while for sprayed it ranged from 5 to 22%. Yield performance under no spray treatment ranged from 7 to 20 T/ha while under spray treatment, yield ranged from 13 to 25 T/ha. Four of these clones (396026.103, 396034.103, 393280.82, and 396038.107) have been recommended for release as potential varieties for farmers.

Key words: Field resistance, Phytopthora infestans, Solanum potato.