Pathogenic variability of Phaeoisariopsis personata (Berk. and Curt.) V. Arx in resistant and susceptible peanut (Arachis hypogaea L.) genotypes
1999
Md Delowar Hossain | Ilag, L.L. (Philippines Univ. Los Banos, College, Laguna (Philippines). Dept. of Plant Pathology)
Eight isolates of Phaeoisariopsis personata (Berk. and Curt.) V. Arx, the fungus causing late leafspot disease in peanut, were studied. Initial disease symptoms appeared within 10 to 12 days in susceptible genotype ICG-7827. Isolate 1 produced the highest number of lesions per leaflet, the largest lesion size, the greatest number of spores per lesion, and the highest percentage defoliation. Isolate 5 gave the lowest values for the above parameters. The most virulent and the least virulent isolates were inoculated on resistant and susceptible peanut genotypes from the Institute of Plant Breeding, University of the Philippines Los Banos (IPB, UPLB), and from the International Crops Research Institute for the Semi-Arid Tropics (ICRISAT), India. In the resistant genotypes, symptoms appeared later by an average of 2.09 days. Lesion number per leaflet was lower by 42.41 percent, lesion size by 50 percent, spore production per lesion by 88.60 percent, and defoliation by 64.83 percent compared to the susceptible genotypes. Symptoms in plants inoculated with the least virulent isolate appeared later than in those inoculated with the most virulent isolate by an average of 1.25 days in both resistant and susceptible genotypes. On the average, lesion number per leaflet was reduced by 28.84 percent, lesion size by 20.96 percent, spore production per lesion by 48.12 percent, and defoliation by 24.41 percent
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