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Resistance

Reaction of Cotton Species and Cultivars to Four Isolates of Ramularia areola. Y. Rathaiah, Laboratoire de Pathologie Végétale, Institut National Agronomique Paris-Grignon, Centre de Grignon, 78850 Thiverval-Grignon, France. Present address: Department of Plant Pathology, College of Agriculture, Andhra Pradesh Agricultural University, Rajendra Nagar, Hyderabad-500030, India; Phytopathology 66:1007-1009. Accepted for publication 20 January 1976. Copyright © 1976 The American Phytopathological Society, 3340 Pilot Knob Road, St. Paul, MN 55121. All rights reserved.. DOI: 10.1094/Phyto-66-1007.

Twenty-four cultivars of cotton were tested in the glasshouse for resistance to isolates of Ramularia areola from Madagascar, Tchad, Ivory Coast, and India. Infection symptoms on cotyledons differed from leaf symptoms and were described. The Madagascar isolate was the most aggressive followed by the isolate from Tchad. Ivory Coast and Indian isolates were weakly aggressive. Cultivars BJA 592, Réba BTK 12 of Gossypium hirsutum, and cultivars Tadla 16, Pima 67 of G. barbadense were hypersensitive against the four isolates.