A Technique to Screen Muskmelons for Resistance to Alternaria Leaf Blight. B. E. Carmody, Former Graduate Research Assistant, Department of Plant Pathology and Microbiology, Texas A&M University, College Station 77843. M. E. Miller, Associate Professor, Texas Agricultural Experiment Station, Weslaco 78596; and M. P. Grisham, Assistant Professor, Department of Plant Pathology and Microbiology, Texas A&M University, College Station 77843. Plant Dis. 69:426-428. Accepted for publication 14 November 1984. Copyright 1985 The American Phytopathological Society. DOI: 10.1094/PD-69-426.

Five muskmelon cultivars were evaluated for resistance to Alternaria leaf blight in the cotyledon and first-leaf stages. Differences in resistance among cultivars were noted after cotyledons were inoculated, whereas no differences were detected when first leaves were inoculated. Cultivars with a flecking lesion or three or fewer lesions per plant were rated resistant, and those with more than three lesions per plant were rated susceptible. Corroborative field studies confirmed seedling ratings. The technique was tested on 27 muskmelon breeding lines. Breeding lines showing resistance in the cotyledon stage were also resistant in the field.

Keyword(s): Alternaria cucumerina, Cucumis melo, cucurbits, plant breeding, screening techniques.