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Genetics

Genetics of Host-Parasite Interactions Between Alfalfa and Peronospora trifoliorum. D. Z. Skinner, Research assistant, Department of Plant Pathology, Kansas State University, Manhattan 66506; D. L. Stuteville, professor, Department of Plant Pathology, Kansas State University, Manhattan 66506. Phytopathology 75:119-121. Accepted for publication 5 July 1984. Copyright 1985 The American Phytopathological Society. DOI: 10.1094/Phyto-75-119.

All possible populations derived from self- and cross-pollinations and some F₂ populations of three diploid alfalfa clones (PI, P5, and P6) were inoculated with conidia of three monoconidial isolates (I-5, I-7, and I-8) of Peronospora trifoliorum. Segregation ratios suggested a gene-for-gene relationship involving at least five corresponding gene pairs, each capable of preventing conidial production. Clones P5, P6, and P1 were postulated to have four, three, and no genes conditioning resistance, respectively. Four, five, and two corresponding genes conditioning avirulence were postulated for isolates I-5, I-7, and I-8, respectively. F₂ data suggested the presence of many other genes with additive effects leading to increased susceptibility.