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Genetics

Genetic Studies on Selected Traits of Nectria haematococca. K. J. Tegtmeier, Graduate research assistant, Department of Plant Pathology, Cornell University, Ithaca, NY 14853, Present address of senior author: Department of Agricultural Biochemistry, University of Nebraska, Lincoln 68583; H. D. VanEtten, associate professor, Department of Plant Pathology, Cornell University, Ithaca, NY 14853. Phytopathology 72:604-607. Accepted for publication 25 August 1981. Copyright 1982 The American Phytopathological Society. DOI: 10.1094/Phyto-72-604.

The feasibility of using the sexual stage of the fungus Nectria haematococca mating population VI (MP VI) for genetic studies was examined by studying segregation patterns among the progeny from crosses between parents differing in mating type, perithecial color, growth habits (specifically, sporulating colonial and mycelial), and female fertility. All of the traits except female fertility appeared to be monogenically controlled, and no linkage was detected. Female sterility required at least two genes for expression in the progeny of one cross. In two crosses, traits that were expected to segregate did not. In one of these crosses, the failure of segregation was restricted to one tetrad of the eight tetrads analyzed, and could be attributed to selfing. In the other cross, however, two traits failed to segregate in any of the progeny while a third trait (mating type) segregated normally. Despite the unexplained results obtained from this cross, we concluded that N. haematococca MP VI is amenable to classical genetic study, since the majority of the crosses examined showed simple segregation patterns.