Genetic Resistance to Reniform Nematodes in Soybeans. B. G. Harville, Associate Professor, Department of Agronomy, Louisiana Agricultural Experiment Station, Louisiana State University, Baton Rouge 70803. A. Green, Research Associate, Department of Agronomy, Louisiana Agricultural Experiment Station; and W. Birchfield, Research Plant Pathologist, U.S. Department of Agriculture, ARS, Louisiana State University, Baton Rouge 70803. Plant Dis. 69:587-589. Accepted for publication 14 January 1985. Copyright 1985 The American Phytopathological Society. DOI: 10.1094/PD-69-587.

A study was conducted to determine the number of genes by which four soybean (Glycine max) cultivars differ for resistance to the reniform nematode Rotylenchulus reniformis. The cultivars Davis, Bragg, Dare, and Pickett 71 are classified as susceptible, moderately susceptible, moderately resistant, and resistant, respectively. Four F₁ soybean populations had mean egg mass ratings that did not differ from those of their respective susceptible parents. Resistance to the reniform nematode in soybeans is concluded to be quantitative in nature and controlled by two pairs of genes with unequal effects. The proposed genotypes of the four parental cultivars were Davis Rn₁ Rn₁ Rn₂ Rn₂, Bragg Rn₁ Rn₁ rn₂ rn₂, Dare rn₁ rn₁ Rn₂ Rn₂, and Pickett 71 rn₁ rn₁ rn₂ rn₂.