Inheritance of Resistance to Grassy Stunt Virus in Rice. F. L. Nuque, Assistant Plant Pathologist, Department of Plant Pathology, International Rice Research Institute, Los Baños, Laguna, Philippines. V. M. Aguiero, Research Assistant, and S. H. Ou, Former Principal Plant Pathologist and Head, Department of Plant Pathology, International Rice Research Institute, Los Baños, Laguna, Philippines. Plant Dis. 66:63-64. Accepted for publication 28 April 1981. Copyright 1982 American Phytopathological Society. DOI: 10.1094/PD-66-63.

Six cross combinations of the susceptible Oryza sativa cultivars IR8, IR20, IR22, IR24, and IR773A-1-3 with the resistant Oryza nivara accession 101508 were used to determine the inheritance of resistance to the grassy stunt virus. All F₁-crossed progenies of the crosses were comparable in resistance to the selfed progenies of O. nivara. The F₂ populations segregated into a ratio of three resistant to one susceptible. The progenies of the first, second, and third backcrosses to the recurrent susceptible parents gave a ratio of one resistant to one susceptible. These results support the hypothesis that resistance to the grassy stunt virus in O. nivara is governed by a single dominant gene.

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