VIEW ARTICLE

Genetics

Inheritance of Resistance in Sorghum to Three Pathotypes of Peronosclerospora sorghi. Jeweus Craig, Research plant pathologist, Agricultural Research Service, U.S. Department of Agriculture, Plant Pathology and Microbiology Department, and Soil and Crop Sciences Department, Texas A&M University, College Station 77843; K. F. Schertz, research plant geneticist, Agricultural Research Service, U.S. Department of Agriculture, Plant Pathology and Microbiology Department, and Soil and Crop Sciences Department, Texas A&M University, College Station 77843. Phytopathology 75:1077-1078. Accepted for publication 15 May 1985. This article is in the public domain and not copyrightable. It may be freely reprinted with customary crediting of the source. The American Phytopathological Society, 1985. DOI: 10.1094/Phyto-75-1077.

The F₁, F₂, and F₃ generations of the cross of sorghum (Sorghum bicolor) inbred line SC 414-12 (which is resistant to pathotypes 1, 2, and 3 of Peronosclerospora sorghi) and the universally susceptible sorghum line Tx 412 were used to determine inheritance of resistance to P. sorghi. In SC 414-12, resistance was expressed as an incompatible host/pathogen interaction which inhibited pathogen development and sporulation in leaves inoculated with conidia of P. sorghi. The reactions of the parental lines and progenies to conidial inoculum of the three pathotypes supported the hypothesis that resistance of P. sorghi to these pathotypes was conferred by a single dominant gene. The F₂ phenotypic ratios were 3 resistant : 1 susceptible; F₂ genotypic ratios were 1 homozygous resistant : 2 heterozygous : 1 homozygous susceptible.