VIEW ARTICLE

Genetics

Genetic Control and Distorted Segregation of T-Toxin Production in Field Isolates of Cochliobolus heterostrophus. C. R. Bronson, Department of Plant Pathology, Iowa State University, Ames 50011-1020; M. Taga(2), and O. C. Yoder(3). (2)(3)Department of Plant Pathology, Cornell University, Ithaca, NY 14853-5908, (2)Current address: Sakata Seed, Chiba, Japan 292-01. Phytopathology 80:819-823. Accepted for publication 29 March 1990. Copyright 1990 The American Phytopathological Society. DOI: 10.1094/Phyto-80-819.

T-toxin is a family of linear polyketols responsible for the high specific virulence of race T of Cochliobolus heterostrophus on cms-T maize. To date, a single locus, Tox1, has been shown to be involved in T-toxin synthesis. In an attempt to find additional loci, 12 race T (Tox+) and 11 race O (Tox?) field isolates were examined. Crosses to genetically defined strains demonstrated that all the race T isolates had the TOX1 allele and that all the race O isolates had the alternate allele, tox1. There was no evidence that these isolates differed at any other loci controlling T-toxin production. Five of the race O isolates carried a factor that caused distorted segregation at Tox1.