Wheat Seedling Response to Root Infection by Cochliobolus sativus and Fusarium acuminatun . J. P. HILL, Associate Professor, Department of Plant Pathology and Weed Science, Colorado State University, Fort Collins 80523. D. L. BLUNT, Former Graduate Student, Department of Plant Pathology and Weed Science, Colorado State University, Fort Collins 80523. Plant Dis. 78:1150-1152. Accepted for publication 30 August 1994. Copyright 1994 The American Phytopathological Society. DOI: 10.1094/PD-78-1150.

Noncontaminated seedling roots of winter wheat cultivars Sandy and CO86 were inoculated with single germinated conidia of Cochlioholus sativus and/or macroconidia of Fusarium acuminatum to determine if resistance to these fungi could be identified. Four days after inoculation, seedlings were transplanted to soil and placed in a growth chamber at 18 or 29 C with or without water stress. Height, total leaf length, dry shoot weight, dry root weight, and root/ crown discoloration were recorded for each plant after 4 wk. At 29 C, infection of CO86 with C. sativus resulted in a significant height reduction compared with Sandy. These cultivars are field rated as susceptible and resistant, respectively, to dryland root rot in Colorado. There were no consistent significant differences in other traits between cultivars, whether inoculated with C. sativus or not. Inoculation with F. acuminatum did not significantly (P = 0.05) affect any traits or enhance the effects of C. sativus when inoculated on the same seedling. The current experimental procedure, although providing some information, does not seem to be able to consistently select genotypes for increased general resistance to these pathogens.

Keyword(s): foot rot