Submitted to: American Phytopathology Society
Publication Type: Abstract Only
Publication Acceptance Date: 6/12/2007
Publication Date: 7/1/2007
Citation: Funnell, D., Pedersen, J.F. 2007. Comparison of inoculation strategies to assess biological interactions between sorghum lines and fungi. American Phytopathology Society 97:S37-S38. Interpretive Summary:
Technical Abstract: Comparison of inoculation strategies to assess biological interactions between sorghum lines and fungi Bioassays were assessed for utility to characterize fungal species associated with sorghum or to screen germplasm for advancement in breeding programs. Isolates of Alternaria alternata, Fusarium equiseti, F. solani, F. thapsinum and F. verticillioides, were tested. Wound-inoculation of peduncles of developing heads indicated that isolates FRC-M-3790 (F. thapsinum) and FRC-M-1141 (F. verticillioides) were pathogenic and that an A. alternata isolate also may be pathogenic on some lines. The duration of this assay was shortened by use of an early-maturing sorghum line. Spray inoculation of developing heads had inconsistent results: in one assay, weight per 100 seed and percent germination suggested that FRC-M-3790 and FRC-M-1141 were pathogenic but in other assays, there were no biologically relevant differences among treatments. In a seedling assay, plants grown in sterile conditions were inoculated without wounding. Stalk lesion length and percent infection of roots indicated that isolate FRC-M-3790 was an aggressive pathogen. This assay indicated whether an isolate infected roots or stalks; root symptoms were readily assessed. The study emphasizes the importance of selecting appropriate plant lines for characterizing fungal virulence traits. Use of previously characterized highly virulent and low virulence isolates when screening germplasm is also suggested.