Submitted to: Phytopathology
Publication Type: Abstract Only
Publication Acceptance Date: 3/31/2003
Publication Date: 5/1/2003
Citation: CHEN, W., COYNE, C.J., PEEVER, T., MUEHLBAUER, F.J. CHARACTERIZATION OF CHICKPEA DIFFERENTIALS FOR ASCOCHYTA RABIEI USING AN IMPROVED VIRULENCE ASSAY. PHYTOPATHOLOGY 93(Supplement):S16 Interpretive Summary: Ascochyta blight is an important disease of chickpea, and using chickpea differentials has been a very useful tool in describing virulence of the pathogen. Previous studies used different sets of differentials and different isolates of the pathogen, which has made it difficult to compare results across studies. This study tested the previously reported differentials using a defined set of pathogen isolates. Results showed that many of the differentials have similar reactions to Ascochyta inoculation and, therefore, the number of differentials can be reduced significantly, simplifying future tests employing chickpea differentials.
Technical Abstract: Previous studies of chickpea Ascochyta blight used different sets of chickpea differentials and different fungal isolates which has made it difficult to compare results across studies. This study was designed to characterize the various differentials using a defined set of isolates. Nineteen differentials were tested using six isolates of A. rabiei with a mini-dome technique. Two wk-old seedlings were inoculated with conidia (105 spores ml-1), and immediately covered with plastic cups for 24 hours. Disease severity was rated 14 days after inoculation using the 1 (no disease) to 9 (dead plant) rating scale. All the differentials were either resistant or susceptible to pathotype I isolates, whereas their reactions to pathotype II isolates are quantitative with disease ratings ranging from 2 to 9. Results showed that many of the differentials reacted similarly to A. rabiei inoculation which means that the number of differentials can be significantly reduced without sacrificing accuracy in describing virulence of A. rabiei.