|Samac, Deborah - Debby|
Submitted to: Phytopathology
Publication Type: Abstract Only
Publication Acceptance Date: 8/8/1999
Publication Date: N/A
Technical Abstract: Programs for breeding disease-resistant alfalfa plants have relied on symptoms to infer the presence of plant pathogens. A project was initiated to compare this traditional approach with various other pathogen detection systems. Alfalfa seedlings (var. WIS 11) were grown in the greenhouse and inoculated with either Clavibacter michiganense subsp. insidiosum, Fusarium moxysporum f. sp. medicaginis, or Verticillium albo-atrum. Survivors were transplanted into the field and monitored for one field season. Plants surviving exposure to natural conditions were returned to the greenhouse, and harvested forage was subsequently assessed for the presence of vascular pathogens using agar plating and polymerase chain reaction (PCR). Of 167 samples of dried, basal stem tissue assessed by PCR with pathogen-specific primers, 27 were positive for Clavibacter, 8 were positive for Fusarium, and 3 were positive for Verticillium. Results of PCR were used to model correlations with near infrared spectra. The efficacy of the three detection systems and the significance of the presence of pathogens in symptomless plants will be discussed.