Interested Members of the University Community are invited to attend the Final Oral Examination for the Degree of Master of Science of  George Austin of the Department of Plant Agriculture 

Date: November 21, 2022
Time: 11:00 AM
Online: https://zoom.us/j/94445147105?pwd=MnNqRit5S2hnUStFdHc5MDlxWSsvQT09 
Meeting ID: 944 4514 7105
Passcode: 544522 

Thesis Title: A Bioassay for Asparagus (Asparagus officinalis L.) Resistance to Stemphylium vesicarium 

Advisory Committee
Dr. Mary Ruth McDonald, Advisor
Dr. David Wolyn, Co-advisor
Dr. Katrina Jordan

Examination Committee
Dr. Milad Eskandari, Chair
Dr. Mary Ruth McDonald
Dr. David Wolyn
Dr. Melanie Kalischuk

ABSTRACT 

Field assessments of asparagus cultivar resistance to Stemphylium vesicarium (Wallr.) E. Simmons have provided inconsistent results. Four cultivars, Jersey Giant, Guelph Millennium, Guelph Eclipse, and Gijnlim were examined in the field and in detached-spear controlled environment assays for reaction to S. vesicarium infection. Consistent results were achieved in the controlled environment assays and cultivar, location on the spear, isolate, wounding, and lighting were each found to affect lesion formation. In the field, an interaction was identified between cultivar resistance and acute weather, especially heavy rainfall, before and during a critical infection period. In controlled environment studies there was an interaction between cultivar and location of inoculation on the spear, whether near the top or base. The bioassay was useful for assessing some mechanisms of resistance, but inoculating attached spears in the field, while accounting for weather, is recommended for determining realistic field results.