Organizing Committee


Poster Presentations


Poster Presentations


Evaluation of quantitative resistance to Phakopsora pachyrhizi in Vietnam

Presenter: T. D. Vuong

All authors and affiliations: T. D. VUONG (1), B. T. Nguyen (2), L. D. Tran (2), A. T. Pham (3), H. T. Nguyen (1), T. VanToai (4), M. R. Miles (5), and G. L. Hartman (3,5). (1) Division of Plant Sciences and NCSB, University of Missouri, Columbia, MO 65211; (2) National Plant Protection Institute (NPPI), Hanoi, Vietnam; (3) Department of Crop Sciences, University of Illinois, Urbana, IL 61801; (4) USDA-ARS-SDRU, Columbus, OH 43210; and (5) USDA-ARS, University of Illinois, Urbana, IL

Soybean rust (Phakopsora pachyrhizi Sydow) has been reported throughout the southern states and a few midwestern states in the United States. Many efforts have been made to screen soybean germ plasm for resistance to the disease, and race-specific and non-race-specific resistance has been identified. The objective of this study was to compare quantitative resistance using different disease severity assessments. Twelve soybean accessions, including preselected plant introductions (PIs) and local checks, were studied in repeated experiments conducted in 2005 and 2006 at NPRI. Three severity assessments were used to evaluate the resistance. Data was used to calculate AUDPC values for each assessment method. In addition, AUDPC of each canopy level and correlations with overall AUDPC were also computed for the evaluation of simplicity and reliability. The results demonstrated that all methods were useful in identifying resistant accessions. One of the methods differentiated disease progress among soybean genotypes better than the other two methods. Disease severity assessment of the mid and upper canopies provided better separation of accessions in terms of quantifying resistance than did assessments of the lower canopy.

View Poster                                         Back to Poster Presentations