Standard area diagram development for Fusarium oxysporum symptom and disease progression rating in Beta vulgaris.
Standard area diagrams (SADs) are disease progression diagrams that have both a written and visual component designed to help a rater estimate plant disease severity in a uniformly repeatable way. The goal of our study was to record the disease ratings given by volunteers with varying experience rating fusarium oxysporum infected sugar beets. Participants rated the same set of images twice, first using a previously published 1-5 scale and again using the standard area diagram. The new fusarium oxysporum sugar beet disease progression SAD uses a percentage scale that accounts for leaf wilt, yellowing and necrosis. Use of a SAD was proposed to improve the accuracy of raters compared to a previously published scale. The efficiency of sugar beet breeding programs depends on accuracy of the screening methods. Thus, an improved and replicable rating scale based on a standard area diagram will benefit both public and private breeding efforts and ultimately sugar beet growers. This updated tool will ensure that the USDA-ARS Fort Collins pre-breeding program is properly and thoroughly screening accessions to get the strongest and most stable Fusarium oxysporum resistance for sugar beet production.