Submitted to: National Soybean Rust Symposium
Publication Type: Proceedings
Publication Acceptance Date: 9/30/2006
Publication Date: 11/14/2006
Citation: Vuong, T.D., Pham, A.T., Tran, L.D., Nguyen, H.T., Vantoai, T.T., Miles, M.R., Hartman, G.L. 2006. Evaluation of soybean germplasm for soybean rust (phakopsora pachyrhizi) resistance in Hanoi, Vietnam. Proceedings of the National Soybean Rust Symposium, November 14-16, 2005, Nashville, Tennessee. Available at http:www.plantmanagementnetwork.org/infocenter/topic/soybeanrust/symposium/posters/32.asp.
Technical Abstract: Soybean Rust (Phakopsora pachyrhizi Syd.), a fungal pathogen causing significant yield losses in many soybean production areas of the world, was reported in the continental U.S. in November 2004. The U.S. commercial soybean cultivars were all presumably susceptible to the rust fungus. Evaluation of the USDA soybean germplasm collection, as well as other germplasm, for resistance to the disease is a need for developing soybean rust resistant cultivars. The objective of this study was to evaluate soybean accessions from the U.S. and Vietnam for resistance to the disease at the Vietname Agriculture Science Institute (VASI). Fifty-seven soybean entries from the U.S. that had been previously evaluated under containment at Ft. Detrick, MD and local checks were blocked by maturity and grown in the field in 1 m plots with three replications. Plants were inoclulated with 5x10 4 spores/ml twice at the V6 and R1 growth stages. From R2 through R6 stages, disease severity was assessed on five plants at three canopy positions (middle, upper, and lower) on each plant, using a 0-3 severity scale, where 0=no symptoms and 3=heavy number pustules (>500). Area under disease progress curve (AUDPC)was computed for statistical analysis using SAS with linear models. An additional evaluation was also conducted in a net house using similar inoculation technique and disease severity assessment. Several U.S. soybean plant introductions (PIs) had soybean rust assessments similar to the local resistance check in both net house and field evaluations. These PIS and local cultivars may serve as resistance sources for developing lines with soybean rust resistance.