Location: Crop Genetics ResearchTitle: Evaluating soybean germplasm and commercial varieties for resistance to Phomopsis seed decay Author
Submitted to: Phytopathology
Publication Type: Abstract Only
Publication Acceptance Date: 5/2/2013
Publication Date: 6/1/2013
Citation: Li, S., Rupe, J., Holland, R., Steger, A., Chen, P., Sun, S., Sciumbato, G. 2013. Evaluating soybean germplasm and commercial varieties for resistance to Phomopsis seed decay. Phytopathology. 103:S2.80. Interpretive Summary:
Technical Abstract: Soybean Phomopsis seed decay (PSD) is the major cause of poor seed quality in most soybean production areas of the United States. Very few soybean cultivars currently available for planting in the US have resistance to PSD. To identify new sources of resistance to PSD, a multistate and multiyear research project funded by the United Soybean Board with support from the USDA-ARS was initiated in 2009. A total of 135 germplasm lines collected from 28 countries were field screened by natural infection in 2009 in Arkansas, Mississippi, and Missouri. Based on the seed assay results in 2009, 42 lines with the most resistant or susceptible reactions were selected and evaluated in 2010, 2011, and 2012 with Phomopsis inoculated and non-inoculated treatments. Significant differences in seed infection by the causal pathogen Phomopsis longicolla were observed among soybean lines with some lines having no infection while others had levels as high as 85%. These differences between lines also were reflected in visual seed quality and seed germination. Soybean lines with low seed infection and high germination rate at all locations and in four years will be selected and used to develop breeding or mapping populations. Another study funded by the Mississippi Soybean Promotion Board, evaluated commercial varieties for resistance to PSD with inoculated and non-inoculated treatments and two harvest times at R8 and R8+2 weeks stages (normal vs. delayed) in 2011 and 2012. Several varieties were identified with low disease incidence and good seed quality.