ARS | Publication request: Identification of soybean accessions with resistance to Phomopsis seed decay: joint effort from USDA and university scientists

Submitted to: APS Annual Meeting
Publication Type: Abstract Only
Publication Acceptance Date: June 10, 2011
Publication Date: June 23, 2011
Citation: Li, S., Chen, P., Rupe, J., Wrather, A., Sciumbato, G., Smith, J.R., Nelson, R.L. 2011. Identification of soybean accessions with resistance to Phomopsis seed decay: joint effort from USDA and university scientists. APS Annual Meeting. 101(6):S103.

Technical Abstract: Soybean Phomopsis seed decay (PSD) is primarily caused by Phomopsis longicolla along with other Phomopsis and Diaporthe spp. This disease causes poor seed quality and suppresses yield in most soybean-growing states in the United States. In 2009, PSD caused yield loss of over 12 million bushels in 16 southern states. To identify new sources of resistance to PSD, seed of 208 representative maturity group V soybean lines, obtained from the USDA Soybean Germplasm Collection in 2006, were plated and assayed for the percentage of Phomopsis seed infection. Based on disease data in 2006, 122 accessions without Phomopsis seed infection were selected and field-screened naturally in Stoneville, MS in 2007. Based on the results of seed assays from 2006 and 2007, 14 accessions were selected for further evaluation with inoculated and non-inoculated treatments in 2008 and 2009. In addition, 135 soybean germplasm lines (maturity groups III, IV, and V), including PSD resistant and susceptible checks from 28 countries were field screened by natural infection in 2009 at Kibler, AR, Stoneville, MS and Portageville, MO. Based on the seed assay in 2009, 42 lines along with six resistant and susceptible checks were selected and field-tested with inoculated and non-inoculated treatments in these states in 2010. In 2009, frequent rainfall during seed maturation led to high levels of seed infection by Phomopsis (up to 80%) and other fungal pathogens for most soybean lines but several lines were identified that had low percentage of seed infection, good visual quality, and high germination rates. These resistant sources will be used to develop cultivars resistant to PSD.