Submitted to: American Society of Agronomy Meetings
Publication Type: Abstract Only
Publication Acceptance Date: April 18, 2007
Publication Date: November 4, 2007
Citation: Li, S., Smith, J.R. 2007. Evaluation of Selected Soybean Genotypes for Resistance to Phomopsis longicolla, the Fungus That Causes Soybean Seed Decay. American Society of Agronomy Meetings, 2007, published online: http://a-c-s,confex.com/crops/2007am/techprogram/P31445.HTM Technical Abstract: Phomopsis seed decay of soybean is a major cause of poor quality soybean seed in the United States, especially in the mid-southern USA. The disease is caused primarily by the fungal pathogen, Phomopsis longicolla. To identify soybean lines resistant to this pathogen, 16 soybean plant introductions were selected based on previous tests of seed quality that included two lines previously reported to be resistant. A field experiment was established using a randomized complete block design with six replications at Stoneville, Mississippi on April 18, 2006. Plants were inoculated at the R5 stage with a spore suspension (10-4/ml) prepared from a combination of 10 Mississippi isolates. A total of 240 seed from each line, harvested at two stages (R8 and R8 plus two weeks), was plated on acidified potato dextrose agar and assayed for the incidence of P. longicolla. Non-inoculated seed was also tested. Several lines were identified that had low disease incidence and good seed quality. A second field trial in 2007 will confirm the resistance of those lines.