1a.Objectives (from AD-416)
Screening soybean varieties for resistance to Phomopsis seed decay (PSD)
1b.Approach (from AD-416)
Field screening and laboratory seed quality assays will be conducted to determine:. 1)The disease resistance of commercial available soybean varieties to PSD; and. 2)The virulence/aggressiveness of PSD isolates collected in Mississippi.
During this reporting period, 50 soybean lines including 34 commercial soybean varieties and 16 breeding lines (Maturity group (MG)IV and MG V) were planted in Stoneville, Mississippi on May 11, 2011, to evaluate them for resistance to Phomophsis seed decay (PSD). Seeds were planted in 10 ft long row plots with 8 seeds/ft of row on 40-inch row spacing. A total of 800 plots were planted. We will have inoculated and non-inoculated treatments on those 50 soybean lines and two harvest times in the field trials to evaluate plants for resistance to Phomophsis seed decay. The inoculated plots will be sprayed with Phomophsis spores at the R5 growth stage. Evaluations will be made when the soybeans are mature, which will include seed plating assay to determine the PSD incidence, germination tests, and visual seed quality scoring of seeds harvested from each field plots.