1a. Objectives (from AD-416):
To improve management of soybean pathogens and pests by monitoring the spread, diversity, and impact of soybean pathogens and pests on soybean productivity. Improve management of soybean diseases by identifying and characterizing resistance in cultivated soybean and related annual and perennial species.
1b. Approach (from AD-416):
Soybean samples will be collected from field sites with various treatments including pesticides (seed and foliar applied fungicides and insecticides, and seed nematicides), plant defense elicitors, and certain cover crops prior to soybean. These samples will be assayed for various pathogens and pests of soybeans. Some of these assays will be completed through traditional approaches of isolation and enumeration; others will be assayed using quantitative detection of target DNA using PCR. Most of the pathogen and pest assay data will be related to field observations of diseases and pests, and to the yield of soybeans in the experimental plots. Objective 2: Seeds of soybean germplasm including commercial cultivars and accessions (both soybean and wild perennial accessions from the USDA Soybean Germplasm Collection) will be assembled for resistance evaluation to various soybean pathogens and pests. These evaluations will be done using common greenhouse inoculation techniques, as well as other techniques like detached leaves or leaf disks that are not yet standard prodecures. The most resistance genotypes will be retested in the field (if possible) and again using different strains of the pathogen and/or pest to confirm resistance.
3. Progress Report:
Field samples were dried and milled, DNA was successfully extracted, and qPCR quantifications were successfully completed, for the several hundred roots. High levels of pathogen were found on some root samples, and not in others. Soil samples were obtained, dried, milled, DNA was successfully extracted, and qPcR quantifications were successfully completed for over 360 soil samples obtained. High levels of pathogen were found in some of the soil samples. This data on pathogen and pest assays will be related to field observations of diseases and pests, and to the yield of soybeans in the experimental plots. Seeds of soybean germplasm including commercial cultivars and accessions (both soybean and wild perennial accessions from the USDA Soybean Germplasm Collection) were evaluated for resistance to a number of pathogens and pests. This included evaluation of over 1,000 plant introductions for resistance to the soybean aphid biotype 1. In addition, over 1,000 commercial breeding lines and/or cultivars were evaluated for multiple diseases including charcoal rot, sudden death syndrome, and Phytophthora root and stem rot.