Location: Crop Genetics Research
2022 Annual Report
Objectives
1. Identify novel sources of resistance to existing and newly emerging soybean cyst nematode (Heterodera glycines, SCN) populations, and develop and deploy new soybean germplasm with broad resistance using traditional and marker-assisted breeding.
1.A. Phenotype Glycine max accessions available in USDA soybean germplasm collection for reaction to SCN populations and evaluate entries in Uniform Soybean Tests, Southern States for resistance to SCN.
1.B. Identify new sources of SCN resistance, pyramid resistance gene(s) for SCN, charcoal rot (CR), and frogeye leaf spot (FLS), and develop germplasm using molecular markers associated with resistance.
2. Determine host-pathogen interactions of fungal diseases in soybeans, including CR and FLS, identify new sources of resistance using improved screening methods, and develop innovative strategies for managing these diseases.
2.A. Identify new resistant soybean genotypes using improved screening methods against virulent pathotypes.
2.B. Evaluate the effects of cultural practices on CR and FLS severity and yield and develop alternate management practices for control of these diseases in soybean.
2.C. Evaluate the mechanism of defense in host pathogen interaction for CR.
3. Develop innovative methods and/or enhance existing methods to assay soil and root infection for improved plant-parasitic nematode detection, identification, and management, and design effective cultural methods for mitigating plant-parasitic nematodes in grower fields.
3.A. Evaluate existing and novel methods to increase detection and screening of plant-parasitic nematodes.
3.B. Determine the impacts of cultural practices and resistance on plant-parasitic and free-living nematodes to ascertain information about soil health and yield.
Approach
Identify and characterize new sources of resistance to nematode and fungal diseases of soybean that will potentially broaden diversity among resistance genes in soybean cultivars and may provide more durable resistance. New soybean germplasm lines with combined resistance will be developed in maturity groups IV and V with resistance to soybean cyst nematode, root-knot nematode, frogeye leaf spot, charcoal rot, as well as other fungal pathogens. Parasitic and free-living nematode communities will be characterized in soybean fields, especially those with corn and/or cotton in the rotation. New or enhanced methods to detect plant-parasitic nematodes in soil or roots will be developed. Valuable data for the reaction of breeding lines to nematode populations will be available to be utilized by the breeders for potential release to public and private sectors. The new releases in combination with effective cultural practices will also be developed and made available to the public to manage nematode and fungal population shifts.
Progress Report
This is a new project which was approved in February 2022. It replaces project 6066-21220-013-000D. Please see the report for 6066-21220-013-000D for a summary of the research progress and accomplishments over the past five years.
ARS researchers at Jackson, Tennessee, have completed planting all their experimental field tests in mid-May 2022. We will continue to work to identify new sources of resistance to soybean cyst nematode populations and the fungi that cause the diseases frogeye leaf spot and charcoal rot, and to incorporate the resistance into new varieties of soybean for growers in Tennessee and other southern states. We will perform multi-environment, replicated field testing to identify breeding lines that possess exceptional soybean cyst nematode and disease resistance and have favorable agronomic performance. We will initiate new breeding populations with outstanding disease resistance and yield potential through novel cross combinations. We are also evaluating the effects of cultural and agronomic practices such row spacing, seeding rates, and cover crop on nematode, charcoal rot, and frogeye leaf spot diseases. The effects of soil microbiome on nematode and charcoal rot diseases will also be investigated. This information will be used to improve crop management recommendations to better manage these diseases.
Progress has been made in the form of obtaining 100 lines of germplasm from the USDA soybean germplasm collection to continue screening work for HG Types 0 and 1.2.5.7. Sixty-four lines have been obtained for Tennessee Soybean Variety Test screening for reaction to HG Type 1.2.5.7. Two hundred ninety-eight lines for Uniform Soybean Tests, Southern States screening were obtained, and half of the lines have been screened for reaction to HG Type 1.2.5.7. Work will continue to screen the remaining half of the lines for this HG Type as well as all lines for HG Types 0 and 2.5.7.
Additionally, nematode cultures have been increased using a new method, to ensure adequate supplies of HG Types 0, 2.5.7, and 1.2.5.7 for future and continued Uniform Soybean Tests, Southern States screening, Tennessee Soybean Variety Test screening, USDA germplasm collection screening, and additional screening from ARS breeding lines in Stoneville, Mississippi.
Accomplishments
