Location: Crop Genetics Research
2017 Annual Report
Objectives
Objective 1: Identify sources of resistance to newly emerging soybean cyst nematode populations, develop new soybean germplasm with resistance, and develop methods for managing soybean cyst nematodes in soybeans using traditional and marker assisted breeding methods.
Subobjective 1a. Phenotype Glycine max accessions available in USDA soybean germplasm collection for reaction to SCN populations. Identify new/additional sources of resistance, characterize for unique resistance genes and develop molecular markers associated with resistance.
Subobjective 1b. Pyramid nematode resistance genes into elite backgrounds of maturity groups IV and V in combination with resistance to charcoal rot and Frogeye leaf spot to develop new germplasm/cultivars.
Subobjective 1c. Determine the effect of soybean cyst nematode in combination with other plant-parasitic nematodes on crop damage in Mid South soybean production fields.
Subobjetive 1d. Evaluate entries in USDA Uniform Soybean Tests for Southern States and ARS breeding lines for reaction to SCN.
Objective 2: Determine mechanisms underlying host-pathogen interactions in soybean for the fungal diseases charcoal rot and frogeye leaf spot, identify new sources of resistance in soybean to these diseases using improved screening methods, and develop methods for managing these fungal diseases using traditional and marker assisted breeding methods.
Subobjective 2a. Evaluate and identify new sources of germplasms, breeding lines, and cultivars for charcoal rot and frogeye leaf spot resistance in stress and non-stress environments for use in breeding programs.
Subobjective 2b. Evaluate the effects of cultural practices on charcoal rot and frogeye leaf spot severity and yield and develop alternate management practices for control of these diseases in soybean.
Approach
Identify new sources of resistance to nematode populations in soybean that will potentially broaden diversity among resistance genes in soybean cultivars and may provide more durable resistance. New soybean germplasm line or lines will be developed in two different maturity groups IV and V with resistance to soybean cyst nematode, frogeye leaf spot, and charcoal rot, as well as other fungal pathogens, nematodes and insect pests. Nematodes will be found in soybean fields, especially those with corn and/or cotton in the rotation. 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. New accessions and germplasm lines with resistance to charcoal rot and
frogeye leaf spot will be identified and released.
Progress Report
This project was established in February 2017. It replaces project 6066-21220-011-00D (Genetics and Management of Soybean Cyst Nematodes and Diseases for Sustainable Production). As this project has just initiated, there is no significant progress to report for FY 2017. Please see the report for 6066-21220-011-00D for a summary of the research progress and accomplishments over the past five years.
This project will continue our efforts to reduce crop losses caused by soybean cyst nematode, a wormlike, round, microscopic organism that grows and reproduces on the soybean plant roots. Young nematodes feed on the root nutrients for their survival and reduce soybean yields. Fungal pathogens, charcoal rot and frogeye leaf spot, are also yield reducing organisms. Combined soybean yield losses in the United States are estimated to be nearly $3.0 billion. The losses have remained relatively stable at current levels with the use of resistant cultivars especially for soybean cyst nematode. However, because resistant cultivars for soybean cyst nematode have a limited genetic base of host plant resistance, over time nematodes adapt to them. Cultivars with combined resistance to soybean cyst nematode, charcoal rot, and frogeye leafspot are more profitable to growers, but are not available. By combining resistance to these three pathogens together with newly developed cultural practices, resistance can be more durable. We will develop commercially acceptable soybean lines with combined resistance to these yield reducing pathogens by adopting traditional breeding methodology combined with modern genetic technology. Expected outcomes from this project include germplasm resistant to soybean cyst nematode, charcoal rot, frogeye leafspot and a package of effective cultural practices to manage losses. This will result in economically and environmentally sustainable soybean production in the United States and worldwide, resulting in lowered economic risk for growers.
Accomplishments
