Location: Crop Genetics Research
2021 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
Progress was made on both objectives for this long-term research project. We continue to work to identify new sources of resistance to soybean cyst nematode populations, charcoal rot and frogeye leaf spot and to incorporate the resistance into new varieties of soybean for growers in Tennessee and other southern states. We are also evaluating the impact of cultural practices such as tillage and planting date on disease severity and yield losses. This information will be used to improve crop management recommendations to better manage these diseases.
ARS researchers in Jackson, Tennessee, are making progress related to developing soybean with resistance to one or more diseases. We previously developed and released soybean JTN-5203 for its broad resistance to soybean cyst nematode populations, reniform nematode, charcoal rot and frogeye leaf spot diseases combined with high yield potential and this line continues to be field planted in several southern states. We evaluated resistance to charcoal rot in a set of 120 soybean accessions reported to have resistance to one or more races of soybean cyst nematode and identified 12 accessions with combined resistance to races of soybean cyst nematode and charcoal rot. This progress is related to Sub-objectives 1a and 2a.
DNA (genetic material) from leaves of the greenhouse-grown seedlings was collected and laboratory tests were conducted using 13 known DNA markers linked to soybean cyst nematode resistance. This methodology is called marker assisted selection and is intended for further confirmation of resistance. The plants with the markers for resistance were selected, and further evaluations will follow.
Work to combine resistance to multiple diseases into a single soybean line continued in 2021 (Sub-objectives 1b and 2a). Unique advanced progenies derived from previously made crosses to combine resistance to soybean cyst nematode, charcoal rot, and frogeye leaf spot were evaluated in the greenhouse for soybean cyst nematode resistance and in the field for charcoal rot and frogeye leaf spot resistance. The traditional breeding methods of selection used in the field and the standard greenhouse techniques adopted for testing together with marker assisted selection have allowed us to produce unique progenies. Presumably, most of them have combined resistance to these three major diseases. The strategy to combine resistance to all three diseases into a single plant is called gene pyramiding and is difficult to achieve. This is a time-consuming process and will continue.
A set of soybean lines was evaluated for charcoal rot and frogeye leaf spot resistance. Among the commercial Roundup Ready cultivars that were evaluated, 18 lines were identified as having moderate resistance to charcoal rot. Within conventional breeding lines evaluated, 24 were resistant and 13 were moderately resistant to charcoal rot. These lines were in maturity groups IV and V. For resistance to frogeye leaf spot, 8 lines in Roundup Ready and 21 lines in conventional breeding lines had low levels of frogeye leaf spot severity with less than 10% infection. This screening was intended to identify alternative sources of resistance to those lines derived from the cultivar ‘Davis’. Davis is the source of resistance for all current resistance commercial cultivars (Sub-objective 2a).
In addition, we developed the next generation of several germplasm lines based on their prior resistance using individual plant selection for charcoal rot. After several cycles of selections, nine of these lines showed complete resistance and two lines showed moderate resistance reaction (Sub-objective 2a). The highly resistant lines have been entered in a yield performance test in 2021 in Jackson that also helps increase seed for entering in the Uniform Soybean Tests – Southern States program in the future.
Work on Sub-objective 1c began in early 2021, after a critical scientific vacancy was filled. Soil samples were collected in May 2021 and are currently being assayed to determine population densities of soybean cyst nematode and other plant-parasitic nematodes. The critical germplasm screening for soybean cyst nematode resistance for the Uniform Soybean Tests for Southern States under Sub-objective 1d, will continue under the direction of the new Plant Pathologist/Nematologist. Work is generally on schedule, although progress has been slower than normal.
Accomplishments
1. Combined resistance for soybean cyst nematode and charcoal rot identified. Two infectious root diseases that cause significant yield losses worldwide in soybean are charcoal rot and the soybean cyst nematode. Identifying combined resistant lines for these economically important diseases will enable soybean breeders to incorporate the resistance trait into new varieties to help soybean for growers increase their yield. A set of 120 lines publicly available lines reported to have resistance to one or more races of soybean cyst nematode were evaluated for their resistance to charcoal rot to identify lines with resistance to charcoal rot by ARS researchers in Jackson, Tennessee. The result showed that 12 accessions with moderate resistance to charcoal rot were identified. These lines also have resistance to one to two races of soybean cyst nematodes. Within these lines nine had yellow seed coat, a desirable agronomic trait. These lines can be used as parents in soybean breeding programs for developing soybean cultivars with combined resistance to both charcoal rot and soybean cyst nematode.
2. Three conventional breeding lines with high oil content, broad disease resistance, and high-yield potential released. Soybean growers are constantly faced with yield losses caused by several fungal and plant parasitic nematodes. ARS researchers in Jackson, Tennessee, collaborated with researchers at the University of Missouri to meet the growing demand from growers and industry for high-yielding soybean germplasms with broad disease resistance and elevated oil and meal protein contents. The breeding progenies for each cross were tested in multiple environments across the United States to determine their resistance and yield potential. These breeding lines namely: 'S13-1955C' which has broad resistance to soybean cyst nematode, southern root-knot nematode, reniform nematode, sudden death syndrome, and frogeye leaf spot; ‘S13-3851C’ which has resistance to stem canker, sudden death syndrome, charcoal rot, and Phytophthora root rot; and ‘S13-2743C’ which has resistance to soybean cyst nematode races 3 and 14, Phytophthora root rot, stem canker, sudden death syndrome, and charcoal rot. These three lines are attractive choices for both public and private plant breeders to incorporate into their breeding programs targeting these traits.
Review Publications
Chen, P., Shannon, G., Scaboo, A.M., Crisel, M., Smothers, S.L., Clubb, M.W., Selves, S.W., Vieira, C., Ali, L.M., Lee, D., Nguyen, H.T., Li, Z., Mitchum, M., Bond, J., Meinhardt, C.G., Klepadlo, M., Li, S., Mengistu, A., Robbins, R.T. 2021. 'S13-1955C': A high-yielding conventional soybean with high oil content, multiple disease resistance, and broad adaptation. Journal of Plant Registrations. 15:318-325. https://doi.org/10.1002/plr2.20112.
Nouri, A., Lee, J., Yoder, D.C., Jagadamma, S., Walker, F.R., Yin, X., Arelli, P.R. 2020. Management duration controls the synergistic effect of tillage, cover crop, and nitrogen rate on cotton yield and yield stability. Agriculture, Ecosystems and Environment. https://doi.org/10.1016/j.agee.2020.107007.
Chen, P., Shannon, G., Crisel, M., Smothers, S.L., Clubb, M.W., Vieira, C.C., Ali, L.M., Selves, S.W., Lee, D.H., Scaboo, A.M., Klepadlo, M., Nguyen, H.T., Mitchum, M.G., Meinhardt, C.G., Bond, J.P., Robbins, R.T., Li, S., Smith, J.R., Mengistu, A. 2020. Registration of ‘S14-15138GT’ soybean as a high-yielding RR1/STS cultivar with broad disease resistance and adaptation. Journal of Plant Registrations. 14:311-317. https://doi.org/10.1002/plr2.20054.
Chen, P., Shannon, G., Scaboo, A.M., Crisel, ., Smothers, S.L., Clubb, M.W., Selves, S.W., Vieira, C., Ali, L.M., Mitchum, M.G., Nguyen, H.T., Meinhardt, C.G., Klepadlo, M., Li, Z., Bond, J.P., Li, S., Smith, J.R., Gillen, A.M., Zhang, B., Mozzoni, L.A., Mengistu, A., Robbins, R.T. 2021. Registration of ‘S13-2743C’ as a conventional soybean cultivar with high oil content, broad disease resistance, and high-yield potential. Journal of Plant Registrations. 15:306-312. https://doi.org/10.1002/plr2.20081.
Chen, P., Shannon, G., Ali, L.M., Scaboo, A.M., Crisel, M., Smothers, S.L., Clubb, M.W., Selves, S.W., Mitchum, M.G., Nguyen, H.T., Li, Z., Bond, J.P., Meinhardt, C.G., Klepadlo, M., Li, S., Mengistu, A., Robbins, R.T. 2020. Registration of ‘S14-9017GT’ soybean cultivar with high-yield, resistance to multiple diseases and high seed oil content. Journal of Plant Registrations. 14:347-356. https://doi.org/10.1002/plr2.20011.
