Location: Soybean and Nitrogen Fixation Research
2012 Annual Report
Using molecular marker technology in combination with field and lab studies, we will assess the genetic potential of accessions in the USDA soybean germplasm collection for improving soybean yield potential, seed composition, disease resistance, and drought tolerance. We will identify the genomic location of alleles which govern these traits.
Approximately 20,000 experimental plots were harvested in pursuit of these objectives. To improve yield potential, advanced breeding lines derived from exotic pedigree were grown in more than 8000 yield plots. 22 USDA-ARS breeding lines with Asian pedigree were evaluated across the South in USDA Regional Trials. 46 additional USDA-ARS breeding lines with Asian pedigree were grown in a separate regional Southern Diversity Trial. 9 ARS breeding lines tracing 50% of pedigree to the wild progenitor of domesticated soy were evaluated in regional Southern Diversity tests and 7 were included in USDA Regional Trials. To improve drought tolerance, more than 4000 yield plots were evaluated at a drought-prone field site. From this work, 4 advanced breeding lines were submitted to regional testing trials. DNA extraction and SNP analysis were completed for 3 QTL populations. 4000 yield plots were grown in support of the breeding effort to improve seed composition.
We are continuing a Marker Assisted Backcrossing (MAB) program to introgress two high oleic alleles (FAD2-1A and FAD2- 1B) into advanced soybean breeding lines. We expanded our ARS winter nursery in Puerto Rico to make an additional crossing cycle per year. We also added two additional loci to our MAB program (FAD3A and FAD3C mutations) which reduce linolenic acid concentration of soybean oil to about 3%. The combination of these alleles and traits will significantly improve the oxidative stability of soy oil. We are also characterizing additional high stearic mutations, employing selective genotyping.
Purple stain disease, caused by Cercospera kikuchii, is a problem in soybean for some southern states. An assay of green seed harvested 35 days after flowering was used to characterize fungal seed colonization and expression of 25 host defense genes. Reverse transcription polymerase chain reaction (q RT-PCR) technologies were employed. Expectations are that certain defense genes will differ between soybean varieties that have shown resistance in the field. Results will provide important clues which will aid soybean breeders.
The interaction of antibodies with food proteins is the basis for allergenic response in mammals. Allergenic responses are common in livestock, especially when feeding soy-protein based feed to pigs. This basis of the allergenic problem was investigated by challenging peptides from a seed storage protein of soybean (the conglycinin subunit) with sera from 30 pigs. Specific regions of the soy protein were identified as immunogenic (i.e. allergenically reactive). A previously reported allergenic region was confirmed, and a second allergenic region was discovered.
Carter Jr, T.E., Koenning, S., Burton, J.W., Rzewnicki, P.E., Villagarcia, M.R., Bowman, D.T., Arelli, P.R. 2011. Registration of ‘N7003CN’ maturity group VII soybean with high yield and resistance to race 2 soybean cyst nematode. Journal of Plant Registrations. 5(3):309-317.
Ray, J.D., Smith, J.R., Taliercio, E.W., Fritschi, F.B. 2011. Genomic location of a gene conditioning a miniature phenotype in soybean. Plant Biology. 55:26-32.
Maxwell, J.J., Lyerly, J.H., Srnic, G., Murphy, P., Cowger, C., Parks, W.R., Marshall, D.S., Brown Guedira, G.L., Miranda, L.M. 2012. MlNCD1: A novel Aegilops tauschii derived powdery mildew resistance gene identified in common wheat. Crop Science. 52:1162-1170.
Feng, L., Burton, J.W., Carter Jr, T.E., Miranda, L.M., St. Martin, S., Brownie, C. 2011. Genetic analysis of populations derived from matings of southern and northern soybean cultivars. Crop Science. 51:2479-2488.
Burton, J.W., Miranda, L.M., Carter Jr, T.E., Bowman, D. 2012. Registration of ‘NC- Miller’ soybean with high yield and high seed oil content. Journal of Plant Registrations. 6:294-297.
Hussein, A., Carter Jr, T.E., Purcell, L., King, A., Ries, L., Chen, P., Schapaugh, W., Sinclair, T., Boerma, R. 2012. Mapping of quantitative trait loci for canopy wilting trait in soybean (Glycine max L.. Journal of Theoretical and Applied Genetics. 125:837-846.
Place, G.T., Reberg-Horton, S.C., Carter Jr, T.E., Brinton, S.R., Smith, A.N. 2011. Screening Tactics For Identifying Competitive Soybean Genotypes. Communications in Soil Science and Plant Analysis. Vol. 42, Issue 21.
Ries, L.L., Purcell, L.C., Carter Jr, T.E., Edwards, J.T., King, C.A. 2011. Physiological traits contributing to differential canopy wilting in soybean under drought. Crop Science. Vol. 52. pp. 272-281.
Upchurch, R.G., Ramirez, M.E. 2011. Effects of temperature during soybean seed development on defense-related gene expression and fungal pathogen accumulation. Biotechnology Letters. 33:2397-2404. 2011.
Upchurch, R.G. 2011. Soybean fatty acid desaturase pathway: reponses to temperature changes and pathogen infection. Pp. 113-128. In D. Krezhova (ed.) Soybean-genetics and novel techniques for yield enhancement. InTech Open Access Press. Vienna, Austria. 2011.