Location: Plant Genetics Research
Project Number: 5070-21000-040-15-R
Project Type: Reimbursable Cooperative Agreement
Start Date: Oct 1, 2017
End Date: Sep 30, 2018
We will evaluate the utility of molecular markers identified in recently discovered MG 4 soybean genotypes that wilt more slowly, have higher water use efficiency (WUE), have cooler canopy temperatures, and fix larger amounts of nitrogen. In addition, we will, anddetermine the stability of these traits across extremely different environments, and pyramid favorable genes for each trait as well as stack these traits into improved germplasm lines for release.
Previous studies by this team identified at least 21 different genetic loci putatively associated with WUE. To confirm and refine these associations, 200 lines of an F6-derived recombinant-inbred line (RIL) population will be grown and phenotyped at three field locations: 1) Stoneville, MS, 2) Pine Tree Branch Station, AR , and 3) Columbia, MO. The resulting phenotypic data will be used to identify markers associate with WUE in the RIL population. Mapping WUE in this RIL population will confirm putative loci from our GWAS results and allow the targeting of specific genes along with the identification of associated molecular markers. In combination with the WUE experiment, an on-going breeding program combining high WUE and high germinability (HG) will be continued. Agronomically- improved F6:7 breeding lines with high WUE and HG as well as breeding lines with low WUE and HG will be evaluated. Up to 10 F6:8 lines with high WUE and 10 with low WUE (all with high germination) will be used in the experiment. We will initiate irrigated and non- irrigated yield trials of these 20 lines coupled with WUE measures and seed quality traits (germination, protein, oil, etc.) in multiple locations. The best yielding, most WUE lines, will be identified for release. In separate experiments, a soybean diversity panel consisting of 200 strategically selected genotypes will be grown at four locations under well-watered and rainfed conditions. All entries will be phenotyped for drought-related traits. Plasticity/stability for the traits will be assessed by two methods: 1) ‘static stability’ – the phenotypic variance of a genotype across environments and 2) ‘dynamic stability’ –the ratio of the slope of the regression for a specific genotype derived from its phenotype values in different environments and the slope of the regression for the population mean phenotype values in the different environments.