Updated March 1, 2021:
Towards the development of new cultivars with optimized protein, oil and yield, we have developed a selection index for estimated processing value which incorporates protein, oil, and yield, as well market prices. This model has been applied to advanced and preliminary lines harvested from breeding programs in Ohio (McHale) and North Carolina (Mian) and will be applied to the Missouri (Chen) and Arkansas (Mozzoni) breeding programs to compare to traditional yield-based selection. Due to their balanced oil and protein profiles with high EPV and high yield, nine breeding lines have thus far been released and licensed by companies in 2020.
We also aim to identify, characterize, and develop markers for alleles which break oil, protein, and yield negative relationships. Due to COVID-19 working restrictions, analysis of the eight populations grown in 1-2 locations for their seed protein and oil content this has been delayed.
In an effort to generate and evaluate transgenic events that produce innovative oil products, we have designed transgenic alleles to produce more lipids or novel fatty acid profiles. The omega-3 fatty acid EPA accumulates to approximately 3-5% in the seed of pPTN1331 events. However, F2 populations, derived from a cross with selected pPTN1331 events and a transgenic allele carrying a AtFad3 transgenic allele (generated many years ago) displayed EPA levels ranging from 11% up to 23%. Secondly, the pPTN1331 stacked with AtWri1 and AtKasII or AtDGAT1 helps mitigate the loss of oil.
Finally, seeds from check cultivars and breeding soybean lines, harvested in the Fall 2020, are being analyzed for their carbohydrate content and composition. Thorne embryos develop readily in culture conditions we have developed and reach a labeling steady state after five days of incubation with 13C-labeled substrates. Parallel labeling experiments are ongoing to determine how the carbon taken up by the embryos is stored into biomass components; these labeling data will be implemented into the mathematical model that we developed in order to calculate flow of carbon through metabolic pathways. The results obtained will provide a better understanding of the carbon distribution in soybean embryos.