2013 Annual Report
1a.Objectives (from AD-416):
Determine the genetics of the high protein and protein quality traits for the G. soja source alone and in combination with a separate source and to generate novel soybean breeding germplasm with higher protein content and quality in combination with lower allergen and lower phytate. This project will determine the genetics and combining ability of protein content and protein quality improvement possible with a novel source of the high protein trait. In addition, the high protein content trait will be combined with the low P34 allergen and low phytate trait and the resulting soybean germplasm will be made available to public soybean breeders. The research will address the question of whether there are a spectrum of alleles present in the high protein donor that can be separated and captured along with reasonable oil content in adapted breeding lines. In addition, the combining ability with an independent source of the high protein trait will be evaluated.
1b.Approach (from AD-416):
Molecular genetics and plant breeding experiments will be conducted to evaluate the molecular genetics of protein content and quality in the seeds. An established population will be used, so phenotyping and mapping can be completed efficiently. Trait combination will be assisted with developed and new molecular marker assays. Seeds will be phenotyped for their oil and protein contents by NIR or by NMR. Amino acid analyses will be performed in house using an existing method for HPLC or contracted out, depending on preliminary experimental results. DNA will be prepared from each of approximately 300 lines of the population and used for associating the high protein trait with the components of the genome responsible for the trait utilizing the Illumina Golden Gate Array in conjunction with ARS researchers in Beltsville, MD. Yield of selected lines from the mapping population will be analyzed in multiple Missouri field locations. Conventional plant breeding utilizing crossing and selection with existing molecular markers will be used to combine the most promising high protein quantity/quality lines trait lines with the low phytate and low P34 allergen traits.
This research relates to the in-house project objective "to develop the molecular basis for modification of the fatty acid components of soybean oil and anti-nutritional components in soybean meal to use in accelerated breeding programs" by exploring the relationship between protein content and quality and by exploring the molecular genetic basis for protein quality traits.
In the course of the project, we identified a soybean line with a novel seed composition phenotype related to the accumulation of phytic acid, and we characterized lines segregating for the trait. The phenotype was not significantly different from control plants in the initial experiment. However, when we combined the mutation with a mutation in a second gene encoding the same enzyme, we were able to develop a novel source of the low phytate trait. We have combined the new trait with other soybean meal traits to better understand the impact of the traits on each other and the overall agronomics of the soybean lines containing improved meal quality traits.