Location: Plant Genetics Research2011 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.
3. Progress Report
The objective of this project is to determine the molecular genetic basis for increased high quality seed protein content in soybean seeds. We evaluated the available soybean germplasm for this project, and selected lines that had the desired characteristics of very high protein content unrelated to the current sources of high protein alleles in different breeding programs. The objective links to the in-house project "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. The genetic basis of the high protein trait was evaluated along with protein quality for this project. Towards the goal of understanding the genetic basis of the high protein trait, we collaborated with ARS scientists in Beltsville, MD to utilize the Illumina Soy 1536 single nucleotide polymorphism (SNP) array on our population of lines segregating for the high protein trait. We now have the complete data set of individual SNP genotypes for the entire population, and we were able to get accurate seed oil content using a nuclear magnetic resonance (NMR) instrument, but we have not yet conducted the experiment to determine accurate protein content (via total nitrogen measurement). We used the oil content data to select lines from our population for field growth that had segregated for the highest and lowest oil contents under the assumption that protein content would be inversely correlated with oil content. In addition to lines described above, we obtained an independent, characterized high protein line in a maturity group (MG) III background to use to develop lines segregating for the major locus controlling high protein as well as the unknown genetic factors in our high protein line. We also selected lines with low P34 allergen and low phytate from our germplasm collection to use in this project. All lines have been planted in our field location.