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ARS Home » Plains Area » Fargo, North Dakota » Edward T. Schafer Agricultural Research Center » Sunflower and Plant Biology Research » Research » Research Project #436130

Research Project: Identification and Mapping of Genetic Factors Affecting the Stability of Oleic Acid in Inbred Lines and Hybrids

Location: Sunflower and Plant Biology Research

Project Number: 3060-21000-043-22-T
Project Type: Trust Fund Cooperative Agreement

Start Date: Jul 1, 2018
End Date: Jun 30, 2020

Objective:
This project aims to build on our research from the previous funding cycle, which concentrated on determining which modifier genes were responsible for small, but practically important, changes in oleic acid in inbred lines, in diverse environmental conditions. We will extend this from the development of inbreds to the development of highly stable, predictable hybrids by: a. Mating parental lines from our previous project to make fully functional hybrids, and then evaluate their fatty acid compositions and map dominance effects by association methods. b. Develop biparental populations between stable and unstable high oleic lines to map a fad2-1 instability locus, and validate using the SAM association mapping population.

Approach:
Experiment (a): We plan to generate seeds of 289 hybrids this winter by mating 17 female lines with 17 male lines in a “North Carolina II” mating design. The hybrids will be grown in our Glyndon, MN, nursery in 2018, and 5 heads Delnet bagged and sampled from each hybrid to conduct fatty acid analysis. Once the fatty acid analysis has been conducted, we will subject the data to an association model which will be altered to separate out female, male, and cross effects for each tested marker. Genomic data has been generated by our previous project, as well as the Sclerotinia Initiative and Genome Canada, so there is no known need for genotyping in this experiment. Results will be compared to our previous project’s results and additional environmental sampling will be conducted in 2019 if any of the important genes with dominance effects are known to react differentially to environmental stresses. Experiment (b): This winter, we plan to generate three biparental cross populations between stable and unstable high oleic lines, based on previous data. One of these crosses will be between HA 481 and an unstable F8 isoline of HA 481 that was discarded from breeder’s seed increases. We are looking at data to guide two other crosses from different parents, but hope to source them from different genetic backgrounds than HA 481 to better understand potential population effects for these loci. F1 plants will be grown in summer 2018, F2 populations grown in winter nursery in 2018-2019, and F2:3 plants will be grown in progeny rows in the summer of 2019. At this stage, instability in high oleic should be evident in a 10 plant sample of each inbred line. Additional inbreeding may be necessary if the genetics are more complicated than it appears from our current data. Skim sequencing (1x coverage) will be conducted on the same lines in the same generation as the fatty acid phenotypes are collected. The sequencing will generate a dense set of genetic markers we can use to map this instability trait. We will also grow high oleic lines from the SAM population to score those lines for stability and use them as validation for any markers we develop.