Location: Sunflower and Plant Biology ResearchTitle: Seed and floret size parameters of sunflower are determined by partially overlapping sets of quantitative trait loci with epistatic interactions
|REINERT, STEPHAN - University Of Colorado|
|GAO, QINGMING - Cibus|
|FERGUSON, MARY - Oak Ridge Institute For Science And Education (ORISE)|
|PORTLAS, ZOE - University Of Vermont|
Submitted to: Molecular Genetics and Genomics
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/26/2019
Publication Date: 9/26/2019
Citation: Reinert, S., Gao, Q., Ferguson, M.E., Portlas, Z., Prasifka, J.R., Hulke, B.S. 2019. Seed and floret size parameters of sunflower are determined by partially overlapping sets of quantitative trait loci with epistatic interactions. Molecular Genetics and Genomics. 295:143-154. https://doi.org/10.1007/s00438-019-01610-7.
Interpretive Summary: Seed size is an important trait for certain sunflower markets, especially the high value, internationally traded confectionery market. Breeders have been increasing seed size to compete in niche international markets, but in doing so, have observed some lines with reduced seed set in hybrid production, presumably because they are avoided by pollinators. Certain pollinators prefer to avoid plants with long florets, which can occur on some large seeded lines. We conducted this study to see if the two traits always occurred together or, on the other hand, if seed size can be selected independently of floret size. We found that, while there is some correlation, it was not strong enough to prevent breeding for large seed size and shorter florets. Further, we developed DNA marker resources for both traits, which should allow breeders to use modern technology to optimize selection for shorter florets and larger seeds.
Technical Abstract: Seed size is an important quality component in marketing commercial sunflower (Helianthus annuus L.), particularly for the in-shell confectionery market, where long and broad seed types are preferred. However, there appears to be a correlation between these traits and increased floret length, which tends to decrease pollinator visitation. Recent studies have shown that commercial sunflower production benefits from pollinator visits, despite being self-compatible, and it remains that sunflower hybrid seed production is completely dependent on pollinators and the two parental, inbred lines need to have similar attractiveness to pollinators in order to have economical seed production. Thus, the goals of our work were to determine the strength of the correlation between seed and floret traits, and map the locations of important trait loci for these traits using genome-wide association analysis in the SAM diversity panel of sunflower. Our results indicate that phenotypic correlations between seed and floret traits are generally low to moderate, regardless of market class, a component of population substructure. Association mapping results mirror the correlations; while a few loci overlap, many loci for the two traits are not overlapping or even adjacent, suggesting that large seed size can be accomplished without producing florets too long for efficient use by pollinators.