Shoot-growth variation in cultivated carrot (Daucus carota L.) genetic resources

Authors: LOARCA, JENYNE - University Of Wisconsin; LIOU, MICHAEL - University Of Wisconsin; DAWSON, JULIE - University Of Wisconsin; Simon, Philipp

Submitted to: Frontiers in Plant Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/26/2024
Publication Date: 4/18/2024
Citation: Loarca, J., Liou, M., Dawson, J., Simon, P.W. 2024. Shoot-growth variation in cultivated carrot (Daucus carota L.) genetic resources. Frontiers in Plant Science. Volume 15. https://doi.org/10.3389/fpls.2024.1342512.
DOI: https://doi.org/10.3389/fpls.2024.1342512

Interpretive Summary: The early growth of a carrot seedling is slower than weeds, making the establishment of the crop challenging for growers. Previous studies have noted that among a small number of carrot cultivated varieties, wide variation from variety-to-variety has been noted. Given those observations, this study evaluated almost 750 diverse carrot varieties and breeding stocks from all global carrot growing regions and held in the USDA pant germplasm collection to characterize this broad diversity for early plant growth. A wide range of early growth rate for above-ground and below-ground growth was observed, and that variation was repeatedly observed over the three years of this study, suggesting a strong genetic basis for the variation observed. Use of carrots with strong early growth in breeding programs may provide a foundation to reduce weed competition, and with that the need for herbicide use and hand weeding; and to accelerate crop development for earlier sales. This study is of interest to carrot growers, seed companies, and plant researchers.

Technical Abstract: Carrot (Daucus carota L.) is a high value, nutritious, and colorful crop, but delivering carrots from farm to table is a struggle for carrot growers. Weed competitive ability is a critical trait for crop success that carrot and its apiaceous relatives often lack owing to their characteristic slow shoot-growth and erratic seedling emergence, even among genetically uniform lines. Our study is the first field-based, multi-year experiment to characterize shoot-growth trait variation over a 100-day growing season in a carrot diversity panel (N=695) that includes genetically diverse carrot landraces from the USDA National Plant Germplasm System. We found moderately high broad-sense heritability for seedling emergence (20 days after seeding, DAS) (0.68