Carrot Improvement for Organic Agriculture (CIOA): Leveraging On-Farm and Below Ground Networks

Project Director: Phillip Simon, University of Wisconsin-Madison

Project overview

Carrots are an economically important crop for organic specialty crop farmers, with 12% of US carrot acreage under organic management bringing more than $120 million in farmgate sales. Yet, challenges with organic weed and disease management and a lack of cultivars with desired market traits limit organic producers’ capacity to take full advantage of the market potential. Since its launch in 2011, the Carrot Improvement for Organic Agriculture (CIOA) project, led by Phillip Simon and researchers at the University of Wisconsin-Madison, has established a robust nationwide network of plant breeders, organic farmers, and small-scale seed companies to develop and release new carrot varieties better suited to organic systems.

‘Carnelian’ carrot Source: High Mowing Seeds

Farmer takeaways

Farmer participatory plant breeding is critical for developing new carrot varieties, including ‘Carnelian’, available through High Mowing Seeds
Carrot roots form beneficial associations with bacteria and fungi, which can mitigate diseases in the field
Breeders are working to optimize the relationship between carrot roots and the soil microbiome in organic systems

Project objectives and approach

Variety development and release

In 2022, 5 organic seed companies evaluated 3 improved carrot varieties to determine interest in commercialization. One is now available commercially from High Mowing Organic Seeds under the name ‘Carnelian’. Other releases are advancing to commercialization.

Expand participatory variety trial and plant breeding network

The online platform SeedLinked was used to collect and share trial evaluation, informing new variety releases. The project expanded its collaboration with farmers across the US through its partnership with the Organic Seed Alliance (OSA) where at least 40 farms per year participate in decentralized on-farm variety trials.

Examine links between microbiomes, nutrient uptake, disease resistance & quality in carrot varieties

One study in this project looked at how microbiomes in carrot taproots differ among cropping systems and regions and whether this influences crop yield and quality. Another explored the relationships between carrot root exudates, soil microbiome characteristics, and carrot quality.

Utilize molecular markers to improve nematode resistance

Molecular markers are being developed to confirm the identity of resistance genes in breeding stocks.

Evaluate and improve carrot flavor, texture and color

Assessment of carrot flavor was integrated into all breeding activities since flavor is a priority trait necessary for the successful adoption of new varieties.

Key findings

Carrot taproots have the potential to be colonized by an abundant and diverse assortment of bacteria and fungi

These endophytes can play an important role in mediating disease resistance and nutrient availability, and it may be possible to select for these beneficial plant-microbial relationships in carrot breeding programs.

Carrot variety makes a difference

Variety affects endophyte abundance and the potential for microbial populations to influence seed germination, seedling growth and disease tolerance.
Carrot varieties differ in their potential to alter soil bacterial communities and stimulate microbially-mediated decomposition of organic materials, influencing nutrient availability and heavy metal uptake in the field.

Implementing soil-building practices common in organic farming systems has the potential to promote beneficial microbes and improve the quality and productivity of carrot crops

Soils in organic systems often have greater total organic matter, microbial biomass, and activity than in conventional systems.

Farmer participatory plant breeding continues to make progress toward new cultivars that combine priority agronomic and market traits

A gallery of carrot types by the Carrot Improvement for Organic Agriculture Project Source: eOrganic

Resources

eOrganic - CIOA Project Website

Triviño, N.J., Rodriguez-Sanchez, A., Filley, T. et al. (2023) Carrot genotypes differentially alter soil bacterial communities and decomposition of plant residue in soil. Plant Soil 486, 587–606.

Abdelrazek S, Simon P, Colley M, Mengiste T, Hoagland L. (2020) Crop management system and carrot genotype affect endophyte composition and Alternaria dauci suppression. PLoS ONE 15(6): e0233783

USDA - Project Report - OREI 2021-51300-34900

Location

Illinois

Collaborators

Pamela Roberts, University of Florida

Erin Silva, University of Wisconsin-Madison

Tim Waters, Washington State University

Lori Hoagland, Purdue University

Micaela Colley, Organic Seed Alliance

Jared Zystro, Organic Seed Alliance

Laurie McKenzie, Organic Seed Alliance

Jaspreet Sidhu, University of California, Davis

Julie Dawson, University of Wisconsin-Madison

Zac Freedman, University of Wisconsin-Madison

Region

North Central

Topic

Weed Management, Disease Management, Insect/Pest Management, Plant Breeding, Varieties, and Seeds

Year Published

2024