by Katie Navarra
Nearly 14.3 percent of the total carrot crop acreage in the United States is grown in organic farming systems. “Carrots are a significant organic production vegetable component in U.S. agriculture,” said Micaela Colley, executive director and research education director for the Organic Seed Alliance.
Given the crop’s importance in organic agriculture, carrots are the focus of a nationwide project aimed at addressing critical needs of organic farmers. The collaborative includes researchers from around the country with specialties in multiple disciplines. The group is working together to develop and identify carrot varieties with improved nematode and disease resistance, increased nutritional value and flavor and improved weed competitiveness.
“For organic consumers, culinary quality is important for organic consumers,” Colley said, “(carrots) have to be sweet and succulent, not harsh or bitter. The various colors of carrots also present a complimentary nutritional quality component that we believe has a strong market demand.”
The Carrot Improvement for Organic Agriculture (CIOA) project was started in 2012. Collaborators are collecting data from test sites and are comparing the relative performance of breeding material in organic versus conventional environments. They hope that the information collected can lead to the identification of carrot varieties that perform better under organic soil conditions.
A webinar hosted by eOrganic provided a detailed explanation of the project, its goals and preliminary results.
Field tests
“Trials are being conducted in Wisconsin, Indiana, Washington and California over a four-year period,” Colley explained, “the trials are paired management trials and include 16 named cultivars and 20 experimental varieties.”
The study includes standard varieties like Western Red, Bolero, Sun 255 and Sugar Snax as well as experimental varieties such as R6637, Y8519 and Nb8524. One foreign cultivar, Brasilia, is also included the trials because of its large top size.
Not only is the CIOA interested in finding carrot varieties with improved nematode and disease resistance, increased nutritional value and flavor and improved weed competitiveness, the project is also spinning off additional research activities focused on the evaluation of foliar disease, the presence and role of microbial activity in the soil among other topics.
“(For example) Lindsey du Toit, Washington State University, Mount Vernon is studying Alternaria and Cercospora leaf blights and powdery mildew,” said Philipp Simon, USDA Ag Research Service and Department of Horticulture, University of Wisconsin-Madison. “Pamela Moreno, a graduate student at University of Wisconsin is looking at Alternaria leaf blight resistance from new genetic sources,” he added.
At Purdue University, Lori Hoagland, assistant professor of specialty crop production, is focusing on research related to soil microbes and their interactions with plants to increase crop productivity and reduce negative impacts of farming systems on the environment.
“The preliminary results from 2014 show that soil microbial biomass activity is greater in organic systems than conventional systems,” she said.
The soil microbial community structure was different in organic compared with conventional samples; however, there was not a noticeable difference in carrot yield based on level of soil microbial activity.
Online resources
The CIOA project includes several online resources designed to provide detailed information about the carrot varieties and the performance of those varieties during the field trials. The website ( features a searchable gallery and an organic variety trial database.
“The 30+ carrot varieties included in the gallery can be searched by color, disease resistance and commercial availability,” said Cathleen McCluskey, communications and outreach associated at the Organic Seed Alliance.
The gallery includes images of most carrot varieties and the information will be updated to include information and links to the results of the field trials as the information becomes available. “The gallery is really easy to use,” she added.
The CIOA website also includes a resources page with links to resources for organic carrot breeding and seed production collected from multiple sources. In addition to the gallery and resources, a link to the Organic Variety Trial Database is available on the website’s homepage. The Organic Variety Trial Database collects and makes available reports from around the United States on the performance of organic crops.
About CIOA
Carrot Improvement for Organic Agriculture (CIOA) is a long-term breeding project that addresses the critical needs of organic carrot farmers by developing orange and novel colored carrots with improved disease and nematode resistance, improved weed competitiveness, and improved nutritional value and flavor.
The Carrot Improvement for Organic Agriculture project will deliver improved carrot varieties; improve understanding of the farming systems influence (organic vs. conventional) on variety performance; and develop a breeding model adaptable to other crops for organic systems.
The lead collaborators are:

  • Philipp Simon, USDA, Agricultural Research Service and Department of Horticulture, University of Wisconsin – Madison
  • Micaela Colley, Executive Director, Organic Seed Alliance
  • Jared Zystro, Research and Education Assistant Director, Organic Seed Alliance
  • Philip Roberts, Professor and nematologist, University of California – Riverside
  • Lori Hoagland, Assistant Professor, Specialty Crop Production Systems, Purdue University
  • Cathleen McCluskey, Communications and Outreach Associate, Organic Seed Alliance

Funding support is being provided by the USDA, National Institute of Food and Agriculture Award no. 2011-51300-3093. Visit to learn more about the CIOA, the project collaborators and early results from the research.
To watch the webinar which provided the information for this article click here.