2018 ASHS Annual Conference

Carrot Improvement for Organic Agriculture 2 (CIOA 2) builds upon accomplishments of the CIOA 1 project funded by the USDA OREI. Plant breeding is long-term work and the proposed project will maximize impacts of the CIOA 1 research by delivering new, improved carrot cultivars and breeding lines to the organic seed trade; developing new breeding populations that combine critical traits identified during CIOA 1; expanding the screening of diverse carrot germplasm and field testing of finished cultivars and advanced materials in diverse organic environments; and advancing our understanding of positive genetic-soil microbial interactions, thereby expanding the potential to breed for nutrient use efficiency, disease resistance, and drought tolerance. The long-term goals are to: 1) deliver carrot cultivars with improved disease and nematode resistance, improved nutrient acquisition, seedling vigor and weed competitive traits, increased marketable yield, superior nutritional value, flavor and other culinary qualities, and storage quality for organic production; 2) determine how carrot genotypes interact with, or influence, the root microbiome to access key nutrients under limiting environments, and limit heavy metal uptake; 3) inform growers about cultivar performance to maximize organic carrot production, markets, and organic seed usage; 4) inform consumers about the positive environmental impacts of organic production systems and about carrot nutritional quality, flavor and culinary attributes; and 5) train undergraduate, graduate, and post-doctorate students in critical organic agriculture issues. A timeline for project activities was developed and on-farm field trials have been initiated in six states to identify promising carrot breeding stocks with stakeholder involvement. New genetic sources of improved flavor, nutritional value and novel colors with promising production characteristics have been identified, and major differences in susceptibility to foliar diseases such as carrot red leaf, Cercospora leaf spot, and bacterial blight have been identified. Fine mapping of resistance genes conditioning root-knot nematode resistance is underway to accelerate the incorporation of resistance into new breeding stocks. In addition, marker-assisted selection was initiated for major pigmentation genes.