Lynn Maher, 2013
Lynn at harvest time

Our research program is currently exploring several themes. We have devoted considerable effort over the years to work on secondary metabolites in carrot, onion, and table beet. We are now pursuing a study on volatiles that are associated with flavor, particularly the geosmins.  Geosmins deliver the earthy flavor to foods and are molecules produced by Streptomyces bacteria that live largely in the soil. Initial investigations suggest the genotypic specificity of geosmin concentration in table beet and presence of geosmin even under sterile culture conditions would be difficult to explain if microbial populations were the sole cause of this trait. We believe that table beet is capable of endogenous production of geosmin, and Solveig Hanson has recently completed a study evaluating the stability of this trait across environments in Wisconsin.

We have completed a project on assessing tocochromanol levels in carrot during crop production and postharvest storage, as well as during the reproductive life cycle of the plant. This work, conducted by Claire Luby and Hiroshi Maeda and published in Horticulture Research, shed light on the flux of these provitamin compounds in carrot and revealed that while levels increase dramatically during reproductive growth, the levels are in general too low to be nutritionally significant.

Chris D’Angelo has been working on studying vernalization and dormancy in onion, trying to understand the environmental conditions and genes that influence these two key developmental processes. Chris’s work has implications for onion breeding and for streamlining the onion life cycle.

Katharina Wigg has been working on breeding table beet for resistance to Rhizoctonia solani, an important disease in this crop. Katharina has developed a greenhouse screening technique and is backcrossing resistance into table beet germplasm.

Solveig Hanson is studying the genetic control of geosmin biosynthesis in table beet, including estimating genotype x environment interactions and mapping genes associated with this trait. She is also involved in a participatory plant breeding effort with Wisconsin farmers and consumers to improve flavor profiles in this crop.

Sovereign Carrot
‘Sovereign’ open source carrot

Finally, we have invested substantial effort in developing an open source seed model for varietal release. More information on our open source project can be found here. Corresponding to that outreach effort is a research project that investigates the proportion of key traits in carrot that are controlled by genes for which we have “freedom to operate” and the proportion that is legally restricted. Using maps of phenotypic variation superimposed on maps depicting germplasm restrictions, we are assembling populations of carrot that contain unrestricted genes, for use in breeding anywhere in the world that carrots grow. We hope to be able to release these populations through the open source framework so that they can have maximum utility for farmers, gardeners, and breeders.

Our breeding work and our research programs are intertwined. We are selecting and evaluating in both conventional and organic environments. We have long-standing partnerships with farmers who have helped support our breeding activities, with the network of Agriculture Research Stations in the College of Agricultural and Life Sciences, and with scientists at seed companies. These partnerships are critical to the continuation of our breeding and research programs.

Our program is a member of the Vegetable Breeding Institute, a public-private partnership fostering interaction between public breeders and vegetable seed companies. For more information on the Vegetable Breeding Institute, follow this link. Our breeding programs, particularly graduate student support for plant breeding in organic systems, have also been supported by USDA, Seed MattersCeres Trust, and NC-SARE.