University of Wisconsin
Professor and Chair, Department of Horticulture
Irwin is a faculty member in the Department of Horticulture at the University of Wisconsin-Madison, where he has worked since 1992. His work focuses on vegetable breeding and genetics, particularly carrot, onion, and table beet. His laboratory studies the interaction between plants and human well-being, with a focus on health-related traits in vegetable crops. His program has developed inbred lines, open-pollinated cultivars, and improved germplasm that are in use by breeders and farmers around the world. Irwin teaches courses in evolutionary biology, plant breeding, vegetable crops and the relationship between plants and human health.
Irwin’s lab is currently breeding carrot, onion, and table beet for conventional and organic production systems. For over 60 years, the University of Wisconsin breeding program has released inbred lines, improved germplasm, and open pollinated populations for use by plant breeders and seed companies. In recent years, they have focused on traits that have direct appeal to consumers, including flavor and color. Irwin has a project to select for earthiness in table beet and a separate program to select for mild and sweet tasting germplasm. He is involved in studying vernalization requirements and dormancy in onion, and in shortening the breeding cycle of this biennial plant. In the last several years, Irwin and his colleagues have helped organize the Open Source Seed Initiative, which has made a number of varieties available through a unique open source pledge that keeps germplasm available for any purpose without restriction and an open, protected commons.