Walter De Jong

My research improves potato genetics by both conventional and molecular genetic means. Our breeding program develops new chipping and tablestock varieties that are adapted to the Northeast and meet ever-changing needs of the regional potato industry. 

Our highest priority is to develop agronomically acceptable varieties that are resistant to the golden nematode -- a soil-borne pathogen present in New York but no other state. Resistant varieties provide the single best means to prevent this nematode’s spread. The discovery of a second race, Ro2, in Long Island and now in upstate New York presents a new and serious challenge: How quickly can we develop varieties resistant to both races? 

To speed this research, we are working to map the gene(s) responsible for Ro2 resistance to permit marker-accelerated selection. The breeding program also seeks to develop potatoes with trichome-mediated broad-spectrum resistance to insects, as well as late-blight resistant varieties.

Potatoes with novel coloration, e.g., red or purple or yellow pigmented flesh, are garnering increasing consumer interest. To support breeding of such varieties, and to develop tools useful for understanding many fundamental aspects of gene regulation in tubers, we are working to isolate the genes responsible for most of the natural variation in tuber coloration. 

To date we have identified genes that correspond to four key color loci – R, required for red tuber color, P, required for purple tuber color, D, required for expression of red or purple in tuber skin, and Y, required for yellow tuber flesh, respectively. 

Most recently, we have begun work aimed at isolating a gene required for round versus long tuber shape (Ro).

More information

• Learn more about our potato breeding trials.
• View De Jong's publications on Google Scholar.

Book Sections

• De Jong, H., Sieczka, J. B., & De Jong, W. S. (2011). The Complete Book of Potatoes: What Every Grower and Gardener Needs to Know. p. 260 Timber Press, Portland, Oregon, USA.