There’s the Columbia root-knot nematode, which costs U.S. growers $20 million annually;the potato tuber moth;and late blight, which caused the Irish Potato Famine of 1845 and is still responsible for significant losses and control expenses today. Chemical fumigants and fungicides have long been a staple defense for these pests and pathogens. But the onset of resistance in new pest or pathogen biotypes—coupled with environmental concerns about long-term pesticide use—has prompted the search for sustainable solutions in the form of genetic resistance.
Nationwide,ARSresearchers are seeking to develop new potato varieties that will not only hold their own against insects and disease, but also maintain their storage quality and deliver nutrients that promote health and well-being in spud lovers the world over.
For example, at ARS’s Small Grains and Potato Germplasm Research Unit in Aberdeen, Idaho, geneticist Rich Novy and plant pathologist Jonathan Whitworth spearhead a program to develop new potato lines that are resistant to different biotypes of the late blight pathogen,Phytophthora infestans. Toward that end, they’re collaborating with Héctor Lozoya-Saldaña, a potato researcher in Chapingo, Mexico, where late blight is endemic.
“We send 2,500 breeding clones annually to Chapingo, where Lozoya-Saldaña evaluates them for late blight resistance,” says Novy. “We then have a duplicate planting of those same breeding clones at Aberdeen, where—based on his late-blight readings—we concurrently select resistant clones and advance them in our program,” based on their agronomic performance under irrigated production in the western United States.
The late blight-resistant cultivar Defender is an example of a recent release (2006) from the program. Defender has helped growers save on fungicides and other expenses associated with controlling late blight, which attacks the crop’s leaves and tubers, rendering the latter unmarketable. Over the next few years, Defender may be joined by one more blight-resistant potato variety, depending on how it performs in ongoing trials in Idaho, Oregon, Washington, California, and Texas.
