Trio of new spuds will help Pacific Northwest growers

A potato that needs no fungicides to withstand late blight is one of three new varieties released this spring by the Tri-State Potato Variety Development Program. Named Defender, the late-maturing, unrusseted "long white" spud develops late blight symptoms so slowly that growers who would otherwise be spraying fungicides weekly need not spray for late blight at all.

Richard Novy, USDA Agricultural Research Service potato breeder at the UI Aberdeen Research and Extension Center, says Defender is the first North American potato whose foliage and tubers are both highly resistant to aggressive forms of the late blight fungus. This fungus, Phytophthora infestans, emerged as a problem for the region's potato growers in the early 1990s. (It also caused the Irish potato famine, 1845-1860.)

Steve Love, tri-state program coordinator and superintendent of the Aberdeen R&E Center, says Defender also outyields Russet Burbank by 10 percent or more under disease-free conditions. At least 80 percent of its tubers rank U.S. No. 1, and their favorable solid-matter content—a critical economic factor for french fry processors—exceeds that of Russet Burbank. Its use will likely be limited to frozen products, because it lacks the russeted skin the Pacific Northwests freshpack market demands.

GemStar Russet generates great interest

The tri-state program—comprised of federal and land-grant potato breeders in the three Pacific Northwest states—also released a drought-tolerant variety called GemStar Russet. According to Love, it consistently produces large quantities of well-shaped tubers despite water stress and also "cooks and eats well." Despite two downsides—unusual susceptibility to both hollow heart and potato virus Y—Love reports "more interest in GemStar Russet at this stage in its development than any other variety we've ever produced."

The third new variety, Western Russet, an oblong russet with high yields and solids and a good proportion of large tubers, outperformed all other potatoes in western regional trials for early-harvest processing and also held up well in late-harvested storages. Resistant to malformations and internal defects, it should be useful for both processing and fresh markets, Love says. Contact Love at slove@uidaho.edu.

--by Marlene Fritz

© 2004 University of Idaho, College of Agricultural and Life Sciences.