Willamette (AO91812-1) is a high yielding round white variety with excellent chipping qualities. Tubers are similar in shape to those of Atlantic but average slightly smaller as shown by higher yields of tubers weighing less than 4 ounces, reduced tuber size may be due in part to later maturity.
Willamette vines are medium large, vigorous and mature later than Atlantic. The flower color ranges from blue-purple violet inner corollas to light gray acumen, or petal tips.
Willamette has typically shown fewer internal defects, especially brown center, hollow heart and internal brown spot, than Atlantic. The two clones show similar external defects. The tubers sometimes have a pronounced folded bud end and tend to cling to stolons when harvested immature. It produced lighter fry color than Atlantic from both 40 and 50°F storage.
Willamette has shown more resistance to Verticillium wilt, early blight and net necrosis than Atlantic. Both varieties have shown similar foliar susceptibility to late blight in western Oregon but Willamette has typically been much more susceptible to blight-induced tuber decay.