Transformed Russet Burbank and Lemhi Russet clones which contained three different transgene constructs were evaluated for performance under field conditions in Idaho. The transgenic lines were characterized over two growing seasons, using plants grown from both greenhouse produced minitubers (first year) and field grown seed (second year). Individual clones were evaluated for a variety of agronomic and quality properties. Many of the transformed clones showed reduced yield and increases in percent malformed and undersized tubers. Other characteristics, such as specific gravity and fry color, showed less variability. The variation observed in non-transgenic clones regenerated from tissue culture was less than that of the transformed lines. Out of an original population of 57 transgenic lines in tissue culture, maintenance of key agronomic and quality properties of the parental material was observed in only four clones. These results suggest that experiments designed to generate transgenic lines for the marketplace should be initiated with a large number of transgenic clones.