Potato yield improvement in the United States has concentrated on cultural practices, disease eradication, and the development through breeding programs of new, disease-resistant, high yielding potato cultivars. Three strains of Norgold Russet—M, #35 and #19—have increased yields and vigor, and mature later than “regular” Norgold Russet. In trials conducted in Texas at Hereford (7 years), Olton (6 years) and Springlake (4 years), these strains have shown an average of 33, 29 and 20% increase in total yields, respectively. At Hermiston, Oregon (3 years), the mean total yield increases were 10, 17 and 12%, respectively. Strains M and #35 are more vigorous, and they mature 10 to 15 days later than Norgold Russet. Strain #19 is the most vigorous and upright of the strains; it matures 20 to 25 days later than regular Norgold Russet. Of all the Norgold Russet strains, strain M is the most popular. From Superior, a strain, New Superior, which matures 15 to 20 days later and is more vigorous, was selected. In Florida, New Superior’s yields averaged 26% greater than regular Superior but the specific gravity and chip color were not changed. Two strains of Red La Soda—#5 and #10—were selected for their earlier maturity. Strain #10 matures 7 to 10 days earlier than regular Red La Soda, and strain #5 matures 15 to 17 days earlier. However, these strains yield less. In Texas, at Olton (3 years) and Springlake (2 years), yields were reduced 23 and 34% for strains #10 and #5, respectively