Sather, Kent P., authorThompson, Asunta L., advisorHolm, David G., advisorNissen, Scott J., committee memberWallner, Stephen J., committee member2023-01-272023-01-272003https://hdl.handle.net/10217/236177Covers not scanned.Russet Norkotah line selections may be utilized to increase yields and profitability while reducing nitrogen applications normally required when producing Russet Norkotah. The Solanum tuberosum L. cultivar, Russet Norkotah, has increased in acreage since its release in 1987. Since the early 1990's, several breeding programs have made line selections that possess superior production potential under lower nitrogen rates. Five line selections and Russet Norkotah, were grown for two years at three rates of nitrogen in the San Luis Valley, Colorado. Selections included were Colorado 3 (CO3), Colorado 8 (CO8), Texas 112 (TXNS112), Texas 223 (TXNS223), and Texas 278 (TXNS278). The low, medium and high rates of nitrogen applied were approximately 100, 148 and 192 kilograms per hectare, respectively. Total and marketable yields generally increased as nitrogen rates increased. Yields were fairly consistent between years, except for standard Russet Norkotah. In 1998, selections at the low rate out yielded Russet Norkotah under higher rates. In 1999, selections grown under the low rate yielded similarly to Russet Norkotah at the high rate. Selections grown at the medium and high rate yielded significantly more. CO3 was the best producer overall. As vine fresh weight increased, tuber yield also increased. These results indicate acceptable tuber yields may be attained with Russet Norkotah line selections grown at lower nitrogen rates than currently used for standard Russet Norkotah production. Using Russet Norkotah line selections may result in increased profitability by increasing yields and reducing input costs, and may also minimize nitrogen loss due to leaching and run-off.masters thesesengCopyright and other restrictions may apply. User is responsible for compliance with all applicable laws. For information about copyright law, please see https://libguides.colostate.edu/copyright.PotatoesCrops and nitrogenText