3:45:00 PM-4:00:00 PM              Postharvest performance of promising breeding clones from the Northwest Potato Variety Development Program
Jacob Blauer, Washington State University

               The Northwest Potato Variety Development Program (NWPVDP) was started in 1983 with industry support and was informally known as the Tri-State Potato Breeding Program.  Today, the NWPVDP is composed of specialized researchers from Washington State University, Oregon State University, the University of Idaho, and the USDA-ARS, and with partners from the Washington, Idaho, and Oregon Potato Commissions.  Collectively, the NWPVDP has released 55 varieties across all market segments with notable success in the French fry market.  Recent breeding efforts within the French fry industry has identified six novel breeding clones with potential for commercial release.  These varieties are, A12305-2adg, AFA5661-8, A09086-1LB, OR12133-10, AOR13064-2, and AOR11217-3.  All six clones have been tested in the NWPVDP for a minimum of three years and in the National Fry Processing Trials (NFPT).  In all NPFT tests, these varieties have generally performed at ‘target’ to ‘acceptable’ for processing characteristics including acceptable levels of acrylamide below 500 ppb in early crop trials.  Evaluations at Washington State University demonstrate these six varieties are superior to Russet Burbank (RB) for postharvest merit and similar to Ranger Russet (RR) and Clearwater Russet (CR) with the exception of AOR13064-2 and AOR11217-3 which out-performed all three checks.  These new varieties range in specific gravity from 1.078 to 1.089, have a percent bruise rating equivalent to RR to significantly better than RB, have a length-to-width ratio similar to CR and RB, and superior flavor to RB.  Fry color at harvest and post storage was equivalent to RB with exceptional performance from AFA5661-8 and AOR13064-2 which demonstrated cold-sweetening resistance when stored at 4°C for 60-days.  A12305-2adg demonstrated the best dormancy potential and was the most similar to RB when sprouting was evaluated.  Overall postharvest results of these varieties suggest improvements in the industry for storage quality and provide additional opportunities for trait introgression in other breeding programs.

4:00:00 PM-4:15:00 PM    Colorado State University Variety Releases and Potato Breeding Program Update
Caroline P Gray, Colorado State University

               Two potato cultivars developed by the Colorado Potato Breeding and Selection Program, Horizon Russet and Crystal Russet, will be released and protected in both Canada and the United States. Horizon Russet is an early maturing fresh market russet with heat and drought tolerance. Horizon Russet, previously known as CO05189-3RU, was derived from a cross of CO97138-7RU and Canela Russet. Horizon Russet has excellent long-term storage potential. Crystal Russet is a high yielding dual purpose russet with fresh market and processing potential. Crystal Russet, previously known as CO08231-1RU was derived from a cross of Crestone Russet and Sage Russet. Crystal Russet has a high percentage of marketable yield and good French fry color. The next clone in the cultivar release pipeline is Snowcap, a later maturing chipper which will be released and protected in partnership with AIS Consulting, LLC. The Colorado State University Potato Breeding and Selection Program is committed to developing potato varieties with disease resistance (PVY, PMTV, TVR) and climate resilience with the goal of reducing inputs such as pesticides, nitrogen, and water. The CSU potato breeding program will continue to use applied and molecular breeding techniques to make selections and identify key traits. Since 2022 the CSU potato breeding program has marker screened germplasm for PVY resistance genes the Ryadg and Rysto. During the 2023 field season, two breeding populations were genotyped using Rapid Genomics flex-seq technology and will be phenotyped for disease susceptibility. The goals of these disease resistance studies are to identify the unknown source of PVY resistance present in Fortress Russet and to identify PVY and TRV resistant germplasm. Tuber physiological maturity is another metric being explored to facilitate breeding for potato varieties with early maturity.

4:15:00 PM-4:30:00 PM     In-Field Agronomic Results of Six Promising Potato Varieties from the Northwest Potato Variety Development Program            
Rhett Spear, University of Idaho

Researchers with the Northwest Potato Variety Development Program (NWPVDP), composed of researchers from the Pacific Northwest institutions of the University of Idaho, Washington State University, Oregon State University and the USDA-ARS, evaluate new potato varieties annually using Russet Burbank as a standard variety. Since its inception in 1983, the NWPVDP has released 55 varieties for use in the fresh, chipping, dehydrated, and frozen process markets. Results from field trials during 2019 to 2023 suggest that six new varieties (A12305-2adg, AFA5661-8, A09086-1LB, OR12133-10, AOR13064-2, and AOR11217-3) may be suitable for use in the frozen process market and/or fresh markets. In addition to 3 to 5 years of trials in the NWPVDP, each of these varieties were entered into the national frozen processing trials (NFPT) for two to three years. Four of six varieties significantly outyielded Russet Burbank by a range of 23% to 47%. Increased yields and improved tuber size and quality resulted in significantly increased economic returns of 52% to 149% for all six varieties compared to Russet Burbank. A12305-2adg has the added benefit of extreme resistance to potato virus Y, which is a consistent problem for potato growers and often results in yield and quality reductions. Overall agronomic results coupled with postharvest storage and processing suggest that these varieties may offer potato growers additional options to improve over Russet Burbank and may provide potato breeders with parent material that can be used to improve future crosses.

4:30:00 PM-4:45:00 PM              A Comparison of Field Performance and Postharvest Quality Across 12 Popular Commercial Potato Varieties In the French Fry Industry
Daphne Crum, Washington State University

               "Potato cultivar performance has a significant impact on production, postharvest quality, and sustainability. Thus, holistic, comparative evaluations on cultivar performance are critical when selecting appropriate cultivars for the industry, given that not all cultivars are appropriate for all markets, and that quality metrics are controlled by numerous factors (e.g. environmental and edaphic effects, genetics, and management practices). To clarify cultivar performance for the French fry market, this study aims to compare the field performance and postharvest quality of 12 popular cultivars for two years grown in Othello, WA and Parma, ID. WA produced 27.2% higher overall yields than ID, indicating the significance of growing location on field performance. The cultivar Alturas produced the highest total yield in both WA and ID, while Russet Burbank produced the lowest yield. There were no significant differences in specific gravities when averaged across WA and ID cultivars. Postharvest quality evaluations focused on fry color quality. Samples of each cultivar from each state were fried at harvest and after 60-days of storage at 4°C or 9°C. Photovolt stem-end reflectance values were measured to assess fry color. Potatoes exposed to significant cold (<9°C) can be susceptible to low temperature sweetening (LTS), the over-accumulation of reducing sugars associated with darker colored fries arising via the Maillard reaction. No cultivars stored at 4ºC scored higher than USDA 1 in color class after frying, indicating no evidence of LTS resistance on our scale. Both states produced acceptably light fries when stored at 9°C. The cultivars Alturas, Clearwater Russet, and Umatilla Russet produced the lightest fries at 9ºC and 4ºC across WA and ID. The results of this study will provide the industry with a direct comparison of cultivar performance in the Pacific Northwest, promoting cultivar selection improvements for the industry.

4:45:00 PM-5:00:00 PM                             Tuber Yield and Quality of Rainier Russet and Russet Burbank Cultivars in Response to Different Nitrogen Rates    

Ruijun Qin, OSU

Potatoes (Solanum tuberosum L.), known as the fourth most nutrient-rich dietary crop, have a high nitrogen (N) requirement. In the Columbia Basin region of North America, Russet Burbank has long been the standard for nitrogen (N) management in potato cultivation. However, as new varieties emerge, assessing their response to N application and updating N management practices becomes essential. Therefore, a two-year study was conducted to examine and compare the tuber yield and quality of the Rainier Russet with Russet Burbank under different N application rates (157, 280, 404, 527 kg ha−1), including control with no applied N. Results indicated that Rainier Russet exhibited higher tuber yield with sizes exceeding 283 g, while Russet Burbank demonstrated superior yield for tubers smaller than 170 g and culls. Nitrogen application had a significant impact on the U.S. No 1 tubers and tubers within the size range of 113−170 g and above 283 g. Nitrogen application significantly enhanced fry color, with the most favorable color observed at 404 kg N ha−1, which was statistically similar to that at 527 kg N ha−1. According to a polynomial model, the peak US No. 1 yield for Rainier Russet was attained at 350 kg N ha−1, whereas for Russet Burbank, it occurred at a rate of 300 kg N ha−1. Following the variable response of varieties to different N application rates and significant seasonal impact, further research is critical to gain a better understanding of optimizing N application rates based on the desired objectives.