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Potato Progress Volume 22 Number 5

Potato Progress Volume 22 Number 5


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Potato Progress

Volume 22 Number 5

10 June 2022 

potato plants

2022 Washington State Commercial Seed Lot Profile

and Potato Field Day Preview


Mark Pavek, Zach Holden, Tim Waters, Carrie Wohleb, Raul Garza Jr., and Vito Cantu

Washington State University

Washington State University has conducted the Commercial Seed Lot Trial in cooperation with the Washington State Potato Commission and industry for 59 years (1961-78, 1982-2022).  We incorporate a virus/disease reading training session into our program as a routine requirement prior to the first field reading.  The goal of the training session is to improve our plant-reading accuracy by training the unexperienced and fine-tuning the expert. Plant disease experts from across the NW, including the Washington, Montana, and Oregon potato seed certification teams, continue to assist in the seed lot readings as well as the proof-readings. The results will be available under "2022 Washington Commercial Seed Lot Trials" at

Poor quality potato seed will impact commercial grower income.  Major quality factors are disease, virus, herbicide damage, frost damage, and seed-piece handling.  Commercial potato growers in Washington State typically purchase their seed potatoes from seed-growing regions outside of Washington.  For quality control, it is essential that each seed lot be grown under controlled conditions for approximately 70 days and evaluated by professionals.  The Seed Lot Trial provides Washington potato growers, seed suppliers, and handlers a side-by-side comparison of seed lots utilized by Washington commercial potato producers.  The associated field day provides buyers and sellers an opportunity to observe performance of seed lots of common interest and discuss results.  To improve field disease diagnostic skills, WSU, USDA, and potato industry personnel from across the western U.S. exchange ideas and share expertise on field diagnosis of disease symptoms and other seed tuber quality factors.

‍In the last five years, there has been a decline in the number of submitted seed lot samples. WA growers submitted 251 seed lots into the 2022 WA Commercial Seed Lot Trial, compared with 266 in 2021 (Figure 1, bars). Last year, WA growers planted 160,000 acres; acreage for 2022 has yet to be published. WA acreage typically fluctuates between 155,000 and 170,000 (Figure 1, dotted line).

Montana and Idaho provide WA growers with the most seed potatoes, followed by WA, CAN, OR, and other states (Figure 2). The composition of the 2022 Seed Lot Trial included 20% Clearwater Russet, 20% Russet Burbank, 18% Umatilla Russet, 14% “Other” (newer and/or non-mainstream varieties), 10% Alturas, 9% Ranger Russet, 5% Russet Norkotah and RN strains, and 3% Ivory Russet (Figure 3).  The 2022 “Other” category was composed of 23 new, non-mainstream, or specialty varieties, (compared with 18 in 2021 and 33 in 2020) ranging from newly released varieties like Mountain Gem Russet to older specialty varieties like Chieftain. Clearwater Russet seed lots continue to increase as McDonalds® has accepted this variety for its French fries. The number of Clearwater Russet seed lot samples equaled those of Russet Burbank but surpassed all other varieties this year. Clearwater Russet accounted for 20% of seed lots in 2022, 19% in 2021, 24% in 2020, 17% in 2019, 12% in 2018, 7% in 2017, 6% in 2016, and 4% in 2015 (Figure 3). Russet Burbank seed lot numbers declined for 7 straight years between 2014-2020 but rebounded slightly in 2021 and 2022 (Figure 3). Tri-State developed varieties like Clearwater Russet, Umatilla Russet, and Ranger Russet are slowing replacing Russet Burbank for french-fry processing.

Eight percent of all seed lots were of non-U.S. developed varieties (data not shown). Varieties developed by the Northwest Potato Variety Development Program/PVMI accounted for 57% (58% in 2021 and 63% in 2020) of the seed lots entered into the 2022 trial and included: Alturas, Clearwater Russet, Mountain Gem Russet, Ranger Russet, and Umatilla Russet. The most significant change in the WA seed lot profile in the past 50 plus years has been the increase in the number varieties WA growers are planting. In 1962, 8 varieties were entered into the seed lot; in 2022, there were 32 (Figure 4).

The potato field day program starts at 8:55 am on THURSDAY, June 23 at the WSU Othello Research Farm (see program below).  As a special treat, a potato disease-sniffing dog and her owner will provide a demonstration targeting Potato Virus Y. In addition, you will be able to view this year’s seed lots and participate in one of two concurrent sessions.  Sessions I and II will allow you to view a sample of this year’s in-field research. Both sessions will offer CCA recertification credits; however, only session II (pest management tour) will offer WA, OR, and ID pesticide recertification credits.  A hosted lunch, offered between 12:00 and 1:00 pm, will complete the field day.  The agenda, seed lot information, and a map to the research center can be found on our website: For the program, see below.

WSU Potato Field Day – Thursday June 23, 2022

Located at WSU Othello Research Unit – 1471 W Cox Rd, Othello

(4.5 miles east of Hwy. 26/17 Junction, On Booker Rd, ¼ Mile South of Hwy. 26)

8:30–8:55 am Coffee and donuts


8:55-9:00 am Sponsors recognition


9:00-9:15 am Dog demo: A black Lab, Zora, will sniff out PVY

Andrea Parish - Nose Knows Scouting


9:15-9:20 am Potato Virus Y Demo Introduction

Mark Pavek – WSU Pullman, Jonathan Whitworth -- USDA-ARS, Idaho, Nina Zidack -- MSU, Bozeman, and Alex Karasev – UI, Moscow


9:20-10:00 am Commercial Seed Lot Trial and Potato Virus Y Demo Interactive Viewing

Mark Pavek – WSU Pullman, Jonathan Whitworth -- USDA-ARS, Idaho, Nina Zidack -- MSU, Bozeman, and Alex Karasev – UI, Moscow

Concurrent Session I:  Potato Cultural Management Practices Field Tour

10:10 Promising chip and specialty selections from the Tri-state Breeding Program

Vidyasagar “Sagar” Sathuvalli – OSU, Hermiston


10:25 Breeding for Columbia root-knot nematode resistance

Max Feldman– USDA-ARS, Prosser


10:40 Ongoing potato physiology trials and program update

Jacob Blauer – WSU, Pullman


10:55 Impact of planting date on physiological age and seed performance

Morgan Southern and Jacob Blauer – WSU, Pullman


11:10 Role of seed wound healing intervals on field performance and environmental factors regulating periderm development

Conor Buckley and Jacob Blauer – WSU, Pullman


11:25 Maximizing economic return by optimizing seed management practices for potato

Alexa Hintze, Zach Holden, Rudy Garza, Vito Cantu, and Mark Pavek – WSU, Pullman & Othello


11:40 Long season varieties: nitrogen application timing, potato canopy growth, and crop maturity

Mark Pavek, Jacob Meeuwsen, Zach Holden, Rudy Garza, Vito Cantu – WSU, Pullman


11:55 am – 1:00 pm                          HOSTED LUNCH

Concurrent Session II: Potato Pest Management Field Tour


10:00 Potato Virus Y strains circulating in the PNW across the past 10-11 years

Alex Karasev– Univ. of Idaho, Moscow


10:20 Solutions for Potato Virus Y control

Jonathan Whitworth – USDA-ARS, Aberdeen, ID


10:40 Alternative methods to initiate sprouting in potatoes to facilitate PVY testing

Nathan Gelles and Nora Olsen – Univ. of Idaho, Kimberly


11:00 Classification of potato pathogenic and non-pathogenic strains of Verticillium dahliae with hyper-spectral images

Sudha Upadhaya, C. Zhang, S. Sankaran, T. Paulitz, and D. Wheeler – WSU Pullman


11:20 Control of Colorado potato beetle

Tim Waters – WSU, Benton/Franklin Counties


11:40 Potato mop-top virus in Washington seed lots

Kylie Swisher Grimm, R. Quick, L. Cimrhakl, C. Brown, Z. Holden, R. Garza, V. Cantu, & M. Pavek

12:00 pm – 1:00 pm                           HOSTED LUNCH


CCA and pesticide recertification credits have been applied for (WA, OR, & ID)