Washington State University

Potatoes at WSU

Postharvest Information

Overall Postharvest Rating

Highest scoring clones:  AO98133-2, A97142-3, and A97287-6

Lowest scoring clones:  RB, A96023-6, and A96108-12

Low temperature Sweetening

Most resistant:  AO98133-2, A97142-3, and A97287-6

Most susceptible:  A96023-6, and A96108-12

Taste Panel

Highest rated:  AO98133-2, AO96141-3, and A97142-3

Lowest rated:  RB, and A96023-6

Blackspot Bruise Susceptibility

Most resistant:  A98104-4, A96108-12, and AO96141-3

Most susceptible:  RR, AO98133-2, and A97142-3

Variability in Tuber Shape & Fry Yield (8- to 10-oz tubers)

Least variable:  AO96141-3, AOA98133-2, and A96023-6

Most variable:  A98104-4, A97229-1, and A97287-6


  • The specific gravity rating scale was updated to reflect contract penalties for undesirably low as well as high gravities (see Materials and Methods).  For example, WA-grown AO96141-3 produced a gravity of 1.000, which received a low score of “1” under the new system (rather than a high score of “5” under the old system).
  • When averaged across states, all entries received higher overall postharvest scores than Russet Burbank.  However, A97229-1, Ranger Russet, A96023-6, and A96108-12 scored lower than Russet Burbank when grown in WA.
  • AO98133-2 was the highest rated entry, scoring 33.7 out of 38 points.  This clone had significant resistance to low temperature sweetening, with ID- and OR-grown samples producing USDA 0 fries and the WA-grown samples producing USDA 1 and 2 fries when stored for 60 days at 40 and 44oF, respectively.
  • A98104-4 had specific gravities ranging from 1.066 to 1.077; too low for most processing contracts.  At the other extreme, the gravities of AO96141-3 were 1.096 and 1.100 when grown in OR and WA, respectively, which were too high for most contracts.
  • A97142-3, AO96141-3, and AO98133-2 were the favorites in the taste panels, receiving ratings of 3.5 to 4.0 from all growing locations.  A96023-6 received the lowest “flavor” rating, resulting in an overall three-state taste score average of 3.0.
  • On average, the WA-grown samples fried darker than ID- and OR-grown samples after 60 days of storage at all three temperatures. A97287-6 and AO98133-2 fried with USDA “0” from 40oF from ID and OR.  A97142-3 may also have resistance to sweetening at 40oF; however, uniformity of color (stem-bud) may be an issue in this clone.
  • In controlled bruising studies, ID-grown samples bruised less than samples from OR and WA.  A98104-4, A96108-12 and AO96141-3 were the most bruise resistant.  Bacterial soft rot susceptibility was relatively equal across clones.
  • On average, ID-grown tubers had the highest L/W ratios (8-10 oz tubers) compared with those grown in WA and OR.  A97142-3, A96108-12, and A98104-4 had the lowest L/W ratios (average=1.65).  AO96141-3 had the highest L/W ratio (2.06).  A98104-4, A97229-1, and A97287-6 showed the greatest variation in shape across growing locations.  The L/W ratios of AO96141-3, AO98133-2, and A96023-6 were least affected by growing location.
Potatoes at WSU, PO Box 646414, Washington State University, Pullman WA 99164-6414, 509-335-9502
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