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Potatoes at WSU

2001 Late Harvest Regional Trial Evaluations

Regional trials are conducted throughout the western United States, including Washington. Entries in these trials are chosen by a coordinating committee and are grown for both early and full season harvests. This years’ full season trial contained four cultivars and fifteen clones, two of which are the Norkotah strains (TXNS102 & TXNS296). All the entries in the early trial, except Shepody, were also included in the late trial. The following is a summary of the Washington field results along with postharvest results from the Washington, Idaho, and Oregon locations.

Postharvest Information:

The postharvest evaluations are intended to identify those clones acceptable to the French fry processing industry. Samples are obtained from the Washington, Idaho and Oregon field adaptation trials for analysis in Pullman.

Eight numbered clones and three cultivars were tested from each growing location. Note that Ranger and Russet Burbank from OR have the same values in the Tri-State and Regional Trials for all evaluations except the taste panel, due to limited sample.

AC91014-2 was the highest scoring clone this year with a 3-state average of 31.4 points (out of 35). This is the first season for this clone in the trials. The 2nd highest scoring entry was ATX9202-3Ru (28.4 points), matching its performance from last year’s trials. The 3rd highest entry this year was A9014-2 (27.9 points). This clone has been a consistent performer, scoring highest among all clones in the 2000 Regional Trials, and 1st and 2nd highest in the 1999 and 1998 Tri-State Trials, respectively.

Many of the entries arrived with relatively high stem end sugars this season. The Washington samples had some nematode damage that may have contributed to the dark fries; however, Oregon and to a certain degree Idaho also produced entries that fried darker than expected at harvest. For example, AC87138-4 had an at-harvest USDA color rating of 2 in Washington and Oregon and only a slightly better 1 when grown in Idaho.

AC91014-2, A9014-2 and ATX9202-3Ru produced the lightest French fries at harvest and after 59 days storage at 44 and 40°F, reflecting significant resistance to low-temperature-induced sweetening (LTS). On average, ID-grown tubers of these clones retained more of their at-harvest processing quality than those grown in OR and WA. However, when compared with many of the other clones, retention of processing quality during storage of ATX9202-3RU and A9014-2 at 44°F was less variable among samples grown across the tri-state region. AO92017-6 and AC91014-2 showed the highest variability in retention of at-harvest processing quality during storage at 44°F, when assessed across tri-state production sites.

AC87138-4 (18.6) and Stampede Russet (19.1) were the lowest scoring clones, however, their postharvest scores equaled that of Russet Burbank (18.7). Along with A90586-11 and A9045-7, Stampede and AC87138-4 produced darker colored fries at harvest and showed little resistance to LTS during storage.

Stampede Russet was the only entry to produce tubers at or below the cutoff of 1.070 specific gravity across WA, ID and OR production sites this season. It also was the only entry to receive extremely low ‘taste’ ratings, with a range of 1.7 to 2.3 out of 5 possible points (data not shown).

AC91014-2 showed resistance to blackspot bruise, particularly when grown in WA and ID.

The wound healing abilities of AO92017-6, A8893-1, ATX9202-3RU and AC 91014-2 were significantly better than those of A90586-11, Stampede, AC87138-4 and Ranger.

The 8 to 10 oz tubers of ATX9202-3RU had a relatively low length to width (L/W) ratio of 1.53, making it the ‘roundest’ entry in the trial. Thus, the estimated yield of French fries ³ 3 inches in length (by number) from these tubers was only 64%. Yield of fries from 8 to 10 oz tubers of A9014-2, A90586-11, AC87138-4, AC91014-2 and AO92017-6 averaged 72%. Stampede, ATX9202-3RU, A8893-1 and A9045-7 showed more variation in tuber shape and thus fry yield across the tristate production sites, compared with the other clones.

Potatoes at WSU, PO Box 646414, Washington State University, Pullman WA 99164-6414, 509-335-9502
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