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2002 Late Regional Trial Postharvest Evaluations

The postharvest evaluations are intended to identify those clones best suited for the French fry processing industry. Tuber samples for these evaluations are obtained from the field adaptation trials grown in Washington, Idaho and Oregon.

The 2002 trial included nine numbered clones and Stampede Russet, along with Ranger Russet and Russet Burbank as the check cultivars again this season. Please note that results for Ranger Russet and Russet Burbank from the Oregon Tri-State and Regional Trials are the same for all postharvest evaluations except taste panels, due to limited samples.

TC1675-1Ru, a new entry this season, was the highest scoring clone, with a three state average of 31.3/35. This entry produced tubers with an average specific gravity of 1.092 and had one of the highest scores in the taste panel evaluations. When reconditioning ability was averaged across states, TC1675-1Ru tubers stored at 40oF for 75 days reconditioned back to a USDA “0” from a “4”. This clone was also one of the least susceptible to bacterial soft rot. It typically produced tubers with a length to width ratio of 1.7, resulting in 70% of the tuber producing French fries that were ³ 3 inches in length. It also produced tubers that showed the lowest variability in tuber shape (length to width ratio) across production sites. Its only downfall may be blackspot bruise susceptibility.

A9304-3 and A9305-10 were the next highest scoring numbered clones in the 2002 Regional Trial. These clones were advanced from the Tri-State to the Regional Trial this season. A9305-10 was the 3rd highest scoring entry in the 2001 Tri-State Trial last year, indicating consistency in its performance.

A9304-3 (28.5/35) and NDC5372-1Ru (27.8/35) both produced fries with a stem end USDA rating of “0” after 28 days of reconditioning from 40°F storage.

CO92077-5Ru was the lowest scoring clone this year, with a three state average of only 17.8 out of 35 possible points. It only averaged 2.5/5 on taste panel evaluations, with comments of “soggy” and “oily” on many of the raters sheets. This was probably due to its low specific gravity (1.067 – 1.078). It also tended to “shatter” rather than produce a blackspot bruise when impacted.

Again this season Stampede Russet produced tubers with specific gravities ranging from 1.062 when grown in Oregon, to a high of l.071 when grown in Washington. It was the second lowest scoring clone (2.8/5) in the taste panel evaluations.

Three entries, CO92077-5Ru, NDC5372-1Ru and Stampede Russet, had a higher than average susceptibility to bacterial soft rot. It is also interesting to note that these entries also showed a relatively low wound healing ability.

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