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Potatoes at WSU

2002 Late Tri-State Trial Postharvest Evaluations

The postharvest evaluations are intended to identify those clones best suited for the French fry processing industry of the Pacific Northwest. Tuber samples are obtained from the Washington, Idaho and Oregon field trials for evaluations of storage and processing quality in Pullman.

Eight numbered lines and the two check cultivars, Ranger Russet and Russet Burbank, were tested from each growing location. 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 a limited supply of tubers.

The four highest scoring entries were A93157-6LS (32.5/35), A91814-5 (31.1/35), A91186-2 (30.5/35) and A94053-5 (30.0/35). A91814-5 was the highest scoring entry in the 2001 trial, while A93157-6LS was the second highest. Both of these entries produced fries with stem end USDA ratings ranging from “1” to no darker than “3” when stored at 40°F, indicating resistance to low-temperature sweetening. They also reconditioned back to USDA “0” ratings following 71 days storage at 40oF. A91814-5 is being developed for the dehydration industry and thus its tuber shape is round, with an average length to width ratio of only 1.2-1.3. This ratio translates into an estimated French fry yield of only 51% per tuber.

A93116-3 was the lowest scoring clone (21.4/35). This clone produced unacceptably dark fries from the 44°F-stored Washington-grown tubers, and only slightly better fry color from tubers grown in the other two states. For the second year, however, this entry has shown the most resistance to blackspot bruise. It also had the highest average wound healing ability this season and was second in wound healing ability among the clones evaluated last season.

The clones in this year’s trial showed the widest range in tuber length to width ratios of 8- to 10-ounce tubers in the history of the Tri-State Trials. The Idaho-grown Ranger Russet tubers had an average ratio of 2.5 (72% yield of fries per tuber), indicating that the tubers were two and a half times as long as they were wide, in contrast to the round tubers produced by A91814-5. AO94110-203 produced the largest variability in tuber shape across growing locations, while A93116-3 was the least variable.

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