2007 - Potatoes at WSU - Washington State University

OVERALL CULTIVAR & CLONE PERFORMANCE
Merit Score Methods
Overview: Overall performance for each entry was rated on a scale of 1 to 5; 5 indicating the
best performance possible. The methods are explained below. Economic analysis methods are
explained near the front of this book.
FRESH MARKET MERIT SCORE METHODS:
75% Fresh market economic value
25% Internal quality – blackspot bruise, shatter bruise, hollow heart, internal brown spot, and brown
center. An average merit value is taken. Of the five internal categories listed above, the worst
internal defect or bruise rating for each cultivar is weighted 50% so serious bruise or defect problems
are reflected in the final merit score.
Researcher’s Discretion: The overall merit score may be reduced by up to 50% for any
unacceptable trait not quantified in the data (e.g. poor appearance or poor flavor).
EARLY PROCESS MARKET MERIT SCORE METHODS:
75% Early harvest process market economic value
25% Internal quality – blackspot bruise, shatter bruise, hollow heart, internal brown spot, and brown
center. An average merit value is taken. Of the five internal categories listed above, the worst
internal defect or bruise rating for each cultivar is weighted 50% so serious bruise or defect problems
are reflected in the final merit score.
Researcher’s Discretion:The overall merit score may be reduced by up to 50% for any
unacceptable trait not quantified in the data.
LATE PROCESS MARKET MERIT SCORE METHODS:
For the late process market, a merit score is listed for both field and post-harvest performance.
Field/Economic Performance – methods were the same as “Early Process Market Merit Score
Methods” shown above, with the exception that a late harvest economic analysis was conducted.
Post-Harvest Performance – see “Postharvest Procedures” section near front of book.
Researcher’s Discretion:
The overall merit score may be reduced by up to 50% for any unacceptable trait not quantified in the
data.
2007 Potato Cultivar Evaluations 8 WSU Potato Research Group