Vol: 39 Page: 169

Authors:
Bogna Zawieja
Wiesław Pilarczyk
Bogna Kowalczyk

Title:
 The comparison of uniformity decisions based on COYU and Bennett’s methods - oilseed rape data

Language: English

Keywords:
Bennett method
COYU method
DUS testing
oil seed rape
uniformity

Summary:
Uniformity of new varieties for quantitative characteristics is usually checked using the COYU (combined over years uniformity) method after collecting results from three years of trials. There are some other possibilities of testing uniformity as indicated for example in papers by Zawieja and Pilarczyk (2005, 2006, 2007). In these papers the conclusions concerning uniformity of rye varieties based on the UNIF (COYU) approach and on the Bennett’s test were compared. The conclusions were generally similar but in some cases differences appeared.
All our previous studies were limited to one species (winter rye). The potential user of this new approach, the international organization UPOV, is interested in checking usefulness of proposed test for wider set of species, see document TWC25/8. This document and a paper by Zawieja and Pilarczyk (2007) were aimed at explanation if there was a relationship between the degree of correlation between levels of expression of characteristics and log transformed values of standard deviations, and decisions concerning uniformity supported by the two mentioned methods. It was also suggested to apply McNemar’s (McNemar, 1947) test instead of a test of independence. In this document these problems are addressed again with the use of DUS data for oilseed rape varieties.

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