Vol: 41 Page: 19

Authors:
Bogna Zawieja
Wiesław Pilarczyk
Bogna Kowalczyk

Title:
 On an alternative method of testing varietal uniformity in DUS trials

Language: English

Keywords:
Bennett's method
coefficient of variation
COYU method
oilseed rape
simulation
test F
variety uniformity

Summary:
In this paper frequencies of decisions concerning uniformity of new varieties taken using the COYU (combined over years uniformity) method and the Bennett method were compared. The Bennett method was applied in two versions, namely in its traditional form as described by Bennett [1976] and in a new version in which the chi–square statistic was replaced by F–Fisher statistics as described by Forkman (2009). All the three methods were applied earlier by the same authors, see Zawieja and others (2009, 2010), to real data from DUS (distinctness, uniformity and stability) trials on rye and oil–seed rape. In all analyzed previously data sets the number of candidate varieties were very limited. To avoid this shortcoming, in this paper these methods were applied to partly simulated data (data for reference varieties were real – taken from oil–seed rape trials – while data for candidate varieties were simulated). Some differences between decisions appeared but – in general – the decisions were statistically equivalent.

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