The use of morphological and RAPD markers for distinguishing canola, Brassica napus L., varieties
New plant varieties must be distinct to be granted plant breeders' rights in Canada. Morphological characteristics are used for distinctness testing. Field study results showed significant differences among varieties for 23 characteristics. Investigations included significant environment x variety effects, optimum sample sizes, and the minimum detectable difference between varieties. Statistical procedures including the 2 x 1% rule, combined over years distantness (COYD) criterion, and the t-score method were applied to distinguish varieties. The COYD criterion was the simplest to apply, although sensitive to strong environment interactions. A 1% probability level was too stringent to detect differences while a 5% probability level differentiated among varieties using all three statistical procedures. This study also characterized 36 RAPD markers for reproducibility and usefulness in fingerprinting 24 canola varieties. Correspondence between morphological and molecular data was weak. Cluster analysis of both methods grouped canola varieties into their respective breeding programs, although neither method grouped varieties by pedigree relationships. Both morphological and molecular data successfully distinguished among all varieties.