Fingerprinting of Oilseed Rape Cultivars

Abstract

Abstract Although oilseed rape was domesticated relatively recently, breeding of Brassica napus and other oilseed Brassicas has been very intensive in the last few decades. However, it has focused only on some of the most important agronomic/economic traits. Because of the convergent nature of this process in all areas of rape breeding, the genetic basis of new cultivars has been decreasing. It is, therefore, very difficult to characterize rape cultivars on the basis of phenotypic characters. Likewise, registration and protection of new rape cultivars rely on a relatively small number of morphological characters, and as the number of cultivars increases, the ability to distinguish them on a morphological basis alone becomes more difficult. New descriptors, like molecular markers, are required to maintain the efficiency of registration testing. To complement morphological traits, isozyme analysis has been used for cultivar identification and was included in DUS testing. Isozyme analysis allows a more direct observation of the genotype of a cultivar, but the number of isozyme markers is limited. It seems that DUS testing would benefit from the use of DNA markers that have been shown to be more rapid and cost‐effective, and their several types have been used to assess genetic diversity in the genus Brassica . Molecular markers in general can also be used as potential techniques for cultivar identification. In comparison with morphological traits, molecular markers have many advantages and these have been successfully applied in registration activities like cultivar identification and controls of seed purity of hybrid varieties. A relatively high number of different molecular (protein and nucleic acids) techniques and approaches are available for plant genotyping purposes. The marker systems differ in information content, number of scorable polymorphisms, degree of automation and labor, and financial costs. Principles and advantages of particular marker techniques, application of molecular markers in rapeseed cultivar identification, and in Brassicas‐breeding programs are discussed in this chapter.