Molecular Characterization of Some Texa of the Genus Raphanus L. (Cruciferae=Brassicaceae)

Abstract

In the present study, molecular genetic fingerprints for 7 Raphanus L. samples belonging to 2 species (Raphanus raphanistrum L. and Raphanus sativus L.) were carried out to elucidate relationships among these samples. Extracted DNA from fresh leaf samples was used to identify the molecular fingerprints. Fifteen 10-mer arbitrary oligonucleotide primers were initially used to establish their randomly amplified polymorphic DNA based on polymerase chain reaction (RAPD-PCR) fingerprints and to discriminate among them. Only 6 primers successfully generated reproducible polymorphic products. These primers are; UBC 43, 51, 66, 71, 77 and 91. The fingerprints generated by these primers revealed characteristic profiles for each Raphanus L. genotypes, in terms of number and position of RAPD bands. The results revealed that both the number and size of the amplified products varied considerably with the different primers. A sum of 66 polymorphic bands was generated by these primers in the Raphanus L. genotypes under study. A total of 20 unique bands were identified out of the polymorphic ones. These unique bands were used to discriminate among the studied Raphanus L. samples. Most samples of the studied Raphanus L. samples were discriminated by one or more unique bands.The family CruciferaeϭBrassicaceae is a large natural family of major economic importance. Heywood (1993), recorded about 380 genera and 3000 species in this family, whereas, Mabberley (1997) reported the number of genera to be 365 and the number of species to be 3250. On the other hand, Judd et al. (1999) recorded 419 genera and 4130 species belonging to this family.Cruciferae is well represented in the Egyptian flora. Täckholm (1974) reported 61 genera and 106 species distributed in the different habitat types of the country. From them 5 species belonging to genus Brassica L. and only one species belong to genus Raphanus L. On the other hand, El-Hadidi and Fayed (1995) recorded 55 genera and 108 species for the family. Of these species, 5 were recorded for Brassica L. and 2 for Raphanus L.Development of cultivar-specific genetic markers is desirable for plant taxa identification and protection as well as seed purity determination. Moreover, knowledge of genetic diversity in economical plant gene pools is central to the development of effective ex-situ and in situ germplasm conservation strategies (Demissie and Bjernstad 1997, Wolff andMorgan-Richards 1998). Traditional cultivar identification based on morphological traits requires extensive observations of mature plants (Wrigley et al. 1987). Furthermore, morphological traits cannot serve as unambiguous markers because of environmental influences (Yang and Quiros 1993). Also, the adequate levels of phenotypic polymorphism are not available in many plant taxa (Tatineni et al. 1996). Nowadays, molecular markers have been developed to solve this problem. These markers are independent of environmental conditions and show higher levels of polymorphism. Several methods such as SDSprotein, isozymes and RAPD-PCR ban...

Development of DArT Marker Platforms and Genetic Diversity Assessment of the U.S. Collection of the New Oilseed Crop Lesquerella and Related Species

“…Molecular markers have been very useful in efforts to accurately identify gaps and redundancy within and among individual germplasm collections and have helped resolve important genebank management issues [10], [11], [12]. Examples of markers used in specific Brassicaceae collections include microsatellites for examining diversity in B. napus [13], [14], [15], lesquerella [16] and wild relatives such as Capsella , Crambe and Sinapis [17]; AFLPs in B. oleracea [18] and Lepidium [19]; and RAPD markers in Raphanus [20].…”