Three molecular markering techniques: inter-simple sequence repeat (ISSR); start codon targeted (SCoT), conserved DNA-derived polymorphism (CDDP) markers were compared for fingerprinting of 40 varieties of bread wheat. The number of scoreable and polymorphic bands produced using the ISSR, SCoT and CDDP primers for varieties was more than that of genotypes. Average polymorphism information content (PIC) for ISSR, SCoT and CDDP markers was 0.39, 0.41 and 0.34, respectively, and this revealed that three different marker types were equal for the assessment of diversity amongst genotypes. Cluster analysis for three different molecular types revealed that genotypes taken for the analysis can be divided in three and four distinct clusters. There were no significant differences among these markers in terms of the evaluation of genotypes. These results suggest that efficiency of SCoT, CDDP and ISSR markers was relatively the same in fingerprinting of genotypes but SCoT and CDDP analysis are more effective in fingerprinting of wheat genotypes. To our knowledge, this was the first detailed report of a comparison of performance among two targeted DNA region molecular markers (SCoT and CDDP) in comparision with ISSR technique on a set of samples of wheat cultivars. Overall, our results indicate that SCoT, ISSR and CDDP fingerprinting could be used to detect polymorphism for genotypes of wheat.
Authors:G. Mangini, D. Nigro, B. Margiotta, P. De Vita, A. Gadaleta, R. Simeone, and A. Blanco
During the last century wheat landraces were replaced by modern wheat cultivars leading to a gradual process of genetic erosion. Landraces genotyping and phenotyping are strategically useful, as they could broaden the genetic base of modern cultivars. In this research, we explored Single Nucleotide Polymorphism (SNP) markers diversity in a collection of common and durum wheats, including both landraces and Italian elite cultivars. A panel of 6,872 SNP markers was used to analyze the genetic variability among the accessions, using both the Principal Components Analysis (PCA) and the Neighbour Joining clustering method. PCA analysis separated common wheat accessions from durum ones, and allowed to group separately durum landraces from durum elite cultivars. The Neighbour joining clustering validated PCA results, and moreover, separated common wheat landraces from common elite cultivars. The clustering results demonstrated that Italian durum landraces were poorly exploited in modern breeding programs. Combining cluster results with heterozygosity levels observed, it was possible to clarify synonymy and homonymy cases identified for Bianchetta, Risciola, Saragolla, Timilia and Dauno III accessions. The SNP panel was also used to detect the minimum number of markers to discriminate the studied accessions. A set of 33 SNPs were found to be highly informative and used for a molecular barcode, which could be useful for cultivar identification and for the traceability of wheat end-products.
Davies, C. S. (2002) Methylation-sensitive restriction fingerprinting. In: Mills, K. I., Ramsahoye, B. H. (eds) Methods in Molecular Biology, Volume 200 : DNA Methylation Protocols. Humana Press, New Jersey, pp. 43