LAUSR

Molecular markers could be used to screen for somaclonal variation during the process of genetic transformation. We aimed to test target region amplified polymorphism (TRAP) marker to quickly predict similarity to the parental line of different transgenic lines. DNA of transgenic lines, wild-type genotypes and additional sugarcane clones was genotyped with TRAP markers. Amplification products were separated by electrophoresis on polyacrylamide denaturing gels, images were analyzed, and bands were transformed into a 0/1 matrix. Similarity was calculated using the Jaccard coefficient and dendrograms generated using UPGMA analysis. TRAP was initially used to determine whether the close growth resemblance between six herbicide-tolerant lines and their parental cultivar RA87-3 was also true at the genetic level. The genetic characterization confirmed the preliminary phenotypic evaluations since transformed lines exhibited none or only minor genetic changes whereas lines with growth aberrations also included in the analysis showed a significant degree of polymorphism. The incorporation of other genotypes as controls allowed us to internally evaluate the accuracy of the survey ensuring that a significant number of polymorphic bands were analyzed. These markers were routinely applied to evaluate transgenic lines of LCP85-384, TUCCP77-42, TUC95-10 and TUC03-12 at early stages of the characterization process. Our results showed that the use of TRAP markers is a rapid and recommendable first approach to identify transformed plants that are genetically close to their parental genotype as they could be applied at the early stages of evaluation to select for the most valuable lines to carry out field tests.