Utilização de marcadores moleculares RAPD e EST's SSR para estudo da variabilidade genética em cana-de-açúcar

Abstract

Molecular markers of the type RAPD and ESTs SSR were used as tools to evaluate the variability, and estimate the genetic divergence between commercial varieties and sugarcane clones from self-pollination. Twenty-three genotypes from the Program for the Genetic Improvement of Sugarcane of the Interuniversity Network for the Development of the Sugar-alcohol Sector (PMGCA/RIDESA), were used in this study. The extraction of genomic DNA followed CTAB methodology, with modifications being made for sugarcane. Eleven RAPD oligonucleotides, obtained from Operon Technologies, and 7 ESTs SRR, found after an extensive review of the literature, were used. Analyses of genetic diversity were carried out using the GENES software. The RAPD markers detected a high degree of genetic polymorphism, producing 61 bands, of which 58 were polymorphic. The ESTs SSR markers amplified 38 alleles, 34 being polymorphic. Three groups being formed with the population studied. Most of the genetic variation was maintained among progeny, indicating the occurrence, for purposes of breeding, of a high degree of genetic variability among the genotypes of each progeny. Through estimated genetic divergence, it was possible to identify divergent parent plants, which could be used in hybridization in order to obtain superior clones with characteristics of interest to the sugarcane industry. The molecular markers RAPD and ESTs SSR were equally efficient in estimating the genetic variability in the genotypes tested, and in preparing crossbreeds to be used in breeding programs.