Genetic stability among in vitro eggplant clones induced by different plant growth regulators

Many factors may influence the genetic stability of cloned in vitro plants, among which are the genotype and the regenerative process induced by plant growth regulators. The resulting somaclonal variations may be useful for breeding projects, but may be detrimental to germplasm conservation. The objective of this work was to evaluate the genetic stability of Solanum melongena cv. Florida Market clones, obtained in response to different plant growth regulators. For the production of clones, leaf explants were used from commercial seeds in vitro germinated. The explants were inoculated in Murashige and Skoog medium supplemented with different plant growth regulators at pre-defined concentrations. The DNA was extracted by the CTAB method from leaves of complete plants obtained by somatic embryogenesis induced by naphthaleneacetic acid (NAA) or indirect organogenesis induced by benzylaminopurine (BAP) or thidiazuron (TDZ). For the RAPD, 117 DNA samples were amplified by ten decamer primers and 49 specific bands were selected among the products for the comparative study. A total of 5733 fragments were obtained, with a rate of 5.37% polymorphism. NAA induced clones showed no polymorphism. The highest rate of polymorphism was observed in BAP induced clones (14.28%). Two RAPD primers were identified as markers for monitoring the genetic stability of eggplant. The polymorphic pattern was observed only in clones originating from indirect organogenesis. These results indicate the usefulness of a monitoring protocol for studies using in vitro cloned eggplants.