In vitro cloning of a selected Eucalyptus pilularis tree and genetic stability analysis of micropropagated plants

Abstract

Establishing vegetative propagation techniques to promote the rejuvenation/reinvigoration of genotypes is essential for the rescue of adult trees of the Eucalyptus genus used in species and provenance tests. The aim of this study was to evaluate the induction of epicormic buds and shoots in pruned branches and the in vitro establishment, multiplication, genetic fidelity and elongation of three 44-year-old Eucalyptus pilularis selected plants. M1, M2 and M3 represent selected plants 1, 2 and 3, respectively. M1 was the best in terms of number of epicormic buds, number of shoots, oxidation, and non-responsive explants. In the establishment phase, M3 was the best in contamination, number of shoots, and shoot length. In the multiplication phase, the highest vigour and shoot length values of were found in the 15th subculture. Phenolic oxidation had its highest value in the 12th subculture, decreasing from the 13th. The highest value for number of shoots was found in the 11th subculture. No polymorphism was observed between the selected plants and the clonal plants obtained in the 15^th subculture. In elongation, the use of culture medium containing 0.10 mg L^-1 BAP and 1.00 mg L^-1 NAA provided the lowest means for oxidation, and the highest for vigor, number and length of shoots per explant. The emission of adventitious roots was observed, demonstrating that, through micropropagation, it was possible to induce the competence to root the material, even at an advanced ontogenetic age.