Effects of gamma-rays doses on shoot apex of banana (Musa sp.) plants developed in vitro aiming at mutation induction

Abstract

Shoot tips from banana cv. Maçã, were gamma-irradiated (20, 40, 60, 80 and 100 Gy) and subcultivated in vitro for 4 vegetative generations (MIV4). Based on leaf variegation observed in vitro it was concluded that MIV4 is the minimum number of generations to be used before the screening of mutants. At greenhouse, besides leaf variegation others phenotypic changes (anthocyanin, disturbed plant and leaf architecture) were also quantified. The frequency of this variants increased with the dose, and, the treatment with 40 Gy produced the highest frequency of 13,49% while in control plants it was only 0.85. So, this dose is recommended to be applied in mutation breeding with this cultivar. Inoculation of 2765 young plants were carried out in green-house with spores suspension of Fusarium oxysporum f. sp. cubense. No resistant plants were found, but this system permitted a quick and efficient screening of the susceptible ones and can be utilized for the selection of the mutants from big populations of banana cultivars.