DETERMINATION OF SENSITIVITY TO GAMMA RAYS AND MUTATION INDUCTION IN MANDEVILLA SP. CUTTINGS
The Mandevilla genus, from the Apocynaceae family, has 151 known species and a great potential for ornamental and pharmacological uses. Despite the beauty of its flowers, only a few species of this genus are currently used as ornamental plant. Induced mutagenesis has been applied in several breeding programs and resulted in thousands of mutants officially released. In this study we determined the sensitivity of Red Mandevilla cuttings to several doses of gamma rays. We selected mutant plants after irradiation and use of repeated pruning method. Cuttings containing about six axillary buds each were subjected to irradiation with 8 different doses of mutagen: 0, 7.5, 15.0, 22.5, 30.0, 37.5, 45.0 and 52.5 Gy. Besides, the effect of protecting the base of the cuttings with lead cylinders as well as the influence of roots was evaluated. Survival rate decreased with increasing irradiation dose, independently for rooted or non-rooted cuttings and also in cuttings with protected or unprotected bases. Dose of gamma rays reducing the survival with 30 and 50% (LD30 and LD50) were determined. In a larger experiment, 1,296 non-rooted cuttings with their bases protected by lead cylinder were irradiated using LD50 and LD30 doses of mutagen. After applying the method of repeated pruning in irradiated plants, screening was performed in M1V3 generation. No mutants were found in control treatment and at the lower dose. However, in the cuttings irradiated with the higher dose two mutants were selected: one dwarf plant and one plant with different flower colors.
Gomes da Costa, E., Latado, R.R. and Tulmann, A. (2015). DETERMINATION OF SENSITIVITY TO GAMMA RAYS AND MUTATION INDUCTION IN MANDEVILLA SP. CUTTINGS. Acta Hortic. 1087, 365-371
irradiation, flowers, ornamental breeding