Studies on the radiosensitivity of macropropagated corm buds of banana for the improvement of commercial triploid banana cultivars
Listed in
This article is not in any list yet, why not save it to one of your lists.Abstract
The improvement of commercial triploids of banana through conventional breeding or sexual hybridization has been very difficult due to female sterility, parthenocarpy and polyploidy. Mutation breeding appears to be a promising alternative that may induce the desired variability by altering one or more traits of a usually acceptable cultivar without retaining its original genotype unaltered. Given this background, the present study was designed to determine the radiosensitivity of corm buds and macropropagation of irradiated corms of banana cv. ‘Martaman’ (Musa AAB) with the objective of determining the lethal dose (LD50) for macropropagated buds and optimizing the radiation dose for the induction of putative mutants with one or more desired traits, such as biotic and abiotic stress tolerance or resistance, dwarfness, increased yield or improved fruit quality. Healthy decorticated corms (12–13 cm in diameter) were exposed to various doses of gamma rays ( 60 Co) at strengths of 10, 20, 30, 40, 50 and 60 Gy, with an effective dose rate of 04.348 KGy/hr. The control plants received no radiation exposure. The results revealed that the survival rate of corm buds was the lowest (19.50%) due to the irradiation dose of 60 Gy, while it was the highest (96.25%) under the control (without irradiation). The lethal dose (LD50) for the irradiated corms of banana cv. ‘Martaman’ on the basis of the 50% survival rate and number of induced primary buds per corm were 37.71 Gy and 38.95 Gy, respectively, followed by a significant decrease in growth. The growth characteristics decreased in proportion to an increase in the gamma-ray dose. The results suggest that gamma irradiation between 20-30 Gy (below the LD50) could be used to induce morphological variation among populations via the macropropagation technique and the selection of putative mutant plants, which can be used in future breeding programs for the banana cv. ‘Martaman’.
