ISSN: 1659-2751

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Aseptic Establishment in the in vitro Micropropagation of Banana Williams (AAA, subgroup Cavendish)

Abstract

Sexual reproduction of plants is an important technique for the multiplication in vitro of banana, due to the sterility of the species. The in vitro multiplication has permitted the massive reproduction of the species for commercial plantations. However, one of the limitations for in vitro micropropagation of Musa sp. has been the high rate of contamination of the explants of the Phase 1 of the plant, principally due to endogenous contamination, accentuated in tropical zones where the conditions of temperature and high rainfall provide an ideal environment for microbial proliferation. There exists a need to establish a disinfection protocol for the establishment of explants of banana Williams with a low percentage of contamination, for the initial phase of in vitro micro-propagation of the species, using meristems. The experiment was conducted in a laboratory at EARTH University, whose campus in located in the humid tropic region of Cost Rica. The explants of banana Williams were obtained from the plantations of the commercial farm on campus. Seven protocols or treatments were designed with 25 repetitions each, that consisted of P1: [4 % NaClO + Tween 80 for 20 min] + [1,5 % NaClO + Tween 80 for 10 min]; P2: [I 1 % in 70º ethanol] + P1 with individual disinfection; P3: [I 1 % in 70º ethanol] + P1; P4: drying treatment of the explants in the greenhouse for seven days + [70º ethanol for 5 min] + [4 % NaClO + Tween 80 for 30 min] + [1,5 % NaClO + Tween 80 for 15 min]; P5: water stress treatment, in the greenhouse, for seven days + P1; and P6: P4 + planting in MS liquid with streptomycin / penicillin, double trial with 100 mg/L and 200 mg/L. The results were evaluated seven days after planting, analyzing the variables viable explants, no contamination and non-viable explants, contaminated and necrotic. The protocol that considerably reduced the contamination, in the aseptic establishment phase of Musa sp., was P6. The positive effect of disinfection with 70° ethanol and the increase in times of double disinfection with hypochlorite is enhanced by the treatment of the explants with an antibiotic solution of streptomycin / penicillin

Key words: banana Williams, streptomycin, ethanol, explants, hypochlorite, meristems, penicillin, protocol, iodine.

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