Effects of Sterilization and Phytohormones on shoot Tip Culture of Telfairia Occidentalis

Abstract

Telfairia occidentalis is highly heterozygous with continuous out-crossing. Therefore, conservation of its genetic resources will require the culture of explants from vegetative tissue rather than seeds, in order to maintain improved or superior genotypes. Experiments were carried out to establish a procedure for the sterilization of shoot tip explants from field grown seedlings and to induce organogenesis using different treatment combinations of phytohormones. Shoot tip explants obtained from 4 to 5 weeks old seedlings were surface sterilized using 3 concentrations of sodium hypochlorites (NaOCl) (0.5%, 0.75% and 1%) at 3 exposure time (10minutes, 15minutes and 20minutes). The percentage clean cultures were recorded after 4, 8 and 12 days. The lowest frequency of clean culture (0.33) was obtained when shoot tip explants were treated with 0.5% of NaOCl for 20minutes. Sterilization was most effective when shoot tip explants were treated with 1% NaOCl for 15minutes and 20minutes, after 4 and 12 days. Ninety three percent clean and viable cultures were obtained. Surface sterilized shoot tip explants were inoculated on ½ N6 media supplemented with different concentrations and combination of BAP, NAA, IAA and 2,4D. Shoot tip explants in ½ N6 media supplemented with 0.05mg/l BAP showed the highest shoot length of 1.46 cm and highest shoot number of 1.60. In all concentrations and combination of BAP and NAA, there was callus formation. In all concentrations and combination of BAP and 2,4D, calluses were formed to prevent shoot bud induction while there was induction of multiple shoot in treatment combination of 0.5mg/l BAP and 0.1mg/l 2,4D. In all concentrations and combination of BAP and IAA, there were formation of calluses, but not formed in the treatments containing 0.5mg/l BAP and 0.1mg/l IAA, while BAP 2.0mg/l and IAA 1.0mg/l induced tiny shoots.

Keywords: Conservation, Telfairia occidentalis, Surface sterilization, Explants, Organogenesis