EFFECTS OF COPPER SULPHATE AND COBALT CHLORIDE ON IN VITRO PERFORMANCES OF TRADITIONAL INDICA RICE (Oryza sativa L.) VARIETIES IN SRI LANKA

Abstract

This study was carried out to investigate the effects of copper sulphate and cobalt chloride on the rate of callus proliferation and the in vitro regeneration in nine indica rice varieties and a Japonica variety. The disinfected seeds were inoculated in callus initiation medium composed of N6 basal elements, 1000 mg/l proline, 2 mg/l 2,4-D and 3% (w/v) sucrose to screen high responsive varieties. Calli of screened varieties were used to determine the effects of additives on in vitro responses in proliferation and regeneration media. Taipei 309, Pachcha Perumal, Heenati Vee and Suvandel were screened as high responsive varieties at P  0.05. The rate of callus proliferation in the screened varieties was significantly higher in the medium supplemented with 5 mg/l copper sulphate and 5-10 mg/l cobalt chloride together (P<0.05). In regeneration, the highest number of normal plants with the least number of albino plants could be obtained in the media containing 5 mg/l copper sulphate in combination with 5 mg/l cobalt chloride. The results in this study indicate that the in vitro performance in Sri Lankan traditional indica rice varieties can be improved by using the media containing both copper sulphate and cobalt chloride.