Production of Somatic Hybrids in Taro (Colocasia esculenta Schott)

Abstract

Somatic hybrid plants were obtained by electrofusion between protoplasts isolated from suspension cells of taro (Colocasia esculenta Schott) 'Yatsugashira' and 'Malaysia No.4'. Friable calli were obtained from these two cultivars which proliferated on Murashige and Skoog's (MS) medium supplemented with 30 g·liter^-1 sucrose, 1 mg·liter^-1 2, 4-D and 2ip ('Yatsugashira') or 2 mg·liter^-1 2, 4-D and 2ip ('Malaysia No.4'). Suspension cells were derived from the friable calli and the protoplasts isolated from these suspension cells were fused by electrofusion. The fused protoplasts were cultured in the liquid media consisting of half strength MS inorganic salts, Kao and Michayluk (1975) organic substances, 0.2 mg·liter^-1 NAA and 2 mg·liter^-1 BA, 0.1 M glucose and 0.3 M mannitol. Shoot regeneration from protoplast-derived calli occurred on solid MS medium supplemented with 30 g·liter^-1 sucrose, 0.2 mg·liter^-1 NAA and 2 mg·liter^-1 BA. The shoots initiated roots after being transferred to a MS medium without phytohormones. About 200 plants which were obtained from fused protoplasts grew vigorously in the field. The morphology of their corm and cormels were intermediate between 'Yatsugashira' and 'Malaysia No.4'. Their leaf shapes were compact as compared with the two parents. The chromosome number of regenerated plants was 2n=4x=56, which is the sum of two parents. We considered them to be somatic hybrids based on their morphological characters, chromosome numbers and electrophoretic pattern of corm proteins.