Abstract

Collocasia esculenta (L) Schott. (Taro) genotypes cultivated in Kenya rarely produce flowers, thus improvement via pollination is hindered. Somatic hybridization is an attractive alternative to circumvent flower pollination constrain and hence explored in this study. The aim of this study was to optimize isolation and binary fusion of protoplast obtained from C. esculenta (Dasheen) and C. antiquorum Eddoe) genotypes. Protoplast was isolated from embryogenic calli and leaf tissues using cellulase R-10 (1.0% w/v) combined with pectinase R-10 (0.15% w/v). Fusion of leaf- and calli-derived protoplast was conducted using PEG 6000 (0-30% w/v), CaCl₂ (0-0.15 M) and NaNO₃ (0-4% w/v). Overall, 2 to 4 h enzyme incubation and PEG (10 or 20%) treatments for 10 to 20 min, were optimal for isolation of viable protoplast and fusion, respectively. The capacity of binary fusions to form cell colonies was higher when fusion was undertaken using PEG at either 10 or 20% after 10 and 20 min incubation. The study demonstrates that optimized protoplast fusion is a viable alternative for taro improvement that by passes flowering constrain.

Key words: Taro, protoplast, binary fusion, somatic hybridization, PEG 6000, heterokarya.