Abstract

High cost involved in micro propagation is a major constraint to its popular use in sugarcane (Saccharum spp. hybrid). This study describes two technologies for cost reduction in sugarcane micropropagation, that is, direct regeneration of complete plantlets on the same medium and substituting in vitro rooting by ex vitrorooting in conventional micro propagation. A protocol for one step regeneration of complete plantlets was developed for sugarcane cultivar CoS96268. Complete plantlets were regenerated in 42 days on regeneration medium using leaf disc explants, pretreated on MS medium supplemented with 3 mg/l 2,4-D for eight days. More than 95% explants exhibited regeneration with an average of 23 shoots per explants. After 42 days on regeneration medium, each explants produced 6 to 8 healthy plantlets which could be successfully hardened. A protocol for ex vitrorooting of micro shoots, raised from axillary bud culture was also standardized. In vitro shoots, 5 to 6 cm long, treated overnight with 20 mg/l NAA, led to formation of complete plantlets with more than 90% root induction. These plantlets possessed more than 6 roots of 4 cm average length per plantlet and exhibited 95% survival when transferred to polybags containing soil. Thus, direct adventitious regeneration and ex vitro rooting can be applied to sugarcane micro propagation to reduce cost of plant production.

Key words: Ex vitro rooting, direct organogenesis, sugarcane.