PLANT-REGENERATION FROM CALLUS-CULTURES OF MORUS-INDICA L DERIVED FROM SEEDLINGS AND MATURE PLANTS

A protocol for efficient plant regeneration from callus cultures deriv ed from mature as well as seedling explants of Morus indica L. cultiva r 'S-13' is described. Callus was successfully induced from internodal segments taken from a 5-year-old tree on Murashige and Skoog (MS) med ium supplemented with a combination of 2.0 mg l(-1) 2,4-dichlorophenox yacetic acid (2,4-D) and 0.5 mg l(-1) N-6-benzyladenine (BA). Hypocoty l segments derived from 15-day-old in vitro germinated seedlings callu sed on MS medium supplemented with 2.0 mg l(-1) 2,4-D alone. The inter nodal callus proliferated well on MS with 0.5 mg l(-1) BA, 100 mg l(-1 ) casein acid hydrolysate (CH) and 15% fresh coconut water (CW), where as the hypocotyl callus required a combination of 2.0 mg I-1 1-naphtha leneacetic acid (NAA) and 0.2 mg l(-1) BA for its proliferation. High frequency regeneration (83C/e) coupled with maximum number of shoot bu d formation (about six buds per callus) was achieved from internodal c allus cultured on MS supplemented with 0.5 mg l(-1) BA. In hypocotyl-d erived callus shoot bud regeneration occurred (65%, about four buds pe r callus) on MS with BA at the optimal level of 1.0 mg l(-1). Histolog ical observations confirmed de novo regeneration from callus derived f rom both types of explants. Internodal explants were more responsive t han hypocotyl explants with respect to callus development and organoge nesis. The regeneration potential was greatly influenced by the callus age. Rooting was induced in 98% of the regenerated shoots on half-str ength MS supplemented with 1.0 mg l(-1) indole-3-butyric acid (IBA). T he rooted plantlets were hardened off and successfully established in the experimental field.