SOMATIC EMBRYOGENESIS AND PLANTLET REGENERATION ON CALLUSES DERIVED FROM SEEDLING EXPLANTS OF KINNOW MANDARINE (CITRUS-NOBILIS LOUR X CITRUS-DELICIOSA TENORA)

Callus cultures of 'Kinnow' mandarin (Citrus nobilis Lour. x Citrus de liciosa Tenora) were established from a range of different somatic exp lants excised from three week old in vitro-grown nucellar seedlings. T he explants tested included leaf, epicotyl, cotyledon and root segment s. All cultured explants initiated callus from the cut ends after a we ek, when cultured on a modified Murashige and Tucker (1969) medium; co tyledon segments were the best explant for callus induction. The calli derived from epicotyl segments were also the best source of somatic e mbryos. Embryogenic calluses were subcultured on MS medium fortified w ith BAP (3 mg l-1) +NAA (0.5 mg l-1) + malt extract (500 mg l-1) showe d further growth, development, budding and germination of somatic embr yos. Root initiation took 7-10 d after culturing on various rooting me dia. The number of roots per shoot varied from 1-2 to 6-8 on MS medium containing NAA and/or IBA. Plantlet survival in vitro was directly re lated to the number of roots produced per shoot.