INDUCTION OF TETRAPLOIDY IN THE TANIER CULTIVAR INGLESA [XANTHOSOMA-SAGITTIFOLIUM (L.) SCHOTT]

Induction of tetraploidy in commercial tanier was successfully achieve d in vitro. Tissue cultures of a tanier [Xanthosoma sagittifolium (L.) Schott cv. 'Inglesa', 2n = 26] were established and maintained on mod ified nutrient media containing various concentrations of MURASHIGE an d SKOOG basal salts, vitamins, sucrose, BA and IAA or 2,4-D. Cultures were exposed continuously for 8 days to 0, 12.5, 25 and 50 mg/l colchi cine incorporated in the media. The colchicine-treated tissue cultures yielded diploids (2n = 26), tetraploids (2n = 52) and aneuploids (2n - 2 = 24) respectively. The diploids produced on average one leaf and 4 suckers more per plant than the tetraploids, while plant height incr eased at about the same rate. Continuous exposure of tanier tissue cul tures to colchicine is an effective method for the production of synth etic tetraploids that may be hybridized with non-commercial root rot-r esistant tetraploids.