Abstract A successful protocol for high frequency callus induction and plant regeneration from Anthurium andrea- num Linden ex Andre´ cv. Tropical half-anthers is descri- bed. Different variables using Winarto and Teixeira and Murashige and Skoog basal media supplemented with several plant growth regulators [2,4-dichlorophenoxy ace- tic acid (0.1–1.0 mg/l), a-naphthalene acetic acid (0.01–0.2 mg/l), thidiazuron (0.5–2.0 mg/l), 6-benzylami- nopurine (0.5–1.0 mg/l), and kinetin (0.5–1.0 mg/l)] were tested for their ability to induce high frequency callusing in half-anthers, indirect regeneration and rooting of shoots. Basal medium, as well as the combination and concentra- tion of hormones applied, had a significant effect on callus formation, shoot regeneration and adventitious root for- mation. Winarto and Teixeira-1, an original basal medium containing 0.01 mg/l a-naphthalene acetic acid, 0.5 mg/l thidiazuron and 1.0 mg/l 6-benzylaminopurine was suit- able for callus formation while an improved basal medium i.e., New Winarto–Teixeira-3 supplemented with 0.25 mg/l 2,4-dichlorophenoxy acetic acid, 0.02 mg/l a-naphthalene acetic acid, 1.5 mg/l thidiazuron and 0.75 mg/l 6-benzyl- aminopurine enhanced callus formation. High shoot regeneration and multiplication was also possible on New Winarto–Teixeira-3. Shoots formed a strong adventitious root system on New Winarto–Teixeira-3 containing. 0.2 mg/l a-naphthalene acetic acid and 1.0 mg/l kinetin. Plantlets that varied in size and performance were suc- cessfully acclimatized and adapted to ex vitro conditions. Cytological analysis of 180 acclimatized-plantlets ex vitro revealed that 34 were haploid (n = 14–18), 15 aneuploid (n = 20–26), 126 diploid (n = 28–34) and 5 triploid (n = 45–57). The potential use of this protocol for devel- oping half-anther culture of other Anthurium species or cultivars is discussed.
