Highly Morphogenic Callus of Arachis Paraguariensis from Agar and Suspension Cultures
Arachis paraguariensis (Chod. et Hassl.) is a wild species of peanut with 2n=20. Callus cultures derived from anthers of this species were highly morphogenic, producing shoots, leaves, and flowers at a high frequency. A much lower percentage regenerated into complete plants with roots. Anthers from flowers with no petal showing were used to initiate callus, using the salts and organics of N6 medium (Chu et al.) supplemented with casein hydrolysate, 500 mg/1; myo-inositol, 100 mg/1; sucrose, 20 g/1; L-proline, 3 g/1; 4-amino-3,5,6-trichloropicolinic acid (picloram), 0.2 mg/1; N6-benzyladenine (BA), 0.25 mg/1; and agar, 6 g/1. Calli were maintained on the same N6 medium with picloram levels of 0.008 mg/1, 0.25 mg/1 BA, and 60 g/1 sucrose. Buds appeared on calli after 30 to 40 days. When these buds were transferred to Murashige and Skoog medium (MS) with 0.01 mg/1 BA or with no hormones, shoots developed with leaves and flowers. Callus was used to initiate suspension cultures in N6 liquid medium that contained casein hydrolysate, 500 mg/1; myo-inositol, 100 mg/1; sucrose, 20 g/1; picloram, 0.008 mg/1; BA, 0.2 mg/1; and L-proline, 1.7 g/1. Suspension cultures were maintained by transferring clumps of tissue between 210 and 840 μm in size on a weekly basis.