Regeneration of fertile Arachis paraguariensis plants from callus and suspension cultures

Highly morphogenic callus cultures were isolated from stamens of a wild peanut species, Arachis paraguariensis. These cultures were initiated on modified N6 medium containing 0.2 mg1l^-1 4amino-3,5,6-trichloro-picolinic acid (picloram) and 0.5 mg l^-1 6-benzylaminopurine (BAP) and were maintained on modified N6 medium with 0.008 mg l^-1 picloram and 0.25 mg l^-1 BAP. Buds formed on the calli growing on the maintenance medium developed into shoots when they were transferred to a MS salts based medium with no hormones. The cultures could also be maintained as a suspension culture in N6 liquid medium. When cell clumps larger tham 840 m were collected from the suspension culture and transferred to MS medium without hormones, they formed shoots in liquid culture. Root formation rarely occurred in agar or liquid cultures. Therefore, grafting to stems of rooted seedlings was used to obtain plants from regenerated shoots. Eight out of 50 field grown plants produced viable seed.