Plant regeneration from embryo-derived callus in Phaseolus vulgaris L. (common bean) and P. acutifolius A. Gray (tepary bean).

Regeneration-competent callus of Phaseolus vulgaris and P. acutifolius was obtained from mature embryo explants on a medium containing thidiazuron and indole-3-acetic acid. For the P. vulgaris genotype Xan-159, regeneration was achieved from cotyledon explants, but not from embryonic axis explants. Both explants could be used for the P. acutifolius genotype NI 574 but embryonic axes gave the best results. In-vitro-rooted plantlets of P. acutifolius could readily be established in the greenhouse. For P. vulgaris hardening problems with in-vitro-rooted plantlets could be overcome by means of in vitro grafting. The potential of the described procedure for obtaining transgenic P. vulgaris plants is discussed.