PLANT-REGENERATION FROM EMBRYO-DERIVED CALLUS IN PHASEOLUS-VULGARIS L. (COMMON BEAN) AND PHASEOLUS-ACUTIFOLIUS GRAY,A (TEPARY BEAN)

Regeneration-competent callus of Phaseolus vulgaris and P. acutifolius was obtained from mature embryo explants on a medium containing thidi azuron and indole-3-acetic acid. For the P. vulgaris genotype Xan-159, regeneration was achieved from cotyledon explants, but not from embry onic axis explants. Both explants could be used for the P. acutifolius genotype NI 574 but embryonic axes gave the best results. In-vitro-ro oted plantlets of P. acutifolius could readily be established in the g reenhouse. For P. vulgaris hardening problems with in-vitro-rooted pla ntlets could be overcome by means of in vitro grafting. The potential of the described procedure for ob raining transgenic P. vulgaris plant s is discussed.