Enhanced shoot organogenesis and regeneration in the common bean (Phaseolus vulgaris L.)

Four cultivars of common bean (Phaseolus vulgaris L.) were tested for regeneration efficiency. Embryo axes from mature seeds were incubated on Murashige and Skoog or Gamborg media containing 6-benzyladenine (10 mg/l), without and with adenine hemisulphate (20 mg/l). Efficient regeneration was achieved when explants were incubated on Gamborg media amended with 6-benzyladenine, without adenine hemisulphate. This medium provided high regeneration efficiency in the four cultivars tested: Apetito G13637 (98-100%), Flor de Mayo Anita (96-98%), ICA Palmar G4523 (88-97%) and Pinto Saltillo (83-84%). The division and transfer of organogenic shoot of all cultivars to induction and multiplication medium every 15 days resulted in the formation of three to five new organogenic embryo axes per transfer. A single 5-mm cluster formed up to 20 shoots, from which two to three whole plants were regenerated. Regeneration efficiency differed significantly between the two basic media; Gamborg induced high organogenic shoot formation (98-100%) and whole plant regeneration (93%), whereas Murashige and Skoog media showed lower and inconsistent organogenic shoot formation (15-73%) and whole plant regeneration (29%). The protocol that included Gamborg media show high regeneration efficiency across different bean genotypes, resulting in whole plants comparable to seed-produced plants.