Plant regeneration from epicotyl segment and callus of Vigna angularis (cv. Tanbadainagon)

Epicotyl segments (approximately 1 cm in length) of Vigna angularis (cv, Ta nbadainagon) inoculated with Agrobacterium rhizogenes produced hairy roots and/or adventitious buds. Mikimopine and the predictable PCR band for rol g ene were detected in the hairy roots, and plantlets obtained from the adven titious buds were negative for both products. These results suggested that the segments can induce the formation of adventitious buds without an infec tion of A. rhizogenes; therefore this possibility was examined. As a result , adventitious buds were formed from the segments on a hormone-free medium and promoted by low concentrations of 6-benzyladenine (BA) and 1-naphthalen eacetic acid (NAA). When the calli induced on the medium containing BA and/ or NAA were transplanted onto the hormone-free medium, they induced an orga nogenic callus, which was growing with the formation of a green leaflike st ructure. Especially, the frequency of organogenic callus formations was ver y high in calli that had once produced adventitious buds. The development o f shoots from organogenic callus was induced on the medium containing gella n gum with NAA. Shoots (more than 1 cm in length) cut from epicotyl segment s and organogenic callus produced roots and developed actively on the hormo ne-free medium. The procedures obtained in the present study are useful for the genetic improvement of the plant via biotechnology.