DIRECT AND EFFICIENT PLANT-REGENERATION FROM LEAF EXPLANTS OF SOLANUM-TUBEROSUM L CV BINTJE

A two-step procedure was used for plant regeneration from in vitro gro wn leaf strips (2-3 mm wide) of cv. Bintje. Step I medium was designed with 2,4-dichlorophenoxycetic acid (2,4-D) at 0.0 or 9.0 mu M, in com bination with 2.28 mu M kinetin (K), benzyl adenine (BA), zeatin (Z) o r zeatin riboside (ZR). Step II media were 2,4-D-free media containing 5.78 mu M gibberellic acid (GA3) and growth regulators similar to tho se of step I media. Leaf explants cultured in medium I containing zeat in riboside or zeatin for 6 days and then subcultured in medium II con taining zeatin riboside produced numerous shoots without callus format ion. Zeatin riboside containing step I and II media caused shoot regen eration in a high number (97.5+/-2.2) of explants. Approximately, 33.7 +/-8.4 shoots were regenerated from each leaf explant.