Regeneration of grape (Vitis labruscana cv. Kyoho) by shoot-tip culture

We investigated the optimal levels of growth regulators, culture media, and pH on callus growth and organogenesis of in-vitro cultured ‘Kyoho’ grapes. Calli were induced by culturing leaf blades on an MS basal medium supplemented with 1 mg/IL BA and 0.01 mg/L 2,4-D. In addition, calli originating from the exocarp and mesocarp of grape fruits devel-oped on MS media supplemented with 0.1 mg/L IAA, NAA, or 2,4-D, or with 0.2 mg/L BA. In testing the potential for plant regeneration from shoot tips on various media, we found that the Nitsch medium, with I mg/L BA, was optimal for caulogenesis. The type of shoot development depended on the pH of the medium, with vigorous multiple-shoot devel-opment occurring at pH 6.0, and single shoots forming at pH 5.0. Finally, we were able to obtain rooted seedlings from the regenerated shoots that had been cultured on 1/4-strength Nitsch medium supplemented with 0.03 mg/L NAA.