Efficient plant regeneration via organogenesis in winter squash ( Cucurbita maxima Duch.)

Abstract

Using cotyledonary explants excised from seedlings germinated in vitro, efficient plant regeneration via organogenesis was established for two winter squash ( Cucurbita maxima Duch.) cultivars. To establish optimal conditions for adventitious shoot induction, a variety of explants were prepared from seedlings of different ages and these were cultured using media containing different concentrations of 6-benzylaminopurine (BA). For both cultivars, plant regeneration was optimal when the proximal parts of cotyledons from 4-day-old seedlings were cultured on induction medium composed of Murashige and Skoog (MS) medium with 1 mg/l BA. After 3 weeks of culture in induction medium, 82 and 92% of explants from the two cultivars regenerated shoots. Adventitious shoots were subcultured on elongation medium composed of MS medium with 0.1 mg/l BA and the elongated shoots were successfully rooted in MS medium without growth regulators for 2 weeks. Flow cytometric analysis revealed that most of the regenerated plants were diploid.