Optimisation of a highly efficient shoot regeneration system using leaf explants of Chinese jujube (<i>Ziziphus jujuba</i> Mill.) by response surface methodology

<p>Chinese jujube (<i>Ziziphus jujuba</i> Mill.) is a major fruit crop in Asia. In this study, response surface methodology (RSM) was successfully employed to establish a highly efficient <i>in vitro</i> propagation and regeneration system for the ‘Teapot’ jujube via shoot organogenesis. Among the tested factors, gibberellic acid (GA₃) concentration showed the most significant positive effect. The pre-culture darkness timing and medium were also important factors for highly efficient shoot regeneration of the ‘Teapot’ jujube. The highest regeneration (> 75%) was achieved by 1 week in darkness and culture on wood plant medium (WPM) containing 0.25 mg·L⁻¹ GA₃, 0.5 mg·L⁻¹ 6-benzylaminopurine (BAP) and 0.1 mg·L⁻¹ 3-indoleacetic acid (IAA). <i>In vitro</i>-derived shoots rooted very well in the modified ¹/₂ Murashige and Skoog (MS) medium containing 0.4 mg·L⁻¹ 3-indolebutyric acid (IBA), resulting in a 100% rooting rate. These findings suggest that the RSM can be employed to optimise the protocols needed for successful <i>in vitro</i> plant regeneration of jujube cultivars, with potential applications in plant genetic transformation practices, polyploidy induction and germplasm preservation.