Shoot regeneration from leaf segments of peach × almond hybrid, GF677 rootstock

The GF677, a peach × almond hybrid, is a promising rootstock for both peaches and almonds and is exploited worldwide. To improve this rootstock via genetic engineering is prerequisite to have an efficient regeneration protocol. In order to evaluate the effect of different concentrations of auxin and cytokinin upon shoot regeneration from leaf segments of GF677 plantlets grown in vitroin AP medium containing 0.5 mg/l BAP, 4 mg/l GA3, and 200 mg/l casein hydrolysate was used. Leaf segments were placed with abaxial side down on regeneration media with NAA (0, 0.2, and 0.3 mg/l) and BAP (0.5, 1, 1.5, and 2 mg/l). Callus induction was observed in all treatments, but it was not influenced by different combinations of plant growth regulators. Substitution of BAP with TDZ evoked similar results in terms of callus induction and callus growth with no shoot regeneration. Among the three cytokinins investigated (TDZ, BAP, and Zeatin), only TDZ caused shoot induction in GF677 leaf segments on AP medium. Finally, to determine the most efficient TDZ level, shoot induction was recorded in all evaluated TDZ concentrations (5, 10, and 15 mg/l) without any significant difference among them.