Effect of Cytokinins, Carbohydrate Source and Auxins on In Vitro Propagation of the ‘G × N-9’ Peach Rootstock

Abstract

ABSTRACT The cultivar ‘G × N-9’ is an almond x peach hybrid rootstock, the main characteristic of which is resistance to several root-knot nematodes (Meloidogyne spp.). Although its propagation by hardwood cutting in the fall is recommended, optimization of ‘G × N-9’ in vitro propagation is currently needed. Thus, the objective of this study was to evaluate the effect of the cytokinins [6-benzylaminopurine (BAP) and Kinetin (KIN)], and the carbohydrate sources (sucrose and sorbitol) on shoot proliferation and elongation, as well as the influence of indole-3-butyric acid (IBA) on in vitro rooting and acclimatization of ‘G × N-9’ rootstock. This study reports enhanced on shoot proliferation and elongation based on the interaction between BAP and KIN. When comparing the effects of sorbitol and sucrose, sorbitol at 15 and 30 mg L−1 was the most effective for the induction of shoot proliferation (5.75 ± 0.19 and 6.39 ± 0.21 shoots per explant, respectively). The highest number of roots per explant was in QL medium supplemented with 0.6 and 1.2 mg L−1 IBA. After 30 days of acclimatization, the treated-plants with 1.2 mg L−1 IBA showed the smallest root length, but the higher number of roots per explant (8.35 ± 0.41). The successful acclimatization of plantlets depended on the use of IBA during in vitro culture, to induce a healthy and well-developed root system.