The use of consecutive micrografting improves micropropagation of cherimoya ( Annona cherimola Mill.) cultivars

Abstract

Clonal propagation of cherimoya via micropropagation is known to be problematic and its difficulty varies depending on the cultivar used. In order to improve the micropropagation process, the use of successive micrografting was applied to three cherimoya cultivars: ‘Fino de Jete’, ‘Bonita’ and ‘Pazicas’. Grafting nodal tissue onto a rootstock derived from ‘Fino de Jete’ juvenile material improved bud sprouting significantly in all tested cultivars. Rooting of sprouted shoots from non-grafted nodal tissue was extremely poor, however, shoots derived from explants after 1–3 consecutive micrografts displayed enhanced rooting. While ‘Fino de Jete’ and ‘Bonita’ shoots displayed 50% of rooting after two micrografts, Pazicas cultivar shoots required three micrografts to reach this percentage. Rooting was maximum after three micrografts, with 70%, 60% and 50% of rooting for ‘Fino de Jete’, ‘Bonita’ and ‘Pazicas’ shoots, respectively. Rooted plantlets were mycorrhized and acclimatized under greenhouse conditions and displayed a high rate of survival (90–100%) for all cultivars, indicating that the micrografting technique could also have an effect on the acclimation of plants.