In vitro micrografting of cherry (Prunus avium L. 'Regina') onto 'Piku® 1' rootstock [P. avium X (P. canescens X P. tomentosa)]

An early diagnosis for compatibility between cherry varieties and rootstocks is required to launch new plant material on the market. An in vitro, slit-micrografting technique for Prunus avium L. 'Regina' on 'Piku (R) 1' rootstock [P. avium x (P. canescens X P. tomentosa)] is presented as a model for cherry species. In vitro shoot tips, cut in a V-shape, were used as scions, while shoots induced for in vitro rooting were used as rootstocks. The success of various parameters was examined: micro-scion size, carbon source, number of in vitro scion multiplication cycles, composition of the medium, and grafted tissue treatment. Micrografts were cultured on a modified Murashige and Skoog (MS) medium without added plant growth regulators (PGRs). The highest percentages of successful grafts (80% at 4 weeks after grafting and 58% at 3 months after acclimatisation) were obtained using glucose as the sole carbon source, vermiculite in the agar medium, and 3 5 mm-long shoot tips formed in vitro as scions. Additional chemicals such as kinetin, ascorbic acid, citric acid, polyvinylpyrrolidone (PVP), or 6-benzyladenine (BA) did not improve grafting, but a rapid micrografting process was most important. The number of in vitro scion multiplication cycles was shown to have no effect. Using in vitro cultures of both scion and rootstock, aseptic conditions were maintained throughout the micrografting process and no problems of contamination were encountered.