ROBOTIZATION IN THE PRODUCTION OF GRAFTED SEEDLINGS

Robotization in the production of grafted seedlings is strongly required in view of supplying seedlings in production of fruit vegetables. In the present study, robotization in the production processes of grafted seedling were attempted for the purpose of the quality improvement of grafted seedlings and the labor-saving for grafting processes.

Principle of grafting is to join perfectly the vascular bundles of scion and stock. Malconnection of vascular bundles should be recovered by cell proliferation and differentiation, but it takes a longer time. Thus, the minimization of malconnection, resulting in a shorter time to connect the vascular bundles located in both sides, is always required for the assured grafting. The method proposed here can be recognized as one of improved techniques for minimizing malconnection of vascular bundles.

To meet with the aim of this improvement, we propose 'Plug-in method' which is as follows; 1) For scion, a stem will be shaped up as a form of plug like a pencil-tip, using a vibration cutter (115Hz) with 14 deg. of cutlery angle. 2) For stock, a stem will be drilled to make a conical hole, using a taper drill (4500rpm). 3) The conically shaped scion is then plugged into the conical hole of the stock to complete grafting. The plug-in method requires rapid and precise processing of scion and stock to avoid desiccation of processed surface and malconnection of vascular bundles. Practical implementation of the plug-in method can be achieved by distinctive mechanical processing for soft plant materials.

Crop species attempted here were tomato, egg plant, and watermelon. The grafted seedlings prepared in employing the plug-in method demonstrated a faster joining and a vigorous activity in their growth.