Rapid diagnostic of vein necrosis disease by in vitro micrografting technique
Abstract
The in vitro micrografting of shoots is a very easy technique to observe clear symptoms of vein necrosis disease when we graft indicator variety 110 R on infected grapevines. Explants of candidate vines and 110 R were cultivated aseptically in MS-based medium. Shoots of the index variety were grafted onto an internode of the clones to be tested. The cleft grafting allowed a rapid growth of scions and roots. Typical and severe symptoms appeared in less than 30 days incubation. Final readings were made after 45 days. At that time, 110 R indicator exhibited vein necrosis symptoms on leaves, petioles, shoots and sometimes on callus.
As reported in the present paper, the results with different sources of infected clones showed a very high correlation between in vitro indexing and usual indexing by green grafting. But with this last method symptoms appeared only 2 to 3 months after grafting. The presence of this latent virus desease into many varieties is discussed.
The rapid response and the safe reading are two arguments to propose to use in vitro micrografting like a current technique for sanitary selection.