RAPID IN-VITRO INDEXING OF GRAPEVINE VIRAL DISEASES - THE EFFECT OF STRESS-INDUCING AGENTS ON THE DIAGNOSIS OF LEAFROLL

The release of new virus-free propagation material and new cultivars o f grapevine would be advanced if more rapid diagnostic methods could b e developed. a method enabling rapid in vitro indexing of grapevine le afroll is described. Diseased explants poorly express symptoms when pl aced in culture. However, when placed under mild stress conditions (4% sorbitol), a variety of distinct symptoms appear within 4 to 8 weeks. This method could potentially replace the conventional 18- to 30-mont h indexing procedure.