Thirty-six trees of nine varieties were selected as basic material for the certification programme in the framework of the project for the obtention of virus and virus-like disease-free, true-to-type budwood and seedlings. Besides trueness-to-type assessment, pomological and technological tests, indexing for virus diseases was made with biological tests (grafting to indicators), accompanied by ELISA and electrophoresis. Clones were sanitated by shoot tip grafting in combination with termotherapy. In Turkey, certified propagating material must be free from tristeza, stubborn, exocortis, cachexia and psorosis.