Citrus variety improvement programs

Abstract

Citrus virus and virus-like diseases producevery important economic losses to the citrus industry. In most cases this problem can besolved in new plantings by using virus-free propagative material. To obtain this healthy material it is necessary to carry out citrus sanitary improvement programs, that have to include the following steps: 1. Selection of mother trees. 2. Indexing of mother trees. 3. Shoot tip grafting ín vitro. 4. mdexing of resulting plants. 5. Horticultural evaluation of healthy plants. 6 Maintenance of healthy plants. The characteristics of these steps will be discussed, with special reference to the technique of shoottip grafting in vitro.