Preliminary Results on Biotization of Encapsulated Vitro-Derived Propagules of Carrizo Citrange [Citrus sinensis (L.) Osb. × Poncirus trifoliata (L.) Raf].

The encapsulation technology represents a new tool to integratemicropropagation into the nursery activity. It allows combining the advantages ofzygotic or gamic seeds with those of micropropagation. The synthetic or artificialseeds have been defined as “artificially encapsulated somatic embryos, shoots orother tissues which can be used for sowing under in vitro or ex vitro conditions”.This will be a powerful propagation tool in the nurseryman hands, if the levels of thesynthetic seeds conversion can be increased also in the nurseries, without the asepsisof in vitro laboratories and with the presence of many parasitic microorganisms, likebacteria and fungi, responsible for contamination and/or for trophic competition.This research was carried out in order to apply biotization into the synthetic seedtechnology of Carrizo citrange [C. sinensis (L.) Osb. × Poncirus trifoliata (L.) Raf.],one most extensively used citrus rootstock, because of its resistance to the Citrustristeza virus (CTV). With this goal, preliminary experiments to set up protocols forbiotization, through the introduction of Plant Growth Promoting Bacteria (PGPB)into calcium alginate capsules of Carrizo citrange in vitro-derived microcuttings,were carried out, in order to protect the plantlets from abiotic and biotic factors andto promote their growth during the first stages of development. Specifically, theSinorhizobium meliloti wild type strain 1021 and its derivative RD64, thatsynthesizes 80-fold more IAA as compared to the wild type strain, was used toevaluate their performance in inducing rooting of encapsulated microcuttings.