<span name="style_bold"> </span>The objective of this work is to develop a genetic improvement program for guava (<span name="style_italic">Psidium guajava</span> L.) in Cuba, which may contribute to a more efficient use of its genetics resources. It begins with the establishment of the collection, taking into account the prospection of native genotypes, as well as the introduction of wild relatives and accessions with a diverse geographical origin from the main producer countries. These activities are vital for the posterior collection enrichment and maintenance, as well as the different sexual and asexual propagation procedures, which guarantee material multiplication and allow to create new variability sources. Once established, characterization can proceed. For this, a group of minimum descriptors that can be useful to homogenize such studies to an international level and for cultivar catalogues confection are referred to, the latter of great demand from producers and specialists. For a rational germplasm management it is necessary to know the existent variability. In this sense, highly discriminative morphological characters, as well as AFLP and SSR molecular markers, are recommended, whose combination allows to identify accessions and to form diversity groups, not only in guava but also in other Myrtaceae members. All this integral analysis guarantees a  more  efficient  selection  process of promissory genotypes for different purposes (breeding, conservation and commercialization). From them, crosses that can serve to evaluate hybrids with desirable commercial characteristics are recommended, as well as the development of a genetic linkage map and QTLs association, as the a step towards a future marker-assisted selection implementation. The role of tissue culture is also stressed, as an alternative conservation method and for guava improvement, considering the main results obtained in the country. L.) in Cuba, which may contribute to a more efficient use of its genetics resources. It begins with the establishment of the collection, taking into account the prospection of native genotypes, as well as the introduction of wild relatives and accessions with a diverse geographical origin from the main producer countries. These activities are vital for the posterior collection enrichment and maintenance, as well as the different sexual and asexual propagation procedures, which guarantee material multiplication and allow to create new variability sources. Once established, characterization can proceed. For this, a group of minimum descriptors that can be useful to homogenize such studies to an international level and for cultivar catalogues confection are referred to, the latter of great demand from producers and specialists. For a rational germplasm management it is necessary to know the existent variability. In this sense, highly discriminative morphological characters, as well as AFLP and SSR molecular markers, are recommended, whose combination allows to identify accessions and to form diversity groups, not only in guava but also in other Myrtaceae members. All this integral analysis guarantees a  more  efficient  selection  process of promissory genotypes for different purposes (breeding, conservation and commercialization). From them, crosses that can serve to evaluate hybrids with desirable commercial characteristics are recommended, as well as the development of a genetic linkage map and QTLs association, as the a step towards a future marker-assisted selection implementation. The role of tissue culture is also stressed, as an alternative conservation method and for guava improvement, considering the main results obtained in the country.

Guava plant; breeding; biodiversity; molecular markers