Assessment of genetic diversity in Psidium guajava L. using different approaches

Psidium guajava L. is one of the economically most relevant fruit crops in the Myrtaceae family. Genetic diversity studies are an important source of data for breeding programs, as well as taxonomic and evolutionary approaches in this species. Considering that the use of distinct methods enables more reliable information of genetic diversity, this study aimed to screen and characterize the genetic diversity among 28 P. guajava genotypes by morphological, karyotypical, nuclear 2C-value and simple sequence repeat (SSR) marker data. Karyotypic and nuclear 2C-value analyses showed that all genotypes have a stable and very small diploid genome (2n = 2x = 22; 2C = 0.95 pg). In this regard, the species exhibits karyotypic characteristics related to ancestral angiosperm groups. Dendrogram based on morphological and SSR data evidenced diversity among P. guajava genotypes, with better discrimination by SSR. The data obtained for morphology, SSR molecular markers, karyotype and nuclear genome size contributed to expand the knowledge about the genome and genetic diversity of P. guajava. In this context, this information may aid plant breeders to structure crop improvement programs and contribute to evolutionary approaches.

► Associating morphological, SSR marker, nuclear 2C-value and karyotype data to: ► Screen and characterize the genetic diversity among 28 P. guajava genotypes. ► Expand the knowledge about genome and genetic diversity of these genotypes. ► Aid plant breeders to structure crop improvement programs. ► Contribute to evolutionary approaches.