Genome size, base composition and karyotype of Carica papaya L.

Few data concerning Carica papaya DNA content and chromosomal characterization have been reported in specialized bibliography. Considering this fact, flow cytometry and cytogenetic methodologies were applied in order to improve the knowledge about the genome size, base composition and karyotype of C. papaya hermaphroditic plants. Flow cytometry results showed that hermaphroditic C. papaya genome size is relatively small (2 C=0.65 pg) and the base composition (63.49% AT and 36.51% GC) is typical of core dicots. All mitotic cells showed 2n=18 chromosomes, which were classified in metacentric or submetacentric. Despite small and homomorphic chromosomes, it has been made possible to resolve karyogram of hermaphroditic C. papaya. Through classical and banding techniques, the secondary constriction was observed in association to the chromosome 1 centromere. Here, we propose flow cytometry and cytogenetic protocols for studying the C. papaya genome. These methodologies may be useful as a basis for molecular cytogenetic techniques application.