title: Refinement of the karyological aspects of Psidium guineense (Swartz, 1788): a comparison with Psidium guajava (Linnaeus, 1753).
abstract: Euploidy plays an important role in the evolution and diversification of Psidium Linnaeus, 1753. However, few data about the nuclear DNA content, chromosome characterization (morphometry and class) and molecular markers have been reported for this genus. In this context, the present study aims to shed light on the genome of Psidium guineense Swartz, 1788, comparing it with Psidium guajava Linnaeus, 1753. Using flow cytometry, the nuclear 2C value of Psidium guineense was 2C = 1.85 picograms (pg), and the karyotype showed 2n = 4x = 44 chromosomes. Thus, Psidium guineense has four chromosome sets, in accordance with the basic chromosome number of Psidium (x = 11). In addition, karyomorphometric analysis revealed morphologically identical chromosome groups in the karyotype of Psidium guineense. The high transferability of microsatellites (98.6%) further corroborates with phylogenetic relationship between Psidium guajava and Psidium guineense. Based on the data regarding nuclear genome size, karyotype morphometry and molecular markers of Psidium guineense and Psidium guajava (2C = 0.95 pg, 2n = 2x = 22 chromosomes), Psidium guineense is a tetraploid species. These data reveal the role of euploidy in the diversification of the genus Psidium.
authors.affiliation: Laboratório de Citogenética, Departamento de Biologia, Centro de Ciências Agrárias, Universidade Federal do Espírito Santo, CEP: 29.500-000 Alegre - ES, Brazil.
authors.forename: Anelise Machado
authors.initials: AM
authors.lastname: Marques
authors.affiliation: Escola Nacional de Botânica Tropical, Instituto de Pesquisas Jardim Botânico do Rio de Janeiro, CEP: 22.460-036 Rio de Janeiro - RJ, Brazil.
authors.forename: Amélia Carlos
authors.initials: AC
authors.lastname: Tuler
authors.affiliation: Laboratório de Citogenética e Citometria, Departamento de Biologia Geral, Centro de Ciências Biológicas e da Saúde, Universidade Federal de Viçosa, CEP: 36.570-000 Viçosa - MG, Brazil.
authors.forename: Carlos Roberto
authors.initials: CR
authors.lastname: Carvalho
authors.affiliation: Laboratório de Botânica, Departamento de Biologia, Centro de Ciências Agrárias, Universidade Federal do Espírito Santo, CEP: 29.500-000 Alegre - ES, Brazil.
authors.forename: Tatiana Tavares
authors.initials: TT
authors.lastname: Carrijo
authors.affiliation: Laboratório de Genética e Melhoramento Vegetal, Departamento de Biologia, Centro de Ciências Agrárias, Universidade Federal do Espírito Santo, CEP: 29.500-000 Alegre - ES, Brazil.
authors.forename: Marcia Flores da Silva
authors.initials: MF
authors.lastname: Ferreira
authors.affiliation: Laboratório de Citogenética, Departamento de Biologia, Centro de Ciências Agrárias, Universidade Federal do Espírito Santo, CEP: 29.500-000 Alegre - ES, Brazil.
authors.forename: Wellington Ronildo
authors.initials: WR
authors.lastname: Clarindo
keywords: Psidium; SSR markers; cytogenetic; flow cytometry; karyotype evolution; polyploidy