Meiotic analyses of Passiflora L. parents and interspecific F1 hybrids (HD15 progeny)

Passiflora F1 hybrids, with ornamental potential, were confirmed via GISH and analyzed for meiotic compatibility. This study aimed to analyze the meiotic behavior of P. gardneri Mast. and P. gibertii N.E. Brown and four interspecific hybrids resulting from this cross, with the aim of inferring genetic compatibility between parents and the implications of hybridization on the hybrids’ genomes. Flower buds were collected for classical cytogenetic studies and anthesis flowers for pollen viability (PV) using (1) Alexander's solution and (2) fluorescein diacetate. Pollen grains were counted, measured and identified as viable or unviable, with the PV considered to be low. Genomic in situ hybridization (GISH) technique was used in prophase I. Analysis of meiotic behavior showed bivalent formation among the homologous in the parents and homeologous in the hybrids; some irregularities were found, such as lagging chromosomes, asynchrony, spindle fiber irregularities and chromosomal bridges. Post meiosis resulted in anomalous cells such as monads, dyads, triads and polyads. All results were subjected to analysis of variance, with significant differences for all analyses between hybrids, with the exception of monad formation. GISH confirmed the hybrid character and pairing between homeologous chromosomes. The results obtained in this study established the degree of homology between the parent species through analysis of chromosome pairing and chiasma formation, confirmed by GISH. Both parent species showed potential for use as paternal parents.