Reproductive and cytogenetic characterization in Passiflora sublanceolata
2016
Belo, Gabriela de O. | Souza, Margarete M. | Souza, Viviane de O. | Melo, Cláusio Antônio F de
Reproductive biology (pollen-ovule ratio, pollen viability, germination in vitro pollination and stigma receptivity in vivo) and karyotype characterization by classical and molecular techniques were performed in Passiflora sublanceolata. The pollen-ovule ratio was 83.9, suggesting that this species is facultative autogamous. Pollen viability was below 70% during all anthesis period (6:00 a.m. to 12:00 p.m.). Low in vitro germination rates were observed after anthesis beginning, with none percentage at one, four and six hours and medium percentage (52.9%) at five hour. The stigma remained receptive during the whole anthesis (100%). The average fertilization percentages resulting from controlled pollinations varied between 8.4% at six hour after anthesis beginning and 50% at two and three hour. The fruit characteristics did not show significant differences by the effects of pollination time. The chromosome number was 2n = 22. The average chromosome length and the haploid chromosome length were 1.60 μm and 17.61 μm, respectively. Six CMA⁺₃ /DAPI⁻ terminal blocks were observed. By means of the FISH technique it was found that the species presented six 45S rDNA terminal sites, two 5S rDNA sites, terminal and pericentromeric, and telomeric hybridization sites associated only to the terminal regions. Passiflora sublanceolata has great reproductive potential and cytogenetic stability as diploid plant. The results obtained in this work will assist in the use of P. sublanceolata as genitor in interspecific hybridizations with other taxa for breeding programs primarily aimed to obtain hybrids for ornamental plant market.
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