Comportamento meiótico e viabilidade polínica na espécie Jatropha curcas L.

Abstract

The Jatropha curcas, known as physic nut, belonging to the Euphorbiaceae family, figure today as one of the greatest potential of oilseeds for biodiesel production in Brazil. The present study aimed to evaluate meiosis and pollen viability in J. curcas accesses from UFRRJ germplasm collection. To do that, flower buds were collected from 20 plants, these were fixed in acetic acid 3:1 solution and alcohol 70%. The staining of the cells was done by acetic carmine 2% solution and Alexander's triple solution, for the analysis of meiotic and pollen viability, respectively. All observations were carried out under an optical microscope. It was observed that the species has 2n = 2x = 22 chromosomes. It was observed many irregularities during the meiotic division as the presence of sticky chromosomes and irregular meiotic products, such as monads, dyads, triads and polyads, and the occurrence of cytomixis and micronucleus, these latter two anomalies had a higher frequency among the accessions. The meiotic index was estimated in 84.21% and the average pollen viability in 89.85%. The lowest pollen viability was 78% (UFRRJ885), while the maximum observed was 96% (UFRRJ861). Based on the results obtained, although Jatropha curcas presents certain anomalies during meiosis, the accessions analyzed here showed satisfactory pollen viability.