Pollen Viability Of Eucalyptus Spp. With Specific Stains

Hybridization has been intensively used in breeding programs for Eucalyptus and has contributed, significantly, to increase the production, aside from the addition of specific adaptation characteristics of interest to plantation materials. However, the production of hybrids requires controlled pollination using pollen with an appropriate quality and viability. Therefore, accurate pollen viability estimates are essential. The aim of the present study was to define a fast and accurate methodology to determine the viability of Eucalyptus pollen using specific dyes. For this purpose, the colorimetric tests with 2,3,5 chloride, triphenyl tetrazolium (TTC) was used at 0,5 g.L-1, 1,0 g.L-1 and 1,5 g.L-1 concentrations, with incubation periods of 15, 30, 45, 60, 90 and 120 minutes, and also blue aniline in lactophenol (1 g.L-1) with incubation periods of 5, 10, 15, 30, 45 and 60 minutes. The 2,3,5 tripheny ltetrazolium chloride expressed the best pollen viability at 15 and 30 minutes, showing a value very close to germination, with a correlation of 0,96. Therefore, it is a potential dye to analyze the pollen viability of E. urophylla and E. brassiana. For blue aniline in lactophenol, the immersion for a period of 45 to 60 minutes showed better results. However, as this dye overestimated the viability by 20%, compared to in vitro germination, its use in concentrations and periods as used in the present work is not recommended. Therefore new research considering other concentrations and incubation period is recommended.