Técnicas para avaliar a viabilidade do pólen de Eucalyptus brassiana e Eucalyptus urophylla

Abstract

The genus Eucalyptus presents several species with wide use, as raw material for a wood industry, pulp and paper, furniture manufacturing and energy production. Breeding programs have contributed to increasing the productivity and quality of the products of this species. This success is mainly due to the use of hybridization, using a controlled pollination. This technique is useful for the advantages of a hybrid synthesis, besides providing knowledge of the general capacity and for the specific combination of the matrices, the possibility of crossing between relatives with specific characteristics for the forest improvement. For this well-being to be successful, there must be a matter of utmost importance for the use of a viable, properly manipulated, including collection, extraction, drying, storage and analysis of its viability. The present work had as objective to establish a better technique to indicate the viability of Eucalyptus brassiana and Eucalyptus urophylla pollen. The work was carried out in the Pollen Laboratory of Embrapa Florestas, in the municipality of Colombo - Paraná. In this study, the pollen of two species of the genus Eucalyptus was used: E. brassiana S.T. Blake, E. urophylla S.T. Blake. For the in vitro germination tests different culture media were used considering Brewbaker & Kwack medium, and different types of sugars: sucrose, fructose, lactose, galactose, glucose. The germination assays were performed in randomized blocks with four replicates and a 300 gram count. The grains that presented the pollen tube larger than its larger diameter were considered as germinated. Analysis of viability through specific dyes, using and using different dyes and concentrations: 2,3,5 Chloride Of triphenyltetrazolium (TTC) with concentrations of 0.5%, 1.0% and 1.5% and Lactophenol Blue the 1 %. With this, it was possible to improve adequate techniques for the feasibility tests of E. urophylla and E. brassiana pollen employed in the work. The sugar that was most efficient for a higher percentage of germination, 79.17% and 63.50% for E. urophylla and E. brassiana, respectively, and the dye that best expressed a pollen viability for 2,3,5 Chloride Of triphenyltetrazolium at a concentration of 1.5% for 60 minutes.