Effect of Size Classification on Physical and Physiological Quality Aimed at Pelletizing Seeds of Eucalyptus Species

The aim of this work was to verify the effect of size classification on the physical and physiological quality of Eucalyptus spp. seeds to optimize the selection for covering. The seeds were separated in sieves with six size classes: 850, 710, 600, 500, 425 μm, and a non-perforated bottom (< 425 μm). Were evaluated the sieve retention, purity, weight of a thousand seeds, germination, and first count of germination. Sieve classification is effective for the separation of materials according to the best physical and physiological qualities. E. grandis seeds from the 710 μm sieve, E. robusta from the 850 μm sieve, and E. urophylla from the 710 and 850 μm sieves can be selected for covering, as they present maximum physical and physiological quality. For the three species, the smallest materials, retained in the 500, 425, and bottom <425μm sieves, must be discarded due to low purity and germination potential.