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 mu m, and a non-perforated bottom (< 425 mu m). 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 mu m sieve, E. robusta from the 850 mu m sieve, and E. urophylla from the 710 and 850 mu m 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 <425 mu m sieves, must be discarded due to low purity and germination potential.