The objective of this research was to obtain more suitable information concerning coffee seed processing in the air-screen machines and gravity table, studying their effects on the physiological seed quality. One coffee seed lot of the Yellow Catuaí IAC 62 cultivar was processed in a precleaner machine, in an air-screen cleaner and in a gravity table, working in several sequences and combinations, according to technical recommendations for seed processing. The seeds were evaluated as to their physiological quality by the germination test, accelerated aging test, seedling emergence, height and weight of dry matter of seedlings and young plants. The seed moisture was determined at the beginning of the evaluations. The statistical design was randomized blocks with four replications. Mean comparisons were done by the Tukey test at 5 % of probability. It was concluded that: a) physiological seed quality was improved by specific equipments in the several phases of processing, with the best seed quality, obtained with complete operational sequence, where the lot was submitted to the action of the air-screen cleaner and gravity table; b) the gravity table, associated with air-screen cleaner, was effective in removing debris from the seed lot, improving the physiological seed quality; c) larger or denser seeds had superior physiological performance than small sizeor lowdensity seeds, and the large pea berry seeds presented physiological quality similar to the large flat seeds; d) discart of smallest or lightest seeds to improved the physiological seed quality, resulting in homogeneous, and high quality seed lots, and more vigorous young plants.
Coffea arabica L.; seeds; grading; germination; vigor
