Efeito imediato e latente da temperatura do ar de secagem sobre a qualidade fisiológica e tecnológica de sementes de soja produzidas na segunda safra

Abstract

The objective of this work was to determine the immediate and latent effects of different drying air temperatures on the physiological and technological quality of soybean seeds produced in second season crops. The soybean seeds used were from cultivar SYN 1059 RR (V-TOP), which were harvested near physiological maturity, with a water content of approximately 23% w.b.. After harvesting, the seeds were subjected to different drying temperatures (40, 50, 60, 70 and 80 °C) to a water content of 12,5 ± 0,7% w.b., and stored in metal containers under a non-controlled environment for 180 days. The physiological and technological quality were evaluated by specific parameters each subsequent 45 days. The tests performed to evaluated the viability and vigor of the studied material to assess the physiological quality were germination test, first count, seedling lengths, seedling dry matter, modified cold, accelerated aging, electrical conductivity, and tetrazolium. The seed technological quality was assessed through the evaluations of dry matter loss, seed color related parameters, crude protein and lipids content, and extracted crude oil acid and peroxide values. The results found showed that: a) the increase in drying air temperature affected the physiological and technological quality of soybean seeds, effect that was enhanced with the storage time; b) the viability and vigor, in all physiological quality tests used, were diminished as the both factors increase; c) the combined effect of different drying air temperatures and storage times reduced the technological quality of seeds and crude oil from them; d) soybean seeds dried at 40 °C, among all tested, presented the best immediate performance to drying and during storage compared to all tests used.