Qualidade de sementes de milho em função do tipo de secagem, armazenamento e aplicação de ozônio

Abstract

Seed drying and storage are two of the most important post-harvest processes of agricultural products, as it defines the capacity for their utilization as seeds or grains. Techniques include heating the drying air and dehumidifying it before heating. Thus, the choice of the best energy source and the most suitable drying technique justifies the search for efficient drying systems that provide the least damage to the seed. The study of biological contaminant reduction techniques through the application of ozone gas and temperature reduction tends to minimize losses by microorganisms and by the seed respiration process and pest multiplication in storage. Experiments were performed to evaluate the quality of corn seeds as a function of drying processes, storage forms and application of ozone. The experimental design was completely randomized in a 7 × 2 factorial scheme, with seven drying processes (natural, canvas, ear, drying with ambient air, heated air, dehumidified air, and air recirculation), and two storage conditions (chamber temperature and humidity controlled storage, and uncontrolled environment) for the first experiment, and two ozone treatments (with and without application) for the second experiment. At 0, 4, 8, and 12 months of storage the seeds were evaluated for water content, germination, cold test, accelerated aging test, electrical conductivity, and emergence in soil. For the first experiment, it was observed that corn seeds maintain higher germination percentages when stored up to 12 months in storage chambers, regardless of the drying process. Seed water content and vigor evaluated by the accelerated aging test were not affected by different drying processes, regardless of storage time. The seeds presented higher electrical conductivity values when stored in an uncontrolled environment at 4, 8, and 12 months of storage. Higher vigor was observed from the accelerated aging test and cold test on seeds stored inside the chamber at 4, 8, and 12 months of storage. For the second experiment, it was found that corn seeds subjected to ozone application after drying and stored for 12 months showed higher vigor indices than untreated ozone seeds. Ozone application provided lower vigor loss, as assessed by cold test at 12 months of storage. Ozone application has proven to be an important technology and can collaborate in preserving the physiological quality of corn seeds during storage. Under the conditions of the study, the natural drying and ear drying processes maintained the quality of the corn seeds. These results may provide useful information for improving the quality of corn grains and crops.