Qualidades fisiológica e química de sementes de aveia-branca e aveia-preta em função da umidade de colheita e do tempo de armazenamento

Abstract

Oat is a cereal of global importance, standing out as an important alternative winter crop in southern Brazil. Oat cultivation has many fins, an example of crop technology, ground cover, and electrical and animal power. The combination of seeds at the time of harvest, the conditions of their storage, the decisive elements for the physical ones, as well as the quality of the grains throughout the period of environmental storage. Therefore, the objective of this work was to influence the quality at the time of harvesting oat seeds in storage times. They were black oat and white oat seeds, originating from the one used in Passo Fundo. The experiment was completely randomized, with four plots, with treatments arranged in a 3x4 scheme (one experiment x storage time). The seeds were harvested in three humidity ranges: 20+1%, 16+1% and 12+1% for black oat seeds and 20+1%; 17+1% and 12+1% for white oat seeds. Using a stationary dryer, the wetter harvested seeds were dried to a moisture content of 12+2%. Subsequently, the seeds were stored in three conditions: ambient, cold and hermetic, in which their quality was evaluated at different storage times: 0, 60, 120 and 180 days. Each storage condition and each oat cultivar were evaluated as isolated experiments. The variables analyzed were: first germination count, germination, accelerated aging, electrical conductivity, seedling emergence, emergence speed index, seedling length, seedling dry mass, protein content, moisture, fat, fiber, ash, starch , water activity (aw), hydrogenic potential (pH) and drop number. The results suggest that, soon after harvest, the wetter seeds presented better physiological quality in relation to the seeds harvested with low humidity. During the storage time, up to 120 days the seeds harvested drier showed an increase in quality, but at 180 days the seeds harvested with high humidity showed higher physiological quality. It is concluded that, due to the storage time, the seeds undergo changes in moisture, aw and pH, which favors a condition for microbial development and, consequently, seed deterioration. Regarding the chemical composition of the seeds, due to the harvest moisture, there is no disparity in relation to the three moisture ranges, in the three storage conditions. Thus, the seeds can be harvested as close to physiological maturity, dried and stored. With this, it is possible to infer that the producer will be able to carry out the early harvest, removing the seeds from the field in order to avoid that they are exposed to abiotic and biotic factors of the agroecosystem. Storage in a cold and airtight environment favors the quality of the seeds over the storage time.