Qualidade e potencial de armazenamento de sementes “para uso próprio” de soja

Abstract

The use of high quality seeds is one of the factors to establish high productivity. Often, rural producers make their own seeds and are referred to by legislation as “seeds for their own use”. In the Alto Uruguai region of the State of Rio Grande do Sul this practice is common. Thus, the objectives of this work were: to evaluate lots of seeds "for own use" in terms of moisture content, physical purity, germination and vigor; to verify the possible causes of the reduction of vigor in seeds; to verify the storage potential of the lots for use for sowing in the next harvest. For this, five lots of seeds "for own use" were used from the cities of Barão de Cotegipe, Entre Rios do Sul, Três Arroios and Severiano de Almeida. The experiments were carried out in the laboratories of the Federal University of Fronteira Sul, Campus Erechim, using a completely randomized design. The following variables were obtained: purity, moisture content, germination, first germination count, germination speed index (IVG), electrical conductivity (µS cm-1 g-1), tetrazolium (% vigor, % viability and % damage mechanical, humidity and stink bug), sodium hypochlorite test, and accelerated aging for 48 and 72 h. From the results presented in this work, it was possible to conclude that batches 1, 3 and 5 presented high purity values (greater than 99.5%), staying within the standard contained in the legislation. For germination and vigor tests, we would be working with the minimum that the legislation proposes. Only batches 1 and 5 analyzed showed a germination percentage of 80%, being the minimum germination that is sought for a quality seed. The lots presented a low vigor, factors that can limit the plant stand, as well as the physiological development and the productivity of the culture. We must take into account the harvest year, as it was an atypical year for a successful crop, adverse weather conditions made it impossible for producers to have higher quality seeds. Among mechanical, moisture and stink bug damage, the main cause of seed vigor loss was mechanical damage. Therefore, most seed lots “for own use” in the Alto Uruguai region have physical and physiological quality for sowing purposes. However, they have high levels of mechanical damage and only one lot could be stored for sowing in the next crop.