Armazenamento de sementes de soja: efeitos do zinco na manutenção da qualidade fisiológica

Abstract

The present work aims to analyze whether seed treatment and foliar fertilization with the micronutrient zinc, in soybean, helps to maintain physiological quality during storage. The soybean cultivar NA 5909 RG was cultivated in the field with different combinations of Maxi Zinc® applications via foliar or seeds. The combinations of zinc applications in the field were: T1 – cultivation without seed treatment + without foliar application, T2 – cultivation with zinc seed treatment + without foliar application of zinc, T3 – cultivation without zinc seed treatment + with foliar application of zinc. zinc, T4 – cultivation with zinc seed treatment + with foliar application of zinc, where applied doses were 87.5 mL 100 Kg-1 in the seed treatment and 70 mL ha-1 in the foliar application. After harvesting, the seeds were transferred to the laboratory and stored at room temperature for 0, 60, 120 and 180 days. The determination of physiological quality was evaluated through four variables (germination {GERM – %}, accelerated aging {EA – %}, electrical conductivity {EC – μS.cm-1. g-1} and weight of a thousand seeds {PMS – g}). The assumptions of normality of errors and homogeneity of variances were verified using the Lilliefors and Bartlett tests. For the variables GE, EA and PMS, analysis of variance was performed in a 4x4 bifactorial scheme (four boron treatments X four storage times) (α=5%), with bifactorial interaction for GE and EA, thus, adjusting Regression equations for storage times for each of the treatment combinations applied. The PMS variable showed no interaction between the factors and no interference from storage, so Duncan's test (α=5%) was performed for the qualitative factor. As it did not meet the assumptions, the non-parametric Kruskall-Wallis test was used to evaluate the EC variable, followed by the Simes-Hochberg test (α=5%). It was concluded that storage had a negative effect for GE, EA and CE, since the highest indices were expressed at time 0 of storage. In addition, T1 was the best evaluated treatment through the variables GE, EA, PMS and EA, indicating that the application of zinc via seed treatment and via foliar fertilization did not preserve the physiological quality of the seeds during their storage.