Análise digital na interpretação do teste de tetrazólio em sementes de arroz de sequeiro

Abstract

The Seed physiology is one of the main requirements that influence the nature of agricultural productivity. Within the traditional tests used to assess vigor, stands out the tetrazolium test, which makes it possible to analyze the vigor and viability of the seeds as from on the coloration of living tissues as an indicator of embryonic metabolic operation. Despite that, this test needs from the interpretation of human technical visual analysis, which is largely subjective, which can compromise the systematization of results. Given the exposed, the objective of this work was to establish and validate methodologies for evaluating the viability of upland rice seeds (BRS A502) using by the tetrazolium test, through digital image analysis. Human visual analysis was used, assisted by digital scanned images, correlating the results for a better determination of viability classes for rice. The experiment was conducted in the Laboratory of Phytotechnics from the Federal University of Alagoas (UFAL), at the Engineering and Agricultural Sciences Campus (CECA), in the municipality of Rio Largo - AL. Rice seeds were placed in two solutions of 2,3,5-triphenyltetrazolium (0.05 and 0.075%) in for three periods exposure times (1:30, 2:30 and 3:30h), in a completely randomized design, in a 2x3+1 factorial arrangement, with four replicates of 25 seeds each. As preconditioning between paper roll, the longitudinal cutting method to the embryonic axis, under a temperature range of 25°C. After treatment with salt the seeds were scanned, the generated images were evaluated and the seeds classified according to the different patterns of red tones present in the live embryos. The results were expressed as a percentage of live and vigorous seeds, with the concentration of 0.075% in 2.5 hours presented higher germinative viability, differing significantly from the other periods of 1.5 and 3.5 hours. At a concentration of 0.05%, lower results were identified. The proposed methodology proved efficient for evaluating the feasibility of rice seeds rice by tetrazolium test, a concentration of 0.075% is recommended for a coloring time of 2.5 hours. The vigor classes (1 to 4) have proven to be a practical and reliable method for distinguishing the physiological potential of seeds.