Avaliação da viabilidade de sementes de amendoim do nordeste: pré-condicionamento e classes pelo teste de tetrazólio

Abstract

Peanut (Arachis hypogaea L.), a member of the Fabaceae family, is an oilseed that is important for both human and animal nutrition, and is also used in biofuel production. However, due to its high oil content, peanut seeds tend to be susceptible to environmental variations, losing their quality and reducing their viability. Given the above, the objective of this study was to establish a methodology to evaluate the viability of peanut seeds (BR1) using the tetrazolium test, to study two seed preconditioning methods, immersion periods and adequate concentration of the tetrazolium solution, and to determine specific viability classes for the BR-1 variety. The experimental design was completely randomized, in a 3x2 factorial scheme (three immersion periods in the tetrazolium solution x two concentrations), and four replicates of 50 seeds for each combination of period and concentration, totaling 40 experimental plots per seed preconditioning method. The cotyledons containing the embryonic axis were placed in 50 mL plastic cups in the 2,3,5-triphenyl tetrazolium chloride salt solution for immersion periods of 1.5, 2.5, and 3.5 hours, and at concentrations of 0.05 and 0.075%, in the B.O.D. incubator, in the dark at 30 °C. Subsequently, the seeds were washed in running water and evaluated one by one under a 6x magnifying glass. The results were expressed as a percentage of viable seeds. The concentration of 0.075% for 2.5h showed 93% viability, not differing significantly, however, from 0.075% for 3.5h, with 90% of viable seeds. At the concentration of 0.05%, lower viability results were observed. Thus, the concentration of 0.075% for 2.5 or 3.5h, with 93 and 90% of viable seeds, respectively, did not differ significantly in relation to the germination percentage of the control, which was 91%. And classes 1, 2, 3 and 4 represented, respectively, the vigorous, viable, non-viable and dead seeds. For a batch with 91% germination, it is possible to indicate up to four viability classes.