Adaptation of the tetrazolium test for assessing the seed quality of Crateva tapia L.

ABSTRACT: In the seed sector, demand for quick decisions is growing, especially for slow-germinating species such as Crateva tapia L., so the tetrazolium test stands out as a method capable of evaluating seed viability and vigor. The objective was to adapt the tetrazolium test to evaluate the viability and vigor of C. tapia seeds. A completely randomized design was used, with a 2 x 4 x 5 factorial scheme (two lots of seeds, four concentrations of 2, 3, 5 triphenyl tetrazolium chloride salt (0.025; 0.050; 0.075 and 0.1%) and five times of immersion (90; 180; 270; 360 and 450 minutes). The initial characterization of the lots was carried out (physical and physiological quality) and different concentrations and immersion periods were applied, classifying them into class I (viable and vigorous embryos), II (viable seeds) and III (non-viable). Lot I showed greater quality and vigor, confirmed by the 0.075% tetrazolium test for 270 minutes. The concentration of 0.1% made it difficult to interpret the results. Color varies between light pink and white, with the 0.075% tetrazolium salt concentration for 270 minutes of immersion being recommended to evaluate the viability of C. tapia seeds.