Methodology for tetrazolium in cowpea seeds

The objective of this study was to determine the most efficient method for the evaluation of the physiological quality of cowpea (V. unguiculata) seeds by the tetrazolium test. We evaluated two seed lots of two cowpea cultivars, BRS Guariba and BRS Novaera. The tetrazolium test was performed for each batch of seeds and cultivating, which underwent tetrazolium solution at concentrations of 0.075%, 0.25% and 0.5% for 3-4 h in BOD incubator at 35°C in absence of light. The seeds were evaluated for uniformity and intensity of color presented by the tissues, being classified as: weak staining, suitable staining or strong staining. To evaluate the efficiency of the tetrazolium test, seeds of both cultivars and their lots were submitted to the germination and vigor tests. The mean values found in the tests were compared by Tukey test (p <0.05) and calculated the simple correlation coefficients of Pearson (r). It was observed that the tetrazolium is effective to classify the force of cowpea seeds under subsequent immersion in tetrazolium solution at a concentration of 0.075%, for a period 4 h at 35°C.