Electrical Conductivity Test For Predict Sunflower Seeds Vigor
There is no standardised test for predicting sunflower seed vigor. The electrical conductivity test (EC) produces faster results. Before a test is standardised requires a validation process to ensure reliable and reproducible results. The aims were to analyse the repeatability and reproducibility of EC on sunflower seeds without pericarp and the association between EC and field emergence. Seeds with high (lots 3 and 4), intermediate (lots 1 and 5) and low vigor (lots 2 and 6) were distributed in four laboratories. In each laboratory, EC was measured after 24 h at 3, 6, 9, 13 and 19 months of storage and expressed as μS.cm-1. g-1. Field emergence was evaluated by diverse formulas including chronological days and thermal time. After 19 months, lots 3 and 4 presented high vigor (40.0 at 55.23 μs cm-1 g-1). Lots 1, 2, 5 and 6 ranged between 61.27 and 82.57 μs cm-1 g-1 indicating an intermediate vigor. Significant correlation coefficients (r = -0.67 and -0.72) were obtained between EC and percentage of emerged seedlings in the field and daily mean emergence, slightly improving with the use of thermal time. The EC test differentiated sunflower seed vigor through reproducible and repeatable results.