Electrical Conductivity Test for Maize Seeds Stored at Low Temperature.

Electrical conductivity test is recommended to evaluate vigor of pea seeds and suggested for soybean. However, some cares must be taken for this test, especially when conducted for seeds stored at low temperature. As observed for soybean seeds the EC test does not show reduction of vigor of soybean seeds stored at low temperature. Thus, the present work was carried out in order to verify the effect of the rest time at higher temperature, before imbibition, on the electrical conductivity results of maize seeds stored at low temperature (10°C and 60% of air relative humidity). Five seed lots with similar germination levels were used. The laboratory analysis (seed moisture content; germination and vigor: accelerated aging, cold and electrical conductivity tests) were performed initially and repeated periodically after four, eight, 12 and 16 months of storage. Since the second evaluation (four months of storage) a new variable was added to the electrical conductivity test, denominated rest time of the seeds, used between the removal of the seeds from the cold chamber and the beginning of the imbibition for the electrical conductivity test. Rest time periods of zero, six, 12 and 24 hours were used, at two temperatures, 20 e 25 to 30°C (laboratory environment), aimed to verify, in this way, the effect of these periods and temperatures on the results of the electrical conductivity throughout of the storage periods at low temperature. Maize seeds showed increases of the electrical conductivity values throughout the storage period in all rest time used. Rest temperatures of 20 and 25 to 30°C caused no significant changes in the results of electrical conductivity. The rest time of 12 and 24 hours were the most indicated for maize seeds.