Effect of acetic acid treatments and storage on the quality of lettuce (Lactuca sativa L.) seeds

Seedborne fungi negatively affect the quality of lettuce (Lactuca sativa L.) seeds and they are impact on their storability. Using the acetic acid can be an alternative to chemical treatment. Seeds were soaked for 30 minutes in a solution of acetic acid at concentrations of 0.25%, 0.5%, and 2%. Untreated seeds, seeds soaked for 30 minutes with distilled water and seeds treated with Dithane NeoTec 75 were controls. Seeds germination, vigour and seed health before and after 18 months of storage at 4 and 20 °C were tested. Before storage the acetic acid solution at concentrations of 0.25 and 0.5% significantly decreased number of dead seeds and increased germination at first and final counts, 2.0% solution worsened germination and vigour of seeds of both samples. Generally acetic acid solutions limited occurrence of fungi. Seeds stored at a lower temperature (4 °C) were characterized by significantly higher percentages of total germinating seeds (Gmax) and percentage of germination at first and final counts. Deterioration of the germination at first and final counts was found only after soaking the seeds in acetic acid solution at a concentration of 2%. Acetic acid solutions at concentration 0.5 and 2.0% effectively reduced occurrence of Alternaria alternata.