Evaluation of physiological and health quality of lettuce seeds

The evaluation of the seed's physiological potential is an important component of seed quality control programs to ensure satisfactory performance of seeds and there is a close relationship between this potential and seed sanitary quality. The aim of this study was to evaluate the physiological and sanitary quality of lettuce seeds. The study was performed at the Laboratory of Seed Analysis and at the greenhouse of the Department of Plant Science, at the Federal University of Pelotas (UFPel). Four lots of the cultivar 'Grand Rapids' were tested for the following features: initial and final moisture content (after accelerated ageing), germination rate, germination at high temperature, first count of germination, accelerated ageing with saline solution, accelerated ageing before electrical conductivity, electrical conductivity, seedling emergence rate, and sanitary condition. A completely randomized design with four replicates was used for all tests performed. Means were compared by Tukey test (P<0.05). Conclusions were that germination, first count of germination, accelerated ageing test and electrical conductivity tests showed little efficiency to discriminate between seed lots with quality differences. In addition, these tests just detected the lowest quality seed lot among the others. Similar classification in vigor levels were obtained by the germination test at high temperature and seedling emergence. The incidence of fungi associated with seeds of lettuce may interfere negatively in seed vigor and seedling emergence, and seed health testing should be performed to verify seed sanitary conditions.