Evaluation of seed physiological quality has been routinely based on standard germination test. Vigor tests have shown more sensitivity in detecting the potential performance of seedlots in the field (direct seeding) or greenhouse (transplant production) conditions. Five seedlots of ‘Everglades’ lettuce were tested to determine the efficiency of some vigor tests and their relation to germination under adverse temperatures. Seeds were submitted to the germination test (20°C), germination first count, accelerated aging (41°C/48 h), primary root length, germination under adverse conditions (10° and 35°C) and seedling emergence under greenhouse conditions. Seed germination at 20°C was higher than 80% thus showing similarity among the seed lots evaluated. The germination first count and primary root length tests detected significant differences among seedlots. The accelerated aging test was the most efficient in ranking seedlots with different seed vigor. This test and the germination first count and the primary root length may be used for selecting lettuce seedlots for sowing under high temperature conditions.
Lactuca sativa; termoinhibition; dormancy; stand establishment
