Research has emphasized the relationship of laboratory germination and vigor to seedling emergence and stand establishment, but information relating seed vigor to plant performance is less available. The reliable procedures to evaluate onion (Allium cepa L.) seed vigor and decided the differences between seed physiological potential influence plant performance in field conditions were identified in two experimental years. Six seed lots of Petroline cultivar were evaluated for germination and vigor, in laboratory, and field seedling emergence. Field experiments were performed by direct sowing and transplant systems and all treatments had equal stand for both cropping systems. Results demonstrated that saturated salt accelerated aging (41:C/72h) and controlled deterioration (24% moisture content/45:C/24h) were the most valuable vigor tests for onion seeds. The potassium leachate and seedling vigor classification tests were also efficient but less sensitive to vigor differences among seed lots. Initial plant development during the first 56 days, as measured by plant height and dry matter accumulation, was affected by seed vigor mainly when differences on seed physiological potential became wider as a result of the storage period. Influence of seed vigor did not persist during plant vegetative growth and did not affect yield. The use of high vigor seed lots is justified to ensure adequate stand establishment under different environmental conditions.
Allium cepa; seed physiological quality; stand establishment; plant performance
