Onion Seed Germination as Affected by Temperature and Light

Producers need to know whether the germination rate will produce sufficient numbers of seedlings needed for field production of onion (Allium cepa L.). The influence of temperature (5.0, 7.5, 10, 15, 20, 25, 30, 35, or 40°C) and continuous light or continuous dark was tested for effects on percentage germination of normal, abnormal, or diseased seed; production of normal seedlings; and percentage of ungerminated solid and soft seeds of onion. Temperatures from 7.5 to 30°C generally assured a high germination percentage and a high percentage of normal seedlings. The most rapid germination occurred at 25°C in the dark. At 5, 35, and 40°C normal germination was only about 10%. The model from the Weibull function indicated that temperature influenced the time between the beginning of imbibition to germination. Onion seed exposed to temperatures between 10 and 30°C under field conditions could produce a high germination percentage, which should lead to development of normal seedlings.