RESPONSE OF FLUE-CURED TOBACCO CULTIVARS NC 71 AND NC 72 TO SEED PRIMING: I. LABORATORY EVALUATIONS OF LIGHT AND TEMPERATURE EFFECTS ON GERMINATION RATE AND SYNCHRONY

Abstract Seed priming is frequently used in the tobacco seed industry to increase seed germination rate and uniformity and to overcome temperature imposed dormancy. However, it is not known if all seedlots respond equally to priming. This research was conducted to evaluate the influence of temperature, light, and priming on two widely-planted flue-cured cultivars. Experiments were conducted in 1999 and 2000 using the flue-cured tobacco cultivars NC 71 and NC 72. For each cultivar and year, primed and non-primed pelleted seeds from the same seed lot were used. Seeds were germinated at constant 20°C, and alternating 30/20°C, 30/15°C, and 23/20°C in both light and dark environments. The days required to reach 90% germination (D90) and a modified index of synchrony (ISM) were determined. In 1999, priming decreased the rate of germination (higher D90) and reduced ISM for NC 71, but had no effect on speed or uniformity of germination of NC 72 compared with non- primed seeds. Germination of primed seeds of both ...