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 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