Abstract: Tobacco seeds of MS Yunyan 87 and MS K326 were primed with gibberellin(GA3)，then coated into pelleted seeds．The effects of priming temperature，priming time and GA3 concentration on the vigor of pelleted seed and seedling
quality were investigated when pelleted seeds were germinated under 25℃ and 10℃ ．The results showed that when pelleted seeds were germinated under 25℃, the priming treatment of 100 mg／L GA3 under 25℃ and 20℃ for 36 hours were better than other treatments．The gemination index were increased by 18．58％ and 27．91％, vigor index were increased by 30．58％ and 29．98％，average germination time was shortened by 0．69 d and 0．85 d，respectively．The seedling length of MS Yunyan 87 was increased by 0．23 cm, seedling dry weight of MSK326 was increased by 0．29 g as compared to the contro1．When pelleted seeds were germinated under 10℃, the treatment with 100 mg／L GA3 under 25℃ for 24 hours was better for MS Yunyan 87 than others, whose germination index was increased by 18．05％ and germination time was shortened by 1．84 d．Meanwhile，the treatment with 50 mg／L GA3 20℃ for 24 hours was better for MSK326，whose germination index was increased by 14．58％, germination time was shortened by 1．55 d．The results indicated that suitable GA3 priming treatment could enhance the pelleted seed vigor and seedling quality of tobacco，and enhance the chilling resistance
of pelleted seeds．

Key words: tobacco, gibberellin, priming, pelleted seed, seed vigor, seedling quality