Adverse environmental conditions during tobacco seedling growth have been associated with early axillary shoot (sucker) formation on transplanted field plants. Therefore, the influence of temperature and light regimes on development of tobacco float seedlings from two contrasting cultivars grown in environmentally controlled cabinets was investigated. Modifications of photoperiod regime during seedling development seemed not to affect sucker formation. Plants grown with 8-h photoperiod had the same incidence of sucker development as plants grown in 8-h photoperiod but with low irradiance night interruption. In contrast, cold temperatures associated with either short or long photoperiod induced a larger number of suckers with a greater growth per plant. Minimum temperature during dark period was most important than maximum/minimum temperature extremes on initiating sucker formation. A deeper mechanical field transplanting was not sufficient to completely reduce the number of emerging suckers, but it caused a significant suppression of sucker length. Overall, significant cultivar differences were measured for sucker formation. We considered the dynamics of early sucker growth in tobacco to be largely determined by low night temperatures during the seedling development in the float system or prior field transplanting.