Field experiments were carried out to study the effects of plant growth regulator on the yield and quality of flue-cured tobacco cultivar Jiyan 9 under the condition of different nitrogen application rates.The results showed that the treatment of applying 72.45 kg/hm2 nitrogen and spraying plant growth regulator No.2 had the best effects on improving the economic characteristics,content of aroma constituents and smoking quality of tobacco;the treatment of applying 64.95 kg/hm2 nitrogen and spraying plant gr...