Taking K326 as experimental material,the effects of different nitrogen application and planting density on the yield and quality of flue cured tobacco were studied. The results showed that, the yield and the production value were highest when the nitrogen application amount was 97.5 kg/hm2. The yield and the production value showed a downward trend with the increase of nitrogen and planting density. At 850 m and 976 m above sea level, the yield and production value increased firstly and then decreased with the increase of planting density,and the yield and the production value were highest when the planting density amount was 15 150 plants/hm2. At an altitude of 1 057 m,the yield and production value showed a tendency to decline firstly and then raised with the increase of planting density. The difference reached a significant level, and the yield and the production value were highest when the planting density amount was 13 890 plants/hm2. With the increase of nitrogen application, the content of nicotine and chlorine increased, and the total sugar decreased. With the increase of planting density, potassium content increased and nicotine content decreased. According to the experimental conclusion, it was suggested that in the tobacco production in Xianfeng County of Hubei province,the nitrogen application amount of 97.5 kg/hm2 was appropriate, and the planting density should be set at 13 890 plants/hm2 between 15 150 plants/hm2.

Objective]To provide a scientific basis for variety certification, extension and rational layout.[Method]The national tobacco vari-ety regional test was conducted in Xianfeng point in 2015 using K326, Yunyan 87.[ Result] The varieties with better agronomic traits were CF228, YN119, HB030 and Guiyan 8, followed by Yunyan 207, Guiyan 13, Guiyan 5, 09011.The varieties with better economic characters were CF228, YN119, HB030, followed by Yunyan 207, Guiyan 5, 09011, Guiyan 13.The varieties with better quality traits were HB030, Yunyan 207, Guiyan 8, CF228, followed by YN119, Guiyan 5, Guiyan 13, 09011.The varieties with better comprehensive economic charac-ters and quality were CF228, HB030 and Guiyan 8.The total sugar contents of Guiyan 8, Guiyan 5, Guiyan 13, YN119 were low, the potas-sium content of YN119 was low,the intrinsic chemical composition of the other tested varieties was compatible.Appearance quality of 09011, Guiyan 8 was equivalent to K326 and Yunyan 87, appearance quality of the other strains was poorer than K326 and Yunyan 87.In addition to Guiyan 8 and Guiyan 5,the overall performance of the other tested varieties were equivalent to the control species.[Conclusion]HB030, CF228, Guiyan 8 have better comprehensive traits.

In order to identify the influencing factors on flue-cured tobacco quality characteristics in typical ecological areas in Hubei Province, Measurement was conducted at 12 sites in Lichuan, Xuanen, Xianfeng, Fang and Xingshan counties of Hubei Province. Value of output, rate of first class tobacco, the chemical components of flue-cured tobacco, smoking quality indices and their determining factors were analyzed during 2011 and 2013 years. The results indicated that there were significant differences in the value of output and rate of first class tobacco among the five counties. Both remained leaf number and output value were significantly and positively related to amount of nitrogen fertilizer and potassium fertilizer applied. The rate of first class tobacco was significantly and positively related to basal application of nitrogen and phosphorus fertilizers. Aroma quality was significantly and positively related to content of total sugar and reducing sugar, but negatively related to nicotine content. Aroma quantity was very significantly and positively related to total nitrogen content, negatively related to nicotine content, and very negatively related to ratio of nitrogen to nicotine. Chemical components and smoking quality of flue-cured tobacco in these five counties changed greatly. Flue-cured tobacco in Lichuan, Xuanen and Xianfeng counties had the nut-like flavor and Wuling mountain local specialty. Flue-cured tobacco in Fang and Xingshan counties had bean-like flavor of Qingba mountains local specialty.

A regional test of eight tobacco varieties was conducted in Xianfeng county,Hubei province in 2010 using K326 as control.The results showed that for the economic traits,YN110,YN105,HB029 and Y892 were better than the control;Qianyan No.1 and Qianyan No.7 were the same as the control.QL-3 had higher rate of high-quality tobacco and higher average price than the control;but the yield and output value were lower.CF221 was worse than the control on economic traits.Qianyan No.7 and YN105 were susceptible to brown spot disease;while the others had strong disease resistance.The appearance quality of YN105,Qianyan No.7 and QL-3 was better than the control;Y892 had poorer appearance quality than the control;the appearance qualitiy of other varieties was the same as the control.Qianyan No.1,Qianyan No.7 and YN110 had better sensory quality than the control;and the sensory quality of other varieties were the same as the control.The chemical components of the 8 tested varieties were appropriate and coordinate.YN105,YN110 and HB029 had excellent comprehensive traits.

A grey relational analysis of nine new flue-cured tobacco lines for seven important traits was performed in the provincial regional comparison trial of Hubei province.The objective of this study is to provide a scientific reference for breeding new lines with high quality.The results showed that there were identical results between equal weight correlation degree and weighted correlation degree.Among nine new lines,Yunyan97 and A7 significantly performed better than K326(CK),which was coincided with actual performance.As a consequence,the two new lines demonstrated high production potentials and should be paid more attention in further trials.