Effects Of Number Of Remained Leaves And Harvesting Methods Of Upper Leaves On Yield And Quality Of Flue-cured Tobacco In Chenzhou

The number of remained leaves and the harvesting methods of upper leaves were the important factor affecting the yield and quality of flue-cured tobacco.As an important tobacco producing county in Hunan province,there was still a lack of standardized technical guidance for flue-cured tobacco planting in Jiahe Chenzhou.In addition,the supporting technology could not keep up with the renovation of flue-cured tobacco varieties,resulting in the instability of tobacco quality.Field experiment was carried out in Jiahe,Chenzhou of Hunan province in 2015-2016.Through the investigation of agronomic characteristics,economic characteristics and quality of flue-cured tobacco leaves,the effect of different number of remained leaves and upper 5~7 leaf harvesting method on the yield and quality of flue-cured tobacco was studied.The number of remained leaves and harvesting methods of upper leaves of Yunyan 99 in Jiahe Chenzhou was explored to provide the technology guidance for the improvement of the yield and quality of flue-cured tobacco and enhancement of market competitiveness were proposed.The results are as follows:1.The growth stages and agronomic characteristics of flue-cured tobacco were affected by the number of remained leaves.With the increase of the number of remained leaves,the growth period of flue-cured tobacco increased,the plant height increased,while the length and width of leaves decreased.The field uniformity of the number of leaves of 17 and 19 was better,with relatively harmonious length,width and area of leaves.2.The number of remained leaves and harvesting methods had a great influence on the appearance quality of the upper leaves of Yunyan 99.The number of remained leaves had significant effect on the length,width and thickness of flue-cured tobacco leaves.The harvesting method had significant effect on the weight and thickness of leaves.The interaction of the two factors had significant effect on the weight of leaves.From the point of view of the appearance quality,the interaction effect of 19 leaves remained and simultaneous harvesting of the upper leaves was the best.3.The number of remained leaves and the harvesting methods had a great influence on the chemical compositions of upper leaves.There were significant effects of the two factors on the ratio of sugar to nicotine,the ratio of nitrogen to nicotine and the ratio of potassium to chlorine.And there were significant effect of the interaction between the two factors on the ratio of sugar to nicotine and the ratio of nitrogen to alkali.With appropriate increase of the number of remained leaves,simultaneous harvesting of the upper leaves could significantly reduce the content of nicotine in the upper leaves and increase the coordination of chemical components.In this experiment,the chemical composition of flue-cured tobacco was in harmony and the nicotine content was lower with simultaneous harvesting of the upper leaves with 17 and 19 leaves remained.4.The number of remained leaves and the harvesting methods had a great influence on the chemical compositions of middle and lower leaves.With the increase of the number of remained leaves,the contents of nicotine and potassium in the middle and lower leaves were decreased,and the ratio of sugar to nicotine and the ratio of sugar to nicotine gradually increased.The increase of the number of remained leaves could decrease the ratio of potassium to chlorine of middle and lower leaves,while increased the ratio of potassium to chlorine of lower leaves.In this experiment,the chemical composition of middle and lower leaves was in harmony with 17 and 19 leaves remained.5.The number of remained leaves and the harvesting methods had a significant effect on the neutral aroma components of the upper leaves of flue-cured tobacco.With the increase of the number of remained leaves,the neutral aroma components increased first and then decreased.In this experiment,the neutral aroma content was higher with simultaneous harvesting of upper leaves with 17 and 19 leaves remained.6.The number of leaves and harvesting methods had some effects on the sensory quality of the upper leaves of flue-cured tobacco.The number of remained leaves had a great influence on the quality.When the number of remained leaves was 19,the smoking quality of upper leaves of flue-cured tobacco was the highest.The smoking quality would improve with simultaneous harvesting of upper leaves to some extent.In this experiment,the smoking quality was higher with simultaneous harvesting of upper leaves with 17 and 19 leaves remained.7.The number of leaves had a significant effect on the economic characteristics of flue-cured tobacco,and there was no significant effect of harvesting methods and the interaction between the two factors on the economic characteristics of flue cured tobacco.The output value,average price and the proportion of medium-grade and high-grade tobacco leaves were first increased and then decreased with the increase of the number of remained leaves.In this experiment,the economic characteristics of flue-cured tobacco were the best when 17 and 19 leaves were remained.Overall,simultaneous harvesting of upper leaves with 17 and 19 leaves remained could coordinate the chemical compositions of the leaves of the upper,increase the content of neutral aroma components,improve the appearance and sensory quality,and increase the economic benefits of flue-cured tobacco.