| Through the detection and analysis of the distribution characteristics of chemical components of flue-cured tobacco leaves, the quality of tobacco in Qinba flue-cured area of Shaanxi was discussed , it is expected to provide a basis for selecting excellent varieties and improving the quality of flue-cured tobacco leaves. From 2012 to 2017, 197 flue-cured tobacco samples were collected from key tobacco-growing counties in Qinba tobacco area of Shaanxi Province, and the content distribution characteristics of nicotine, total nitrogen, reducing sugar, total sugar, potassium, chlorine and starch in Shaanxi flue-cured tobacco were analyzed. The results showed that the coefficient of variation of chlorine and starch was much higher than that of other components. From the deviation value, it could be seen that the frequency distribution of chemical components in Qinba flue-cured tobacco basically belongs to the left deviation type. There were significant differences in each index between different years, and each index in 2012 was significantly higher than that in other years. There were significant differences in total nitrogen, reducing sugar, potassium content and nitrogen-alkali ratio among different varieties, in which the potassium content of Yunyan 97 was 2.21% and the reducing sugar content was 24.54%, which were significantly higher than those of the other four varieties. The ratios of total nitrogen, reducing sugar, total sugar, potassium and disaccharide were significantly different in different regions. The contents of nicotine, nitrogen, total sugar and potassium in different parts were significantly different. The concentration of nicotine, total nitrogen, reducing sugar, total sugar and potassium in tobacco leaves accorded with normal distribution, while nitrogen-alkali ratio and sugar-alkali ratio conformed to logarithmic normal distribution. The probability of nicotine, total nitrogen, reducing sugar and potassium in flue-cured tobacco conforming to international high-quality tobacco was 80.96%, 91.27%, 16.01% and 75.84%,respectively. Generally speaking, the overall quality in Qinba tobacco area in Shaanxi Province is good, especially the content of nicotine and total nitrogen is in line with the standard of international high quality tobacco, and the chemical composition coordination of Yunyan 97 is better than that of other varieties. According to the chemical composition characteristics of tobacco leaves in different tobacco areas,the technical measures should be taken to further improve their coordination. ; |
