| On the basis of Sanmenxia tobacco-growing areas, the flue-cured tobacco quality and climate conditions were analyzed. And by applying membership function and estimating weight values for each index by using the method of principal component analysis, climate feasibility were comprehensively evaluated. Climate feasibility index (CFI), appearance quality index (AQI), physical property index (PPI) and chemical components usability index (CCUI) of flue-cured tobacco were proposed and estimated. Mineral components, neutral aroma components and sensory quality in flue-cured tobacco leaves were analyzed in Sanmenxia tobacco-growing areas, the influences of climate factors on contents of chemical components in flue-cured tobacco leaves were also studied. The main results were as follows:1. Based on flue-cured tobacco samples from Sanmenxia main tobacco-growing areas, appearance qualities, physical properties, main chemical components, mineral components, neutral aroma components and sensory qualities of flue-cured tobacco leaves were analyzed. The tobacco leaves in Sanmenxia tobacco-growing areas had distinguishing features of high appearance quality with orange or lemon color, ripe or mellow, open, medium, uniform, oily, little, moderate. Physical property overall was good; embedded substances were high; processing performance was good. The contents of total sugar, reducing sugar and TS/Nic were high; main chemical components usability basically reached the level of the high quality flue-cured tobacco. Mineral components as Fe, Mn, Ca and Cu had more unbalanced distribution. Total neutral aroma components were 866.84μg·g-1; browning reaction products were high.2. Appearance qualities, physical properties, main chemical components, mineral components, neutral aroma components and sensory qualities of flue-cured tobacco leaves were analyzed at 4 main tobacco-growing areas of Sanmenxia. The comprehensive evaluation of appearance qualities, physical properties and main chemical components was accomplished. Color, maturity, body, structure, oil, color intensity showed that Lushi and Lingbao scored higher than Shanxian and Mianchi, significant differences (P<0.05) in color were observed among different areas. Appearance quality index (AQI) of different tobacco-growing areas showed that the trend of Lushi (0.801)>Lingbao (0.761)>Mianchi (0.736)>Shanxian (0.708). Significant regional variations of tensile breaking strength of tobacco leaves produced at 4 main tobacco-growing areas of Sanmenxia were observed: tensile breaking strength of tobacco leaves from Mianchi (2.20N) was significant higher than those of tobacco leaves from other counties and cities. Physical property index (PPI) of different tobacco-growing areas showed that the trend of Lingbao (0.745) >Shanxian (0.724) >Lushi (0.711)>Mianchi (0.701). Reducing sugar, K, Cl, TS/Nic and K/Cl had significant difference among different areas. Chemical components usability indexs (CCUI) of different tobacco-growing areas showed that the trend of Lushi (0.712)>Mianchi (0.648)>Shanxian (0.633)>Lingbao(0.604). CCUI of tobacco leaves from Lushi was significant higher than those of tobacco leaves from other counties and cities. Phosphorus content of tobacco leaves from Shanxian was significant higher than those of tobacco leaves from Lushi, Lingbao and Mianchi. But Phosphorus content of tobacco leaves had no significant difference among Lushi, Lingbao and Mianchi. Contents of phenylalanine and cembrane had significant difference among 4 areas. Indexes of sensory qualities had no significant difference among 4 areas. Smoking total scores showed that the trend of Lingbao(75.64)>Lushi (74.86)>Shanxian (74.59)>Mianchi (73.82).3. Main chemical components from main tobacco-growing areas of Sanmenxia tobacco-growing areas were analyzed at different grades and cultivars. And main chemical components from 4 main tobacco-growing areas were also analyzed at the same grade or cultivar. From the bottom to up, total N and nicotine increased, however, K, TS/Nic, N/Nic and K/Cl showed a rather contrary tendency. Contents of K, Cl, and N/Nic had significant difference among different cultivars.Significant regional variations of content of K in lower leaves were observed: content of K in lower leaves from Lushi was significant higher than those in lower leaves from other 3 areas. Contents of main chemical components in middle leaves had no significant difference among 4 areas. Content of K, N/Nic in upper leaves had significant difference among 4 areas. Contents of main chemical components in Yunyan85 had no significant difference among 4 areas. Content of K, N/Nic in Yunyan87 had significant difference among 4 areas. Content of reducing sugar in Zhongyan100 had significant difference among 4 areas.4. Based on climate data for four counties (cities) of Sanmenxia tobacco-growing areas, climate status were analyzed. Coefficient of variation of average temperature in April or May was larger than those in other months during filed stage. Total precipitation was unstable during filed stage. Coefficient of variation of total sunlight hours in August or September was larger than those in other months during filed stage. Coefficient of variation of air humidity in April, May or June was larger than those in other months during filed stage.Average temperature of Sanmenxia tobacco-growing areas was 23.63℃during filed period which was higher than overseas. Accumulated temperature of≥10℃and sunlight hours during field period were enough. Total precipitation during root extending stage (83.11mm) and total precipitation during vigorous growth stage (102.82mm) were relatively lower than overseas, but total precipitation during maturing stage (201.23mm) was more than overseas. Air humidity during filed period was relatively lower than overseas. It showed the warming trend of average temperature during vigorous growth stage (0.015℃/a)>average temperature during root extending stage (0.007℃/a)>average temperature during maturing stage (0.006℃/a) and the decreasing trend of total precipitation during maturing stage (-0.984mm/a)>total precipitation during root extending stage(-0.231mm/a)>total precipitation during vigorous growth stage (-0.114mm/a). Total sunlight hours during field period decreased by -1.519h/a. Air humidity during field period increased by 0.057%/a.5. Based on climate data for four counties (cities) of Sanmenxia tobacco-growing areas, climate factors and climatic indexes during field period were contrasted; besides, climate feasibility indexes were analyzed. Average monthly temperature and average monthly air humidity during field period had significant difference among 4 areas. Total monthly precipitation during field period had no significant difference among 4 areas. Total sunlight hours in April, May, June or September had significant difference among 4 areas.The warming trend of temperature indexes during field period was most obvious in Mianchi, but temperature indexes during field period slightly decreased in Lushi. Rainfall indexes during field period tended to decline in Shanxian. Sunlight hours during field period slightly tended to an increase in Lushi with the decrease in Lingbao, Shanxian and Mianchi. Air humidity during field period reduced in Mianchi, while it generally increased in Lushi, Shanxian and Lingbao. Temperature indexes, accumulated temperature of≥10℃, sunlight hours and air humidity during field period had significant difference among 4 areas. The climate feasibility index (CFI) for Sanmenxia tobacco-growing areas was high. The CFI for Lushi (0.858) was highest but it seems to be the opposite for Shanxian.6. By applying stepwise regression analysis, the effects of climate indexes on chemical components of different positions in tobacco leaves were studied and the best regression equations were established. The results indicated that: different climate factors had different influence on chemical components of different positions in tobacco leaves. On the whole, contents of reducing sugar, total nitrogen, K and N/Nic in lower leaves were significantly influenced by sunlight hours and air humidity during field period. Therefore, improving light intensities and increasing air humidity could be helpful for decreasing reducing sugar and increasing potassium, total nitrogen contents and N/Nic, and could also improve the balance of chemical components in lower leaves. Average temperature during root extending stage had significant negative effect on K content of different positions. Accumulated temperature of≥10℃had significant positive effect on K content in lower leaves, and chlorine content in middle and upper leaves, but had significant negative effect on K/Cl in middle and upper leaves. Total precipitation during vigorous growth stage had significant negative effect on total sugar content in middle and upper leaves, and had significant positive effect on total nitrogen content in middle leaves and K content in upper leaves.
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