The Effects Of Flue-cured Tobacco Varieties And Its Developmental Characteristics On Tar Delivery

Tobacco tar delivery has the quantitative genetic characteristics, therefore, screening low-tar tobacco varieties with regional adaptability is an important foundation for the development of low-tar tobacco leaf materials. Northeast tobacco growing areas produce the typical high-quality low-tar tobacco leaves. Under that ecological conditions, screening adaptive quality low-tar tobacco varieties is of great significance for the development of low-tar tobacco materials. The research has studied the contribution of varieties and ecological conditions to tobacco tar delivery in northeast tobacco growing areas and researched on low-tar tobacco breeding and the effect of growth and development characteristics on tar delivery in Mudanjiang. This paper was designed to provide further theoretical reference for the low-tar breeding. The main results are as follows:1、This study shows that the contribution of varieties to tar delivery is far greater than that of ecological conditions, but ecological conditions show significant influence on the tar delivery by varieties. Flue-cured tobacco tar delivery is mainly influenced by varieties and interaction between varieties and ecological conditions. So screening suitable low-tar tobacco varieties is the focus of the development of low-tar tobacco in northeast tobacco growing areas and followed is the appropriate regional distribution of varieties. Difference in the main effect of ecological conditions on tar delivery is not significant, and the main effect of varieties shows extremely significant difference.2、In2011, the difference of flue-cured tobacco tar delivery between different varieties was confirmed by the multi-varieties test in the same place. The difference between tobacco parts is greater than the difference between varieties and the middle leaves has good representative. So the analysis of the tar delivery is based on the middle leaves. RG17,82-3041, zhongyan98, Coker139and CV87were the low-tar varieties in2011and CF220and Iongjiang911in2012.3、 On the basis of2011and2012experiments, effects of growth and development characteristics on tobacco tar delivery have been studied. By studying the correlation between the agronomic traits and tar delivery, shape evaluation index of tar delivery has been initially established. The tobacco varieties with thicker stem girth,larger length and width of maximum leaf have higher tar delivery, while tobacco with more number of reserved leaf in mature stage belong to low-tar varieties. The discrimination index is a preliminary understanding, needing further verification and analysis.4、 Comprehensive analysis of the relationship between chemical composition and tar delivery showed that the contents of total sugar and reducing sugar were higher in Heilongjiang province and has a positive correlation with tar delivery. Starch and lignin had significant positive correlation with tar delivery, while cellulose had non-significant positive correlation with tar delivery. K and Cl have greater influence on tar delivery. With the improvement of K content, tar delivery is reduced. When the Cl content less than0.08%, tar delivery was negatively correlated with C1content,and when above0.08%, tar delivery was positively correlated with Cl content.5、 The effects of physical indicators on tar delivery is mainly reflected in the filling value, leaf density and single leaf weight. The tar delivery was significant negatively correlated with filling value and significant positive correlated with leaf density and single leaf weight.6、Through the observation of the leaf structure in the process of tobacco growth and development, we found that leaf thickness and spongy tissue thickness experienced the process of ascending firstiy and then descending in the whole growth period,but little change in the palisade tissue thickness. In mature period,irregular leaf structure and the more pores had a larger effect on tar delivery. Varieties,such as0408and Longjiang911with thicker blade thickness and sponge tissue thickness and thinner stockade tissue thickness,was higher in tar delivery. While varieties, such as NC89and zhongyan98with thinner blade thickness and sponge tissue thickness and thicker palisade tissue thickness,was lower in tar delivery.In summary, Varieties is the main factor influencing the tar delivery in northeast tobacco growing areas. Based on two years’ tests,7varieties have been discovered from23varieties and the effect of growth and development characteristics on tar delivery has been analyzed. Agronomic traits is of some reference value for discriminant to low tar varieties. Chemical, physical index and leaf structure changes have some effects on tar delivery.