| Tabacco is a very important economical crop, and its product is a special food and maybe the most widespread genussmittel in the word. China is one of countries that produces andconsumes the most tobacco. But, in fact, the qualities of the cured leaves and tobacco productare relatively poor in comparison to other nations, the tobacco product needs to be improvedin safety, aroma and flavor as well as taste. The contents of chemical components in tobaccoleaves affect the safety, aroma, flavor and taste, while tobacco varieties are the base andinternal factor of the chemical components in tobacco leaves. So, the breeding of high qualitytobacco varieties is the crucial work of producing high quality tobacco product. At the sametime, the genetic diversity of tobacco varieties is the forceful guarantee of breeding. For thesereasons, we chose some tobacco cultivars basing on the genetic diversity analysis of tobacco,and analyzed the contents of main quality components in these cured tobacco leaves. As theresult, we obtained the data related to the quality and harmful components of differenttobacco varieties. These were laying a foundation for the future work about breeding highquality tobacco cultivation and improving the quality of tobacco products.Simple sequence repeats (SSR) and microsatellite-anchored fragment lengthpolymorphism (MFLP) molecular marker techniques were used to detect polymorphisms forgenetic diversity analysis among94tobacco varieties. The result showed that the geneticsimilarity for these varieties ranged from0.55to0.96. Based on the polymorphic data,94tobacco cultivars were classified into7groups by UPGMA method and4populations in thepopulation structure analysis. On this basis,21representative tobacco varieties that were inlarge genetic differences were chose.The contents of tobacco-specific N-nitrosamines (TSNA) in cured tobacco leaves affectthe safety of tobacco produce. The four tobacco-specific N-nitrosamines (TSNA), includingN′-nitrosonornicotine (NNN), N′-nitrosoanatabine (NAT), N′-nitrosoanabasine (NAB) and4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK), in21kinds of cured tobacco leaveswere determined separately by liquid chromatography–mass spectrometry (LC-MS) in thispaper. The result showed that the contents of these TSNAs were obviously differentsignificant, and the content of NAB was the lowest, it couldn't be detected in some leaveseven. The contents of the4TSNAs in different leaves were different too, and the contentvariation of NNN was maximum. In these3types of tobacco including burley tobacco,flue-cured tobacco and sun-cured tobacco, the content of TSNAs in burley tobacco was thehighest, and the contents of NNN and NAB were higher than others in it. The content of TSNAs ranged from38.58to780.5ng/g in flue-cured tobacco, and the content of NNN washigher, there was a special flue-cured tobacco variety (118-3) that the content of NNN in washigher than burley tobacco even. In these tobacco varieties, only were the contents of TSNAsin2flue-cured tobacco vareties (C48and G28) lower than50ng/g. In these four kinds ofTSNAs, the relativity between NAT and NAB was the strongest, while the relativities amongNNN and the others were very weak.The contents of total sugar, reducing sugar, nicotine, total nitrogen, protein, chlorine andpotassium in cured tobacco leaves affect the aroma, flavor and taste of tobacco produce.These7chemical components in19kinds of cured tobacco leaves were determined in thispaper. The result showed that the contents of total sugar and reducing sugar in burley tobaccowere much less than these in flue-cured tobacco and sun-cured tobacco, while the contents ofchlorine and potassium were little higher. In16kinds of flue-cured tobacco leaves, thecontents of total sugar, reducing sugar and chlorine were all very low, while the contents oftotal nitrogen, protein and kalium were just in the best range. There was no flue-cured tobaccothat the contents of7kinds of important chemical components in were all in the best range,but the quality of Xujin-1and KE1were maybe the best in comparison to others. |
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