Analysis Of Four Flue-cured Tobacco Cultivars And Their Three Variant Strains With AFLP Molecular Markers

In China, the genetic variation of tobacco species is rich, but the genetic diversity within species is low. The superior quality of natural variant strains has a great significance for breeding tobacco and improving economic benefit. Researching the genetic relationship between the natural variation strains and the cultivars of tobacco can provide theoretical basis for tobacco breeding, and establish the foundation of further research its variation mechanism and the functions related mutant gene.Because of its high repeatability, simple, rapid and the high sensitivity, AFLP molecular markers has become the main means of researching tobacco germplasm genetic relationship between and breeding. In this research, we use AFLP molecular markers to analyze the genetic relationship between4common flue-cured tobacco cultivars and3variations in Yunnan province. The main results are as follow:(1) Five strong selective AFLP primer combinations have been screen out from100selective AFLP primer combinations, which are highly polymorphic and strong specificity. They can turn the7samples in separate and take a total of1156sites, including479polymorphisms site, the ratio of polymorphism is41.44%.(2) The results of genetic distance analysis show that, on the whole, the genetic distance among all materials was varied from0.3871to0.0442, average is0.1910, genetic differences is not significant, and genetic similarity is high. But the genetic distance among the3variant strains was varied from0.3684to0.1235, average is0.2538. The genetic differences is more significant, and the variability is higher between this3variant strains.(3) The results of UPGMA cluster analysis show that7samples divided into3groups: the first group consisted of N. tobacum cv. honghuadajinyuan and N. tobacum var. earlier flower honghuadajiayuan; the second group consisted of N. tobacum cv. yunyan85, N. tobacum var. later flower honghuadajiayuan and N. tobacum cv. k326; the third group consisted of N. tobacum cv. yunyan97and N. tobacum var. later flower yunyan97. It is the same with the results of genetic distance analysis. On the other hand instructed that, the genetic differences between N. tobacum var. later flower honghuadajiayuan and N. tobacum cv. honghuadajinyuan is bigger but littler with N. tobacum cv. k326and N. tobacum cv. yunyan85. It is thus clear that, there may be other sources of later flower honghuadajiayuan, is not directly by N. tobacum cv. honghuadaj inyuan.(4) The results of PCA analysis show that7samples divided into3groups too:the first group consisted of N. tobacum cv. honghuadajinyuan and N. tobacum var. earlier flower honghuadajiayuan; the second group consisted of N. tobacum cv. yunyan85, N. tobacum var. later flower honghuadajiayuan and N. tobacum cv. k326; the third group consisted of N. tobacum cv. yunyan97and N. tobacum var. later flower yunyan97. It is the same as the results of UPGMA cluster analysis. It is another way to show that compared with this two variant strains, the variation degree of N. tobacum var. later flower honghuadajiayuan is bigger. It is thus clear that, there may be other sources of later flower honghuadajiayuan, is not directly by N. tobacum cv. honghuadajinyuan.