Study On Tobacco Genetic Diversity And The Genetic Analysis Of Major Agronomic Traits In Flue-cured Tobacco

This research used 58 of SSR polymorphisms primers and 12 of SRAP primers, respectively 40 copies of flue-cured tobacco varieties (or lines) and 1 wild species of genomic DNA for genetic analysis, based on molecular genetic cultivars genomic DNA from molecular cluster analysis performed.Four flue-cured tobacco parents with different characters were crossed in full diallel mating system in order to evaluate the heterosis and combiningability of the 15 characters.The correlation analysis of parental DNA molecule genetic distance based on SSR and SRAP markers between heterosis and combining ability of flue-cured tobacco was investigated.The results of the study are as follows:(1)From the two kinds of molecular markers screened 70 polymorphism primers.70 pairs of primers amplified 487 bands, including 450 polymorphic bands(92.4%), each primer amplified 6.69 bands on average, each primer amplified polymorphism bands of article 6.43.By SSR date the GD between parents varied from 0.075 to 0.531,with the average of 0.246.The GD between N. sylvestris and yunyan97 was the maximum (0.531) and that between Narrow Leaf Orinoco and Hicks was the minimum(0.0750).58 of SSR primers amplified 302 bands, including 283 polymorphic bands,by each primer amplified 4.86 polymorphic bands, polymorphism was 93.7%.12 of SRAP primers amplified 185 bands,including 168 polymorphic bands,with an averaged of 14.0 polymorphic bands(90.8%).(2)Cluster analysis was calculated by UPGMA clustering method with MEGA6.0 sofrware.The dendrograms was constructed based on the SSR data.Clustering analysis of 41 tobacco germplasms can be divided into three groups(one of including N. sylvestris from Argentina,one of two cultivars including ZhongYanl4 and ZhenXiongKaoYan from China and 38 cultivars from America and China)at the levels of Ligd=0.15 by the first classification.The accessions could be clustered into 3 groups.As well as the groups of the classifications were basically based on the principles of regional divided into category.And showed that molecular markers of 41 tobacco germplasms clustering analysis result is scientific and reliable.(3)By SSR and SRAP molecular marker computing GD between 41 of tobacco germplasm, By the local, between China and USA the average genetic distance of flue-cured toba(?)co was 0.250、0.244. The flue-cured tobacco germplasm genetic were highest similar of China and the United States. Genetic diversity analysed, The flue-cured tobacco germplasm genetic diversity index was 0.325 and 0.346. The level of genetic diversity were the same.(4)Analysis of the six combinations showed that nearly two-thirds of combinations at yield related traits in the heterosis are more than 15.6%.Six combinations total nicotine content in the quality traits were showed a significant negative transgressive advantage.TS/TA advantages better, the nicotine harm reduction and improve the quality of flue-cured tobacco intrinsic chemical is of great significance.On the analysis of the six combinations showed that GD and the transgressive advantages of F1 internodal length and under the two shed leaf area was a significant positive correlation and negative correlation was of great significance.And Fi plant height, effective number of leaves, yield transgressive advantages in a certain degree of negative correlation, other various characters heterosis and genetic distance between parents show weak negative correlation.