Study On Decreasing Nicotine To Nornicotine Conversion Through Genetic Improvement For Sichuan Burley Tobacco

Early conversion stimulation and converter identification method was used in Dazhou tobacco institute in 2007 to improve the leading burley hybrids. Non-converter plants were strictly selected from parent plants to make cross to produce improved hybrid seeds. In 2008, comparative experiments were carried out in Dazhou to compare the nicotine conversion rate and economic traits between conventional hybrids and improved hybrids.1 Analysis of nicotine conversion rate for individual plants of Dabai burley hybrids and their parentsEarly conversion stimulation and converter identification method was used to analyze the nicotine conversion rate of three burley hybrids and their parents. The results showed that the alkaloid composition and contents in tobacco leaves of different hybrids were significantly different. The problem of nicotine conversion in Dabai 1 and Dabai 2 was less serious, but three existed certain amount of converters, with the proportions of total converters of 10.9% and converters, with the proportions of total converters of 10.9% and 23.7%, respectively, most of which being low converters. The problem of conversion in Dabai 3 was much more serious. with all the tested plants being converters and the majority being high converters: the average conversion rate was 38.3%.The two parents of Dabai 1,MSKY14 and Dasuo 26 both had certain amount of converters in the populations and therefore contributed to the conversion level in the hybrid. The male parent of Dabai 2,Dasuo 26,was the main contributor of conversion gene to the hybrid. the male parent of Dabai 3,Dasuo 27,had extremely high converter proportion and conversion level, and was the exclusive contributor of conversion gene to Dabai 3 which had high nicotine conversion level.2 Proportion of nicotine converters and distribution of conversion rate in plants of Dabai 1 in different areas and varietiesGas chromatograph was used to analyze the alkaloid composition and content of air-cured leaves from different areas and varieties of Dabai 1,the proportion of converters and the conversion rate were calculated. The results indicated that hybrid Dabai 1 had relatively less problem of nicotine conversion, the proportion of converters in 3 locations being 18.0%,18.0%and 52.0%,respectively,and the average conversion rate being 3.5%,3.1% and 14.3%,which can be used after screening and improvement .3 Study on decreasing nicotine conversion through genetic improvementThe study was conducted, through early identification and selection, to investigate the effect of selecting parents on Dabai for nicotine conversion and to compare the effects on reducing converters, decreasing tobacco specific nitrosamine and increasing flavor quality in improved hybrids, Dabai 1 LC,Dabai 2 LC and Dabai 3 LC with the regular hybrid, which had high proportion of converters in the population. The results showed that the proportion of converters in the population were 4.65,4.76 and 6.52,reduced to 18.75,7.74,72.20.The percent nicotine conversions were 1.24,1.33和2.74 .Therefore the improved hybrids had high value of utilization in burley tobacco production.4 Effect of genetic improvement on the main chemical components and sensory evaluation quality after air-curedSeries of Dabai series on the conventional control and improved hybrids after modulation of mixed samples in the upper and the middle of air-cured to the chemical composition analysis and quality analysis of smoking ,results show that nicotine conversion of characters had not significant impact on the economy. The conventional control and improved hybrids in sugar, total nitrogen and mineral elements is not very different and the nicotine conversion rate reduce significantly. Improved on Dabai 1 LC, Dabai 2 LC and Dabai 3 LC the aroma character, pure aroma and aroma quantity increased, reduce irritation. Dabai 1 NH,NL and LN of the three hybrids exist nicotine convert plants so quality poor.