Exploring Of QTL Related To Curing Characteristics Of Flue-cured Tobacco

Tobacco, as an important economic crop, plays a dominant role in agricultural production in our country. Tobacco quality directly affects its economic value and curing is an important link to the tobacco production, and the harvest of fresh leaves must be cured and fixed in order to reflect its excellent quality. It is an effective way to cultivate the varieties of curing characteristics to improve the quality of tobacco leaves.Abundant resources of tobacco from different countries were used as natural populations, with 223 varieties in local and abroad, to conduct genome-wide association analysis. And the use of F₂ separated groups combined between Yunyan 85 and Dabaijin 599, and 24 different tobacco varieties constructed as natural populations, five molecular markers linked to easy curing potential were detected in efficiency. the main results are as follows:1.25 loci related to easy curing potential were detected on the condition of P less than 10^-4, and C16₂.6M was the marker associatied with easy curing potential in the most significant level with the value of –Log P 5.626. 79 loci related to holding curing potential were detected on the condition of P less than 10-5, and C13₁0.8M was the marker associatied with holding curing potential in the most significant level with the value of –Log P 7.210. 4 loci related to curing characteristics were detected on the condition of P less than 10^-4, and C4₄5.5M was the marker associatied with curing characteristics in the most significant level with the value of –Log P 4.742.2.The results based on linkage analysis and association analysis were compared. The results show that the association site C24₄8.5M was close with the located markers that were linked to easy curing potential. The association sites C1₉3.8M, C1₁77.8M and C8₁36.1M were close with the located markers that were linked to holding curing potential. The association sites related to curing characteristics have long distance with linkage marker.3.The physical intervals around the association sites were screened to analyse the gene related to curing characteristics. four genes related to easy curing potential and one genes related to holding curing potential were preliminarily predicted, of which code were respectively Ntab0882330、Ntab0979690、Ntab0979730、Ntab0541180 and Ntab0565630.4.The individuals in F₂ population by crossing Yunyan85 and Dabaijin599 were grouped according to the banding patterns of the two parents. Easy curing potential was showed in significant level or above between the two groups in four markers except for the marker PT53143. In natural population where the allele of easy curing cultivars Yunyan85 was defined as excellent genotype, 24 materials were grouped into two according to the number of excellent allele that the the tested cultivars have, and difference between the two groups was in significant level. Furthermore, the genetic diversity analysis revealed obviously that the tested loci of the better group leaned into conservative, which was a typical symbol of hitchhiking effects. It was speculated that genes related to regulating easy curing potential exists probably near these loci.