Developing genetic linkage map and identification of quantitative trait loci controlling agro-chemical traits in oriental type tobacco

Tobacco (Nicotiana tabacum L.) is an industrial plant that play important role in economy of most countries. Oriental tobacco is a sun-cured, small-leafed, highly aromatic type of tobacco with limited information about its agronomic and chemical characteristics and their genetic control. This research was conducted to prepare the genetic linkage map of oriental type tobacco in a recombinant inbred line population (103 lines) produced from the cross between SPT406 (male parent) and Basma seres 31 (female parent) and identification of genomic locations controlling some agronomic characteristics accompanied with chlorine content under field conditions. Markers including SSR, ISSR, REMAP and IRAP were utilized in construction of genetic linkage map. Linkage map comprising 46 markers was developed which covered 586.1 cM of tobacco genome and the average distance between two markers was 12.74 cM. Number of markers per linkage groups varied between 2 to 13. In this study, 19 QTLs with phenotypic variation between 13.2 to 40.1 were identified for characteristics including leaf length, leaf width, leaf number, plant height, internode distance, stem girth, dry leaf yield, photosynthesis value and leaf chlorine content using composite interval mapping. Co-localized QTLs were recognized in linkage groups 1, 3 and 5. Highest values of phenotypic variation achieved in the present study manifest the possibility for using identified retrotransposon and microsatellite markers in marker assisted selection programs of oriental type tobacco.