烟草生物碱性状的QTL定位OA

Alkaloids are important chemical components in tobacco.In order to understand the genetic architecture of alkaloids in tobacco and identify major effect loci controlling alkaloids related traits,QTL mapping on tobacco alkaloids was performed.A set of 271 recombinant inbred lines(RIL)were constructed with Y3 and K326 as the parents.The RIL population was planted in Yanhe,Yuxi,Yunnan province and Shilin,Kunming,Yunnan province in 2018,2019,and 2020,respectively.Five alkaloid pheno-types including total plant alkali(TPA),nicotine(NIC),nornicotine(NOR),anabasine(ANAB),and anatabine(ANAT)were measured.A linkage map of 46,129 markers was constructed by genome sequencing of the population.QTL mapping was per-formed by the software QTLNetwork 2.0 which was developed based on the mixed linear model.A total of 15 QTLs with signifi-cant additive effects were identified.The contribution rate of additive effect to the corresponding phenotypes varied from 0.58%to 11.57%.Four major QTLs,qTPA14 for total plant alkali,qNIC14 for nicotine,qANAB14 for anabasine,and qANAT14 for ana-tabine,accounted for more than 10%of phenotypic variation of the corresponding traits,which were located in linkage group 14.Six QTLs with significant additive-by-environment interaction effects were detected,their additive-by-environment interaction effects explained the phenotypic variation of 0.80%-1.81%.Five pairs of QTLs with significant additive-by-additive epistasis effects were detected,accounting for phenotypic variation from 0.15%to 2.31%,while two pairs of QTLs were detected with significant epistasis-by-environment interaction effects,which explaining the proportion of phenotypic variation from 0.81%to 1.16%.The results pave a foundation for further isolation of candidate genes,the dissection of genetic mechanism,and the mo-lecular improvement of tobacco alkaloid traits.