QTL Analysis For Fusarium Head Blight (FHB) Resistance And Agronomic Traits Using (N553 × Yangmai13) Recombinant Inbred Lines

Fusarium head blight(FHB)caused mainly by Fusarium graminearum Schwabe.This disease is widely occurred in the humid and semi-humid regions of the world.FHB causes serious yield loss and deteriorated grain quality when warm and wet weather coincide with antithesis.Mycotoxin contamination in harvested grain is also a major health concern for human consumption and animal production.FHB resistance is quantitatively inherited and controlled by a few major genes and several modifying genes,but the expression of these resistances were strongly affected by environment,it is suggested that the flanking markers of QTL may be helpful for pyramiding resistant genes in the wheat breeding for FHB by marker assisted selection(MAS)method.In this study,a recombinant inbred lines(RILs)derived from a cross between N553 and Yangmai13 was used to identify quantitative trait loci(QTL)that contribute to FHB resistance.The results are as following:1.A total of 2018 simple sequence repeats(SSRs)and Sequence Tagged Site(STS)markers were analyzed between parents N553 and Yangmai13 for genetic map construction and QTL scanning.In this research,217 polymorphic markers were identified and used to screen a population of 184 recombinant inbred lines(RILs)derived from the cross of N553 × Yangmai13.The genetic maps spanned 1710.296 c M,respectively,with an average density of one marker per 7.88 cM.2.FHB resistance of RILs was evaluated in Jianyang and Yangzhou for two continuous years.Results showed that,five QTLs were found for FHB resistance using Win QTLcart 2.5 software,among them,two were contributed by N553 and other three by Yangmai13.A stable major QTL,Qfhb.jass-2DS,was detected on the short arm of chromosome 2D,this QTL could explain 8.17% and 11.42% of phenotypic variance for FHB resistance in Yangzhou in 2015 and 2016,respectively.A slightly less stable major QTL Qfhb.jass-3BS was also identified,which was located between marker Xbarc102-gwm493,and explained 5.33%~42.96% of phenotypic variation of the resistance to FHB.Besides,three other minor QTLs on chromosome 2BS,3BL and 4AS with less than 10% of phenotypic variations in individual experiments were also detected.3.To compare the effects of combinations QTL from 2DS and 3BS,the RIL were classified into four groups.variance analysis was performed for number of scabbed spikelets(NSS)evaluated in four groups,and the result showed that the differences in NSS were significant among the four genotype combinations,and when contained two QTLs the resistance level was best.The present study indicated that Fusarium head blight resistance improved when those resistance QTL were combined.4.One QTL were found for spikelet compactness under two years,this QTL could explain 6.08% and 5.36% of phenotypic variance for FHB resistance in 2015 and 2016,respectively.Five QTL were found for plant height under two years,phenotypic variation explained by a single QTL varied from 4.86% to 8.93%,of there,two QTL(QPh.jaas-5BS,QPh.jaas-6BL)were common under two years.5.There were significant positive correlation between FHB with spikelet Compactness.QTL for FHB resistance and spikelet compactness,showing tight linkage.There were no significant correlation between plant height with number of scabbed spikelets of FHB spread,but significant negative correlation with disease index of FHB infection,QTL for FHB resistance and plant height,showing not tight linkage.