Fine Mapping And Marker Development Of QTL-QGpc.hwwgr-4BS,A Major QTL For Grain Protein Content In Common Wheat

The grain protein content(GPC)is an important trait,which is related to the nutritional value of wheat flour and processing quality in wheat.In the previous study,the major QTL—QGpc.hwwgr-4BS was detected on the wheat 4BS chromosome using the “Ning 7840 × Clark” recombinant inbred line(RIL)population,which controled the stable expression of GPC.In this study,we used 660 k SNP arrays technology and BSR-seq technology to fine map the QGpc.hwwgr-4BS,and screen molecular markers that linked closely to the QTL.The results will lay a theoretical foundation for GPC gene cloning,marker-assisted selection of wheat quality breeding.This study obtained the main results as follows:1.The wheat GPC was significantly positively correlated with kernel length and kernel area.The QGpc.hwwgr-4BS was located in the Xgwm368-IWA4662 marker interval of chromosome 4BS,the length of the region was 17.5c M,the LOD peak was close to IWA6850,the explained phenotypic variation of the QTL was 22.0%,and the additive effect value was 6.14g?kg-1.2.A total of 1287 high-quality differential SNPs were discovered by 660 K SNP chip technology,of which 933 SNPs were found on chromosome 4B,accounting for 72.5%.The flanking sequence of SNP markers on this chromosome were used to blast the assembled Chinese Spring survey sequence,and three differential SNP enrichment regions related to wheat GPC were obtained,which were located in 13.39Mb-52.57 Mb,75.95Mb-143.60 Mb and 383.66Mb-465.59 Mb.3.A total of 57445 credible SNPs were screened out using the RNA-seq.The wheat A,B,and D genomes contained 21165,23988,and 11536 SNPs,respectively.Correlation analysis showed that there were only two regions significantly related to the target traits on 4B chromosome,which were located in 82.66 Mb-110.70 Mb and 396.69 Mb-425.08 Mb.4.We developed 12 KASP markers in the target region,and finally located QGpc.hwwgr-4BS between two markers KP1241 and KP0001.In this region,the genetic distance was 2.6c M,the physical interval was 36.46Mb-46.92 Mb,the physical distance was 10.46 Mb,and there were 86 genes in the interval.