Molecular Mapping of Biofortification Traits in Bread Wheat ( Triticum aestivum L.) Using a High-Density SNP Based Linkage Map.

A set of 188 recombinant inbred lines (RILs) derived from a cross between a high-yielding Indian bread wheat cultivar HD2932 and a synthetic hexaploid wheat (SHW) Synthetic 46 derived from tetraploid Triticum turgidum (AA, BB 2n = 28) and diploid Triticum tauschii (DD, 2n = 14) was used to identify novel genomic regions associated in the expression of grain iron concentration (GFeC), grain zinc concentration (GZnC), grain protein content (GPC) and thousand kernel weight (TKW). The RIL population was genotyped using SNPs from 35K Axiom ® Wheat Breeder's Array and 34 SSRs and phenotyped in two environments. A total of nine QTLs including five for GPC ( QGpc.iari_1B , QGpc.iari_4A , QGpc.iari_4B , QGpc.iari_5D , and QGpc.iari_6B ), two for GFeC ( QGfec.iari_5B and QGfec.iari_6B ), and one each for GZnC ( QGznc.iari_7A ) and TKW ( QTkw.iari_4B ) were identified. A total of two stable and co-localized QTLs ( QGpc.iari_4B and QTkw.iari_4B ) were identified on the 4B chromosome between the flanking region of Xgwm149-AX-94559916 . In silico analysis revealed that the key putative candidate genes such as P-loop containing nucleoside triphosphatehydrolase, Nodulin-like protein, NAC domain, Purine permease, Zinc-binding ribosomal protein, Cytochrome P450, Protein phosphatase 2A, Zinc finger CCCH-type, and Kinesin motor domain were located within the identified QTL regions and these putative genes are involved in the regulation of iron homeostasis, zinc transportation, Fe, Zn, and protein remobilization to the developing grain, regulation of grain size and shape, and increased nitrogen use efficiency. The identified novel QTLs, particularly stable and co-localized QTLs are useful for subsequent use in marker-assisted selection (MAS).