Marker-assisted pyramiding of eight QTLs/genes for seven different traits in common wheat (Triticum aestivum L.)

Common wheat (Triticum aestivum L.) contributes substantially to global food and nutritional security. Thus, an important goal of wheat breeding is to develop high-yielding varieties with better nutritional quality and resistance to all major diseases. During the present study, in the background of a popular elite wheat cultivar PBW343, we pyramided eight quantitative trait loci (QTLs)/genes for four grain quality traits (high grain weight, high grain protein content, pre-harvest sprouting tolerance, and desirable high-molecular-weight glutenin subunits) and resistance against the three rusts. For pyramiding eight QTLs/genes, four improved PBW343 lines, each carrying different combinations of the desired QTLs/genes (developed by us earlier), were crossed in pairs to produce two single-cross F-1 hybrids. The single-cross F-1 hybrids were intercrossed to produce a double-cross hybrid (DCH). Using marker-assisted selection in five consecutive generations (DCHF1-DCHF5), four pyramided lines (PYLs) were selected, each with all the eight desired QTLs/genes in homozygous state. The phenotypic characterization of the progenies of these PYLs suggested that the genetic background of PBW343 was retained in all these four PYLs. Therefore, these PYLs should prove useful in future wheat breeding programs for improving not only the grain quality, but also the durability of resistance against all three rusts. Multi-year/multi-location trials are planned for these pyramided lines to evaluate their potential for release as a next-generation improved version of wheat cv. PBW343 for commercial cultivation.