Environment-Specific Agronomic and Quality QTLs Mapping in an Elite by Elite Recombinant Inbred Lines Wheat Population.

Commercially successful wheat varieties provide high yields while maintaining good baking qualities. In this study, we investigated a population of 135 recombinant inbred lines (RIL), developed from a cross between the cultivars ‘Steele-ND’ and the elite line ND 735, for QTLs controlling yield and major quality traits. A linkage map was constructed based on 392 markers. Phenotypic data were collected from four North Dakota environments for days to heading, plant height, spike density, spike length, grain yield, grain volume weight, thousand kernel weight, kernels per spike, kernel size distribution, protein, flour extraction, kernel hardness, kernel diameter, and mixograph peak time. Strong transgressive segregation was observed for all traits, with RILs outperforming the best commercial varieties. Among the 13 environment-specific QTLs detected, four were for yield-related and two were quality-related traits. All QTLs explained large phenotypic variation (R² 16-44 %) as expected for loci determining transgressive segregation. Two major QTLs on chromosomes 5A and 6B affected three yield-related traits and provided up to 252 kg ha ^-1 additional yield. Many QTLs have been identified before for yield and quality, but their polygenic nature has often prevented successful marker assisted selection. In this study, we employed directly the identified QTLs for within population selection, in an extension of the concept of ‘map as you go’.