HighlightThe genetic variation of root system architecture in the A and B wheat genomes is described, providing the necessary knowledge ultimately to fine-tune the expression of the root system architecture.

Improved end‐use quality is an essential goal of many wheat (Triticum aestivum L.) breeding programs. Besides genetic factors, environmental conditions are known to influence wheat quality. Our objective was to identify quantitative trait loci (QTL) for quality traits in a winter wheat population under different soil moisture levels. A population of 185 doubled haploid (DH) lines was derived from a cross between hard white winter wheats CO940610 and ‘Platte’. The population was grown in four environments (two limited irrigation and two fully irrigated) in Colorado in 2007/2008 and 2008/2009, and the grain was evaluated for 14 end‐use quality traits. A linkage map was constructed with 250 molecular markers, including five glutenin protein markers. Composite interval mapping detected clusters of QTL for multiple traits near the glutenin loci Glu‐A1, Glu‐B1, and Glu‐D1. Other QTL clusters were located on chromosomes 2B, 6A, 7B, and 7D; the 2B and 7D QTL may reflect the presence of heading date QTL in the same regions. An epistatic interaction for mixograph traits was found between the chromosome 7B QTL and Glu‐B1, consistent with the presence of a regulatory gene on 7B. An apparently novel QTL for kernel weight and diameter was detected on chromosome 3B. Our results confirm similar genetic control of quality traits, especially for large‐effect QTL, for the levels of moisture stress in this study. These results may guide breeding programs in choosing parents and conducting marker‐assisted selection for improved end‐use quality.

Due to variable moisture conditions in the U.S. Great Plains, it is important to understand genetic control of crop traits under a range of soil moisture levels. Our objective was to identify quantitative trait loci (QTL) for yield, phenology, and morphological traits in wheat (Triticum aestivum L.) under different soil moisture conditions. Field evaluation of a winter wheat doubled haploid population (n = 185) derived from a cross between CO940610 and ‘Platte’ was carried out in Fort Collins and Greeley, Colorado, USA in 2007–2008 and 2008–2009, respectively. At each location, trials were grown under moderate drought stress and fully irrigated conditions. A total of 33 QTL for 11 traits was detected in two or more environments. A cluster of QTL for nine traits was found on chromosome 2B in the vicinity of the photoperiod response gene Ppd-B1. Other stable QTL clusters were detected on chromosome 6A and near the vernalization response gene Vrn-D3 on chromosome 7D. A QTL for grain yield on chromosome 5A was detected in three environments. With minor exceptions, the large-effect QTL were detected in both the water limited and fully irrigated environments, rather than being detected only under specific moisture levels.

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CO940610/‘Platte’ (Reg. No. MP‐6, NSL 510728), a hard white winter wheat (Triticum aestivum L.) doubled haploid (DH) mapping population was developed by the Wheat Breeding Program at Colorado State University, Fort Collins, CO, with assistance from Syngenta Cereals. The population consists of 185 DH lines and was developed to map quantitative trait loci (QTL) for dough rheology, bread‐making quality, and agronomic traits. The population was genotyped with diversity array technology (DArT), simple sequence repeat, sequence tagged site, and glutenin protein markers. The population segregates for five high and low molecular weight glutenin loci, making the population particularly informative for dough rheology and bread‐making quality traits. The genetic map included 250 marker loci on 34 linkage groups on 21 chromosomes. The population was evaluated under fully irrigated and limited irrigation conditions in side‐by‐side trials in Fort Collins and Greeley, CO, in 2007–2008 and 2008–2009, respectively, for a total of four environments. All traits showed a wide range of values under both moisture treatments. A total of 158 QTL was detected in the four environments, with approximately equal numbers detected under full and limited irrigation. The information obtained from this population may be helpful for wheat breeders in choosing parents and conducting marker‐assisted selection for these traits under a range of soil moisture levels.