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Wheat (Triticum aestivum L.) grain quality traits that are controlled by quantitative traits loci (QTL) define suitable growing areas and potential end-use products of a wheat cultivar. To dissect QTL for these traits including protein content (GPC); test weight (TW); single kernel characterization system (SKCS)-estimated kernel weight (SKW); kernel diameter (KD); kernel hardness measured by near-infrared reflectance spectroscopy (NIRS) hardness index (NHI); and SKCS-hardness index (SHI), a high-density genetic map with single nucleotide polymorphism (SNP) and simple sequence repeat (SSR) markers was developed using recombinant inbred lines (RILs) derived from Ning7840 × Clark. The RILs were evaluated for these quality traits in seven Oklahoma environments from 2001 to 2003. A total of 41 QTL with additive effects on different traits were mapped on most wheat chromosomes, excluding 1A, 2A, 3D, 4D, 6D, and 7B. Seven chromosome regions showed either tightly linked QTL or QTL with pleiotropic effects on two to four traits. Ten pairs of QTL showed additive × additive effects (AA), four QTL were involved in additive × environment (AE) effects, and one was involved in AAE effects. Two to eleven QTL for each of the six traits and 139 tightly linked markers to these QTL were identified. The findings shed light on the inheritance of wheat grain quality traits and provide DNA markers for manipulating these important traits to improve quality of new wheat cultivars.

Wheat ( Triticum aestivum L.) morphological and adaptation-related traits that are controlled by quantitative trait loci (QTLs) help define potential growing areas of a wheat cultivar. To dissect QTLs for heading date, lodging, shattering (SH), cold tolerance, plant height, spike length, spike compactness, awn length (AL) and chaff color (CC), a high-density genetic map with single nucleotide polymorphism and simple sequence repeat markers were developed using recombinant inbred lines (RILs) derived from 'Ning7840' × 'Clark'. The RILs were evaluated in eight Oklahoma environments from 2001 to 2004. A total of 31 QTLs with additive effects on different traits were mapped on most wheat chromosomes except for 1D, 3A, 3D, 4D, 6D, and 7B. Six chromosome regions showed either tightly linked QTLs or QTLs with pleiotropic effects for two to three traits. Five QTL pairs showed additive × additive effects (AA). Ten additive QTLs were involved in additive × environment (AE) effects, and one epistatic QTL was involved in AAE effects. Among nine traits evaluated only three (SH, AL, and CC) were controlled by single genes in this biparental population. Seven traits were conditioned by multiple QTLs. A total of 127 markers were tightly linked to the QTLs. The findings shed light on the inheritance of wheat morphological and adaptation-related traits and provide DNA markers for manipulating these important traits to improve wheat production. [ABSTRACT FROM AUTHOR]