Knowledge on the changes in yield potential and associated physiological traits is essential for understanding the main yield‐limiting factors and guiding future breeding strategies. Our objective was to identify physiological traits associated with genetic gains in grain yield of winter wheat (Triticum aestivum L.) in Shandong province, China. Thirteen milestone cultivars and two advanced lines released from 1969 to 2006 were examined over 3 yr at Tai'an during 2006 to 2009. The genetic gain in grain yield was 62 kg ha−1 yr−1, largely associated with increased kernels per square meter, biomass, and harvest index (HI) and reduced plant height. Significant genetic changes were also observed especially for apparent leaf area index (LAI) at heading and anthesis, chlorophyll content (Chl) at anthesis, photosynthesis rate during grain filling, and stem water‐soluble carbohydrate (WSC) content at anthesis. Comparing genotypes having Rht‐D1b and others with both Rht‐D1b and Rht8c (Rht‐D1b+Rht8c) showed increased grain yield, thousand kernel weight, kernels per spike, kernel weight per spike, HI, canopy temperature depression, and Chl at anthesis and LAI at heading with the latter but no difference in height. The results suggested that genetic gains in grain yield in Shandong province were mainly contributed by increases in kernels per square meter and biomass, which were achieved through improving crop photosynthesis at and after heading, and the source for grain filling may have benefited from increased WSC in stems at anthesis.

Grain protein content (GPC) and flour whiteness degree (FWD) are important qualitative traits in common wheat. Quantitative trait locus (QTL) mapping for GPC and FWD was conducted using a set of 131 recombinant-inbred lines derived from the cross 'Chuan 35050 × Shannong 483' in six environmental conditions. A total of 22 putative QTLs (nine GPC and 13 FWD) were identified on 12 chromosomes with individual QTL explaining 4.5-34.0% phenotypic variation. Nine QTLs (40.9%) were detected in two or more environments. The colocated QTLs were on chromosomes 1B and 4B. Among the QTLs identified for GPC, QGpc.sdau-4A from the parent Shannong 483 represented some important favourable QTL alleles. QGpc.sdau-2A.1 and QFwd.sdau-2A.1 had a significant association with both GPC and FWD. The markers detected on top of QTL regions could be potential targets for marker-assisted selection.

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