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Summary One of the major challenges for plant scientists is increasing wheat ( Triticum aestivum ) yield potential ( YP ). A significant bottleneck for increasing YP is achieving increased biomass through optimization of radiation use efficiency ( RUE ) along the crop cycle. Exotic material such as landraces and synthetic wheat has been incorporated into breeding programmes in an attempt to alleviate this; however, their contribution to YP is still unclear. To understand the genetic basis of biomass accumulation and RUE , we applied genome‐wide association study ( GWAS ) to a panel of 150 elite spring wheat genotypes including many landrace and synthetically derived lines. The panel was evaluated for 31 traits over 2 years under optimal growing conditions and genotyped using the 35K wheat breeders array. Marker‐trait association identified 94 SNP s significantly associated with yield, agronomic and phenology‐related traits along with RUE and final biomass ( BM _ PM ) at various growth stages that explained 7%–17% of phenotypic variation. Common SNP markers were identified for grain yield, BM _ PM and RUE on chromosomes 5A and 7A. Additionally, landrace and synthetic derivative lines showed higher thousand grain weight ( TGW ), BM _ PM and RUE but lower grain number ( GM 2) and harvest index ( HI ). Our work demonstrates the use of exotic material as a valuable resource to increase YP . It also provides markers for use in marker‐assisted breeding to systematically increase BM _ PM , RUE and TGW and avoid the TGW / GM 2 and BM _ PM / HI trade‐off. Thus, achieving greater genetic gains in elite germplasm while also highlighting genomic regions and candidate genes for further study.

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22One of the major challenges for plant scientists is increasing wheat (Triticum aestivum) yield 23 potential (YP). A significant bottleneck for increasing YP is achieving increased biomass through 24 optimization of Radiation Use Efficiency (RUE) along the crop cycle. Exotic material such as 25 landraces and synthetic wheat has been incorporated into breeding programs in an attempt to alleviate 26 this, however their contribution to YP is still unclear. To understand the genetic basis of biomass 27 accumulation and RUE we applied genome-wide association study (GWAS) to a panel of 150 elite 28 spring wheat genotypes including many landrace and synthetically derived lines. The panel was 29 evaluated for 31traits over two years under optimal growing conditions and genotyped using the 35K 30Wheat Breeders array. Marker-trait-association identified 94 SNPs significantly associated with 31 yield, agronomic and phenology related traits along with RUE and biomass at various growth stages 32 that explained 7-17 % of phenotypic variation. Common SNP markers were identified for grain 33 yield, final biomass and RUE on chromosomes 5A and 7A. Additionally we show that landrace and 34 synthetic derivative lines showed higher thousand grain weight (TGW), biomass and RUE but lower 35 grain number (GNO) and harvest index (HI). Our work demonstrates the use of exotic material as a 36 valuable resource to increase YP. It also provides markers for use in marker assisted breeding to 37 systematically increase biomass, RUE and TGW and avoid the TGW/GNO and BM/HI trade-off. 38Thus, achieving greater genetic gains in elite germplasm while also highlighting genomic regions and 39 candidate genes for further study. 40 41

To feed an ever-increasing population we must leverage advances in genomics and phenotyping to harness the variation in wheat breeding populations for traits like photosynthetic capacity which remains unoptimized. Here we survey a diverse set of wheat germplasm containing elite, introgression and synthetic derivative lines uncovering previously uncharacterized variation. We demonstrate how strategic integration of exotic material alleviates the D genome genetic bottleneck in wheat, increasing SNP rate by 62% largely due to Ae. tauschii synthetic wheat donors. Across the panel, 67% of the Ae. tauschii donor genome is represented as introgressions in elite backgrounds. We show how observed genetic variation together with hyperspectral reflectance data can be used to identify candidate genes for traits relating to photosynthetic capacity using association analysis. This demonstrates the value of genomic methods in uncovering hidden variation in wheat and how that variation can assist breeding efforts and increase our understanding of complex traits.

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Lodging affects grain quality and grain yield in wheat (Triticum aestivum L.) and is difficult to breed for because its sporadic incidence and laborious protocols to measure lodging traits. Thus, developing molecular markers for these traits can increase selection efficiency in breeding programs. The aim of this article is to identify quantitative trait loci (QTL) associated with stem/anchorage strength and leverage traits (lodging traits) in a doubled-haploid population of UK bread wheat Avalon × Cadenza. Field experiments were conducted in the UK during 2012-2013 near High Mowthorpe and during 2013-2014 at Sutton Bonington. Phenotypic and genetic analysis indicated significant genetic variation for all traits. Stem strength (diameter, wall width, and material strength) and leverage (plant height) traits were highly heritable (0.64-0.95), whereas anchorage strength traits (root plate spread and structural rooting depth) and ear number per plant (leverage trait) were less heritable (0.21-0.33). This study identified 18 QTL for lodging traits and grain yield in chromosomes 1D, 2B, 2D, 3A, 3B, 4A, 4D, 5B, and 6B. Two QTL for stem strength on chromosome 1D and 3B explaining 49.6% of the total phenotypic variation (PVE) are estimated to reduce stem lodging risk and shortening the plant height by 12 cm. One QTL for root plate spread on chromosome 5B explaining 22.4% of the PVE could increase root lodging resistance.