We report malt quality QTLs relevant to breeding with greater precision than previous mapping studies. The distribution of favorable alleles suggests strategies for marker-assisted breeding and germplasm exchange.

International cooperation in barley (Hordeum sp.) germplasm activities include collection, evaluation, and enhancement efforts. A trip to Himalayan countries is among recent collection expeditions. The International Plant Genetics Resources Institute (IPGRI), International Center for Agricultural Research for the Dry Areas (ICARDA), USDAARS, and the U.S. Barley Crop Germplasm Committee (CGC) are actively working on international coordination of barley working collections and core collection formation. An example of current germplasm evaluation is screening barley from the USDA-ARS National Small Grains Collection and breeders lines for barley stripe rust (Puccinia striiformis f. sp. hordei West) resistance in Bolivia. A major germplasm enhancement project is the North American Barley Genome Mapping Project, which has involved >30 scientists from the USA and Canada as well as coordination with overseas counterparts. Much of the cooperation in germplasm activities occurs due to the fact that barley researchers are a cohesive group worldwide.

'Lyon' (Reg. No. CV-356, PI 673045), a spring, two-row, hulled feed barley (Hordeum vulgare L.) cultivar developed and tested as 05WA-316.K, was released in 2013 by Washington State University (WSU). Lyon was derived from the cross 'Baronesse'/'Spaulding' and selected through single-seed descent from F-2 to F-4 and pedigree breeding methods from F-5 to F-6. Lyon was tested in field trials in Pullman, WA, and in multi-environment trials at 8 to 10 locations per year by the WSU Variety Testing Program from 2009 to 2013. In these testing sites, Lyon had a mean grain yield (5699 kg ha(-1)) that was higher than those of check cultivars 'Bob' and Baronesse. Across 37 station years in the Western Regional Spring Barley Nursery, Lyon had an average grain yield of 5284 kg ha(-1), which was higher than check cultivars 'Steptoe', 'Harrington', 'AC Metcalfe', and 'CDC Kindersley'. Lyon showed head emergence significantly earlier than Baronesse, Bob, and 'Lenetah' and was 3.3 cm shorter than Bob and 6.1 cm shorter than 'Champion'. Similar to Champion and Baronesse, Lyon is moderately susceptible to stripe rust (caused by Puccinia striiformis f. sp. hordei Eriks.). Lyon is intended as a high-yielding replacement to barley feed cultivars Bob, Baronesse, and Lenetah in the dryland cropping regions of eastern Washington that receive an average precipitation of 400 mm yr(-1) or higher.

'Muir' (Reg. No. CV-357, PI 674172) is a two-row, spring, hulled feed barley (Hordeum vulgare L.) cultivar developed and evaluated as 07WA-601.6, and released in 2013 by Washington State University (WSU). Muir was derived from the cross 'Baronesse'/'Bob' and selected through single-seed descent from F-2 to F-4 and pedigree breeding methods from F-5 to F-6. Muir was tested in multi-environment trials at 8 to 10 locations per year by the WSU Variety Testing Program from 2011 to 2014. In the low rainfall (<400 mm annual precipitation) testing locations, Muir had a mean grain yield (4787.0 kg ha(-1)) that was higher than those of check cultivars Baronesse, Bob, and Lyon. Muir showed head emergence significantly earlier than Baronesse, Bob, and 'Lenetah' and was 3.3 cm taller than Baronesse and 5.5 cm shorter than 'Champion' across low rainfall zone locations. Muir is resistant to currently prevalent races of the stripe rust pathogen (Puccinia striiformis Westend. f. sp. hordei Erikss.); by comparison, commonly grown cultivars Baronesse, Bob, and Champion are rated as moderately resistant, 'Harrington', Lenetah, and Lyon are rated as moderately susceptible, and 'CDC Copeland' and 'CDC Meredith' are rated as susceptible. Muir was released on the basis of its excellent stripe rust resistance, high grain yield, and agronomic qualities suitable for a feed barley cultivar in low rainfall zones of Washington.

The Genome-Wide Association Studies approach was used to detect Quantitative Trait Loci associated with tocochromanol concentrations using a panel of 1,466 barley accessions. All major tocochromanol types- α-, β-, δ-, γ-tocopherol and tocotrienol- were assayed. We found 13 single nucleotide polymorphisms associated with the concentration of one or more of these tocochromanol forms in barley, seven of which were within 2 cM of sequences homologous to cloned genes associated with tocochromanol production in barley and/or other plants. These associations confirmed a prior report based on bi-parental QTL mapping. This knowledge will aid future efforts to better understand the role of tocochromanols in barley, with specific reference to abiotic stress resistance. It will also be useful in developing barley varieties with higher tocochromanol concentrations, although at current recommended daily consumption amounts, barley would not be an effective sole source of vitamin E. However, it could be an important contributor in the context of whole grains in a balanced diet.

The use of genome‐wide association studies (GWAS) to detect quantitative trait loci (QTL) controlling complex traits has become a popular approach for studying key traits in crop plants. The goal of this study was to identify the genomic regions of barley (Hordeum vulgare L.) that impact five agronomic and one quality trait in U.S. elite barley breeding lines, as well as to identify markers tightly linked with these loci for further use in barley improvement. Advanced recombinant inbred lines submitted to the U.S. Barley Coordinated Agricultural Project (CAP) were genotyped using a platform of 3072 single nucleotide polymorphism (SNP) markers from the barley oligonucleotide pool assays (BOPAs) 1 and 2. In each of 4 yr, approximately 770 lines were evaluated in a replicated, randomized complete block design under both irrigated and dryland conditions. This gave an overall population size of >3000 lines, which we analyzed in a hierarchical fashion, including analyzing the lines in aggregate using a mixed model to account for population structure and relatedness among the lines. We identified 41 significant marker–trait associations, of which 31 had been previously reported as QTL using biparental mapping techniques; 10 novel marker‐trait associations were identified. The results of this work show that genes with major effects are still segregating in U.S. barley germplasm and demonstrate the utility of GWAS in barley breeding populations.

Colored (black, purple, blue, red) cereal grains, rich in anthocyanins, have recently gained popularity in arena of food sector. These colored cereals, especially colored rice, colored wheat, colored maize, and some millets, contain abundant amount of bioactive components, viz., anthocyanins, tocopherol, antioxidants, and vitamins. Anthocyanins are water-soluble pigments that are principally responsible for imparting red, violet, and blue color in grains, fruits, and vegetables. These bioactive compounds are known to have established health benefits by playing major role in cure and prevention of various chronic diseases. In this chapter, authors have focused on the botanical aspects of different cereals. Morphological characteristics of colored cereals are discussed at length, as well as light is thrown on the recent biotechnological advancements in quality and quantity improvement of the colored cereals.

A renewed interest in breeding barley specifically for food end-uses is being driven by increased consumer interest in healthier foods. We conducted association mapping on physicochemical properties of barley that play a role in food quality and processing including grain hardness, polyphenol oxidase activity, total phenolics, amylose content, and β-glucan. We used 3,069 elite two-row and six-row spring barley breeding lines from eight US breeding programs and 2,041 SNP markers for association mapping. Marker–trait associations were identified using a mixed model that incorporated population structure and kinship. We detected two previously identified QTL for grain hardness on chromosome 2H in the telomeric region of 5H along with two novel regions on 4H and 6H. For amylose content, we detected marker–trait associations on 7H from 0.63 to 30 cM. We detected four regions on chromosomes 1H, 2H, 3H, and 4H associated with polyphenol oxidase activity. The chromosome 2H region co-localized with the two previously mapped polyphenol oxidase genes PPO1 and PPO2, and the regions on chromosomes 1H, 3H, and 4H QTL were novel. For total phenolics, we identified three significant regions on 3H, 4H, and 5H. Two regions on 2H and 7H were associated with β-glucan. Both previously identified and novel QTL are segregating in elite US breeding germplasm. Only three of the 24 SNPs that were associated with traits using either the two-row or six-row mapping panel were identified in both panels. Nine SNPs were detected in the individual two-row or six-row panels that were not detected in the analysis using the complete panel and accounting for population structure. The distribution of favorable alleles at these loci that underpin food quality across the breeding programs suggests several strategies to use markers to improve barley for food uses.

BACKGROUND:The widespread acceptance of reduced-tillage farming in cereal cropping systems in the Pacific Northwest of the United States has resulted in increased use of herbicides for weed control. However, soil residual concentrations of widely used imidazalone herbicides limit the cultivation of barley, which is more sensitive than wheat. In addition, increased severity of the root rot disease caused by Rhizoctonia solani is associated with reduction in tillage. Many crops exhibit altered disease responses after application of registered herbicides. In this study, the injury symptoms in barley caused by sublethal rates of two acetolactate synthase (ALS)-inhibiting herbicides, imazamox and propoxycarbazone-sodium, were assessed in factorial combinations with a range of inoculum concentrations of the root rot pathogen Rhizoctonia solani AG-8.RESULTS:Both herbicides and pathogen had negative impacts on plant growth parameters such as root and shoot dry weight, shoot height and first leaf length, and interactions between pathogen and herbicide were detected.CONCLUSIONS:The results suggested that sublethal rates of herbicides and R. solani could alter severity of injury symptoms, possibly owing to the herbicide predisposing the plant to the pathogen.

Induced mutagenesis can be an effective way to increase variability in self-pollinated crops for a wide variety of agronomically important traits. Crop resistance to a given herbicide can be of practical value to control weeds with efficient chemical use. In some crops (for example, wheat, maize, and canola), resistance to imidazolinone herbicides (IMIs) has been introduced through mutation breeding and is extensively used commercially. However, this production system imposes plant-back restrictions on rotational crops because of herbicide residuals in the soil. In the case of barley, a preferred rotational crop after wheat, a period of 9–18 mo is required. Thus, introduction of barley varieties showing resistance to IMIs will provide greater flexibility as a rotational crop. The objective of the research reported was to identify resistance in barley for IMIs through induced mutagenesis. To achieve this objective, a sodium azide-treated M2/M3 population of barley cultivar Bob was screened for resistance against acetohydroxy acid synthase (AHAS)-inhibiting herbicides. The phenotypic screening allowed identification of a mutant line showing resistance against IMIs. Molecular analysis identified a single-point mutation leading to a serine 653 to asparagine amino acid substitution in the herbicide-binding site of the barley AHAS gene. The transcription pattern of the AHAS gene in the mutant (Ser653Asn) and WT has been analyzed, and greater than fourfold difference in transcript abundance was observed. Phenotypic characteristics of the mutant line are promising and provide the base for the release of IMI-resistant barley cultivar(s).

ABSTRACTKernel hardness is not a well‐characterized food quality trait in barley. Unlike wheat, not much is known about the effect of barley kernel hardness on food processing. Ten barley genotypes differing in single kernel characterization system hardness index (SKCS‐HI) (30.1–91.2) of dehulled kernels were used to determine the association of barley HI with other physical grain traits and food processing parameters. Thousand kernel weight (TKW) values of 10 genotypes were 29.7–38.1 g. Values for bulk density of grains were 721.1–758.9 kg/m3. Crease width and depth values were 0.9–1.3 mm and 0.4–0.7 mm, respectively. Barley HI showed no significant association with TKW, bulk density, or kernel crease dimensions. Kernel loss due to pearling after 325 sec of abrasion was 28.8–38.4% and showed significant negative correlation with HI (r = –0.87, P < 0.01). Proportion of barley flour particles >106 μm had values of 34.5–42.0%, and starch damage values were 1.8–4.5% among those 10 barley genotypes. HI showed significant positive correlations with both proportion of barley flour particles >106 μm (r = 0.93, P < 0.01) and starch damage (r = 0.93, P < 0.01). Water imbibition of barley kernels and cooked kernel hardness did not show significant correlation with HI.

Kernel hardness, an important quality trait of cereal grains, is known to influence pearling properties and malting quality of barley. To understand the endosperm micro-structural features of kernels and their relationship to kernel hardness, endosperms of three hard and three soft hulled spring barley lines based on single kernel characterization system hardness index were observed under light (LM) and scanning electron (SEM) microscopy. Under LM, endosperm cell wall of the three hard kernel lines was significantly thicker than that of the three soft kernel lines. Hard and soft lines showed differences in the degree of starch-protein association and continuity of protein matrix under the SEM. Hard kernel lines with a continuous protein matrix exhibited greater starch-protein adhesion than the soft kernel lines, suggesting that starch-protein binding may be one of the factors influencing barley kernel hardness. SEM of flour particles of soft kernel lines showed numerous well defined individual A and B-type starch granules, while, flour of hard kernel lines mostly showed small flour aggregates with few individual starch granules.

Contributors. Preface. 1: Significance, Adaptation, Production, and Trade of Barley. 2: Barley Origin and Related Species. 3: Barley Genome Organization, Mapping, and Synteny. 4: Genome Analysis: The State of Knowledge of Barley Genes. 5: Cytogenetics and Molecular Cytogenetics of Barley: A Model Cereal Crop with a Large Genome. 6: Application of Molecular Genetics and Transformation to Barley Improvement. 7: Barley Germplasm Conservation and Resources. 8: Barley Breeding History, Progress, Objectives, and Technology. 9: Cultural Practices: Focus on Major Barley-Producing Regions. 10: Abiotic Stresses in Barley: Problems and Solutions. 11: Biotic Stress in Barley: Disease Problems and Solutions. 12: Biotic Stress in Barley: Insect Problems and Solutions. 13: The Development, Structure, and Composition of the Barley Grain. 14: Biochemistry, Physiology, and Genetics of Endosperm Mobilization in Germinated Barley Grain. 15: Malting and Brewing Uses of Barley. 16: Barley Feed Uses and Quality Improvement. 17: Food Uses of Barley. 18: Adapting Cereal Plants and Human Society to a Changing Climate and Economy Merged by the Concept of Self-Organization. Index. Color plate is located between pages 340 and 341.

This chapter contains sections titled: Significance of Barley Adaptation of Barley Global Production of Barley Global Trade of Barley Concluding Remarks References

With 2 figures and 2 tables Abstract To study the genetic control of malting quality, in North American and European barley varieties, over five contrasting environments, 106 doubled haploid (DH) lines, from the cross ‘Triumph’ × ‘Morex’, were grown at Pullman (Washington State, USA) in 2002, Dundee (Scotland) in 2003 and 2005 and Lleida and Valladolid (Northern Spain) in 2006. The vrs locus, associated with two‐row vs. six‐row ear type, had a significant effect, as two‐row lines had higher grain protein content at all sites. This had variable effects on other malting parameters, but hot water extract (EXT) was not significantly affected at the two Spanish sites. Quantitative trait loci associated with malting characters were distributed across all seven chromosomes, but the most influential, with effects on EXT and alcohol yield, at more than one site, were on 1H, with ‘Morex’ providing the increasing allele and 5H, with the increasing allele from ‘Triumph’. Transgressive segregation, in both directions, occurred at all sites. It was concluded that crosses between European and North American germplasm could enhance quality attributes in barley cultivated across diverse environments.

ABSTRACTKernel hardness is an important trait influencing postharvest handling, processing, and food product quality in cereal grains. Though well‐characterized in wheat, the basis of kernel hardness is still not completely understood in barley. Kernels of 959 barley breeding lines were evaluated for hardness using the Single Kernel Characterization System (SKCS). Barley lines exhibited a broad range of hardness index (HI) values at 30.1–91.9. Distribution of kernel diameter and weight were 1.7–2.9 mm and 24.9–53.7 mg, respectively. The proportion of hull was 10.2–20.7%. From the 959 breeding lines, 10 hulled spring barley lines differing in HI values (30.1–91.2) were selected to study the associations of HI with proportion of hull, kernel weight, diameter, vitreousness, protein, β‐glucan, and amylose content. Vitreousness, evaluated visually using a light box, showed a clear distinction between hard and soft kernels. Hard kernels appeared translucent, while soft kernels appeared opaque when illuminated from below on the light box. Kernel brightness (L*), determined as an indicator of kernel vitreousness, showed a significant negative correlation (r = –0.83, P < 0.01) with HI. Protein, β‐glucan, amylose content, proportion of hull, kernel weight, and diameter did not show any significant association with HI.

Previous studies have shown that there is considerable population structure in cultivated barley (Hordeum vulgare L.), with the strongest structure corresponding to differences in row number and growth habit. U.S. barley breeding programs include six‐row and two‐row types and winter and spring types in all combinations. To facilitate mapping of complex traits in breeding germplasm, 1816 barley lines from 10 U.S. breeding programs were scored with 1536 single nucleotide polymorphism (SNP) genotyping assays. The number of SNPs segregating within breeding programs varied from 854 to 1398. Model‐based analysis of population structure showed the expected clustering by row type and growth habit; however, there was additional structure, some of which corresponded to the breeding programs. The model that fit the data best had seven populations: three two‐row spring, two six‐row spring, and two six‐row winter. Average linkage disequilibrium (LD) within populations decayed over a distance of 20 to 30 cM, but some populations showed long‐range LD suggestive of admixture. Genetic distance (allele‐sharing) between populations varied from 0.11 (six‐row spring vs. six‐row spring) to 0.45 (two‐row spring vs. six‐row spring). Analyses of pairwise LD revealed that the phase of allelic associations was not well correlated between populations, particularly when their allele‐sharing distance was >0.2. These results suggest that pooling divergent barley populations for purposes of association mapping may be inadvisable.