Barley Breeding Research Articles

Resistance to Powdery Mildew in Barley Recombinant Lines Derived from Crosses between Hordeum vulgare and Hordeum bulbosum

Barley recombinant lines obtained from crosses and backcrosses of common barley (Hordeum vulgare L.) cultivars Emir and Golden Promise with bulbosus barley grass (H. bulbosum L.) were tested against differential set of 14 Blumeria graminis D.C. Golovin ex Speer f. sp. hordei – synamorph Erysiphe graminis DC. f. sp. hordei Em Marchall isolates, pathogenic fungus causing powdery mildew. Powdery mildew resistance was found in 22 from 24 lines tested. Presence of unknown genes was postulated in 13 lines. In six of these lines the unknown genes were postulated present besides Mla12 allele originated from H. vulgare parent (cv. Emir). The only line resistant to infection, from all isolates used, was 181P94/1/3/1/1/1-2. Four other lines could be considered highly resistant, because they were susceptible to only one powdery mildew isolate. The possibilities to use the hybrid lines with identified resistance to powdery mildew, especially line 181P94/1/3/1/1/1-2 in barley breeding programs were discussed.

Genetic patterns of breeding upon creation of the first Ukrainian waxy barley cultivar Shedevr

Aim. The study’s purpose was to establish genetic patterns of waxy barley breeding on the basis of determination of genetic and breeding characteristics of accessions with different fractional composition of starch during 10/11-year cycles of the breeding process upon creation of waxy barley cultivars. Methods. Analysis of variance, calculus of variations, correlation analysis, genetic and breeding methods were used to investigate peculiarities of genotypes in topcross, diallel and pair-crossing designs. Results. The important scientific problem concerning establishment of genetic patterns of waxy spring barley breeding was solved. We determined morpho-biological features, variability, correlations and genetic peculiarities of inheritance, heritability, genetic variation and combining ability for quantitative traits of plants as well as for amylopectin content in starch of F1 hybrids derived from forms with different fractional composition of starch. As a result of establishing the patterns, the effectiveness of creation of valuable lines and waxy barley cultivar Shedevr with amylopectin starch was demonstrated. Conclusions. The morpho-biological, breeding and genetic peculiarities of plant traits with different fractional composition of starch were determined. On this basis, the genetic patterns of waxy barley breeding were established, and the first Ukrainian waxy barley cultivar Shedevr (with amylopectin starch) was created.
 Keywords: Hordeum vulgare L., accession, cultivar, amylopectin starch, genetic peculiarities.

Spatial analysis in multi-environment trials of malt barley in Ethiopia

Selection of superior genotypes and measuring heritability are some of the basic objectives of plant breeding. For this purpose, plant breeders grow crops across environments. Understanding the pattern of response across environments is an integral component of selection of superior and stable genotypes. The objective of this study was to improve selection strategies in barley breeding of Ethiopia through modeling spatial field trend. A set of multi-environment trials (MET) data from the national variety trial series conducted over four years, was taken from the Ethiopian Barley Breeding Programme, spanning stages from early generation to national variety trial testing for yield, was used in this study. The trials were analysed in a linear mixed model framework. Then, fitting a one-stage model for MET data, including a correlated spatial process for field trend within each trial, and combining a factor analytic (FA) model for genotype by environment interaction was conducted. The genetic correlations from this MET analysis were then used to cluster the environments based on their similarity. Performance of genotypes across these environmental clusters indicate broad (Bekoji-2005 and Bekoji-2004) and specific adaptation (Sgonder-2007 and Sgonder-2006) of genotype to certain types of environments. In addition, analysis of this historical MET data shed light on how breeding programme design can be improved to capture responses across the target population of environments, as it can inform the adequacy of the current number of barley grown areas in Ethiopia and the improvement in measuring heritability. Key words: Barley MET, heritability, linear mixed model

Mapping malting quality and yield characteristics in a north American two-rowed malting barley × wild barley advanced backcross population

Due to the stringent quality requirements imposed by the US malting barley industry, barley breeders have been reluctant to introduce exotic germplasm into cultivar development programs. To determine whether wild barley (Hordeum vulgare ssp. spontaneum) contains favorable alleles for yield and malting quality characteristics, we mapped quantitative trait loci (QTL) for heading date, height, lodging, yield, and nine malting parameters important to the malting and brewing industry. Traits were mapped in a wild x cultivated barley BC2-derived advanced backcross mapping population. Harrington, the recurrent parent, is a North American two-rowed malting barley cultivar, and OUH602, the donor parent, is a wild barley accession that exhibits resistance to multiple barley diseases. The 98 derived lines were grown in replicated field trials at St. Paul and Crookston, MN in 2009–2011. One to four QTL were identified for each trait, for a total of 36 QTL. Trangressive segregants for increased yield were identified and four lines had higher yield than Harrington across all environments; however, for yield QTL the OUH602 alleles decreased the trait value. Wild barley alleles had both positive and negative effects on the malting traits of diastatic power, free amino nitrogen, and soluble protein. Combined with the previously identified QTL associated with resistance to fungal diseases, this population represents a rich resource for barley breeding. To facilitate future breeding and genetics studies with this population, a set of pre-introgression lines composed of 28 BC2-derived and 6 BC3-derived lines were identified that collectively contain introgressions across the entire OUH602 genome.

Mapping of agronomic traits, disease resistance and malting quality in a wide cross of two-row barley cultivars.

Wide crosses between genetically diverged parents may reveal novel loci for crop improvement that are not apparent in crosses between elite cultivars. The landrace Chevallier was a noted malting barley first grown in 1820. To identify potentially novel alleles for agronomic traits, Chevallier was crossed with the modern malting cultivar NFC Tipple generating two genetically diverse recombinant inbred line populations. Genetic maps were produced using genotyping-by-sequencing and 384-SNP genotyping, and the populations were phenotyped for agronomic traits to allow the identification of quantitative trait loci (QTL). Within the semi-dwarf 1 (sdw1) region on chromosome 3H Chevallier conferred increased plant height and reduced tiller number, with QTL for these traits explaining 79.4% and 35.2% of the phenotypic variance observed, respectively. Chevallier was also associated with powdery mildew susceptibility, with a QTL on 1H accounting for up to 19.1% of the variance and resistance at this locus most likely resulting from an Mla variant from Tipple. Two novel QTL for physiological leaf spotting were identified on 3H and 7H, explaining up to 17.1% of the variance and with the Chevallier allele reducing symptom severity on 7H. Preliminary micromalting analysis was also undertaken to compare the malting characteristics of Chevallier and Tipple. Chevallier malt contained significantly lower levels of both α-amylase and wort β-glucan than Tipple malt, however no significant differences were observed for the remaining malting parameters measured. This suggests that the most obvious improvements in barley since the introduction of Chevallier are for agronomic traits such as height, yield and lodging resistance rather than for malting characteristics. Overall, our results demonstrate that this wide cross between Chevallier and Tipple may provide a source of novel QTL for barley breeding.

Ethiopian barley landraces: useful resistant sources to manage Barley yellow dwarf and other foliar diseases constraining productivity

One hundred sixty-five advanced lines were subjected to marker-assisted selection using Cleaved amplified polymorphic sequence-polymerase chain reaction (CAPS-PCR) primer against Barley yellow dwarf (BYD) resistant Yd2 gene. In addition, phenotypic evaluation was employed to screen the advanced lines for multiple disease resistance. Effect of host growth rate and incubation period on BYD development was also assessed. Results of marker PCR showed that Yd2 gene was detected in 96 (58.2%) out of 165 accessions tested. Data on relationships of days to heading (DtH) and BYD symptoms development revealed that barley accessions having shorter DtH (66 days), BYD severity appeared low, and vice versa on accessions having longer DtH (79–83 days). Screening for multiple disease resistance gave interesting results. Among 11 accessions (with Yd2) selected as the best for multiple diseases, 6 accessions [Chelia local, 4304–2(2), 4818(1.3), 1822–1(1), 1831–2-2(2), and 4915–1(1.2)] were highly resistant to leaf rust and net blotch, while other five lines had moderately resistant reaction. Study on the relationship of host resistance and incubation period showed that BYDV was detectable 5 days earlier in susceptible than in resistant lines. This can be used as an alternative method in preliminary screening of large number of genotypes against BYDV. From this study, it was evident that the identified resistant genotypes are a good resource for barley improvement program targeting BYDV and other important foliar pathogens. Barley breeders are encouraged to take advantage of this opportunity in producing multi-disease resistant barley genotypes in an agronomically enhanced genetic background in the country and beyond.

Variability of performance and its structural elements in spring barley cultivars

The aim and tasks of the study. Mutual influence of performance elements and the strength of this influence to predict the effectiveness of selections for performance in spring barley breeding were studied, and the least varying performance traits were identified.Material and methods. The study was conducted in variety testing experiments with a plot area of 10 m2 in 2015–2018. Thirty typical plants were harvested for structural analysis. The significance of differences was assessed by analysis of variance in a Microsoft Excel spreadsheet. Six varieties selected out of 25 accessions, because they were the most highly productive and adapted, were taken as the test material.Correlation analysis was performed, and the variation coefficients were computed, as BA Dospekhov described [22] using the Microsoft Excel spreadsheet and STATISTICA 10 software; their significance levels were assessed with the STATISTICA 10 software.Results and discussion. We found that in this sample of cultivars the spike length (V = 1.46–5.18%) was the least varying, depending on the growing conditions, and the grain weight per spike (V = 11.8–45.7%) and performance (V = 8.50–43.90%) were the most varying. There was only a close linear relationship between the performance and the grain number in the main spike; the productive tillering did not always determine the performance, as it depended on the weather conditions. In terms of variability degree, we established that in this sample of cultivars Avhur was the most plastic and responded to changes in the growing conditions, and Khors and Ahrarii showed stable performance.Changes in the direction and strength of correlations between the performance elements depended on the growing conditions. Under the influence of specific conditions, the contributions of structural elements to the performance redistributed, that is, a compensatory effect was observed.Conclusions. The expression variability of the performance elements and their correlations depended on the growing conditions; therefore, many years of research are needed to establish patterns. For this sample of high-yielding cultivars, the productive tillering is not always a determinant of the performance; selecting high-yielding accessions, one should focus on the grain number per spike. Cultivar Avhur can be recommended for breeding as a source of high performance, and cultivars Khors and Ahrarii - as sources of stable performance.

Genome‐Wide Association Mapping of Seedling Net Form Net Blotch Resistance in an Ethiopian and Eritrean Barley Collection

ABSTRACTThe net form of net blotch, caused by Pyrenophora teres f. teres (Ptt), is an economically important disease of barley (Hordeum vulgare L.) that is best managed by breeding for resistance. Previous linkage mapping and genome‐wide association studies (GWAS) have identified many resistance quantitative trait loci (QTL) in barley. Here we report eight novel resistance QTL identified in a unique collection of barley landraces from Ethiopia and Eritrea (EEBC) using a GWAS approach. Lines from the EEBC were genotyped with the Illumina barley iSelect chip and phenotyped with four Ptt isolates. A GWAS was conducted using the efficient mixed model association (EMMA) method with principal components and kinship to control false positives. Using a significance threshold of false discovery rate (FDR) of 0.05, two marker–trait associations (MTAs) were found on chromosomes 6H and 5H, respectively. Since this is a stringent method, markers in the lower 0.1 percentile of the p value distribution were also considered significant, identifying 20 unique MTAs. The 20 MTAs corresponded to 15 unique genomic loci, based on analysis of local linkage disequilibrium. Of the 15 QTL identified, one was identified in chromosome 1H, six in 2H, three each in 3H and 5H, and two in 6H. Eight of these QTL appear to be novel and thus could be of value to barley breeding programs to introgress novel net blotch resistance.

Genetic analysis of four main flavonoids in barley grain

Genetic analysis of 4 major flavonoids in barley interspecific hybrids which were used as parents for half diallel crossingwas carried out. Compared with seven parents, the highest general combining ability of catechin content was Clipper barley, the higest general combining ability (GCA) of myricetin content were Schooner barley and Huangchangguang barley, the highest general combining ability of quercetin content were Ziguangmang barley and Kuanying barley, the highest general combining ability of kaempferol content were Ziguangmang barley and Schooner barley, the highest general combining ability of flavonoids are Schooner barley and Huangchangguang barley. The hybrid combination of a good matching were Clipper barley, Schooner barley, Ziguangmang barley and Kuanying barley, as a comprehensive general combining ability, specific combining ability, and combinations of which can be used as flavonoids in barley breeding.

The anther-specific CYP704B is potentially responsible for MSG26 male sterility in barley.

Plant male sterility is a valuable trait in breeding and hybrid seed production. The barley male-sterility gene msg26 was mapped to a 0.02-cM region that anchors to a 506-kb low-quality assembly between two cleaved amplified polymorphic sequence (CAPS) markers, SP1M14 and SP1M49. The barley gene HORVU4Hr1G074840, which encodes a putative cytochrome P450 CYP704B protein, appears to be a strong candidate for the MSG26 trait. Barley (Hordeum vulgare L.) is an important cereal crop worldwide. Traditional breeding in barley is time-consuming and labor-intensive. The use of male-sterile genotypes may significantly improve the efficacy of hybrid breeding and seed production. The barley accession 'GSHO745' is a spontaneous male-sterile mutant from the barley variety, 'Unitan'. The male sterility in 'GSHO745' is controlled by the recessive gene, msg26 (originally named as ms-u). We revealed that the barley plants homozygous for msg26 proceeded normally through Meiosis II until the tetrad stage, but became fully defective in the late uninucleate microspores and developed pollen-less anthers. Using seven barley F2 populations, we mapped MSG26 to a 0.02-cM region that anchored to a 506-kb low-quality assembly between two cleaved amplified polymorphic sequence markers, SP1M14 and SP1M49. The HORVU4Hr1G074840 gene that encodes a putative cytochrome P450 protein (CYP704B) was identified as the most plausible candidate for MSG26. First, HORVU4Hr1G074840 is located in a collinear region of the rice CYP704B2 and the maize CYP704B1. Both of these genes are essential for male gamete production. Second, the male-sterile allele of HORVU4Hr1G074840 in GSHO745 contained a 4-bp deletion in the last exon. The resulting frame shift causes a Gly436Gln substitution, scrambles the sequence of the remainder of the protein, and forms a new termination site at the 70th triplet of the shifted reading frame. We thus called the variant protein CYP704B:p.G436Qfs*70. Third, the barley HORVU4Hr1G074840 gene was specifically expressed in anthers. Altogether, HORVU4Hr1G074840 represents a strong candidate for MSG26 in barley.

The intrinsic and regulated proteomes of barley seeds in response to fungal infection

Barley is an important cereal grain used for beer brewing, animal feed, and human food consumption. Fungal disease can impact barley production, as it causes substantial yield loss and lowers seed quality. We used sequential window acquisition of all theoretical ions mass spectrometry (SWATH-MS) to measure and quantify the relative abundance of proteins within seeds of different barley varieties under various fungal pathogen burdens (ProteomeXchange Datasets PXD011303 and PXD014093). Fungal burden in the leaves and stems of barley resulted in changes to the seed proteome. However, these changes were minimal and showed substantial variation among barley samples infected with different pathogens. The limited effect of intrinsic disease resistance on the seed proteome is consistent with the main mediators of disease resistance being present in the leaves and stems of the plant. The seeds of barley varieties accredited for use as malt had higher levels of proteins associated with starch synthesis and beer quality. The proteomic workflows developed and implemented here have potential application in quality control, breeding and processing of barley, and other agricultural products.

Deoxynivalenol-3-Glucoside Content Is Highly Associated with Deoxynivalenol Levels in Two-Row Barley Genotypes of Importance to Canadian Barley Breeding Programs.

Barley (Hordeum vulgare L.) is a multipurpose crop that can be harvested as grain or cut prior to maturity for use as forage. Fusarium head blight (FHB) is a devastating disease of barley that reduces quality of grain. FHB can also result in the accumulation of mycotoxins such as deoxynivalenol (DON). Breeding FHB resistant varieties has been a long-term goal of many barley-producing countries, including Canada. While the genetic basis of DON detoxification via production of less-phytotoxic conjugates such as DON-3-glucoside (DON3G) is well documented in barley, little information exists in reference to varietal response. Over two years, 16 spring, two-row barley genotypes, of importance to western Canadian barley breeding programs, were grown as short-rows and inoculated following spike emergence with a Fusarium graminearum conidia suspension. Half of the plots were harvested at soft dough stage and then dissected into rachis and grain components, whereas the remainder was harvested at maturity. Multiple Fusarium-mycotoxins were assayed using liquid chromatography-mass spectrometry. Mycotoxin content was elevated at the earlier harvest point, especially in the rachis tissue. DON3G constituted a significant percentage (26%) of total trichothecene content and thus its co-occurrence with DON should be considered by barley industries. DON3G was highly correlated with DON and 3-acetyl-deoxynivalenol (3ADON). The ratio of D3G/DON exhibited consistency across genotypes, however more-resistant genotypes were characterized by a higher ratio at the soft-dough stage followed by a decrease at maturity. Plant breeding practices that use DON content as a biomarker for resistance would likely result in the development of barley cultivars with lower total DON-like compounds.

Genetic structure of a Pyrenophora teres f. teres population over time in an Australian barley field as revealed by Diversity Arrays Technology markers

Net form of net blotch caused by Pyrenophora teres f. teres (Ptt) is a major foliar disease of barley (Hordeum vulgare) worldwide. Knowledge of the evolution of Ptt pathogen populations is important for development of durable host‐plant resistance. This study was conducted to investigate changes in genetic structure of a Ptt population within a barley field during three cropping years. The susceptible barley cultivar Henley was inoculated with Ptt isolate NB050. Leaf samples were collected during the years 2013–15 and 174 single spore Ptt isolates stored. Genotyping using Diversity Arrays Technology markers identified that 25% of isolates were clones of the inoculated isolate and 75% of isolates were multilocus genotypes (MLGs) differing from the original inoculated genotype. The novel genotypes probably originated from a combination of windborne spores from neighbouring fields, infected seed and sexual recombination in the field. The rapid change in the genotypic composition of the Ptt population in this study suggests adaptive potential of novel genotypes and demonstrates the need for barley breeders to use multiple sources of host‐plant resistance to safeguard against resistance being overcome.

ASSOCIATION MAPPING OF MORPHOLOGICAL AND PHYSIOLOGICAL TRAITS OF FLAG LEAF RELATED TO DROUGHT TOLERANCE IN BARLEY

Association mapping has proven to be a powerful approach for dissecting the genetic basis of complex traits. In this study, QTLs controlling flag leaf characteristics under drought stress were detected in a set of 148 modern spring barley cultivars using AM analysis. Flag leaf length (FLL), flag leaf width (FLW), relative water content (RWC), chlorophyll content, and maximum quantum efficiency of PSII (Fv/Fm) which are important in photosynthetic rate, were evaluated under normal irrigation and drought stress conditions at grain filling stage. Population structure was estimated using Structure 2.3 and linkage disequilibrium (LD) was estimated by the ‘Full Matrix LD’ using Tassel 5.0 . Significant marker/trait associations were investigated based on K-Q matrix using Tassel 3.0 . The analysis of population structure divided the cultivars into two sub-groups. Significant LD values (P < 0.01) between polymorphic sites with regions of high and low LD were observed. A total of 84 significant putative genomic regions were identified, which delineated into 37 QTLs under two water treatments. Two stable QTLs on 2H and 3H were detected for FLL in drought stress treatment. A QTL for FLL were detected on 2H in normal treatment, which alone explained around 11% of phenotypic variance of FLL. This QTL was also associated with the expression of FLW and explained around 7.5% of phenotypic variance. The results suggest that major loci are located on chromosomes 2H, 3H, 4H and 5H involved in the development of flag leaf characteristics and could be used as selection criteria in barley breeding for drought tolerance.

Identification of Ideal Allele Combinations for the Adaptation of Spring Barley to Northern Latitudes.

The northwards expansion of barley production requires adaptation to longer days, lower temperatures and stronger winds during the growing season. We have screened 169 lines of the current barley breeding gene pool in the Nordic region with regards to heading, maturity, height, and lodging under different environmental conditions in nineteen field trials over 3 years at eight locations in northern and central Europe. Through a genome-wide association scan we have linked phenotypic differences observed in multi-environment field trials (MET) to single nucleotide polymorphisms (SNP). We have identified an allele combination, only occurring among a few Icelandic lines, that affects heat sum to maturity and requires 214 growing degree days (GDD) less heat sum to maturity than the most common allele combination in the Nordic spring barley gene pool. This allele combination is beneficial in a cold environment, where autumn frost can destroy a late maturing harvest. Despite decades of intense breeding efforts relying heavily on the same germplasm, our results show that there still exists considerable variation within the current breeding gene pool and we identify ideal allele combinations for regional adaptation, which can facilitate the expansion of cereal cultivation even further northwards.

Dissecting the Genetic Basis of Grain Size and Weight in Barley (Hordeum vulgare L.) by QTL and Comparative Genetic Analyses.

Grain size and weight are crucial components of barley yield and quality and are the target characteristics of domestication and modern breeding. Despite this, little is known about the genetic and molecular mechanisms of grain size and weight in barley. Here, we evaluated nine traits determining grain size and weight, including thousand grain weight (Tgw), grain length (Gl), grain width (Gw), grain length-width ratio (Lwr), grain area (Ga), grain perimeter (Gp), grain diameter (Gd), grain roundness (Gr), and factor form density (Ffd), in a double haploid (DH) population for three consecutive years. Using five mapping methods, we successfully identified 60 reliable QTLs and 27 hotspot regions that distributed on all chromosomes except 6H which controls the nine traits of grain size and weight. Moreover, we also identified 164 barley orthologs of 112 grain size/weight genes from rice, maize, wheat and 38 barley genes that affect grain yield. A total of 45 barley genes or orthologs were identified as potential candidate genes for barley grain size and weight, including 12, 20, 9, and 4 genes or orthologs for barley, rice, maize, and wheat, respectively. Importantly, 20 of them were located in the 14 QTL hotspot regions on chromosome 1H, 2H, 3H, 5H, and 7H, which controls barley grain size and weight. These results indicated that grain size/weight genes of other cereal species might have the same or similar functions in barley. Our findings provide new insights into the understanding of the genetic basis of grain size and weight in barley, and new information to facilitate high-yield breeding in barley. The function of these potential candidate genes identified in this study are worth exploring and studying in detail.

Modelling G×E with historical weather information improves genomic prediction in new environments.

MotivationInteraction between the genotype and the environment () has a strong impact on the yield of major crop plants. Although influential, taking explicitly into account in plant breeding has remained difficult. Recently has been predicted from environmental and genomic covariates, but existing works have not shown that generalization to new environments and years without access to in-season data is possible and practical applicability remains unclear. Using data from a Barley breeding programme in Finland, we construct an in silico experiment to study the viability of prediction under practical constraints.ResultsWe show that the response to the environment of a new generation of untested Barley cultivars can be predicted in new locations and years using genomic data, machine learning and historical weather observations for the new locations. Our results highlight the need for models of : non-linear effects clearly dominate linear ones, and the interaction between the soil type and daily rain is identified as the main driver for for Barley in Finland. Our study implies that genomic selection can be used to capture the yield potential in effects for future growth seasons, providing a possible means to achieve yield improvements, needed for feeding the growing population.Availability and implementationThe data accompanied by the method code (http://research.cs.aalto.fi/pml/software/gxe/bioinformatics_codes.zip) is available in the form of kernels to allow reproducing the results.Supplementary information Supplementary data are available at Bioinformatics online.

Barley: Global challenges and perspectives under non-tropical dry areas

The International Center for Agricultural Research in Dry Areas (ICARDA) is one of the 15 CGIAR centers and has a global mandate for barley improvement, specifically for more than 16 million ha of barley is grown in non-tropical dry areas across the globe. ICARDA’s barley improvement program has been reorganized into spring barley for high and low input environments and winter barley programs to address the requirements of different agro-climatic conditions/regions. The spring barley program targets germplasm improvement for feed, food and malt purposes, targeting germplasm enhancement for global stressed environments in hulled and huskless barley. The winter barley program is basically focused to improve germplasm for colder regions in West and Central Asia where cold and frost are the major stresses along with drought. Each year, nearly 10000 advanced lines are evaluated for various agronomic, biotic and abiotic stress tolerances, and grain quality parameters in the breeding program. ICARDA’s gene bank holds more than 33,000 barley accessions of which 2042 accessions are wild relatives of barley. The Focused Identification of Germplasm Strategy (FIGS) approach is utilized to mine efficiently this collection by selecting manageable subsets with higher frequencies for finding the sought traits. ICARDA’s barley improvement program annually shares more than 330 sets of international trials and nurseries, with more than 60 collaborators in 35 to 40 countries. During 1977-2018, more than 269 barley varieties have been released across the globe by different countries, with direct introduction of germplasm from ICARDA’s barley breeding programs, out of which 53 are released during last 10 years. In recent year, ICARDA’s feed and food barley improvement program aims at improving nutritional qualities of barley, specifically Zn, Fe, and β-Glucan contents. Simultaneously, the malt barley improvement is targeting to identify better malting quality germplasm for developing countries in Africa and Asia with a possibility of additional income to farmers through premium price for better quality in East Africa and South Asia. Doi.org/10.25174/2249-4065/2018/85893

Registration of the S2MET Barley Mapping Population for Multi‐Environment Genomewide Selection

Market changes in the malting and brewing industries have increased the demand for locally produced barley (Hordeum vulgare L.) in many regions across North America. Breeding for productive barley cultivars in diverse growing environments is complicated by genotype × environment interactions (GEIs), which can make selection for broad adaptation difficult but may be exploited to select optimal cultivars for each environment. Genomewide selection has recently become a useful tool to make efficient selections on individuals using genomewide marker data. To support the use of genomewide selection to breed locally adapted barley cultivars, the University of Minnesota barley breeding program is publicly releasing a panel of two‐row barley lines, and accompanying data, called the S2MET (Spring Two‐Row Multi‐Environment Trial) (Reg. No. MP‐2, NSL 526938 MAP). The S2MET includes 233 breeding lines grouped into a 183‐line training population and a 50‐line validation population. The entire panel was genotyped using genotyping‐by‐sequencing and phenotyped for 14 important traits in 44 location‐year environments between 2015 and 2017. All data are freely available at the Triticeae Toolbox (https://triticeaetoolbox.org/barley/), and we describe several on‐tap projects and breeding advances that are exploiting this resource. We believe this panel and dataset will be useful for answering important breeding questions related to genomewide selection and GEIs and developing locally superior barley cultivars.

Structural organization and functional divergence of high isoelectric point \u03b1-amylase genes in bread wheat (Triticum aestivum L.) and barley (Hordeum vulgare L.)

BackgroundHigh isoelectric point α-amylase genes (Amy1) play major roles during cereal seed germination, and are associated with unacceptable high residual α-amylase activities in ripe wheat grains. However, in wheat and barley, due to extremely high homology of duplicated copies, and large and complex genome background, the knowledge on this multigene family is limited.ResultsIn the present work, we identified a total of 41 Amy1 genes among 13 investigated grasses. By using genomic resources and experimental validation, the exact copy numbers and chromosomal locations in wheat and barley were determined. Phylogenetic and syntenic analyses revealed tandem gene duplication and chromosomal rearrangement leading to separation of Amy1 into two distinct loci, Amy1θ and Amy1λ. The divergence of Amy1λ from Amy1θ was driven by adaptive selection pressures performed on two amino acids, Arg97 and Asn233 (P > 0.95*). The predicted protein structural alteration caused by substitution of Asp233Asn in the conserved starch binding surface site, and significantly expressional differentiation during seed germination and grain development provided evidence of functional divergence between Amy1θ and Amy1λ genes. We screened out candidate copies (TaAmy1-A1/A2 and TaAmy1-D1) associated with high residual α-amylase activities in ripe grains. Furthermore, we proposed an evolutionary model for expansion dynamics of Amy1 genes.ConclusionsOur study provides comprehensive analyses of the Amy1 multigene family, and defines the fixation of two spatially structural Amy1 loci in wheat and barley. Potential functional divergence between them is reflected by their sequence features and expressional patterns, and driven by gene duplication, chromosome rearrangement and natural selections during gene family evolution. Furthermore, the discrimination of differentially effective copies during seed germination and/or grain development will provide guidance to manipulation of α-amylase activity in wheat and barley breeding for better yield and processing properties.