Seed dormancy is an important trait associated with pre-sprouting and malting quality in barley. Genome-wide association studies (GWASs) have been used to detect quantitative trait loci (QTLs) underlying complex traits in major crops. In the present study, we collected 295 barley (Hordeum vulgare L.) accessions from Australia, Europe, Canada and China. A total of 25,179 single nucleotide polymorphism (SNP)/diversity arrays technology sequence markers were used for population structure, linkage disequilibrium and GWAS analysis. Candidate genes within QTL regions were investigated, and their expression levels were analysed using RNAseq data. Five QTLs for seed dormancy were identified. One QTL was mapped on chromosome 1H, and one QTL was mapped on chromosome 4H, while three QTLs were located on chromosome 5H. This is the first report of a QTL on the short arm of chromosome 5H in barley. Molecular markers linked to the QTL can be used for marker-assisted selection in barley breeding programmes.

Understanding seed moisture desorption and adsorption isotherms is important for seed quality maintenance and better predicting seed storage lifespan. Freshly harvested oilseed rape and barley seeds were dried and then rehydrated twice. Seed equilibrium relative humidity (eRH) and moisture content (MC) were determined at different humidity levels so that two cycles of desorption and adsorption could be constructed. In addition, seeds were dried to 30% RH and then rehydrated to 50% RH for five cycles to determine whether they shift to the adsorption isotherm. Monolayer MC was determined using the Gugenheim-Anderson-de Boer model. Storage experiments were conducted for seeds equilibrated at 30, 40, 50, 60 and 70% RH for two cycles of desorption and adsorption at 45°C. Isotherm curves’ shapes were similar for oilseed rape and barley, although spanning a greater MC range in barley. The hysteresis effect was observed for oilseed rape and barley seeds when dried over silica gel at <10% RH. However, this effect was only observed for barley seeds when dried to 30% RH, but not for oilseed rape seeds. Longevity was greater for adsorbing seeds than desorbing seeds at a given eRH, however, there was no significant difference in σ (the standard deviation of the normal distribution of seed deaths over time)–MC log–log relationship. The relationship shifted for seeds on the second cycle. In conclusion, if seed lots are stored at a specific RH, reaching equilibrium by desorption or adsorption can strongly influence their longevity. Also, when seeds of different species are dried to low RH, they will respond differently to a subsequent increase in RH, which could profoundly affect their longevity.

Barley is one of the most consumed cereals, with many different cultivars available worldwide. Like other crops, its yield has been affected by climate change and soil degradation. This work proposes controlled-release protein-based matrices with incorporated zinc to improve barley seed germination and zinc content in the plant. Thus, the main objective of this study was to investigate the use of controlled-release protein-based matrices for massive crops, such as barley. Different barley cultivars of barley were studied: Barke, Golden Promise, Morex, WB-200, WB379, and WB-446. The seeds of each cultivar were also analyzed in order to explain the behavior of plants observed during the growth. To this end, the physico-chemical (FT-IR, Raman spectroscopy, and Zn concentration) and microstructural (SEM) properties of the different seeds were firstly evaluated to establish differences between the studied cultivars. In addition, the use of controlled-release soybean protein-based matrices without zinc (M) or with zinc incorporated (MZ) was evaluated as fertilizers in the different barley cultivars. In this sense, the use of these matrices as a zinc carrier improved seed germination and zinc content in the plants, indicating that the use of matrices improves the amount of zinc assimilated by the crops (up to 30 and 50% with M and MZ, respectively) and allows the proper root growth of all cultivars of barley. In conclusion, this article shows the potential of controlled-release protein-based matrices as substitutes for conventional fertilization.

Three suspected resistant (R1, R2, and R3) corn marigold populations collected from winter cereal fields located in central Greece were studied to confirm and elucidate the mechanisms of resistance to acetolactate synthase (ALS) inhibitors and their competitive ability against barley. Whole-plant dose–response assays proved that the three suspected R populations were highly cross-resistant to the ALS inhibitors tribenuron, pyroxsulam + florasulam, and imazamox, whereas their control with synthetic auxin plus ALS inhibitors co-formulated mixtures was increased in the order of tritosulfuron + dicamba < florasulam + clopyralid < tribenuron + mecoprop-P < florasulam + aminopyralid. The ALS gene sequence revealed a point mutation in 11 plants of the R1, R2, and R3 populations, which resulted in the substitution of Pro-197-Thr or Trp-574-Leu. By contrast, all three sequenced plants of the susceptible (S) population were found with the wild-type allele encoding Pro-197 and Trp-574. This is the first report of ALS-inhibitor resistance in corn marigold. The competition study between barley and four densities of the S, R2, or R3 populations indicated similar biomass rates for all three populations, suggesting lack of association between the competitive ability of the R populations and the target-site resistance mechanism, which was also confirmed by the similar biomass reduction rates of barley grown in competition with S or R populations.

Adoption of cover crops in arid agroecosystems has been slow due to concerns regarding limited water resources and possible soil moisture depletion. In irrigated organic systems, potential ecosystem services from cover crops also must be considered in light of the concerns for water conservation. A constructive balance could be achieved with fall-sown small grain cover crops; however, their impacts on irrigated organic systems are poorly understood. Our first objective was to determine the ability of fall-sown small grains [cereal rye (Secale cereale L), winter wheat (Triticum aestivum L.), barley (Hordeum vulgare L.) and oat (Avena sativa L.)] to suppress winter weeds in an irrigated, organic transition field in the southwestern USA. Small grains were planted following the legume sesbania (Sesbania exaltata (Raf.) Rydb. ex A.W. Hill) during Fall 2012 and Fall 2013. In Spring 2013 and 2014, weed densities and biomass were determined within each cover crop treatment and compared against unplanted controls. Results indicated that both barley and oat were effective in suppressing winter weeds. Our second objective was to compare weed suppression and soil moisture levels among seven barley varieties developed in the western United States. Barley varieties (‘Arivat’, ‘Hayes Beardless’, ‘P919’, ‘Robust’, ‘UC603’, ‘UC937’, ‘Washford Beardless’) were fall-sown in replicated strip plots in Fall 2016. Weed densities were measured in Spring 2017 and volumetric soil moisture near the soil surface (5.1 cm depth) was measured at time intervals beginning in December 2016 and ending in March 2017. With the exception of ‘UC937’, barley varieties caused marked reductions in weed density in comparison with the unplanted control. Soil moisture content for the unplanted control was consistently lower than soil moisture contents for barley plots. Barley variety did not influence volumetric soil moisture. During the 2017–2018 growing season, we re-examined three barley varieties considered most amenable to the cropping system requirements (‘Robust’, ‘UC603’, ‘P919’), and these varieties were again found to support few weeds (≤ 5.0 weeds m−2). We conclude that several organically certified barley varieties could fill the need for a ‘non-thirsty’ cover crop that suppresses winter weeds in irrigated organic systems in the southwestern United States.

New production from public and exclusive varieties released by the small grains breeding program at Virginia Tech generated cumulative discounted benefits of $41 million from 2000 to 2018. Fitted yields from field trials were combined with acreage estimates to generate weighted average yields based on adoption of new varieties. Benefits were estimated as the value of additional production from the release and adoption of improved varieties. Public varieties were responsible for most program benefits. The program was found to have a significant impact in Virginia and out-of-state, with much of these benefits due to public-private collaboration.

Limited information exists on the global economic impact of glyphosate-resistant (GR) weeds. The objective of this manuscript was to estimate the potential yield and economic loss from uncontrolled GR weeds in the major field crops grown in Ontario, Canada. The impact of GR weed interference on field crop yield was determined using an extensive database of field trials completed on commercial farms in southwestern Ontario between 2010 and 2021. Crop yield loss was estimated by expert opinion (weed scientists and Ontario government crop specialists) when research data were unavailable. This manuscript assumes that crop producers adjust their weed management programs to control GR weeds, which increases weed management costs but reduces crop yield loss from GR weed interference by 95%. GR volunteer corn, horseweed, waterhemp, giant ragweed, and common ragweed would cause an annual monetary loss of (in millions of Can$) $172, $104, $11, $3, and $0.3, respectively, for a total annual loss of $290 million if Ontario farmers did not adjust their weed management programs to control GR biotypes. The increased herbicide cost to control GR volunteer corn, horseweed, waterhemp, giant ragweed, and common ragweed in the major field crops in Ontario is estimated to be (in millions of Can$) $17, $9, $2, $0.1, and $0.02, respectively, for a total increase in herbicide expenditures of $28 million annually. Reduced GR weed interference with the adjusted weed management programs would reduce farm-gate monetary crop loss by 95% from $290 million to $15 million. This study estimates that GR weeds would reduce the farm-gate value of the major field crops produced in Ontario by Can$290 million annually if Ontario farmers did not adjust their weed management programs, but with increased herbicide costs of Can$28 million and reduced crop yield loss of 95% the actual annual monetary loss in Ontario is estimated to be Can$43 million annually.

Replacing tillage with cover crops (CC) for weed management in corn (Zea mays L.)-soybean [Glycine max (L.) Merr.] systems with mechanical weed control has many soil health benefits but in the western Corn Belt, CC establishment after harvest is hampered by cold temperatures, limited labor and few compatible CC species. Spring-planted CC may be an alternative, but information is lacking on suitable CC species. Our objective was to evaluate four spring-planted CC with respect to biomass production and weed suppression, concurrent with CC growth and post-termination. Cover crop species tested were oat (Avena sativa L.), barley (Hordeum vulgare L.), brown mustard [Brassica juncea (L.) Czern.] and yellow mustard (Brassica hirta Moench). They were compared to no-CC treatments that were either tilled pre- and post-planting of soybean (no-CC tilled) or not tilled at all (no-CC weedy). CC were planted in late March to early April, terminated 52–59 days later using an undercutter, and soybean was planted within a week. The experiment had a randomized complete block design with four replications and was repeated for 3 years. Mustards and small grains produced similar amounts of biomass (1.54 Mg ha−1) but mustard biomass production was more consistent (0.85–2.72 Mg ha−1) than that of the small grains (0.35–3.81 Mg ha−1). Relative to the no-CC weedy treatment, mustards suppressed concurrent weed biomass in two out of 3 years, by 31–97%, and small grains suppressed concurrent weed biomass in only 1 year, by 98%.

Six weeks after soybean planting, small grains suppressed weed biomass in one out of 3 years, by 79% relative to the no-CC weedy treatment, but mustards did not provide significant weed suppression. The no-CC tilled treatment suppressed weeds each year relative to the no-CC weedy treatment, on average 87%. The ineffective weed control by CC reduced soybean biomass by about 50% six weeks after planting. While spring-planted CC have the potential for pre-plant weed control, they do not provide adequate early season weed suppression for soybean.

Chaff lining and chaff tramlining are harvest weed seed control (HWSC) systems that involve the concentration of chaff material containing weed seed into narrow (20 to 30 cm) rows between or on the harvester wheel tracks during harvest. These lines of chaff are left intact in the fields through subsequent cropping seasons in the assumption that the chaff environment is unfavorable for weed seed survival. The chaff row environment effect on weed seed survival was examined in field studies, and chaff response studies determined the influence of increasing amounts of chaff on weed seedling emergence. The objectives of these studies were to determine the influences of (1) chaff lines on the summer–autumn seed survival of selected weed species and (2) chaff type and amount on rigid ryegrass seedling emergence. There was frequently no difference (P > 0.05) in seed survival of four weed species (rigid ryegrass, wild oat, annual sowthistle, and turnip weed) when seeds were placed beneath or beside chaff lines. In one instance, wild oat seed survival was increased (P < 0.05) when seed were placed beneath compared to beside a chaff line. The pot studies determined that increasing amounts of chaff consistently resulted in decreasing numbers of rigid ryegrass seedlings emerging through chaff material. The suppression of emergence broadly followed a linear relationship in which there was approximately a 2.0% reduction in emergence with every 1,000 kg ha–1 increase in chaff material. This relationship was consistent across wheat, barley, canola, and lupin chaff types, indicating that the physical presence of the chaff was more important than chaff type. These studies suggested that chaff lines may not affect the survival over summer–autumn of the contained weed seeds but that the subsequent emergence of weed seedlings will be restricted by high amounts of chaff (>40,000 kg ha–1).

Polyhalite is a multi-nutrient mineral ore containing potassium (K), calcium (Ca), magnesium (Mg) and sulphur (S). Historically, it has enjoyed minor use as a fertilizer, but the opening of a new mine in the UK will make larger quantities available. Therefore, an examination of the performance of crops fertilized with polyhalite, or selected commercial alternatives, was pertinent and is reported here.

Four field trials were carried out between 2013 and 2016 to investigate the response of winter barley (Hordeum vulgare L.) and forage maize (Zea mays L.) to different application rates of polyhalite, potassium chloride (muriate of potash, MOP) and potassium sulphate (sulphate of potash, SOP) fertilizers. Potassium and S nutrition were the focus of these trials as they limit field production more often than Mg and Ca.

Polyhalite was found to be an effective source of both K and S for crop production. In three out of four trials, application of polyhalite resulted in similar or greater K offtake compared with both MOP and SOP; MOP application resulted in greater K offtake in one trial. In three out of four trials, application of polyhalite resulted in similar or better S offtake compared with both MOP and SOP; SOP application resulted in greater S offtake in one trial. Polyhalite and MOP treatments produced similar total dry weight in all four trials, but were slightly inferior to SOP treatment.

Dynamics of abscisic acid (ABA) and indole-3-acetic acid (IAA) contents were followed in developing barley caryopses of the ABA-deficient mutant AZ34 and its parental cultivar Steptoe. Distribution of these hormones and HvPIP2 aquaporins (AQPs) was studied with the help of immunohistochemical methods in the roots and coleorhiza of developing embryos. In Steptoe, maturation of the caryopsis was accompanied by vast accumulation of ABA, while this hormone accumulated more slowly in the caryopsis of AZ34 and its content was lower than in Steptoe. Accumulation of ABA was accompanied by a decline in IAA level in the developing caryopsis, the process being delayed in AZ34 in accordance with the slower accumulation of ABA. ABA accumulated to high levels in the coleorhiza cells of Steptoe, while the effect was absent in AZ34. The high level of ABA was likely to be important for maintaining the barrier function of the coleorhiza, preventing germination of seminal roots and enabling seed dormancy, while the absence of ABA accumulation in coleorhiza of AZ34 may be responsible for the initiation of root germination inside the caryopsis. The abundance of HvPIP2 AQPs in the seminal roots was higher at the beginning of maturation of Steptoe caryopsis and declined afterwards, while the levels of APQs increased later in AZ34 in accordance with the delay in ABA accumulation. These results suggest the importance of ABA accumulation in coleorhiza for preventing precocious growth of seminal roots, and suggest regulation of IAA and aquaporin levels by this hormone during maturation of embryos.

Soil salinity is one of the major abiotic stresses affecting seed germination, crop growth and productivity. In this study, seeds of three wheat (Triticum aestiveum L.) and three barley (Hordeum vulgare L.) cultivars were treated with different concentrations of NaCl to investigate the effect of salt on seed germination physiology and metabolism through the characterization of seed germination pattern, gamma-aminobutyric acid (GABA) shunt metabolite accumulation [GABA, glutamate (Glu) and alanine (Ala)] and glutamate decarboxylase (GAD) expression using RT-PCR. A trend of decreasing germination percentage with increasing NaCl concentrations was observed. Under all salt stress treatments, data showed significant increase with positive correlation (r = 0.50–0.99) between abundance of GABA shunt metabolites and salt concentration in all wheat and barley cultivars for 5 days. Increased GABA content was associated with a small but significant increase in Ala and Glu content in all cultivars. In all NaCl treatments, the transcription of GAD in terms of RNA abundance showed a significant increase in all cultivars with positive correlation (r = 0.50–0.98). Data showed significant association between GAD RNA transcription and the response of germinating seeds to salt stress in terms of GABA shunt metabolite accumulation. The elevated expression of GAD under salinity suggests the need for elevated activity of the GAD-mediated conversion of Glu to GABA during seed germination, which provides alternative metabolic routes to the respiratory machinery, balancing carbon and nitrogen metabolism and osmolyte synthesis in germinating seeds of wheat and barley under salt stress.

Cultivar mixtures of winter barley and spring barley, together with their component monocultures, were grown in field trials to assess the effect of cultivar combinations on both straw and grain yield. The overall grain yields for all trials were significantly higher for the cultivar mixtures than for the corresponding component monocultures. Also, significant decreases in rhynchosporium disease severity for cultivar mixtures were recorded for most non-fungicide treatments. The size of these responses was often significantly correlated with the component number of the mixtures. The amount of straw produced in mixtures was sometimes changed significantly, but not always in a positive direction and it was only correlated with increasing mixture component number in two environments. No correlation of straw yield potential of cultivars with performance in mixtures was found. Cultivar × cultivar mixture × environment interactions appeared to affect the relative yield of grain and straw differentially and therefore it was not possible to predict the effect of mixtures on the harvest index.

In the conventional cropping systems, increased costs and resource pollution are attributed to the intensive use of chemical inputs. The adoption of cover crops could be a part of a suitable strategy for improving the sustainability of the agro-ecosystems due to their ability to affect nutrient and weed management. A 2-yr field experiments were conducted in Gorgan, North of Iran, with the aim of assessing the effect of cover crop residue management and herbicide rates on weed management and the yield of tomato crop. The treatments consisted in: (a) three winter soil management: two cover crops [annual medic (Medicago scutellata L.) and barley (Hordeum vulgare L.)] and no covered soil; (b) two soil tillage (no-tillage, where cover crop residues were left in strips on the soil surface, and conventional tillage, where cover crop residues were green manured at 30 cm of soil depth); and (c) three pre-emergence herbicide rates (no-herbicide application, half rate recommended or full rate recommended ). Cover crops were sown in early September and mechanically suppressed in March about 2 weeks before tomato transplanting. At cover crop suppression, annual medic showed the highest aboveground biomass [569 g m−2 of dry matter (DM)], while barley showed the lowest weed content (32 g m−2 of DM). At tomato harvesting, weed density and aboveground biomass ranged from 6.9 to 61.5 plants m−2 and from 33.6 and 1157.0 g m−2 of DM, respectively. Cover crop residues placed on soil surface suppressed weeds more effectively than incorporated residues, especially in barley, mainly due to the physical barrier of residues which reduced the stimulation of weed germination and establishment. As expected, herbicide rate decreased both weed density and biomass, even if the adoption of annual medic and barley cover crops before the tomato cultivation could allow a possible reduction of herbicide rate while maintaining similar fruit yield. Tomato yield was higher in annual medic than barley and no cover regardless of tillage management (on average 62.3, 51.8 and 50.1 t ha−1 of fresh matter, respectively) probably due to an abundant availability of soil nitrogen throughout the tomato cultivation. This was confirmed by high and constant values of tomato N status grown in annual medic and evaluated using SPAD chlorophyll meter. Although further research of cover crop residue management is required to obtain a better understanding on herbicide rate reduction, these preliminary results could be extended to other vegetable crops which have similar requirements of tomato.

This study aimed to examine the effects of replacing rolled barley (high in starch) with citrus pulp (high in digestible fibre) in a supplement on intake and performance of young growing cattle offered grass silage ad libitum for 101 days. Weaned, early- and late-maturing breed, male suckled beef calves (n=120) were blocked by sire breed, gender and weight and from within block randomly assigned to one of two concentrate supplements based mainly on rolled barley (BAR) or citrus pulp (CIT) and formulated to have similar concentrations of true protein digestible in the small intestine. On day 87, blood samples were taken before and 2 h after feeding, and rumen fluid samples were collected 2 h post-feeding. Supplement type did not affect (P>0.05) grass silage intake, live weight gain, final live weight, ultrasonically assessed body composition or measurements of skeletal size. Rumen pH (6.64 v. 6.79), ammonia (51 v. 81 mg/l) and acetate-to-propionate ratio (2.7 v. 3.2) were lower (P<0.001) for CIT than BAR. In conclusion, citrus pulp can replace barley in concentrate supplements for growing cattle without negatively affecting performance.

Cover crop residues are not widely used for weed control because, as a stand-alone tactic, they do not effectively suppress all weeds and their duration of weed control is too short. Field experiments were conducted in 1995 and 1996, under both irrigated and rainfed conditions, to quantify Amaranthus spp., Setaria spp., and soybean emergence and growth in residues of fall-planted, spring-killed barley, rye, triticale, wheat, and hairy vetch. For both weed species, seedling emergence was reduced 3 wk after soybean planting by rye and wheat residues (≥ 2, 170 kg ha−1) in 1996. In 1996, Amaranthus spp. canopy volume was reduced 38 to 71% by residues 3 wk after planting. Likewise, Setaria spp. canopy biomass was reduced 37 to 97% in residues 5 wk after planting over both years. The response comparison index was used to identify frequency by which weed growth was placed at a disadvantage relative to soybean growth. Amaranthus spp. and Setaria spp. growth suppressions 3 to 5 wk after planting indicate potential times for intervention with other integrated weed management tactics such as reduced postemergence herbicide rates and interrow cultivation.