Two-rowed Cultivars Research Articles

Optimum seeding rates for hulless barley production in eastern Canada

Hulless barley is a relatively new crop in eastern Canada. Best cultural practices must be developed for hulless barley to achieve its maximum yield potential. A study was carried out to identify the optimum seeding rates for hulless barley in eastern Canada. Six barley lines consisting of two-row and six-row covered and hulless varieties (AAC Azimuth, AAC Starbuck, CDC Ascent, AAC Bloomfield, AAC Ling, and CH2720-1) were seeded in six different seeding rates (250, 350, 450, 550, 650, and 750 seeds m−2) in a factorial experiment with four replications at seven sites across eastern Canada. The results showed that the optimum seeding rate for covered barley was 250–350 seeds m−2, but those for hulless barley higher yield potentials were achieved at seeding rate from 450 to 550 seeds m−2. Two-row varieties were higher yielding and had higher protein concentration than six-row varieties. The results of this study show that there is potential for further development of high-yielding two-row cultivars for eastern Canada.

Management of Pyrenophora teres f. teres, the Causal Agent of Net Form Net Blotch of Barley, in A Two-Year Field Experiment in Central Italy.

Pyrenophora teres is the causal agent of barley net blotch (NB), a disease that can be found in two different forms: net form (NFNB), caused by P. teres f. teres, and spot form (SFNB), caused by P. teres f. maculata. A two-year field experiment was carried out to evaluate the response to NB of six different barley cultivars for malt or feed/food production. In addition, the efficacy of several recently developed foliar fungicides with different modes of action (SDHI, DMI, and QoI) towards the disease was examined. After NB leaf symptom evaluation, the identification of P. teres forms was performed. Grain yield was determined, and pathogen biomass was quantified in the grain by qPCR. In the two experimental years characterized by different climatic conditions, only P. teres f. teres was detected. The tested cultivars showed different levels of NFNB susceptibility. In particular, the two-row cultivars for malt production showed the highest disease incidence. All applied fungicides exhibited a high efficacy in reducing disease symptoms on leaves and pathogen accumulation in grains. In fact, high levels of fungal biomass were detected only in the grain of the untreated malting barley cultivars. For some cultivars, grain yield was positively influenced by the application of fungicides.

Analyses of MADS-box Genes Suggest HvMADS56 to Regulate Lateral Spikelet Development in Barley.

MADS-box transcription factors are crucial regulators of inflorescence and flower development in plants. Therefore, the recent interest in this family has received much attention in plant breeding programs due to their impact on plant development and inflorescence architecture. The aim of this study was to investigate the role of HvMADS-box genes in lateral spikelet development in barley (Hordeum vulgare L.). A set of 30 spike-contrasting barley lines were phenotypically and genotypically investigated under controlled conditions. We detected clear variations in the spike and spikelet development during the developmental stages among the tested lines. The lateral florets in the deficiens and semi-deficiens lines were more reduced than in two-rowed cultivars except cv. Kristina. Interestingly, cv. Kristina, int-h.43 and int-i.39 exhibited the same behavior as def.5, def.6, semi-def.1, semi-def.8 regarding development and showed reduced lateral florets size. In HOR1555, HOR7191 and HOR7041, the lateral florets continued their development, eventually setting seeds. In contrast, lateral florets in two-rowed barley stopped differentiating after the awn primordia stage giving rise to lateral floret sterility. At harvest, the lines tested showed large variation for all central and lateral spikelet-related traits. Phylogenetic analysis showed that more than half of the 108 MADS-box genes identified are highly conserved and are expressed in different barley tissues. Re-sequence analysis of a subset of these genes showed clear polymorphism in either SNPs or in/del. Variation in HvMADS56 correlated with altered lateral spikelet morphology. This suggests that HvMADS56 plays an important role in lateral spikelet development in barley.

'Spikelet stop' determines the maximum yield potential stage in barley.

Determining the grain yield potential contributed by grain number is a step towards advancing the yield of cereal crops. To achieve this aim, it is pivotal to recognize the maximum yield potential (MYP) of the crop. In barley (Hordeum vulgare L.), the MYP is defined as the maximum spikelet primordia number of a spike. Many barley studies assumed the awn primordium (AP) stage to be the MYP stage regardless of genotypes and growth conditions. From our spikelet-tracking experiments using the two-rowed cultivar Bowman, we found that the MYP stage can be different from the AP stage. Importantly, we find that the occurrence of inflorescence meristem deformation and its loss of activity coincided with the MYP stage, indicating the end of further spikelet initiation. Thus, we recommend validating the barley MYP stage with the shape of the inflorescence meristem and propose this approach (named 'spikelet stop') for MYP staging. To clarify the relevance of AP and MYP stages, we compared the MYP stage and the MYP in 27 barley accessions (two- and six-rowed accessions) grown in the greenhouse and in the field. Our results reveal that the MYP stage can be reached at various developmental stages, which greatly depend on the genotype and growth conditions. Furthermore, we propose that the MYP stage and the time to reach the MYP stage can be used to determine yield potential in barley. Based on our findings, we suggest key steps for the identification of the MYP stage in barley that may also be applied in a related crop such as wheat.

Identification of novel plant architecture mutants in barley

In grasses, biomass and grain production are affected by plant architecture traits such as tiller number, leaf size and orientation. Thus, knowledge regarding their genetic basis is a prerequisite for developing new improved varieties. Mutant screens represent a powerful approach to identify genetic factors underpinning these traits: the HorTILLUS population, obtained by mutagenesis of spring two-row cultivar Sebastian, is a valuable resource for this purpose in barley. In this study, 20 mutant families from the HorTILLUS population were selected and evaluated for tiller number, leaf angle and a range of other plant architecture and agronomic traits using an unreplicated field design with Sebastian as a check cultivar. Principal Component Analysis revealed strong relationships among number of tillers, upper canopy leaf angle, biomass and yield-related traits. Comparison to the Sebastian background revealed that most mutants significantly differed from the wild-type for multiple traits, including two mutants with more erect leaves and four mutants with increased tiller number in at least one phenological stage. Heatmap clustering identified two main groups: the first containing the two erect mutants and the second containing Sebastian and the high-tillering mutants. Among the high-tillering mutants, two showed significantly higher biomass and grain yield per plant compared to Sebastian. The selected mutants represent promising materials for the identification of genetic factors controlling tillering and leaf angle in barley.

Resistance of European Spring 2-Row Barley Cultivars to Pyrenophora graminea and Detection of Associated Loci

Pyrenophora graminea is the seed-borne pathogen causal agent of barley leaf stripe disease. In this work, we screened a collection of 206 spring two-row barley cultivars from Europe for their resistance to the fungal pathogen. Artificial inoculation with the highly virulent isolate Dg2 revealed a continuous variation for the incidence of infection, with few highly resistant or highly susceptible genotypes. On average, old cultivars showed higher resistance than the more modern ones. Genome-Wide Association Scan was performed by exploiting available molecular data for >4000 SNP markers and revealed a single, highly significant association on the short arm of chromosome 6H, in a genomic position where quantitative trait loci (QTL) for barley resistance to P. graminea were not detected before. Based on the last version of the reference barley genome, genes encoding for proteins with a kinase domain were suggested as candidates for the locus.

Levels and variability of valuable economic characteristics of spring barley, depending on genotype and hydrothermal conditions

Purpose and Objectives. The purpose was to evaluate the yield, the growing period length, resistance to diseases and lodging of spring barley, depending on genotype and hydrothermal conditions, and to select starting material for combining breeding.Materials and Methods. One six-row cultivar and two-row chaffy and naked cultivars and lines of spring barley were studied. The experiments were conducted in accordance with methods qualifying examination of plant varieties at the Plant Production Institute named after V.Ya. Yuriev of NAAS in 2018–2020. The plot area was 10 m2, in four replications. Data were statistically processed by analysis of variance in the STATISTICA 10 software; posteriori comparison was performed by homogenous groups (Fisher LSD).Results and Discussion. It was found that naked accessions gave lower yields compared to the check cultivar Vzirets under any growing conditions. The sample of chaffy accessions was homogeneous in terms of yield, hence, no significant excess was noted, and cultivar Grace was the only one which consistently exceeded the the check cultivar. As to the growing period length, all the accessions under investigation were mid-ripening.Resistance to lodging was strongly dependent on genotype and weather. In 2020, severe waterlogging combined with low temperatures favored the vegetative mass development and severe lodging. Therefore, in 2020, none of the accessions of the studied sample was completely resistant to lodging. Cultivars Merlin and Krasen can be distinguished by very high or high group resistance to head smut, net blotch and powdery mildew.Conclusions. The study singled out six cultivars as breeding-valuable ones with a set of economic characteristics (high low-variable yield [11.06–18.59%], resistance to lodging [8.3–8.8 points], high resistance to the pathogens of head smut [7–9 points] and brown spot [6–9 points]): Grace, Khors, Vzirets, Gladys, Krasen, and Herkules. Awnless accessions were identified as sources of resistance to head smut. Line 14-561 called Herkules was submitted to the qualifying examination of plant varieties.

Resistance of Two-Rowed Barley Cultivars and Collection Accessions to False Loose Smut in Western Siberia

False loose smut caused by the fungus Ustilago nigra Tapke causes significant damage to barley crops in Russia. The aim of this work was to estimate the false loose smut resistance in spring double-row barley varieties created by the Omsk Agrarian Research Center and samples from the Collection of the Vavilov All-Russia Institute of Plant Genetic Resources (VIR) in Western Siberia. Cultivars were assessed in the field in 2016–2019 according to common methods. The artificial inoculation of seeds with U. nigra teliospores was carried out before sowing. The damage to cultivars significantly varied, which was due to contrasting weather conditions during periods critical for plant infection. Stable resistance to disease was observed for cultivars Omsky 91 and Sasha, while damage to other cultivars of Omsk breeding increased. The collection cultivars of Russian and Western European breeding showed high resistance to false loose smut under conditions favorable for infection, as well as in drought with high temperatures. Ukrainian and Latvian cultivars showed high resistance to infection under conditions of high humidity and low temperature. High resistance under contrasting conditions was observed for cultivars Vorsinsky 2, Yasny, Vakula, Zadel 3, Yastreb, Inklyuziv, and Vzirez. The best combination of resistance to the disease and yields were demonstrated by cultivars Vorsinsky 2, Zernogradsky 770, Vakula, Vzirets, and Inklyuziv. These cultivars are promising to be used as sources of false loose smut resistance for barley breeding in Western Siberia.

Evaluating Winter Barley Cultivar Using Data Envelopment Analysis Models

Unlike feed barley, malting barley must meet a specific set of quality standards for acceptability by maltsters. Multiple quality criteria in addition to the grain yield makes ranking of genotypes challenging. The objective of this study was to apply data envelopment analysis (DEA) models to rank the efficiencies of 27 winter barley entries based on grain yield and quality indices. Four methods of DEA including Charnes, Cooper and Rhodes (CCR), Färe and Grosskopf (FG), Banker, Charnes and Cooper (BCC), and Seiford and Thrall (ST) used for the ranking. Testing trial included 14 two-rows and 13 six-rows winter barley. All entries except two, demonstrated high winter survival ratings. Overall, the six-row cultivars out-yielded the two-row cultivars by 18%. However, in terms of brewing quality, the two-row entries performed better than six-row entries and had 40% lower thinness, 12% higher plump, and lower grain protein content. The six-row entries had 32% higher germinative energy than two-row entries. The ranking by four models were not similar, however, SU-Mateo and Calypso had the highest efficiency (1.0) by all four models followed by Wintmalt and Vincenta.

Comparisons of Modern United States and Canadian Malting Barley Cultivars with Those from Pre-Prohibition: V. Bmy1 Intron III Alleles and Grain β-Amylase Activity and Thermostability

This study was conducted to determine the variation in Pre-Prohibition and modern barley malting genotype β-amylase activities and thermostabilities with differing Bmy1 intron III alleles. Sequencing of the endosperm specific β-amylase gene Bmy1 intron III of two- and six-row of Pre-Prohibition barley varieties revealed that both two- and six-row varieties had the Bmy1.a intron III allele. This is unusual in that previously there has been only one documented case of a two-row cultivar having the Bmy1.a intron III allele. In this study, all modern cultivars were found to have the expected Bmy1.b intron III allele and Bmy1.a intron III allele for two- and six-row cultivars, respectively. On a fresh weight or unit protein basis, the mean grain β-amylase activities of modern malting cultivars were significantly higher (P < 0.0001) than the mean for Pre-Prohibition malting varieties. This indicates that the many years of selection for diastatic power (DP) since the end of Prohibition in North America have increased the β-amylase activity significantly. Many studies have shown that DP strongly correlates with β-amylase activity. The β-amylase activities of modern cultivars with the highest β-amylase activity were significantly higher (P < 0.0001) than all Pre-Prohibition varieties. The β-amylase activities of Pre-Prohibition varieties with the lowest β-amylase activity were significantly lower (P < 0.0001) than all modern cultivars. Modern cultivars were significantly higher (P = 0.022) than for Pre-Prohibition varieties; although, the differences for most genotypes, be they Pre-Prohibition or modern, were not large. The two-row Pre-Prohibition varieties Hanna and Hannchen were the exceptions, being highly significantly lower (P < 0.0001) in thermostability than all other Pre-Prohibition and modern genotypes.

УРОЖАЙНОСТЬ МНОГОРЯДНОГО ЯРОВОГО ЯЧМЕНЯ РАЗНОВИДНОСТЕЙ PALLIDUM В СУХОСТЕПНОЙ ЗОНЕ

Background. Cultivated in the arid steppe zone of Volgograd Province is mainly two-rowed spring barley of the varieties nutans and medicum (Hordeum vulgare L. subsp. distichon (L.) Koern. var. nutans Schuebl. and H. vulgare L. subsp. distichon (L.) Koern. var. medicum Koern.). The areas under multi-rowed spring barley, with higher yield potential, are minimal. The aim of this work was to study multi-row spring barleys of the variety pallidum (H. vulgare L. subsp. vulgare var. pallidum Ser.) of various origins in the arid steppe environment. Materials and methods. The research was conducted in the arid steppe zone of Volgograd Province, with its light-chestnut heavy loamy soils, on the experimental field of the Lower Volga Research Institute of Agriculture. The nursery was set up according to the standard technique, and 120 multi-rowed spring barley accessions representing the pallidum variety from 11 countries were selected for the research. The commercialized two-rowed barley cultivar ‘Donetsky 8’ of the medicum variety was chosen as a reference. Results and conclusions. In the arid steppe environment of Volgograd Province, on light-chestnut heavy loamy soils, with the precipitation amount of 51.6–168.1 mm during vegetation and the hydrothermal coefficient (HTC) of 0.5–0.83, the productivity of all multi-rowed spring barley accessions of the pallidum variety was lower than that of the reference. Under dryer conditions (HTC = 0.5), the accessions from Tajikistan and Turkmenistan demonstrated good results, while in a wetter year (HTC = 0.83), those from Kyrgyzstan, Peru, Turkmenistan and Uzbekistan proved better. During all the years of experimenting, the accessions from Mexico and Bolivia were producing 1.2–1.5 times lower yields than the average for the collection. The accessions from Egypt had the highest economic efficiency ratio (36.9%–41.4%).

Effect of cultivar and agronomic management on feed barley production in Alberta environments

The area sown to barley (Hordeum vulgare L.) in Alberta, Canada, and the rate of yield increase relative to other major crops have declined in recent decades. Advanced agronomic management of feed barley may increase the seeded area and differentially influence cultivar performance. Field experiments were conducted from 2014 to 2016 at 11 rainfed and three irrigated environments in Alberta to evaluate the performance of 10 feed barley cultivars under standard and advanced agronomic management. Advanced management included supplemental postemergence N, the plant growth regulator chlormequat chloride, and two foliar fungicide applications. Cultivars responded similarly to management in the low disease pressure environments encountered in the study. The two-row cultivars CDC Austenson, Xena, and CDC Coalition were the highest yielding overall, while Champion had the greatest yields in moisture-limited environments. The feed grain quality of two-row cultivars was superior to six-row cultivars. Recently released six-row cultivars were among the lowest yielding. Negative or static yield increases were observed for all newer cultivars (2006–2013 registrations) compared with the older cultivar, Xena (2000 registration). In comparison, the overall 9.3% yield increase from advanced management was notable. Advanced management yield increases were greater (8%–18%) in environments with 251–502 mm of precipitation and smaller (1%–3%) in moisture-limited environments. Management had negligible effects on lodging and grain quality. Optimal yield and quality were achieved with the two-row cultivars, CDC Austenson, Xena, or CDC Coalition, and advanced management in high precipitation environments. In environments with less precipitation, optimal yields were achieved with Champion and standard management.

Grain Yield, Quality, and Nutrient Concentrations of Feed, Food, and Malt Barley

ABSTRACTBarley (Hordeum vulgare L.) is a cereal grown for animal feed, human consumption, and malting. Nutrient concentrations are important as they provide information regarding the dietary values of barley consumed by animals or human beings. In addition, grain nutrient removal may be useful for refining fertilizer recommendations. A study was conducted in 2015 and 2016 investigating the cultivar effects on grain yield, quality, and grain nutrient concentrations and removal under irrigated conditions for two-row barley cultivars. Adjunct and feed cultivars produced the highest yields compared with the all-malt and food cultivars. Specific quality and nutrient values were greater than or equal to in the food cultivar compared to the malt or feed cultivars. Variations in nutrient concentrations were measured among the adjunct and all-malt cultivars, which could potentially affect the malting and brewing qualities. Grain yield, quality, nutrient concentrations and nutrient removal varied among cultivars grown under identical environmental conditions, which may influence end-use.

Response of two-row and six-row barley to fertiliser N under Irish conditions

Abstract A range of cultivar types, including two-row and six-row types as well as line and hybrid types, are used for winter barley production in Ireland. There is little information available on the fertiliser nitrogen (N) requirements or the N use efficiency of these different types, particularly under Irish conditions. The objectives of the work presented here were to compare the response to fertiliser N of a two-row line cultivar, a six-row line cultivar and a six-row hybrid cultivar in terms of grain yield and aspects of N use efficiency. Experiments were carried out over three growing seasons, in the period 2012-2014, on a light-textured soil comparing the response of the three cultivars of winter barley to fertiliser N application rates ranging from 0 to 260 kg N/ha. There was no evidence that cultivar type, regardless of whether it was a two-row or six-row line cultivar or a six-row hybrid cultivar, influenced the response to fertiliser N of winter barley. There were some indications that six-row cultivars were less efficient at recovering soil N but used accumulated N more efficiently than the two-row cultivar. This work provided no evidence to support adjustment of fertiliser N inputs to winter barley based on cultivar type.

Assimilate and nitrogen remobilization of six-rowed and two-rowed winter barley under drought stress at different nitrogen fertilization

ABSTRACTField experiments were conducted to investigate the effects of irrigation regimes and N levels on assimilate remobilization of two barley cultivars (Yousefsix-rowed and Nimrouztwo-rowed) in 2011 and 2012. There were three levels of water regimes (full irrigation (I100), 75% and 50% of I100: I75 and I50, respectively) in 2011. Rain-fed treatment (I0) was included in 2012. Three N levels (0, 60, and 120 kg ha−1) were used. Grain yield and assimilate remobilization decreased by severe water stress (I0), however, the reduction of them were intensified by N fertilizer application. The N remobilization was negatively affected by N fertilization and water stress. The two-rowed showed higher N remobilization (10.7%) and contribution of N remobilized to N content of grain (5.8%) than the six-rowed. The two-rowed cultivar showed significantly higher assimilate remobilization and grain yield than the six-rowed under I50 (26.3% and 6.5%, respectively) and I0 (48.7% and 17.1%, respectively), while the six-rowed had similar or higher performances in terms of these traits under I100 and I75. This study showed that optimizing irrigation and N rates (decrease N level with increasing water stress) and selection of the suitable cultivars (Nimrouztwo-rowed) might increase assimilate remobilization and consequently grain yield under drought stress conditions.

Maltose Effects on Barley Malt Diastatic Power Enzyme Activity and Thermostability at High Isothermal Mashing Temperatures: I. β-Amylase

The hypothesis that maltose would increase the thermostability of barley malt β-amylase activity during isothermal mashing was tested. Malts of the two-row cultivar Harrington and the six-row cultivar Morex were incubated in maltose concentrations of 0–500 mM at 68, 73, and 78°C and compared with isothermal mashing at 63°C. Incubations with additions of mannitol from 0 to 500 mM at the same temperatures were used to compare with incubations containing maltose. Incubations were sampled every 30 min for 120 min, and β-amylase activities were determined. In the absence of exogenous sugars, extracts of Harrington had higher initial β-amylase activities than did extracts of Morex at 63, 68, and 73°C but not at 78°C, for which the reverse was observed. In the absence of exogenous sugars, extracts of both cultivars had the highest activities at 63°C, and both exhibited maximal responses to sugar additions with 500 mM maltose (889% increase for Morex and 541% for Harrington) compared with 0 mM controls at 63°C. Activities in extracts of both cultivars were significantly influenced by maltose additions starting at 50–100 mM and as early as 30 min at 63°C, and these effects were pronounced at and above 200 mM maltose. The maximum % survival of β-amylase at 120 min compared with 0 min for both cultivars occurred at 63°C (85–93% for Morex and 90–91% for Harrington) when incubations were with 400 and 500 mM maltose. A comparison of β-amylase thermostability between the cultivars was calculated as the % activity detected under the most favorable condition (0 min at 63°C) and that detected under the least favorable condition (120 min at 78°C). Our study showed that β-amylase in Harrington extracts was more thermostable than that in Morex extracts (10.1 and 5.9%, respectively). β-Amylase in both Harrington and Morex extracts showed some increases in activity and thermostability when mannitol was included in incubations. Increases were most pronounced at 63°C with 500 mM mannitol. However, these effects were not as great or as consistent as seen with maltose additions to the incubations. The extent of the maximum response to both maltose and mannitol on the thermostability of β-amylase from Morex malts was 60% greater than that of the β-amylase from Harrington malts.

Maltose Effects on Barley Malt Diastatic Power Enzyme Activity and Thermostability at High Isothermal Mashing Temperatures: II. α-Amylase

This study was conducted to determine if maltose, the primary product of starch degradation during mashing, would affect the activity of or increase the thermostability of barley malt α-amylase activity at high temperatures used in mashing and temperatures above those normally used in mashing. Malts of the two-row cultivar Harrington and the six-row cultivar Morex were mashed for 2 h with maltose concentrations of 0–500 mM at temperatures from 63 to 78°C. Worts were sampled every 30 min for 120 min and α-amylase activities determined utilizing the Megazyme Ceralpha assay. Mannitol, a polyhydric alcohol, was used for comparison. Polyhydric alcohols are known to enhance enzyme thermostability. At 63°C both cultivars had relatively thermostable α-amylase without the addition of maltose or mannitol. However, Morex, and to a lesser extent Harrington, α-amylase activity was significantly elevated by high levels of either maltose or mannitol, indicating a stimulatory effect on activity in which thermostability was apparently not involved. At 73 and 78°C increasing concentrations of maltose conferred considerable and highly significant (LSD analysis, P < 0.0001) thermal protection of α-amylase in both cultivars. For example, at 30 min of mashing at 73°C, maltose concentrations of 400 and 500 mM resulted in α-amylase activity in Harrington of 227 and 252% and in Morex 349 and 314%, respectively, of the 0 mM maltose activity. At 60 min of mashing at 73°C, concentrations of 400 and 500 mM maltose resulted in α-amylase activities of Harrington of 290 and 431% and Morex of 489 and 501%, respectively, of the 0 mM maltose activity. High mannitol incubations at higher temperatures such as at 73°C rendered lesser α-amylase thermal protection than maltose; however, it was also considerable and highly significant (P < 0.0001) for both cultivars (e.g., 30 min incubation at 73°C, with 400 and 500 mM maltose, respectively, α-amylase activities of Harrington were 163 and 174% and Morex were 188 and 260% of the 0 mM maltose activity). These data suggest that the production of maltose, as could be expected in high-gravity mashes, significantly increases the activity and thermostability of barley malt α-amylase.

QTL mapping for salt tolerance in barley at seedling growth stage

Barley (Hordeum vulgare L.), an important food and fodder crop, is potentially tolerant to salinity. To identify quantitative trait loci (QTLs) controlling salt tolerance, the population of 162 recombinant inbred lines (RILs) derived from F8 generation of Arigashar (an extremely salt tolerant Iranian six-rowed barley landrace) crossed with Igri (a salt semi-sensitive two-rowed cultivar) were evaluated. The growth of shoots, roots, and coleoptiles, and root numbers are four important growth characteristics severely affected by salt stress at seedling growth stages. A linkage map was constructed using 106 AFLP and SSR markers spanning six barley chromosomes including 2(2H), 3(3H), 4(4H), 7(5H), 6(6H), and 1(7H). Out of totally 26 detected QTLs, 17 QTLs were found effective for salt tolerance at 250 and 350 mM NaCl which localized on chromosomes 2H, 3H, 4H, 6H, 7H, and linkage group L1, whereas considering equivalent overlapped QTLs with a pleiotropic effect led to detection of totally 9 distinctive QTLs (QClgH2.1b, QSdgH2.1b, QSlgH2.1c, QNrgH2.1b, QTwgH2.2c, QSdg3Hb, QSlg4Hb1, QClg4Hb, and QSlg6Hc2) effective for salinity tolerance. 2(2H), 4(4H), and 6(6H) were major chromosomes harboring QTLs which effectively controlled salt tolerance in the Igri×Arigashar population. An interesting QTL, QTwg4Hc, was localized on chromosome 4H in the XE41-M61 marker distance that controls several traits including shoot and coleoptile lengths and shoot fresh mass under salt stress. A dense marker cluster around a resistance gene could offer a starting point for positional cloning.

BRS Sampa: malting barley cultivar for irrigated production

Barley BRS Sampa is a late heading, dwarf two-rowed malting barley cultivar released for irrigated production in Brazil. It combines high yield and kernel plumpness, disease and lodging resistance with malting quality. It is adapted to all major irrigated production regions of Brazil.

Nitrogen and water use efficiencies and yield response of barley cultivars under different irrigation and nitrogen regimes in a semi-arid Mediterranean climate

Experiments were conducted to determine barley cultivars (Yousefsix-rowed and Nimrouztwo-rowed) response to different water and nitrogen (N) regimes at Fars Agricultural Research Center using split-split-plot design. There were three levels of water regimes (full-irrigation (I100), 75% and 50% of I100: I75 and I50, respectively) in 2010. Rainfed treatment (I0) was included in 2011. Three N levels (0, 60 and 120 kg ha−1) were used. Grain and biomass water use efficiencies (WUEg and WUEb, respectively) were positively affected by N supply. The I75 improved WUEg and WUEb by 17% and 20% as compared to I100, respectively. Two-rowed cultivar showed higher WUEg and WUEb than six-rowed. Nitrogen use efficiency (NUE) was negatively affected by water stress and N fertilization. The highest grain yield was achieved by 120 and 60 kg N ha−1 under I100 and drought stress conditions, respectively. Two-rowed cultivar showed significantly higher NUE and grain yield than six-rowed cultivar under I50 and I0; by contrast, six-rowed cultivar had similar or higher performances in terms of these traits under I100 and I75. This study showed that optimizing irrigation and N rates and selection of suitable cultivars in semi-arid Mediterranean climate might increase NUE, WUE and produce economic grain yield.