Manipulation of Barley Development and Flowering Time by Exogenous Application of Plant Growth Regulators

Matching flowering time to the optimal flowering period in Mediterranean cropping zones is pivotal to maximize yield. Aside from variety selection and sowing date, growers have limited options to alter development in season. Plant hormones and growth regulators are used in perennial horticultural systems to manipulate development and floral initiation. In this study, a range of plant hormonal products were tested to analyze their effects on barley (Hordeum vulgare L) development by exogenous spray applications. Plants were grown in controlled conditions under long and short photoperiods with different vernalization treatments. The gibberellin (GA) products demonstrated the greatest potential for altering development. The GA inhibitor trinexapac-ethyl was able to delay the time to flowering in genetically divergent barley cultivars by up to 200 degree days under controlled conditions. A similar delay in flowering could be achieved via application at both early (GS13) and late (GS33) stages, with higher rates delaying flowering further. Notably, trinexapac-ethyl was able to extend the duration of pre-anthesis phases of development. By contrast, GA3 was unable to accelerate development under extreme short (8 h) or long (16 h) day lengths. There was also little evidence that GA3 could reproducibly accelerate development under intermediate 10–12 h day lengths. In addition, sprays of the cytokinin 6-benzyladenine (6-BA) were unable to reduce the vernalization requirement of the winter genotype Urambie. The present study provides baseline data for plant growth regulator treatments that delay cereal development. These treatments might be extended in field studies to align flowering of early sown crops to the optimal flowering period.

Optimization of Potassium Supply under Osmotic Stress Mitigates Oxidative Damage in Barley

Potassium (K) is the most abundant cation in plants, playing an important role in osmoregulation. Little is known about the effect of genotypic variation in the tolerance to osmotic stress under different K treatments in barley. In this study, we measured the interactive effects of osmotic stress and K supply on growth and stress responses of two barley cultivars (Hordeum vulgare L.) and monitored reactive oxygen species (ROS) along with enzymatic antioxidant activity and their respective gene expression level. The selected cultivars (cv. Milford and cv. Sahin-91Sahin-91) were exposed to osmotic stress (−0.7 MPa) induced by polyethylene glycol 6000 (PEG) under low (0.04 mM) and adequate (0.8 mM) K levels in the nutrient solution. Leaf samples were collected and analyzed for levels of K, ROS, kinetic activity of antioxidants enzymes and expression levels of respective genes during the stress period. The results showed that optimal K supply under osmotic stress significantly decreases ROS production and adjusts antioxidant activity, leading to the reduction of oxidative stress in the studied plants. The cultivar Milford had a lower ROS level and a better tolerance to stress compared to the cultivar Sahin-91. We conclude that optimized K supply is of great importance in mitigating ROS-related damage induced by osmotic stress, specifically in drought-sensitive barley cultivars.

Creating Amylose-Free Barley Cultivars with High Soluble Sugar Content By Genome Editing

Background Amylose biosynthesis is strictly associated with granule-bound starch synthase I (GBSSI) encoded by the Waxy gene. Waxy barley has extensive prospects for application in functional food development and the brewing industry; however, amylose-free waxy barleys are relatively scarce in nature. Results Here we created new alleles of the Waxy gene using CRISPR/Cas9 genome editing. Mutagenesis of single bases in these novel alleles caused absence of intact waxy protein in grain of the edited line. Consequently, B-type granules disappeared. The amylose and amylopectin contents of the edited line were zero and 31.73%, while those in the wild type (WT) were 33.50% and 39.00%, respectively. The absence of waxy protein led to increase in soluble sugar content to 37.30% compared with only 10.0% in the WT. Typical soluble sugars, sucrose and β-glucan, were 39.16% and 35.40% higher in the edited line than in the WT, respectively. Transcriptome analysis identified differences between the edited line and the WT that could partly explain the reduction in amylose and amylopectin contents and the increase in soluble sugar, sucrose and β-glucan contents. Conclusions The barley cultivar with novel alleles of the Waxy gene contained zero amylose, lower amylopectin, and higher soluble sugar, sucrose and β-glucan than the wild type. This new cultivar provides a good germplasm resource for improving the quality of barley.

Productivity indicators and correlations between them in spring barley cultivars of Uman National University of Horticulture

The study of crop formation processes by constituent elements revealed the dependence of the parameters of the number of grains in the ear and the weight of barley grain at the same level of grain yield on the number of productive stems per unit area. It is established that the increase in the number of productive shoots per 1 m2 is accompanied by a significant decrease in the productivity potential of the ear in terms of the number of grains and the parameters of the mass of one grain. The correlation dependence of these yield elements on the stem density of barley is strong. In the studies of 2018–2021, the number of productive stems, plant height, productivity of one ear and weight of 1000 grains of spring barley varieties Daniele, Gezine, Beatrix, Soldo, 5/18, Fabiola, Sangria, Utah, 9/19, Mompi 19, Lyuba and Champush. Correlation holidays between these indicators were also established. The number of productive stems of spring barley varieties on average for 2018–2021 amounted to 0.87–1.39 pieces/1 plant. The average biotype ranged from 0.89 in 2018 to 1.47 in 2021. There was a medium and strong variation in the number of productive stems depending on genotypes. In most collection specimens, the rate varied greatly depending on growing conditions. Collectible samples 5/18 is a semi-dwarf, other biotypes are dwarfs. The highest plants were in 2020. The plant height of most cultivars varied slightly over the years of research. The average productivity of one ear of the analyzed collection samples was 0.63–1.17 g. The lowest indicators were noted in 2018, the highest – in 2020. The average weight of 1000 grains was 45.2–53.5 g with the highest indicator in 2021 g. The correlation between plant height and ear weight per ear was positive medium and close; between the number of productive stems and plant height – positive average, weak and negative average; between the number of productive stems and the mass of grain from the ear – a weak positive and negative correlation; between the number of productive stems and the mass of 1000 grains – the average positive and weak negative; between the height of the plants and the mass of 1000 grains and between the mass of grains from the ear and the mass of 1000 grains – from the average positive to the average negative.

Resistance of modern spring barley cultivars to harmful organisms

Background. Diseases and pests cause great damage to barley stands and harvests. Harvest losses from harmful organisms reach 25–30%.Materials and methods. During 2017–2020, 46 spring barley cultivars from the VIR collection, listed in the State Register for Selection Achievements, were studied for their resistance to fritfly, net and spot blotches, brown rust, and powdery mildew. The tests were carried out in the field with provocative colonization by fritfly and under natural infection pressure of leaf pathogens.Results and conclusions. In 2017, net blotch predominated over other diseases. In 2018, there was an epyphytotic outburst of spot blotch, and cultivars with weak development of this disease were identified. In 2019 and 2020, the incidence of brown rust and powdery mildew was significant, and the virulence of fritfly increased greatly in the same years. Field tests resulted in identification of 3 barley accessions resistant to fritfly: ‘Odon’ (k-31118, Buryatia), ‘Miar’ (k-31203, Orenburg Province), and ‘Omsky 99’ (k-31230, Omsk Province). Cv. ‘Posada’ (k-31245, Germany) was weakly affected by fritfly, brown rust and powdery mildew. Cultivars were selected for their low susceptibility to powdery mildew (up to 5%): ‘Chiraz’ (k-31131, Denmark), ‘Cheerio’ (k-31297, Denmark), and ‘Odyssey’ (k-31333, England), and brown rust: ‘Chiraz’ (k-31131, Denmark), ‘Eifel’ (k-31249, France), ‘Ursa’ (k-31339), and ‘Sunshine’ (k-31129, Germany). Such long-term assessment results can be used in breeding programs to develop cultivars with group or complex resistance to harmful organisms.

Assessment of yield, plasticity and stability of spring barley cultivars grown in the European North of the Russian Federation

In recent years, modern agroclimatic environmental conditions in the European North of the Russian Federation are determined by constant fluctuations of biotic and abiotic factors, which require a high level of plasticity and stability of crop yield and quantitative characteristics from cultivars used in agricultural production. Therefore, determining the plant response to changing environmental factors in order to select the most promising breeding seeds, is an important task for breeders. The research was conducted on experimental field of N. Laverov Federal Center for Integrated Arctic Research of the Ural Branch of the Russian Academy of Sciences, in the nursery of competitive variety testing in 20172019. Cultivars of spring barley of local selection were studied. Indicators of cultivar plasticity and stability were calculated by the method of S.A. Eberhart, W.A. Rassell (1966), the indicator of genetic flexibility by the method of R.A. Udachin (1990). Various weather conditions during the research period enabled to evaluate the breeding material comprehensively. The hydrothermal coefficient (according to G.T. Selyaninov) varied from 1.85 to 3.06 during the research years. Ten cultivar samples of spring barley were analyzed to identify a plastic stable genotype. As a result, a high level of stability was shown by samples k-037712 (Ϭ2 = 0.01), k-038404 (Ϭ2 = 0.02). Samples with a neutral genotype were identified: k-039257, k-036982 (bi 1) and a sample weakly responding to environmental changes k-038806 (bi = 0.23). The bi value is very close to 1 in Kotlassky cultivar, which shows a high ecological plasticity. Sample k-038806 has the lowest coefficient of linear regression (0.23), therefore, it is suitable for cultivation on unfertilized soils. The selected genetic sources will be used in breeding to develop highly productive cultivars of spring barley for the conditions of the European North of the Russian Federation.

In-Vitro Study on Fermentation Characteristics of Different Hulless Barley Cultivar Flakes

Barley (Hordium vulgare L.) grain is an important food ingredient due to the presence of essential compounds like β-glucans, proteins, resistant starch, phenolic compounds etc. β-glucans are able to lower cholesterol level in blood plasma and the glycaemic index, to enhance lipid metabolism and to reduce the risk of colon cancer. Hulless barley cultivars are more suitable to the human diet, because the hulls can be easily removed, as well as minimal grain processing in food production contributes to the full benefit of the whole grain. Several studies show that hulless grains have a higher digestible energy, and they have higher protein content compared to hulled grains. Different cultivars have unique composition and physical properties. The hulless barley cultivars are less studied than hulled barley and oats. The aim of this study was to evaluate the fermentation characteristics of flakes of different hulless barley cultivars in vitro and to analyse the fermentation pattern of β-glucans and proteins. Samples of six hulless barley cultivar flakes with different β-glucan (4.17–6.59%), soluble dietary fibre (18.1–32.0%) and resistant starch (0.74–10.65%) content were boiled in water 10 min, and the obtained porridge samples were treated under in vitro fementation conditions. The concentration of fermented porridge solids as well as β-glucans and proteins was measured. The concentration of undigested solids varied from 38.3 to 61.0% depending on barley cultivar. The concentration of protein was not significantly changed, but β-glucan concentration was significantly decreased after in vitro digestion comparing to indigestible samples.