Improving Nitrogen Status Estimation in Malting Barley Based on Hyperspectral Reflectance and Artificial Neural Networks

Malting barley requires sensitive methods for N status estimation during the vegetation period, as inadequate N nutrition can significantly limit yield formation, while overfertilization often leads to an increase in grain protein content above the limit for malting barley and also to excessive lodging. We hypothesized that the use of N nutrition index and N uptake combined with red-edge or green reflectance would provide extended linearity and higher accuracy in estimating N status across different years, genotypes, and densities, and the accuracy of N status estimation will be further improved by using artificial neural network based on multiple spectral reflectance wavelengths. Multifactorial field experiments on interactive effects of N nutrition, sowing density, and genotype were conducted in 2011–2013 to develop methods for estimation of N status and to reduce dependency on changing environmental conditions, genotype, or barley management. N nutrition index (NNI) and total N uptake were used to correct the effect of biomass accumulation and N dilution during plant development. We employed an artificial neural network to integrate data from multiple reflectance wavelengths and thereby eliminate the effects of such interfering factors as genotype, sowing density, and year. NNI and N uptake significantly reduced the interannual variation in relationships to vegetation indices documented for N content. The vegetation indices showing the best performance across years were mainly based on red-edge and carotenoid absorption bands. The use of an artificial neural network also significantly improved the estimation of all N status indicators, including N content. The critical reflectance wavelengths for neural network training were in spectral bands 400–490, 530–570, and 710–720 nm. In summary, combining NNI or N uptake and neural network increased the accuracy of N status estimation to up 94%, compared to less than 60% for N concentration.

Aluminum resistance of malting barley

Background. Barley is the second cereal crop in Russia in terms of its importance and production volume. It is used for food, feed, and industrial purposes. The production of malting barley in Russia exceeds 1.5 million tons; each year the area under this crop increases by 10–15%, reaching 600,000– 800,000 hectares. Barleys suitable for brewing must have certain physicochemical and technological properties. The main requirements for raw materials are presented in GOST 5060-86 (state standard for malting barley). An important condition for obtaining sustainable harvests is the development and utilization of cultivars resistant to a set of edaphic stressors. The purpose of this work was searching for resistant cultivars for use in targeted breeding.Materials and methods. The material for the study included 161 spring barley cultivars for brewing from the collection of plant genetic resources held by VIR. The laboratory assessment of aluminum tolerance in barley accessions was carried out at the initial phases of plant growth and development, using the method of calculating root and shoot length indices. The tested malting barley was classified into five resistance groups.Results and conclusions. Cultivars resistant to Al3+ ions were identified among different ecogeographic groups of malting barleys. The trait had a wide range of variability in terms of both the root length index (0.17–0.95) and shoot length index (0.47–0.99). Accessions with high resistance to ionic (Al3+) stress can be used in barley breeding targeted at the development of high-yielding malting cultivars most adapted to harmful environmental factors.

Determination of gushing potential of barley

A new control method for the determination of the malting barley susceptibility to gushing was developed. The method is based on the modified Carlsberg test (MCT) after prior stimulation of barley with substances that promote the germination process. Barleys from the harvest of 2020 and malts produced from them were used to develop and verify the method. The selection of barleys was based on the results of gushing potential detected in the produced malts. To optimise and verify the method, the barley variety Sunshine with a high gushing potential of both barley (139±33 g) and malt (144±13 g), and the barley variety Pionier with zero gushing potential of both barley and malt were used. Malt was produced from the Lodestar barley variety with a high content of the mycotoxin deoxynivalenol. Gushing of the malt was 127±10 g. The gushing potential in barley was determined by the MCT method after prior stimulation of germination. For comparison, the gushing potential was also determined by the MCT method without stimulation of germination. It was proved that stimulation of germination is a key process for correct determination of the susceptibility of barley to gushing. The newly developed method was used for the determination of the gushing potential of five barleys from the harvests of 2020 and 2021. Control gushing determination of five malt samples was performed using the MCT method. An agreement between the measured data was found.

Genetic variation among selected pure lines from Turkish barley landrace ‘Tokak’ in yield-related and malting quality traits

Aim of study: Improvement of barley cultivars for malting traits suffers from narrow genetic pool in barley for these traits. Landraces are resources that could be used for this purpose. The present study was conducted to determine the variation for malting quality traits within a Turkish barley landrace. Area of study: The study was undertaken in Tokat, a province in Black Sea Region of Turkey. Material and methods: Twenty-five diverse lines, out of 42 unique genotypes previously identified in ‘Tokak’ landrace (PI 470281) based on DNA markers, were evaluated for malting quality traits along with the malting barley cv. ‘Tokak 157/37’ in four field trials. Thousand-seed weight, test weight, grain yield, lodging, malt extract percentage, diastatic power, alpha amylase and malt beta glucanase activities, malt protein and starch contents were determined. Main results: Principal component analysis of malting quality traits revealed that thousand-seed weight, alpha amylase activity, beta glucanase activity and diastatic power were the most discriminatory traits for the lines. As the average of four trials, 15 of the 25 lines evaluated had higher grain yields and 10 of 25 lines had higher malt extract percentages than the standard cultivar ‘Tokak 157/37’. Malt extract was highest in Line 59 in all environments, and this line also had the highest values for beta glucanase activity and starch content. Line 215 had highest values for alpha amylase activity. Lines 59 and 215 clearly had superior malting quality. Research highlights: These lines could harbor novel alleles for these traits to be used in malting barley improvement.

Winter Malting Barley Growth, Yield, and Quality following Leguminous Cover Crops in the Northeast United States

There is growing interest in malting barley (Hordeum vulgare L.) production in the Northeastern United States. This crop must meet high quality standards for malting but can command a high price if these quality thresholds are met. A two-year field experiment was conducted from 2015 to 2017 to evaluate the impact of two leguminous cover crops, sunn hemp (Crotalaria juncea L.) and crimson clover (Trifolium incarnatum L.), on subsequent winter malting barley production. Four cover crop treatments—sunn hemp (SH), crimson clover (CC), sunn hemp and crimson clover mixture (SH + CC), and no cover crop (NC)—were grown before planting barley at three seeding rates (300, 350, and 400 seeds m−2). SH and SH + CC produced significantly more biomass and residual nitrogen than the CC and NC treatments. Higher barley seeding rates led to higher seedling density and winter survival. However, the subsequent spring and summer barley growth metrics, yield, and malting quality were not different in any of the treatments. There is much left to investigate in determining the best malting barley production practices in the Northeastern United States, but these results show that winter malting barley can be successfully integrated into crop rotations with leguminous plants without negative impacts on barley growth, yield, and grain quality.

The Influence of Proteolytic Malt Modification on the Aging Potential of Final Wort

The dynamic changes in beer flavor are determined by its aging potential, which comprises of present free and bound-state aldehydes and their precursors. Rising flavor-active aging compounds cause sensory deterioration (flavor instability). These compounds are mainly formed upstream in the brewing process through the Maillard reaction, the Strecker degradation, or lipid oxidation. Wort boiling is an especially critical production step for important reactions due to its high temperature and favorable pH value. Amino acid concentration, as an important aging-relevant precursor, is variable at the beginning of wort boiling, mainly caused by the malt modification level, and can further influence the aging potential aging formation during wort boiling. This study investigated the effect of the proteolytic malt modification level on the formation of precursors (amino acids and dicarbonyls) and free and bound-state aldehydes during wort boiling. Six worts (malt of two malting barley varieties at three proteolytic malt modification levels) were produced. Regarding precursors, especially Strecker, relevant amino acids and dicarbonyls increased significantly with an enhanced malt modification level. Concentrations of free and bound aldehydes were highest at the beginning of boiling and decreased toward the end. A dependency of malt modification level and the degree of free and bound aldehydes was observed for 2-methylpropanal, 2-methylbutanal, and 3-methylbutanal. Generally, a higher proteolytic malt modification level tended to increase free and bound aldehyde content at the end of wort boiling. Conclusively, the aging potential formation during boiling was increased by an intensified malt modification level.