Higher Dry Matter Content Research Articles

Enhancing enzymatic saccharification yields of cellulose at high solid loadings by combining different LPMO activities

BackgroundThe polysaccharides in lignocellulosic biomass hold potential for production of biofuels and biochemicals. However, achieving efficient conversion of this resource into fermentable sugars faces challenges, especially when operating at industrially relevant high solid loadings. While it is clear that combining classical hydrolytic enzymes and lytic polysaccharide monooxygenases (LPMOs) is necessary to achieve high saccharification yields, exactly how these enzymes synergize at high solid loadings remains unclear.ResultsAn LPMO-poor cellulase cocktail, Celluclast 1.5 L, was spiked with one or both of two fungal LPMOs from Thermothielavioides terrestris and Thermoascus aurantiacus, TtAA9E and TaAA9A, respectively, to assess their impact on cellulose saccharification efficiency at high dry matter loading, using Avicel and steam-exploded wheat straw as substrates. The results demonstrate that LPMOs can mitigate the reduction in saccharification efficiency associated with high dry matter contents. The positive effect of LPMO inclusion depends on the type of feedstock and the type of LPMO and increases with the increasing dry matter content and reaction time. Furthermore, our results show that chelating free copper, which may leak out of the active site of inactivated LPMOs during saccharification, with EDTA prevents side reactions with in situ generated H2O2 and the reductant (ascorbic acid).ConclusionsThis study shows that sustaining LPMO activity is vital for efficient cellulose solubilization at high substrate loadings. LPMO cleavage of cellulose at high dry matter loadings results in new chain ends and thus increased water accessibility leading to decrystallization of the substrate, all factors making the substrate more accessible to cellulase action. Additionally, this work highlights the importance of preventing LPMO inactivation and its potential detrimental impact on all enzymes in the reaction.

Wide-characterization of high and low dry matter kiwifruit through spatiotemporal multi-omic approach

Despite the widespread use of dry matter content (DMC) as an indicator of kiwifruit quality, the physiological and molecular impact of DMC in fruit ripening remains unknown. Herein, the post-harvest physiological, metabolomic, and transcriptomic influence of DMC status on the pericarp and placenta tissue of ‘Hayward’ kiwifruit at harvest and at the onset of post-cold ripening was investigated. A segregation strategy based on DMC in commercially harvested kiwifruit was achieved with near-infrared spectroscopy for the estimation of DMC in individual fruits. Additionally, kiwifruits with distinct DMC levels were treated with 1-methylcyclopropene (1-MCP) and systematically monitored for ripening changes (20°C) at various intervals after cold storage (0°C). Following 90 and 120 days of cold exposure, high DMC kiwifruit generally exhibited superior physiological characteristics, such as increased pericarp and placenta firmness, and soluble solid and starch contents compared to low DMC kiwifruit, regardless of the 1-MCP application. Evidence is also presented for 1-MCP delaying the ripening of low-DMC fruit to the level of the untreated high-DMC kiwifruit. An accumulation of primary metabolites, particularly sugars and polyphenolic compounds, such as catechin, chlorogenic acid and procyanidin B1/B2 was evidenced in the high DMC group. At harvest, gene expression analysis revealed minor differences between DMC groups, with beta-amylase being the highest up-regulated gene in high DMC kiwifruit. Moreover, the gene expression patterns between DMC groups became more distinct after cold storage. Genes related to starch biosynthesis (i.e., glucose-1-phosphate adenyltransferase), water movement (i.e., aquaporin), polyphenolic biosynthesis (i.e., chalcone synthase) and lipid metabolism (i.e., diacylglycerol acyltransferase) showed strong variations between low and high DMC. Interestingly, the placenta tissue displayed almost 4 times more than DMC-affected differentially expressed genes compared to the pericarp, highlighting the key role of the placenta in kiwifruit ripening, notably following 1-MCP treatment. This study provides insights into the tissue-specific ripening response between kiwifruit with distinct DMC, as well as the gene expression influenced by an interaction of 1-MCP and DMC level, thereby helping develop postharvest programs aimed at improving kiwifruit quality traits.

Assessment of Yellow and White Fleshed Cassava Tuberous Root Cultivars Reveals Different Responses to Post-harvest Physiological Deterioration

Identification of post-harvest physiological deterioration (PPD) tolerance in cassava is crucial, as PPD significantly hampers the cassava tuberous root industry by shortening storage periods post-harvest and diminishing product quality. Characteristics linked to PPD tolerance encompass high carotenoid levels and low dry matter content (DMC). This study aimed to evaluate the PPD responses of six yellow fleshed and ten white-fleshed cassava tuberous roots and determine the source of PPD tolerance. PPD and DMC assessments were conducted using standard methods at three storage periods: 2, 5, and 10 days after harvest (DAH). The k-means clustering analysis revealed six clusters, each corresponding to distinct PPD symptom patterns and tolerance statuses. Cluster 1, comprising three yellow-fleshed and three white-fleshed cassava cultivars, demonstrated PPD tolerance with minimal symptoms up to 5 DAH. Clusters 2 and 3 exhibited a moderate PPD response with elevated symptoms at 5 DAH, comprising three yellow-fleshed and three white-fleshed cassava cultivars. Clusters 4 to 6 displayed a sensitive response to PPD, showcasing a significant increase in symptoms at 5 and 10 DAH, with four white-fleshed cassava cultivars identified within this cluster. These findings underscored the presence of PPD tolerance in both yellow-fleshed and white-fleshed cassava tuberous roots. The correlation between PPD and DMC was significant only at 2 DAH, displaying a moderate positive correlation. Consequently, this study identified three cultivars, “Carvita-25”, “Manggu”, and ““Ubi Kuning””, with high DMC and low PPD incidence at 5 DAH, suggesting their suitability for further breeding programs.

Morphological and biochemical changes in Quercus humboldtii in response to warmer and polluted urban areas in a tropical Andean city

Abstract The rapid growth of urban population has significantly changed human settlement patterns, leading to a decline in air quality and changes in climatic conditions in urban areas. Trees are recognized as nature-based solutions because they can remove particles from the air and regulate the climate. However, trees are negatively affected by pollution and temperatures, which represent a challenge for urban planning, management, and human health. To assess the impact of urban pollution and warmer climates on functional traits, we conducted a study using Quercus humboldtii, an endangered tree species endemic to Colombia and Panamá that dominates Andean forests and urban green areas in Bogotá. We selected three localities with contrasting pollution levels and climate conditions and measured 10 morphological and biochemical traits in six individuals at each location. Our findings revealed that Q. humboldtii adjusted morphological and biochemical traits in response to the environmental challenges posed by urban environments. The functional strategies varied between individuals with thin and large leaves and acidic pH in the colder and unpolluted native forest, while others displayed a conservative resource strategy (high leaf dry matter content) and neutral pH in the warmer and most polluted locality. Despite these differences, several traits indicate that Q. humboldtii is not a species tolerant to pollution. This is further supported by the air pollution tolerance index (APTI) values. Our results suggest that Q. humboldtii should be planted in areas of Bogotá with low pollution levels in order to promote its long-term survival and support ecosystem services.

Teak (Tectona grandis Linn. f) and Edaphic Factors Affecting the Regeneration of Woody Species and Their Functional Traits in Economic Forest Plantation, Northern Thailand

Improved understanding of relationships among plant traits, stand characteristics, and soil properties can provide insights into the regenerating tree communities of commercial teak plantations. We investigated whether plant traits could be used to predict the natural regeneration of woody species in teak plantations with different soil and stand conditions. Data were collected in fifty 20 m × 20 m plots that were established in teak plantations of varying ages in northern Thailand. We analyzed differences in stand characteristics, soil properties, and community-level functional traits among sites. The RLQ analysis was performed to explore the associations among species abundances, plant traits, and a combined set of soil variables and stand characteristics. Our results showed that tree species with high leaf dry matter contents and high wood density dominated communities in an older teak plantation and were associated with high OM and N concentrations. Trees with larger leaves are increased in plantations that had experienced their first teak thinning, and were rich in organic matter. Species with high specific leaf areas increased in sites with high teak basal areas and which had experienced more intense thinning on fertile soils. Thick-leaved species had high importance values on sites with high densities of teak and infertile soils. Our results indicated that tree communities with similar conspecific traits were associated with specific soil and stand conditions in teak plantations. A knowledge of these regeneration dynamics may allow forest managers to encourage increased natural regeneration and enhanced diversity in commercial teak plantations.

Intraspecific leaf trait variation mediates edge effects on litter decomposition rate in fragmented forests.

There is strong trait dependence in species-level responses to environmental change and their cascading effects on ecosystem functioning. However, there is little understanding of whether intraspecific trait variation (ITV) can also be an important mechanism mediating environmental effects on ecosystem functioning. This is surprising, given that global change processes such as habitat fragmentation and the creation of forest edges drive strong trait shifts within species. On 20 islands in the Thousand Island Lake, China, we quantified intraspecific leaf trait shifts of a widely distributed shrub species, Vaccinium carlesii, in response to habitat fragmentation. Using a reciprocal transplant decomposition experiment between forest edge and interior on 11 islands with varying areas, we disentangled the relative effects of intraspecific leaf trait variation versus altered environmental conditions on leaf decomposition rates in forest fragments. We found strong intraspecific variation in leaf traits in response to edge effects, with a shift toward recalcitrant leaves with low specific leaf area and high leaf dry matter content from forest interior to the edge. Using structural equation modeling, we showed that such intraspecific leaf trait response to habitat fragmentation had translated into significant plant afterlife effects on leaf decomposition, leading to decreased leaf decomposition rates from the forest interior to the edge. Importantly, the effects of intraspecific leaf trait variation were additive to and stronger than the effects from local environmental changes due to edge effects and habitat loss. Our experiment provides the first quantitative study showing that intraspecific leaf trait response to edge effects is an important driver of the decrease in leaf decomposition rate in fragmented forests. By extending the trait-based response-effect framework toward the individual level, intraspecific variation in leaf economics traits can provide the missing functional link between environmental change and ecological processes. These findings suggest an important area for future research on incorporating ITV to understand and predict changes in ecosystem functioning in the context of global change.

Participatory on-farm evaluation of new orange-fleshed sweetpotato varieties in Southern Ethiopia

Abstract Sweetpotato is the second most important root crop in Ethiopia, making an important contribution to food security in the densely populated areas of southern Ethiopia. While the white-fleshed sweetpotato (WFSP) varieties have been widely grown, the recently bred pro-vitamin A orange-fleshed sweetpotato (OFSP) varieties are also gaining popularity nationwide. This study evaluated on-farm performances of five new OFSP varieties along with two previously released “check” varieties, one of which is a WFSP, across 13 locations in southern Ethiopia for 2 consecutive seasons (2017 and 2018) with the objective of selecting farmer preferred varieties. The experimental design used was randomized complete block design. Results revealed highly significant differences (p < 0.05) among the tested varieties for all parameters considered. Overall, the new varieties were superior to the check varieties for most of the parameters considered. Kulfo, the OFSP check and the only OFSP variety under production, was inferior in above-ground biomass yield, taste, vegetative, and physical root quality performance. There was a strong negative correlation between altitude and root yields, with the highest root yields being in areas 1,500–1,650 m above sea level. The new varieties were accepted by the farmers due to their better yields, adaptability to the local agro-ecological conditions, and high dry matter content. The results of this study implied that the conventional variety evaluations should be complemented by farmers' participatory processes to ensure the release of acceptable varieties targeting both food security and marketability.

Formation of yield and quality of topinambur tubers with different planting techniques

To expand the production of topimanbur in the Russian Federation, it is necessary to develop adaptive cultivation technologies in various regions of the country. Field research was carried out on the territory of the educational and scientific experimental field of the Perm State Technical University. Three variants of the planting scheme were studied: 70x30, 70x40 and 70x50 cm and three variants of the weight of the planting tuber: 20-40 g, 41-60 g and 61-80 g. The applied agrotechnical measures are generally accepted for the non–Chernozem zone. The technology of planting topinambur is a comb. The research results show that with planting schemes of 70x30, 70x40 and 70x50 cm, topinambur forms the exact yield of tubers – 18.3-19.3 t/ha. When used for planting tubers weighing 41-80 g, the yield increases by 1.1-1.7 t/ha, compared with the planting fraction of 21-40 g, due to an increase in plant density by 0.1 pcs. /m2. Biological yield indicators fully reflect the actual yield. Under the studied planting schemes, it was also the same and amounted to 2002.6-2177.9 g/m2, and when planted with larger tubers, it was 271.7-277.0 g/m2 higher than tubers of 20-40 g. The proportion of tubers of the small fraction – 48-59 % prevails in the Jerusalem artichoke crop. The share of the food fraction is 8-16 %. The fractional composition of tubers in the crop does not depend on the mass of the planting tuber. The share of planting tubers in the harvest with schemes 70x30 and 70x40 cm is higher by 6-8 %. A higher dry matter content in tubers was observed when planting tubers weighing 20-60 g – 21.3-21.6 %, and vitamin C – when planting tubers 61-80 g – 14.5 mg/kg. The planting scheme does not affect the biochemical composition of topinambur tubers.

Establishment of hydrolysates from enzymatic plant and fish protein by-products into fish nutrition

The aim of this research was to scientifically prove the technology for producing plant-fish hydrolysates from sunflower meal and fish waste (carp processing) and to develop scientifically based recipes for protein hydrolysates and feed using it for carp of different ages. Compositions from fish waste and different amounts of sunflower meal have been developed, the chemical composition of the compositions and the digestibility of protein by carp have been studied. It was distinguished that the best characteristics when studing the nutritional value and digestibility of crude protein have the protein hydrolysates of fish waste and sunflower meal, taken in a ratio of 1 to 2. Accordingly, in this case, a high content of dry matter was noted 65.57 ± 0.18%), crude protein 41.92±0.72%, crude fat 2.74±0.12% and low crude fiber 14.34±0.10%, and the apparent protein digestibility coefficient was 78.8%. The compiled enzyme compositions for enzymatic hydrolysis are optimal at a temperature of 50°C and the proportion of the enzyme composition for fermentation in an amount of 5%, containing enzyme preparations: Protozyme - 40%, Cellulase - 35%, Lipase - 10% and Amylorizin - 15%.

Cucumber fruit nutrient quality as influenced by variety and organic fertiliser rate

Abstract The nutrient contents of a product can depend on the quantity of fertiliser supplied. An experiment was conducted at the Federal University of Agriculture, Abeokuta, in the tropical rainforest‑savannah transitional zone of southwestern Nigeria to determine the nutrient contents of three cucumber varieties as influenced by Gateway Organic Fertiliser (GOF) rates. There were 48 plots of 3.0 × 2.0 m each, separated by 1.0 m pathways. The main plot was cucumber variety (Marketmore, Poinsett, and Marketer) while the sub‑treatment was organic fertiliser rate at 0, 5, 10, and 15 t.ha−1 in a split‑plot arrangement fitted into Randomised Complete Block Design (RCBD) with 4 replicates. Fruit nutrient contents differed with cucumber varieties and rates of gateway organic fertiliser. Marketmore variety fruits without application of GOF had higher moisture contents. Poinsett variety fruits cultivated with the application of 5 t. ha−1 GOF had higher dry matter contents. Poinsett variety fruits cultivated with either 10 or 15 t. ha−1 GOF had higher crude protein and carbohydrate contents when compared with other interactions. Poinsett variety cultivated with either 10 or 15 t. ha−1 GOF had higher vitamins A and C contents when compared with other interactions. It was concluded that cultivating the Poinsett cucumber variety with a 10 t.ha−1 GOF rate gave optimum nutrient contents concerning the crude protein, carbohydrate, and vitamin content. The Poinsett cucumber variety cultivated with 10 t. ha−1 Gateway Organic Fertiliser is recommended for optimum nutrient contents.

Evaluation of Grain Maize Harvest Residues as Fodder After Partial Torrefaction Under Microwave

With a project supported by Siirt University (Siirt, Türkiye), we determined the conversion potential of residues of field cropped grain maize into animal feed via torrefaction. Torrefaction application was performed in a microwave device for four different periods of time (0, 4, 8, and 12 minutes) in three replications at three different watts (300, 600, and 900 watts). The dry matter digestion was determined for the ground starter and final materials by the Daisy Incubator Technique (ANKOM). Changes in dry matter, protein, and ADF values were measured by standard feed quality analyses. The effects of applications on dry matter ratio, protein, and in vitro digestibility were found to be statistically significant, whereas the effect on ADF ratio was insignificant. Low-term torrefaction applications significantly increased the dry matter ratio, whereas high power and long application periods significantly increased the protein ratio. In vitro, digestibility was decreased due to the increase in the power application and duration of torrefaction. A material with high dry matter and high protein content but low in vitro digestibility was obtained as a result of the torrefaction applications tested in the study under microwave conditions with grain maize harvest residues. Although the applications tested have decreased the value of maize harvest residues as cattle feed, the obtained material with high dry matter and protein content with this torrefaction method has the potential to be used as a nutrient medium in different living environments (e.g. bacterial or fungal) which may be subjected to further investigations.

Determining the influence of raw milk protein composition on the yield of cheese and its nutrient content

Cheese production is a complex process that is influenced by many factors: protein:fat ratio, acidity, and type of rennet. An option for improving the profitability of the cheese industry is the genetic selection of dairy cows to produce milk with good rennet protein coagulation. The object of the study is the technology of cheeses made from milk from cows with different β-casein genotypes (А1А1, А1А2, А2А2). The subject of the study is the physical-chemical parameters of milk from cows with different genotypes for β-casein; yield of cheese from this milk and its quality indicators. Samples of Gouda cheese were produced according to traditional technology. The research established that the quality indicators of milk samples are typical for fresh cow's milk. The content of fat, protein, and dry matter in the milk of cows with the β-casein genotype A2A2 were slightly higher compared to A1A1 and A1A2. The study of the quality indicators of the cheese samples showed that the type of β-casein did not affect the organoleptic properties of the cheese. However, according to the content of the main chemical components, cheeses made from A1A2 milk had a higher content of dry matter and protein (61,6 % and 19,2 % on average, respectively) and a lower fat content (37.2 %). The amino acid profile of cheese from milk of cows with β-casein A1A2 and A2A2 genotypes showed a higher total content of amino acids – 14.89 mg/g and 13.84 mg/g, respectively. Calculations of cheese yield showed that cheese yield from milk of cows with β-casein genotype A1A2 was higher (mean value 13.1 %) than with A1A1 and A2A2. The obtained results are of practical importance, as it is possible to take into account how changes in the β-casein genotype in milk can affect the yield of cheese, and therefore, the profitability of production

Morpho-Quantitative Traits and Interrelationships between Environmental Factors and Phytophthora infestans (Mont.) de Bary Attack in Tomato

The growing imperative for sustainable development generates research in the field and explores innovative approaches to manage vegetable crops to reduce the usage of synthetic inputs commonly associated with conventional practices as well as to promote the undertaking of organic solutions. Tomatoes are universally recognized as a highly significant and popular fruit vegetable due to their large use palette. Trials were carried out in the Gâlgău area, Transylvania, Romania. Bifactorial experiments were organized to quantify the influence of fertilization and treatments on the morpho-productive and quantitative traits of the Ruxandra tomato cultivar and on Phytophthora infestans levels of infection. The use of mixed fertilization resulted in the best performances of morphological traits (highest leaf area, highest number of leaves and fruits, highest chlorophyll content) and part of the productive traits (highest content of dry matter), and the lowest levels of infection in cv. Ruxandra, while the use of NPK soil fertilization led to the best performances in fruit weight and NUE, whatever the administered treatment. The treatment with herbal extracts showed a similar efficacy in increasing the averages of morpho-productive traits and diminishing the P. infestans level of infection compared with the conventional treatment. The treatment efficacy was mainly influenced by temperature and relative air humidity, regardless of the fertilization strategies applied.

Влияние генотипа крупного рогатого скота на химический состав говядины

Purpose. To study the slaughter qualities of mixed young cattle and the chemical composition of beef obtained from it. Materials and Methods. The object of research is 18-month-old crossbred bulls, obtained as a result of industrial crossing of Kazakh white-headed cattle bulls with heifers of the Simmental breed (group I), Hereford bulls with heifers of the Simmental breed (group II) and Kalmyk bulls with heifers of red steppe cattle (group III). Purebred bulls of the Kazakh white-headed breed were used as a control group. Chemical analysis of beef samples was carried out according to the following methods and GOST standards: moisture content was determined by drying the sample to a constant mass at a temperature of 100-105 °C according to GOST 9793-2016; protein content – by the amount of protein nitrogen by the Kjeldahl method according to GOST 25011-2017; fat content – according to GOST 23042-2015; ash content – according to GOST 31727-2012; the amino acid and vitamin composition was determined according to the method of measuring the mass fraction of amino acids and vitamins by the KE method on the Kapel-105M system, the concentration of hydrogen ions (pH) according to GOST R 51478-99. Calorie content of 100 g / meat was calculated using the formula of V. M. Aleksandrov. Results. To assess the meat productivity of crossbred steers, their control slaughter was carried out, which showed that the largest slaughter weight and slaughter yield were possessed by steers of the II experimental group – 312.4 kg and 61.0%. Beef samples from young animals of the II experimental group had the highest content of dry matter. The difference with peers from the control, I and III groups was 0.27, 0.21 and 0.63%, respectively. It was also noted that the crossbred young of the II experimental group surpassed purebred Kazakh white-headed bulls in protein content by 1.67%. The difference with the crossbreeds from group I and III is 1.38 and 2.3% respectively. A study of the vitamin composition of the beef of experimental young animals showed that the resulting beef was relatively rich in vitamins of group B. beef obtained from crossbred bulls of the II experimental group has a higher biological value (Protein qualitative indicator = 5.86 compared with the control 5.59). The increase in protein qualitative indicator is mainly due to the higher content of tryptophan in beef of the experimental group II – by 9.0% (494.40 mg% compared with 453.86 mg% in the control). The pH value of the water-meat extract in bulls of different genotypes is almost the same and ranged from 5.41 to 5.49. Conclusion. It has been established that the crossing of bulls of meat breeds of cattle with heifers of dairy and combined breeds contributes to the production of young offspring with excellent slaughter qualities, and beef obtained from such offspring has a high biological value.

Flocculating and dewatering of lake sediment: An in-situ pilot study comparing synthetic polymers and biopolymers for restoring lake water quality and reusing phosphorus

Dredging of lake sediment is a method to remove accumulated phosphorus and nitrogen in lakes and thereby reducing the risk of eutrophication. After dredging, the sediment is dewatered to reduce the volume. It is important to get a high dry matter content and ensure that the filtrate does not contain harmful compounds so it can be returned to the lake. A pilot-scale belt filter and flexible intermediate bulk containers (FIBC) were used for dewatering lake sediment with the sediment treated with a synthetic polymer or three different biopolymers. The goal of the study was to retain the phosphorus in the filter cake while returning the filtrate to the lake with a minimal phosphorus content. Results showed dry matter content of up to 16 % in the dewatered sediment and the sediment retained 96–99 % of the phosphorus. Furthermore, nitrogen was reduced by 27–71 % in the filtrate water. Toxicity tests found low ecotoxicity for most biopolymer filtrates, whereas synthetic polymer showed the highest potential ecotoxicity. Consequently, biopolymers provided satisfactory results, proving more environmentally friendly despite requiring longer filtration time.

The fatty acid profile and the quality of breast and leg muscles in female and male pearl gray guinea fowl (Numida meleagris)

The aim of this study was to evaluate the fatty acid (FA) profile and the quality of breast and leg muscles in male and female guinea fowl. In comparison with leg muscles, breast muscles had a higher content of dry matter and total protein, and contained less fat and total collagen (P ≤ 0.05). Sex had no effect on the chemical composition of the studied muscles or the FA profile of intramuscular fat (IMF) (P > 0.05). The IMF of breast muscles was characterized by higher proportions of total saturated fatty acids (SFAs) and polyunsaturated fatty acids (PUFAs), and lower proportions of total unsaturated fatty acids (UFAs) and monounsaturated fatty acids (MUFAs) (P ≤ 0.05) than the IMF of leg muscles. The physicochemical properties of guinea fowl meat were significantly influenced by muscle type (P ≤ 0.05), but not by sex (P > 0.05). Leg muscles were characterized by a higher pH, higher cooking loss, lower lightness (L*), lower drip loss, a higher contribution of redness (a*), and a lower contribution of yellowness (b*) than breast muscles (P ≤ 0.05). The experimental factors had no effect on the sensory attributes or the shear force values of the analyzed muscles (P > 0.05). The unique sensory attributes, high protein content, and low fat content of the analyzed muscles indicate that guinea fowl meat can be a dietary supplement and an addition to other types of meat consumed, especially that most guinea fowl are reared in extensive farming systems that contribute to sustainable food production.

Gospodarska svojstva tradicijskih sorata krumpira Poli i Brinjak

The paper presents the results of a triennial research on the economic properties of two commercial (Désirée and Colomba) and two traditional potato varieties (Poli and Brinjak) in northwestern Croatia. Research was conducted during 2020, 2021, and 2022 at the Experimental Field of the Faculty of Agriculture of the University of Zagreb in non-irrigated conditions. The significantly highest tuber yield (33.10 t ha-1) was achieved in 2020, when the most precipitation fell during the growing season (583.6 mm). In a triennial average, the Désirée (27.37 t/ ha-1) and Poli (26.17 t ha-1) varieties achieved the significantly highest tuber yield. The highest dry matter content was detected in the varieties Poli (23.37 %) and Brinjak (23.26 %), and the lowest one in the variety Colomba (17.39 %). In 2020, when the weather was more favorable for potatoes, whereas the fraction > 55 mm had the largest share of tubers, with the fraction amounting to 35–55 mm in unfavorable years of. Within the > 55 mm fraction, the Désirée variety had the largest share of tubers, while the Poli and Brinjak varieties had it within the 35–55 mm fraction. On average, the Poli variety had the largest share of tubers smaller than 35 mm, and the Colomba variety had the largest share of tubers larger than 55 mm. The highest number of tubers per plant was detected in the Poli variety, and the highest mass of tubers per plant in the Désirée variety, respectively. Although traditional potato varieties are in some respects inferior to the commercial ones, it is necessary to cure them from viruses and preserve them (on-farm) in order to maintain biodiversity and diversity in the gastronomic offer.

Biostimulants Affect Differently Biomass and Antioxidant Status of Onion (Allium cepa) Depending on Production Method

Onions, essential in various salads and cooked dishes, are sought after by producers for high yields, while consumers value their quality, particularly the presence of antioxidant compounds. This study investigates the impact of production methods and biostimulants on the biomass yield and quality of onions. The two-year experiment was conducted in Vojvodina, Serbia, and compared directly seeded (DS) and from-set (FS) onions with four biostimulant treatments: control (C), seaweed extracts (T1), humic and fulvic acids (T2), and Trichoderma sp. (T3). DS onions yielded significantly more biomass, while FS onions had higher dry matter content. DS onions treated with T1 showed a significant increase in phenols (↑ 5.30%), while T2 and T3 led to declines (↓ 8.66% and ↓ 7.55%, respectively). All biostimulants reduced phenol content in FS onions. T1 and T2 significantly increased the flavonoid concentration in DS onions, with no significant changes in FS onions. T1 enhanced antioxidant properties in DS onions and reduced them in FS onions. Additionally, T2 and T3 decreased antioxidant activity in both DS and FS onions, as evidenced by DPPH, FRAP, and ABTS tests. These findings guide onion production, advocating for the fresh consumption of DS onions with higher biomass and industrial processing suitability for FS onions, emphasizing the potential of bio-based products.

Drought‐tolerant grassland species are generally more resistant to competition

Abstract Plant populations are limited by resource availability and exhibit physiological trade‐offs in resource acquisition strategies. These trade‐offs may constrain the ability of populations to exhibit fast growth rates under water limitation and high cover of neighbours. However, traits that confer drought tolerance may also confer resistance to competition. It remains unclear how fitness responses to these abiotic conditions and biotic interactions combine to structure grassland communities and how this relationship may change along a gradient of water availability. To address these knowledge gaps, we estimated the low‐density growth rates of populations in drought conditions with low neighbour cover and in ambient conditions with average neighbour cover for 82 species in six grassland communities across the Central Plains and Southwestern United States. We assessed the relationship between population tolerance to drought and resistance to competition and determined if this relationship was consistent across a precipitation gradient. We also tested whether population growth rates could be predicted using plant functional traits. Across six sites, we observed a positive correlation between low‐density population growth rates in drought and in the presence of interspecific neighbours. This positive relationship was particularly strong in the grasslands of the northern Great Plains but weak in the most xeric grasslands. High leaf dry matter content and a low (more negative) leaf turgor loss point were associated with high population growth rates in drought and with neighbours in most grassland communities. Synthesis: A better understanding of how both biotic and abiotic factors impact population fitness provides valuable insights into how grasslands will respond to extreme drought. Our results advance plant strategy theory by suggesting that drought tolerance increases population resistance to interspecific competition in grassland communities. However, this relationship is not evident in the driest grasslands, where above‐ground competition is likely less important. Leaf dry matter content and turgor loss point may help predict which populations will establish and persist based on local water availability and neighbour cover, and these predictions can be used to guide the conservation and restoration of biodiversity in grasslands.

EFECTUL FERTILIZĂRII CU GUNOI DE PASĂRE ASUPRA CREȘTERII ȘI FRUCTIFICĂRII LA PRUN (PRUNUS DOMESTICA L.)

The investigation was conducted during the period 2018-2021 in an experimental plantation of the Institute of Agriculture – Kyustendil, Bulgaria with plum (Prunus domestica L.) cv. ʻStanleyʼ. The planting was created in 2013. Planting distances were 5x5 m. The following fertilization variants were investigated: V1 – unfertilized – (control), V2 – chicken manure 2.5 kg/tree, V3 – chicken manure 5.0 kg/tree. The correlation between the fertilizer rate and the trunk growth rate of the plum cv. ʻStanleyʼ was positive from the second year of chicken manure Vita organic application. The application of chicken manure at a rate of 2.5 kg/tree increased the canopy volume, and in the third year it was statistically significant at P<0.05 by 56.56%. On average for the period of the experiment, the fertilizer rate of 2.5 kg/tree increased the yield by 79.16%, and the average fruit weight by 5.93%. A higher content of dry matter and acids was found in the fruits at both fertilizer rates.