Bradyrhizobium Japonicum Research Articles

Growth of soybean plants under saline conditions: the role of potassium and Bradyrhizobium japonicum inoculation

This study aimed to evaluate the effects of potassium (K) and Bradyrhizobium japonicum applications on physiological and microbial parameters in soybean plants under salt stress. The study included treatments of control, potassium (2.2 g K2SO4), bacteria (B), and their combinations (K + B), along with versions exposed to 100 mM NaCl salt stress. Key parameters such as leaf water content (RWC), chlorophyll (SPAD, Chlo a/b), oxidative stress indicators (H2O2 and MDA), proline, protein, antioxidant enzyme activities (APX, POD, and CAT), microbial biomass carbon (MBC), and CO2 release from soil were measured. Salt stress reduced RWC in plants by 15%, while H2O2 and MDA levels increased by 25% and 30%, respectively. However, potassium and bacterial applications improved plant resilience against stress by increasing proline levels by 20%, reducing protein loss by 18%, and enhancing antioxidant enzyme activities to mitigate oxidative damage. In soil microbial activities, MBC increased by up to 161%, and CO₂ release increased by up to 27.7% with K + B application. Under salt stress, MBC and CO₂ release were restored by 122% and 50.8%, respectively, demonstrating the positive effects of potassium and bacterial inoculation on microbial activity. These findings suggest that potassium and Bradyrhizobium japonicum applications could be considered effective strategies for enhancing plant tolerance and soil health under salt stress conditions.

Fungal Colonization of the Anatomical Parts of Soybean Seeds Supplied with Different Nitrogen Rates and Inoculated with Bradyrhizobium japonicum

The soybean [Glycine max (L.) Merr.] plays an important role in human and animal nutrition due to its high protein and oil content. The present study was undertaken to determine the effect of different mineral nitrogen (N) rates and inoculation with Bradyrhizobium japonicum bacteria on fungal colonization of the anatomical parts of seeds (APSS) of two soybean cultivars (Aldana and Annushka). Fungi were identified with the use of the macroscopic method and the polymerase chain reaction (PCR) assay. The study demonstrated that fungal colonization was higher on soybeans cv. Annushka than cv. Aldana. The obtained results indicate that fungal colonization intensity was highest in the cotyledons, lower in the seed coat, and lowest in the embryonic axis. The APSS were colonized by pathogenic fungi belonging mostly to the genus Fusarium, as well as saprotrophic fungi represented by Alternaria alternata, Cladosporium cladosporioides, Penicillium spp., and Rhizopus nigricans. Fungal colonization intensity was highest in soybean seeds inoculated with HiStick®Soy and in control seeds, whereas the number of fungal isolates obtained from the APSS was lower in the remaining treatments: 60 kg N ha−1 + HiStick®Soy, 30 kg N ha−1 + HiStick®Soy, Nitragina, and 60 kg N ha−1. In addition, the statistical analysis revealed that fungal abundance and the biodiversity indicators of fungal communities, including relative frequency (Rf), dominance (Y), and species richness (S), differed across the analyzed APSS and years of the study, which indicates that these parameters were significantly influenced by weather conditions. The abundance of pathogenic and saprotrophic fungal species did not differ significantly between the examined soybean cultivars. Spearman’s rank correlation coefficients were calculated to assess the strength of the relationship between weather conditions and the diversity of fungal communities colonizing soybean seeds. The analysis revealed that the development of pathogenic fungi on soybean seeds was determined by temperature and precipitation on 11–30 June and 1–10 August, whereas the prevalence of saprotrophic fungi was influenced only by precipitation on 1–10 and 21–30 July and 1–10 August. The qPCR analysis demonstrated that the colonization of soybean seeds by F. graminearum and P. verrucosum was affected by all experimental factors.

The Pursuit of a Hydroxylation Switch Uncovers a Key Residue for Various Product Outcomes in the ent-Kaurene Synthase from Bradyrhizobium japonicum.

A single residue switch leading to hydroxylation has been identified in ent-kaurene synthases (KSs) from plant gibberellin hormone biosynthesis. In this work, we identified a putative equivalent in the bacterial BjKS from the gibberellin-producing Bradyrhizobium japonicum. Notably, this serves as a key residue that can be varied in concert with a surrounding network to redirect product outcome, with a specificity of up to 94%, providing mechanistic insight into not only BjKS but also (di)terpene synthases more generally.

Molecular Characterization of Root-Nodule Bacteria from Soybean (Glycine Max L. Merrill) Rhizosphere in Three Agro-Ecological Systems in Nigeria

The worldwide increase in population continues to threaten the sustainability of agricultural systems since agricultural output must be optimized to meet the global rise in food demand. This study examined the symbiotic compatibility between indigenous rhizobia population and soybean plant. Soil samples 5kg each were randomly collected from agricultural fields in a total of nine different local governments from Southwest and North central zones of Nigeria at a depth of 0-30cm using sterile soil auger (5cm diameter). The control soil samples were obtained from Badagry beach (a location with no previous history of soybean cultivation). The indigenous microbial population were isolated using serial dilution technique and they were cultured using nutrient agar (NA), yeast-extract mannitol salt agar (YEMA) and sabouraud dextrose agar (SDA) incubated at 26±2oC for 48 hours and 3-5 days respectively. Soybean seeds were sown in each of twenty pots aseptically. The mean pH of soil samples from this study was 6.0 (slightly acidic) while NO3 ˉ N and NH4 ˉ N was relatively low. Molecular characterization of these rhizobia species as well as their genetic diversity in soil were investigated. A total of nine different rhizobia species were isolated from all the soil samples and three of the nine isolates were randomly selected for molecular characterization using 16S rRNA gene sequencing method. The accession number for the selected organisms were confirmed as follows; 0J7 (Accession number: MN0677451.1), Stenotrophomonas maltophilia OJ8 (Accession number: MF767518.1) Agrobacterium tumefaciens, OJ9 (Accession number: NR_181268.1) Rhizobium rhizolycopersici. The other isolates were characterized as Bradyrhizobium japonicum

Ameliorative effect of rhizobacteria Bradyrhizobium japonicum on antioxidant enzymes, cell viability and biochemistry in tomato plant under nematode stress

Root Knot Nematode (Meloidogyne incognita) is a major agricultural pest that significantly reduces crop yield. This study investigates the nematicidal potential of Bradyrhizobium japonicum strain 11477 against M. incognita to regulate its pathogenicity in Solanum lycopersicum. Tomato seeds were treated with bacterial cells and supernatant, grown under controlled conditions and later infested with nematode juveniles (5J2/seedling). After 10 days, nematode infestation led to reduced seedling growth, lower root and shoot biomass and decreased photosynthetic pigments. It also triggered oxidative stress, as indicated by elevated stress markers. Enzymatic and non-enzymatic antioxidants along with phenolic compounds showed increased activity in response to nematode-induced stress. However, B. japonicum treatment significantly reduced gall formation, improved plant growth and enhanced biochemical and histochemical attributes. Rhizobacteria also alleviated stress indices, strengthened antioxidant defenses and increased metabolite production. Confocal microscopy revealed hydrogen peroxide localization, glutathione content and nuclear and membrane damage in root apices, correlating with plant defense responses. This study highlights B. japonicum as a potent biocontrol agent that enhances plant growth and resilience against M. incognita. Notably, this is the first report on the impact of a leguminous rhizobacterium on a non-leguminous tomato plant, providing new insights into its potential for sustainable pest management.

Prospecting the Functional Potential of Bacillus altitudinis 1.4 Isolated from Sediment in Association with Bradyrhizobium japonicum.

Bacteria of the genus Bacillus are ubiquitous in nature and produce several antimicrobial compounds, being increasingly used in plant biocontrol. The objective of this study was to identify the isolate Bacillus sp. 1.4 at the species level and study its bioactive properties prospecting the potential for agricultural application. The bacterial isolate was identified as belonging to Bacillus altitudinis through genomic metrics. The antimicrobial substance extracted with butanol inhibited Listeria monocytogenes ATCC 7644 and Bradyrhizobium japonicum CT 00345 with inhibition halos of 16 and 13mm, respectively. In the exopolysaccharide production assay, B. altitudinis 1.4 presented a negative result and in the assessment of motility through the swarming assay, 90mm halos were observed in both agar concentrations (0.3 and 0.7%) for up to 72h of incubation. Genomic analysis revealed genes potentially encoding traits that could be beneficial to plants, such as phytohormone and siderophores production, polyamine metabolism, biofilm formation, exopolysaccharide, and motility. These characteristics may be important to improve the competition of B. altitudinis 1.4 in the soil. This bacterium was able to solubilize inorganic phosphate, coexist with B. japonicum CT 00345 and form biofilm. Based on the results found and with new tests to be carried out, it is suggested that the isolate B. altitudinis1.4 could be a candidate for plant growth promoter.

Agronomic Efficiency of Compost Extracts and Nitrogen-Fixing Bacteria in Soybean Crops.

Regenerative agriculture and the use of bioinputs have been gaining prominence in the global agribusiness sector, driven by the growing demand for healthier foods produced with minimal impact on ecosystems. In this context, compost and its derivatives (compost extracts and teas) are used to provide effective microorganisms to crops, although production processes affect the efficiency of compost extracts, as well as the soil microbiota. Thus, the hypothesis raised was that the organic matter source used for compost formation affects the agronomic efficiency of compost extracts. The objective of this study was to evaluate the effect of compost extracts based on litterfall of angiosperm (AC) and gymnosperm (GC) species, and the use of inoculation with the nitrogen-fixing bacteria Bradyrhizobium japonicum and Azospirillum brasilense (Bra+Azo), on soil quality, crop growth, grain yield, and disease control in soybean (Glycine max L.) crops. Using AC and GC resulted in varying effects on soybean growth and soil microbial biomass carbon (SMBC), confirming the hypothesis that the organic matter source affects the agronomic efficiency of compost extracts. Plants inoculated with Bra+Azo exhibited higher chlorophyll contents, resulting in a higher photochemical yield than for those treated with compost extracts (AC and GC). However, plants inoculated with AC and GC exhibited high plasticity in mitigating photochemical stress, reaching similar photosynthetic and transpiration rates to those observed in plants inoculated with Bra+Azo. Additionally, inoculation with Bra+Azo, overall, improved the photosynthetic efficiency of soybean plants, and the compost extracts (AC and GC) were more effective than the inoculation with Bra+Azo in increasing soybean 1000-grain weight, probably due to improvements in root development. The growth promotion observed with AC and GC is likely attributed to increases in SMBC by these compounds, denoting improvements in soil quality and biocontrol of damage caused by insect attacks.

Backbone and side‑chain 1H, 13C and 15N resonance assignments and secondary structure determination of the rhizobial FixJ.

The symbiotic nitrogen-fixing bacterium Bradyrhizobium japonicum (B.japonicum) enables high soybean yields with little or no nitrogen fertiliser. A two component regulatory system comprising FixL, a histidine kinase with O2-sensing activity, and FixJ, a response regulator, controls the expression of genes involved in nitrogen fixation, such as fixK and nifA. Only under anaerobic conditions, the monophosphate group is transferred from FixL to the N-terminal receiver domain of FixJ (FixJN), which eventually promote the association of the C-terminal effector domain (FixJC) to the promoter regions of the nitrogen-fixation-related genes. Structural biological analyses carried out so far for rhizobial FixJ molecules have proposed a solution structure for FixJ that differs from the crystal structures, in which the two domains are extended. To understand the FixJ activation caused by phosphorylation of the N-terminal domain, which presumably regulates through the interactions between FixJN and FixJC, here we have performed backbone and sidechain resonance assignments of the unphosphorylated state of B. japonicum FixJ.

Rhizobium Inoculants Mitigate Corn Herbicide Residual Effects on Soybean Germination

Corn residual herbicides offer a practical approach to comprehensive weed management throughout the growing season. However, the use of residual pre-emergence herbicides can have a negative impact on crops grown in succession or within a rotation. A study was carried out to determine the effect of the residual activity of selected corn herbicides on soybeans. The objective of the study was to evaluate the impact of these herbicides on the germination of inoculated soybean seeds. Experiments were conducted in greenhouse conditions to check the carryover effect on soybean germination. Treatment combinations of two pre-herbicides and two inoculants were applied: atrazine (2241 g ai ha−1), mesotrione (105 g ai ha−1), and Bradyrhizobium japonicum, Bradyrhizobium japonicum + Bacillus subtilis, respectively. A randomized complete block design evaluated six treatment combinations, including the control. All treatments, except uninoculated treatments, presented efficacy in reducing the carryover effects of corn residual herbicides on the germination of soybeans. An increase in final germination percentage was observed with Bradyrhizobium japonicum + Bacillus subtilis co-inoculation plus atrazine (24% increase) and Bradyrhizobium japonicum plus mesotrione treatment combinations (19% increase). Inoculating soybean seeds with rhizobium bacteria can reduce the carryover effects on the germination of soybean seeds grown in soil applied with atrazine and mesotrione.

ISOLATION AND MOLECULAR CHARACTERIZATION OF RHIZOBIAL STRAINS ISOLATED FROM SOYBEAN NODULES IN LIMPOPO PROVINCE, SOUTH AFRICA

Limited nitrogen in the soil is a major constraint to sustainable crop production in most developing countries including South Africa. Soybean productivity in South Africa is limited by drought, poor soil fertility, and the ineffectiveness or unavailability of native strains. Most soil in South Africa contains low or ineffective rhizobium strains for biological nitrogen fixation in legume crops. The study aimed to isolate and characterize compatible rhizobial strains for soybeans in response to soil moisture conservation technologies and Bradyrhizobium japonicum inoculation in Limpopo province, South Africa. The study used a phylogenetic analysis of 21 bacteria' 16S rRNA gene sequences isolated from soybean root nodules in the Limpopo province. Experiments were conducted at Syferkuil farm and Lebopo sites in Limpopo province. DNA was extracted to perform PCR amplification of the 16S ribosomal RNA using primer fD1 and rD1. Sequencing was done at Inqaba Biotec, Pretoria, and edited using Bioedit and Mega X programs. A total of 21 bacterial isolates were isolated from soybean root nodules. The isolated strains from Syferkuil and Lebopo sites had both medium-growing and fast-growing strains; however, they were dominated by fast-growing strains. Phylogenetic results showed four categories of bacterial genera: Agrobacterium, Bradyrhizobium, Bacillus, and Rhizobium. Application of local rhizobium strains and efficient strains could enhance productivity and contribute to the low input cost of soybean production in Limpopo province

The Effects of Bradyrhizobium japonicum Inoculation and Superphosphate Fertilizer on the Growth and Development of Lablab (Lablab purpureus L.)

Nutrient-poor savanna soils severely limit agricultural productivity in Africa, hindering crops and livestock intensification and threatening food security. Addressing these deficiencies is crucial to meeting the world’s growing food demands and ensuring sustainable agricultural development. The experiment was conducted in a greenhouse laid in a randomized complete block design with eight treatments, namely: (T1) control, (T2) 45 kg/ha superphosphate, (T3) 60 kg/ha superphosphate, (T4) 75 kg/ha superphosphate, (T5) Bradyrhizobium japonicum inoculant, (T6) Bradyrhizobium japonicum inoculant +45 kg/ha superphosphate, (T7) Bradyrhizobium japonicum inoculant +60 kg/ha superphosphate, and (T8) Bradyrhizobium japonicum inoculant +75 kg/ha superphosphate. The findings showed that the highest plant height was noted when lablab was supplemented with T4 treatment at day 21, while T2 of superphosphate had the highest leaf area. Conversely, soil supplemented with superphosphate at different levels and/or lablab seeds treated with Bradyrhizobium inoculant did not have a significant effect on the number of leaves. Overall, the application of superphosphate to the soil at different levels and treating lablab seeds with Bradyrhizobium inoculant did not have any significant effect on the plant height, number of leaves, and leaf area. On day 37, the highest leaf chlorophyll was recorded on T1 and became constant amongst all the treatments as the growth progressed. From the current study, it is concluded that growing lablab in a controlled environment would benefit subsistence farmers and rural communities for its leaves consumed as vegetables and ultimately ensure food security.

Enhancing Soybean Yield Through Inoculation of Multifunctional Microbial Consortia

Inoculating multifunctional microbial consortia offers potential benefits for enhancing plant growth and grain yield formation. This study verified the feasibility of inoculating soybean (Glycine max) seeds with multifunctional microbial consortia to improve soybean productivity. Seeds were inoculated with 12 combinations of inoculants [Bradyrhizobium japonicum and B. diazoefficiens for biological N2 fixation, Azospirillum brasilense for growth promotion via phytohormone release, Bacillus megaterium (=Priestia megaterium) and B. subtilis for enhancing P uptake, and Trichoderma harzianum as biopesticide] and grown in BOD chamber, greenhouse, and field experiments. In the chamber, inoculated seeds were subjected to germination tests. In the greenhouse, inoculated seeds were sown in pots with nonsterile soil, and plant growth was monitored until the flowering stage. In the field, plants were cultivated until physiological maturity. Soil and plant samples were collected at three growth stages: vegetative, reproductive, and maturation. Measurements included shoot, root, nodules, grain masses, and grain yield, alongside analyses of seed N, P, lipid, protein, and carbohydrate contents. The highest number of microbial inputs and the inclusion of T. harzianum in the microbial consortia impeded seed germination, hindered initial vegetative growth, and decreased plant densities in the plots. Likely due to the crop’s plasticity and the stimulation of microorganisms, the initial setbacks did not affect grain yield and soybean grain lipid content. Therefore, inoculating multifunctional microbial consortia holds promise as a sustainable approach in agriculture. Still, care should be taken concerning an excessive number of inoculants composing the consortia.

Bacillus velezensis 20507 promotes symbiosis between Bradyrhizobium japonicum USDA110 and soybean by secreting flavonoids.

While co-inoculation with rhizobia and plant growth-promoting rhizobacteria (PGPR) can enhance soybean growth and nodulation, the interaction mechanisms between Bacillus velezensis 20507 and Bradyrhizobium japonicum USDA110 under varying nitrogen (N) supply levels (0-10 mmol/L) remain unclear. This study investigates how their synergistic interactions influence soybean nitrogen content per plant and molecular pathways. Soybean plants were co-inoculated with B. velezensis and B. japonicum across four N levels. Nodulation, plant growth, physiology, and N content were quantified. Transcriptome sequencing of soybean roots under N deficiency compared single and co-inoculation treatments. Flavonoids in B. velezensis fermentation broth were identified via mass spectrometry, and rutin's regulatory effects on B. japonicum nodulation genes (NodD1/NodD2) were tested in coculture. Co-inoculation significantly increased nodulation, biomass, and N content per plant compared to single inoculations across all N levels. Under N deficiency, co-inoculation induced 5,367 differentially expressed genes (DEGs), with Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment in phenylpropanoid (ko00940) and flavonoid biosynthesis (ko00941). B. velezensis produced 29 flavonoids and 4 isoflavonoids (including rutin). Rutin (5-10 mg/L) upregulated NodD1 and suppressed NodD2 in B. japonicum. B. velezensis enhances B. japonicum-soybean symbiosis via flavonoid secretion, particularly rutin, which modulates nodulation gene expression. This metabiotic interaction improves soybean N assimilation and growth, even under low N conditions. The findings provide a foundation for designing composite inoculants to optimize soybean yield and nitrogen-use efficiency.

Application of BioVermigot and Rhizobium spp. on production of Peanuts (Arachis hypogea L.)

BioVermigot is an organic fertilizer produced from a combination of vermicompost fertilizer and Black Soldier Fly fertilizer which is innovated with beneficial microbes such as Azotobacter sp. which has the potential as a Nitrogen-fixing bacteria. The BioVermigot application is expected to help increase peanut production with the help of the Rhizobium spp. as a Nitrogen fixer. This research was carried out from December 2023 to March 2024 in Medan Selayang District, North Sumatra. This research uses Factorial Randomized Complete Block Design (RCBD). The first factor (BioVermigot Dosage) B0 : Control, B1 : 0 ton ha-, B2 : 10 ton ha-, and B3 : 20 ton ha-. Second factor (Dose of Rhizobium japonicum) R0 : Control, R1 10 g kg- and R2 : 20 g kg. Data analysis used variance with the F test and Duncan’s multiple range test at a significance level of 5%. The results showed that there was no interaction between inoculation of Rhizobium spp. and BioVermigot on peanut yield. Independently Rhizobium spp. influences all parameters, while Biovermigot influences the number of pods, the number of pithy pods, the weight of wet pithy pods, the weight of dry pithy pods per plant, and pod yield per plot.

Optimizing Biopolymer Seed Coatings: Impact of Sodium Alginate and Chitosan on the Viability of Trichoderma Harzianum, Bradyrhizobium Japonicum and Soybean Seed Quality

Optimizing Biopolymer Seed Coatings: Impact of Sodium Alginate and Chitosan on the Viability of Trichoderma Harzianum, Bradyrhizobium Japonicum and Soybean Seed Quality

Assessing the impact of arsenic on symbiotic and free-living PGPB: plant growth promoting traits, bacterial compatibility and adhesion on soybean seed.

Arsenic (As) contamination in agricultural groundwater and soil is a significant economic and health problem worldwide. It inhibits soybean (Glycine max (L.) Merr.) nodulation and biological nitrogen fixation in symbiosis with Bradyrhizobium japonicum E109 (E109), a commonly used rhizobial strain for commercial biofertiliser formulation in Argentina. In the context of sustainable and climate-smart agriculture promoted by FAO, co-inoculating legumes with As-tolerant plant growth-promoting bacteria (PGPB) is suggested as a superior alternative to single inoculation. This study aimed to evaluate the impact of As on plant growth-promoting (PGP) traits -siderophore and indole acetic acid production, phosphate solubilisation, diazotrophic activity and hydrolytic enzymes activity- in E109 and three other PGPB strains: Pseudomonas sp. AW4 (AW4), Bacillus pumilus SF5 (SF5) and Bacillus toyonensis SFC 500-1E (Bt). In addition, bacterial compatibility and adhesion on soybean seed were evaluated. Arsenic significantly reduced PGP traits of E109 even at low concentrations, AW4's traits remained unchanged, while those of SF5 and Bt traits were affected (positively or negatively) only at the highest concentrations tested (500µM arsenate, 250µM arsenite). All PGPB strains were compatible with E109 under both control and As-stress conditions. Soybean seed adhesion was reduced for E109, only under As stress. Findings suggest that the effect of As on PGP traits is highly strain-dependent and influenced by As concentration and speciation. AW4, SF5, and Bt strains show promise for co-inoculation with E109 in soybean cultivation.

EFFECT OF BIOFERTILIZERS ON SOYBEAN GROWTH AND THEIR KEY PEST DENSITIES AS ALTERNATIVE APPROACH TOWARD SUSTAINABLE AGRICULTURE PRODUCTION

Soybean (Glycine max L.) is one of the most important crops belong to the leguminous family native to East Asia. Chemical fertilizers are widely used to increase production in quantity and quality. As a result of the harmful effects caused by chemical fertilizers, it become necessary to find alternative solutions as sustainable approach toward supply plant by elements needs such as biofertilizers. In this study, Bradyrhizobium japonicum alone or in combination of microorganism inoculation included (B. japonicum, Bacillus subtilis, Glomus mosseae, and Anabaena azollae) were tested toward soybean growth parameters under open field condition. Results showed that there is a significant differences in terms of plant height, vegetative and dry grain of soybean and other parameters with combined inoculation and B. japonicum alone in compare with control treatments. Moreover, key pest larval density were also affected by treatments such as Popillia japonica, Spodoptera littoralis and Agrotis ipsilon. The results suggest the use of specific combination of microorganism is recommended as alternative approaches toward sustainable agriculture production of soybean crop.

A Preliminary Study of USDA 110 (Bradyrhizobium diazoefficiens) Strain Nodulation Performance and Soybean Growth Under Water Scarcity Conditions

Nitrogen fixation is one of the key benefits of the economic and environmentally sustainable approach that legumes contribute to crop production. With the fruitful cooperation of legume-rhizobia symbiosis, soybean cultivation contributes to this sustainability while drought threatens this sustainable agricultural system. Thus, this study aimed to verify the influence of water deficit on the soybean nodulating performance concerning different inoculants, crop growth and quality. A field experiment was conducted to determine the effects of irrigated and water scarcity conditions (full: WHC 100% and deficit: WHC 50%) on soybean yield and quality and also to test the nodulation performance of two different inoculants USDA 110 (Bradyrhizobium diazoefficiens) and Azotek (Rhizobium spp.) applied to 3 different soybean cultivars (Umut-2002, Cinsoy and Altınay). For this purpose, plant height (cm), first pod height (cm), number of pods per plant, 1000 seed weight (g), seed yield (kg ha-1), SPAD chlorophyll content, leaf area (cm2), crude protein and oil content (%) traits were measured. According to the field and root observations, no nodulation history was observed in both Rhizobia strains under irrigated and water scarcity conditions. Water limitation resulted with the negative impact on soybean yield (≈35% less) and yield formation. In addition to yield reduction, water scarcity caused a significant decrease in SPAD chlorophyll content in the reproductive stages and leaf area of the plant. As a result of this preliminary study, water scarcity has irreversible effects on soybean plant physiology and yield formation in the hot climate conditions of Aydın province. Further field studies are needed to observe the nodulation performance of soybean plants in the region which has not been observed in the field studies so far.

INFLUENCE OF PRE-SOWING SEED INOCULATION ON THE FORMATION OF YIELD OF PEANUT VARIETIES (ARACHIS HYPOGAEA L.)

Prospects for increasing the area of peanuts sown in Ukraine require improving the elements of cultivation technology. In agricultural practice, the use of methods to stimulate biological nitrogen fixation is of great importance, which ensures an increase in crop yields and a reduction in the negative impact of production on the environment. As a legume, peanuts have the ability to fix atmospheric nitrogen through symbiosis with the bacteria Bradyrhizobium japonicum. Thus, successful peanut cultivation requires careful seed inoculation. The purpose of the research was to establish the patterns of peanut yield formation depending on varietal properties and pre-sowing seed inoculation. Field studies were conducted in the conditions of the Poltava region during 2023–2024. The object of the research was studied according to the scheme of a two-factor experiment: factor A - peanut varieties: Valencia Ukrainian, Stepnyak, Veselka, Vechirnii Rio; factor B - options for seed treatment with the Optimize 400 inoculant (1.8 l/t). The obtained data were subjected to statistical processing using the Statistica 6.0 program. According to the results of the field experiment, a positive effect of pre-sowing treatment of peanut seeds with the inoculant Optimize 400 on plant growth and development was established. In the variants with the use of pre-sowing treatment of seeds with the inoculant, an increase in the indicators of the main structural elements of productivity was observed: plant height - 13.50%; number of beans per plant - by 16.5%, number of seeds per plant - 21.1%; seed mass per plant - 26.4%; mass of 1000 seeds - 4.5%. Peanut yield varied from 0.71 t/ha to 2.64 t/ha depending on the individual properties of the variety, weather conditions of the research year and the variant of using the inoculant for pre-sowing treatment of seeds. According to average data for 2023-2024. The highest yield was observed in the variety Vechirnii Rio - 2.1 t/ha, and the lowest in the variety Stepnyak - 9.4 t/ha. It was found that the effectiveness of pre-sowing seed treatment with inoculant for peanut cultivation depended on the weather conditions of the research year. In general, inoculation of peanut seeds contributed to an increase in yield by 15.5%.

Revitalizing Soybean Plants in Saline, Cd-Polluted Soil Using Si-NPs, Biochar, and PGPR.

Excessive irrigation of saline-alkaline soils with Cd-contaminated wastewater has resulted in deterioration of both soil and plant quality. To an investigate this, a study was conducted to explore the effects of biochar (applied at 10 t ha-1), PGPRs (Bradyrhizobium japonicum (USDA 110) + Trichoderma harzianum at 1:1 ratio), and Si-NPs (25 mg L-1) on soybean plants grown in saline-alkali soil irrigated with wastewater. The results showed that the trio-combination of biochar with PGPRs, (as soil amendments) and Si-NPs (as foliar spraying), was more effective than individual or coupled applications in reducing Cd bioavailability in the soil, minimizing its absorption, translocation and bioconcentration in soybean tissues. The trio-combination reduced Cd bioavailability in the soil by 39.1% and Cd accumulation in plant roots, shoots, and seeds by 61.0%, 69.3%, and 61.1%, respectively. Physiological improvements in soybean plants were also observed, including 197.8% increase in root growth, 209.3% increase in chlorophyll content, and 297.4% increase in carotenoid levels. The trio-combination significantly improved soil physicochemical characteristics, enhanced soil microbial indicators and boosted soil enzymes activity, which in turn facilitated nutrient uptake and increased antioxidant enzymes activity. These positive outcomes enhanced photosynthesis, improved productivity and increased seed nutritional value. Overall, the trio-combination of biochar with PGPRs and Si-NPs are considered a reliable approach not only for revitalizing soybean growth but also for immobilizing Cd and improving soil health under wastewater irrigation.