Inoculation Of Crops Research Articles

Enhancement of Drought Tolerance and Plant Growth in Tomato by Trichoderma harzianum Seed Treatment

The proficiencies of soil microorganisms to drought tolerance have been known for many years, but their use as crop inoculants was not explored in agriculture commercially. One possibility to increase the drought tolerance is to use beneficial microorganisms as seed treatment. This study was conducted to investigate the effect of Trichoderma harzianum on the growth and development of Tomato (Solanum lycopersicum L.) plant under water stress condition. Trichoderma harzianum is applied to the seeds by treating seeds with Trichoderma harzianum before sowing. Parameters including germination percentage, chlorophyll content, leaf area, number of leaves, plant height, root length, plant fresh and dry weight and yield were recorded in all the treatments along with the untreated control. Tomato seeds treated with Trichoderma harzianum had higher seed germination percentage and chlorophyll content 95.50%, (2.41%), 42.59 SAPAD units (13.83%) respectively than untreated seed. Maximum leaf area and number of leaves 11.71 cm² (19.40%), 190.75 (15.43%) respectively recorded in the plants of Trichoderma harzianum treated seeds in water stress condition as compared to untreated seeds. Under extreme water stress condition plant height and root length of tomato plant increased significantly 98.25 cm, (19.45%), 41.25 cm (42.24%) respectively in Trichoderma harzianum treated seeds as compare to untreated seed. Also, Trichoderma harzianum seed treatment in tomato showed a significantly higher plant fresh and dry weight 189.43 g (8.65%) and 31.98 g (47.57%) respectively in drought condition as compared to untreated seeds. Trichoderma harzianum seed treatment played critical role in drought condition by increasing yield 731.25 g/plant (27.62%) increase over untreated seeds. Taken together, the study recommends that in drought condition for enhanced tomato growth Trichoderma harzianum should be used as eco-friendly solutions by seed treatment.

Comparative genomic analysis of Bradyrhizobium strains with natural variability in the efficiency of nitrogen fixation, competitiveness, and adaptation to stressful edaphoclimatic conditions.

Bradyrhizobium is known for fixing atmospheric nitrogen in symbiosis with agronomically important crops. This study focused on two groups of strains, each containing eight natural variants of the parental strains, Bradyrhizobium japonicum SEMIA 586 (=CNPSo 17) or Bradyrhizobium diazoefficiens SEMIA 566 (=CNPSo 10). CNPSo 17 and CNPSo 10 were used as commercial inoculants for soybean crops in Brazil at the beginning of the crop expansion in the southern region in the 1960s-1970s. Variants derived from these parental strains were obtained in the late 1980s through a strain selection program aimed at identifying elite strains adapted to a new cropping frontier in the central-western Cerrado region, with a higher capacity of biological nitrogen fixation (BNF) and competitiveness. Here, we aimed to detect genetic variations possibly related to BNF, competitiveness for nodule occupancy, and adaptation to the stressful conditions of the Brazilian Cerrado soils. High-quality genome assemblies were produced for all strains. The core genome phylogeny revealed that strains of each group are closely related, as confirmed by high average nucleotide identity values. However, variants accumulated divergences resulting from horizontal gene transfer, genomic rearrangements, and nucleotide polymorphisms. The B. japonicum group presented a larger pangenome and a higher number of nucleotide polymorphisms than the B. diazoefficiens group, possibly due to its longer adaptation time to the Cerrado soil. Interestingly, five strains of the B. japonicum group carry two plasmids. The genetic variability found in both groups is discussed considering the observed differences in their BNF capacity, competitiveness for nodule occupancy, and environmental adaptation.IMPORTANCEToday, Brazil is a global leader in the study and use of biological nitrogen fixation with soybean crops. As Brazilian soils are naturally void of soybean-compatible bradyrhizobia, strain selection programs were established, starting with foreign isolates. Selection searched for adaptation to the local edaphoclimatic conditions, higher efficiency of nitrogen fixation, and strong competitiveness for nodule occupancy. We analyzed the genomes of two parental strains of Bradyrhizobium japonicum and Bradyrhizobium diazoefficiens and eight variant strains derived from each parental strain. We detected two plasmids in five strains and several genetic differences that might be related to adaptation to the stressful conditions of the soils of the Brazilian Cerrado biome. We also detected genetic variations in specific regions that may impact symbiotic nitrogen fixation. Our analysis contributes to new insights into the evolution of Bradyrhizobium, and some of the identified differences may be applied as genetic markers to assist strain selection programs.

Bioformulation of mineral solubilizing microbes as novel microbial consortium for the growth promotion of wheat (Triticum aestivum) under the controlled and natural conditions

Microbes are a worthwhile organism of the earth that could be formulated as consortium which can be utilized as biofertilizers. Consortium-based bioinoculants or biofertilizers are superior to single strain-based inoculants for sustainable agricultural productivity and increased micronutrient content in yield. The aim of present study was to evaluate the effect of different combinations of beneficial bacteria that are more effective than single-based bioinoculants. The current work focuses on the isolation of rhizospheric microorganisms from various cereals and pseudocereal crops and the development of a single inoculum as well as a bacterial consortium which were evaluated on wheat crop. A total 214 rhizospheric bacteria were sorted out and, screened for mineral solubilizing attributes i.e., phosphorus, potassium, zinc and selenium solubilization. Among all the bacterial isolates, four potential strains exhibiting P, K, Zn and Se-solubilizing attributes were identified with the help of 16S rRNA gene sequencing as Rahnella aquatilis EU-A3Rb1, Erwinia aphidicola EU-A2RNL1, Brevibacillus brevis EU-C3SK2, and Bacillus mycoides EU-WRSe4, respectively. The identified strains formulated as a consortium which were found to improve the plant growth and physiological parameters in comparison to single culture inoculants and control. To the best of our knowledge, the present investigation is the first report that has developed the consortium from bacterial strains Rahnella aquatilis EU-A3Rb1, Erwinia aphidicola EU-A2RNL1, Brevibacillus brevis EU-C3SK2, and Bacillus mycoides EU-WRSe4. A combination of bacterial strains could be used as liquid inoculants for cereal crops growing in mountainous regions.

Bioinoculants for growth enhancement of aromatic plants: Artemisia pallens and Origanum majorana

The use of fertilizers is a common practice to improve soil fertility and increase crop yields. Chemical fertilizers have played a significant role in increasing crop yields, but their widespread use has led to environmental degradation and soil depletion. The continuing challenges in agro-ecosystem and environment require more sustainable solutions than chemical fertilizers. In recent years, there has been a growing interest in the use of biofertilizers as a sustainable alternative to chemical fertilizers. Biofertilizers are natural substances that improve soil fertility, modify soil microbiota and enhance plant growth. Cyanobacteria are one of the well-known bio inoculants for paddy crops. However, the use of cyanobacteria for other plants has not been very well documented. We screened certain cyanobacteria isolated from different natural environments as biofertilizers for certain aromatic plants. Artemisia pallens and Origanum majorana are two plants with aromatic compound productions. The aim of this study was to screen for enhancement in the growth and propagation of the plants for their yield using bio inoculants. Further air-dried, powdered plant materials of the aerial parts of A pallens and O. majorana were extracted using solvents ranging in polarity from non-polar (n-hexane), semi-polar (chloroform) and polar (acetone, methanol). These extracts were tested for antioxidant activity, several plant extracts showed antioxidant activity, with water exhibiting the greatest levels. The purpose of the experiment was to investigate the effects of bioinoculants on the growth of the test plant. Our observation showed that all the tested cyanobacterial strains i.e. KM1, KM2 and VM1, VM2, the bioinoculants, enhanced plant growth to various levels. KM1 and KM2 exhibited a greater ability to increase plant growth. This demonstrates that Artemisia's and Origanum’s growth and herbage output may be successfully enhanced by the use of cyanobacterial bioinoculants.

Thermal and salt stress effects on the survival of plant growth-promoting bacteria Azospirillum brasilense in inoculants for maize cultivation.

The plant growth-promoting bacteria (PGPB) Azospirillum brasilense is widely used as an inoculant for important grass crops, providing numerous benefits to the plants. However, one limitation to develop viable commercial inoculants is the control of PGPB survival, requiring strategies that guarantee their survival during handling and field application. The application of sublethal stress appears to be a promising strategy to increase bacterial cells tolerance to adverse environmental conditions since previous stress induces the activation of physiological protection in bacterial cell. In this work, we evaluated the effects of thermal and salt stresses on the survival of inoculant containing A. brasilense Ab-V5 and Ab-V6 strains and we monitored A. brasilense viability in inoculated maize roots after stress treatment of inoculant. Thermal stress application (> 35 °C) in isolated cultures for both strains, as well as salt stress [sodium chloride (NaCl) concentrations > 0.3 mol L-1], resulted in growth rate decline. The A. brasilense enumeration in maize roots obtained by propidium monoazide quantitative polymerase chain reaction (PMA-qPCR), for inoculated maize seedlings grown in vitro for 7 days, showed that there is an increased number of viable cells after the salt stress treatment, indicating that A. brasilense Ab-V5 and Ab-V6 strains are able to adapt to salt stress (0.3 mol L-1 NaCl) growth conditions. Azospirillum brasilense Ab-V5 and Ab-V6 strains had potential for osmoadaptation and salt stress, resulting in increased cell survival after inoculation in maize plants. © 2024 Society of Chemical Industry.

Can Azospirillum brasilense compensate part of the phosphate fertilizer in soybean crop by promoting plant growth?

Bioinoculants are widely used in Brazil, based on their efficiency and low cost, in addition to increase in grain yield and lower use of fertilizers in agriculture. In this context, we investigated the use of Azospirillum brasilense to compensate part of phosphate fertilization in soybean crop by promoting plant growth. The field trials were carried out in 2020/21 crop season in four locations in Brazil. The treatments consisted of control (no P application and no microbial inoculation); complete fertilization (100% of the recommended P for the crop and no microbial inoculation); standard commercial inoculant + 75% of the recommended P for the crop; Azosphera® (inoculant based on A. brasilense, strains Ab-V5 and Ab-V6) + 75% of the recommended P for the crop. The effects were assessed on grain yield, thousand grain weight, nodulation, root and shoot dry weight, N and P content in grains and leaves. The results obtained show that inoculation of soybean crop with Azosphera® inoculant, combined with 75% of the recommended phosphate fertilization, in general, provided higher nodulation and plant dry weight and increased grain yield compared to control, and these parameters also did not differ from treatment with complete phosphate fertilization. Thus, the results show that the use of Azosphera® inoculant promoted soybean plant growth and it was possible to compensate the 25% reduction in phosphate fertilization, without impairing the development and yield of soybean crop.

Analysis of the endophytic microbiota of roots and culms of two commercial sugarcane cultivars inoculated with a synthetic microbial community

The adoption of bioinputs in agriculture has aroused great interest in recent years and, in this scenario, the inoculation of crops with synthetic microbial communities (SynComs) has shown to be promising. In sugarcane crop, inoculation with nitrogen-fixing bacteria (NFB) in consortium with arbuscular mycorrhizal fungi (AMF) has shown positive results on plant development and nutrition. However, considering that the microbiota plays a fundamental role in the growth and health of the host plant, especially the endophytes, which are closely associated, few studies have explored the effects of SynCom inoculation on the endophytic microbiota of sugarcane. This study aimed to evaluate the impact of SynCom inoculation on the structure of the endophytic microbiota of sugarcane. The results of the analyses revealed that the microbiota diversity remained unchanged due to the inoculation treatment, while differences in microbial communities were found between the two evaluated commercial cultivars, RB867515 and RB92579, and between the two plant organs, roots and culms, under field conditions at the end of the first crop growth cycle (~360 days). Furthermore, microbes specifically detected in roots or culms present potential valuable applications in sugarcane cultivation in the future. Altogether, our data support that the inoculated microorganisms exerted their beneficial effects during the initial stages of plant development, which opens up space for new research with SynComs in these primordial stages of cane cropping.

Endophytic bacteria Klebsiella spp. and Bacillus spp. from Alternanthera philoxeroides in Madiwala Lake exhibit additive plant growth-promoting and biocontrol activities

BackgroundThe worldwide increase in human population and environmental damage has put immense pressure on the overall global crop production making it inadequate to feed the entire population. Therefore, the need for sustainable and environment-friendly practices to enhance agricultural productivity is a pressing priority. Endophytic bacteria with plant growth-promoting ability and biocontrol activity can strongly enhance plant growth under changing environmental biotic and abiotic conditions. Herein, we isolated halotolerant endophytic bacteria from an aquatic plant, Alternanthera philoxeroides, from the polluted waters of Madiwala Lake in Bangalore and studied their plant growth promotion (PGP) and biocontrol ability for use as bioinoculant. ResultsThe isolated bacterial endophytes were screened for salt tolerance ranging from 5 to 15% NaCl concentration. Klebsiella pneumoniae showed halotolerant up to 10% NaCl and Bacillus amyloliquefaciens and Bacillus subtilis showed up to 15%. All three strains demonstrated good PGP abilities such as aminocyclopropane-1-carboxylic acid (ACC) deaminase activity, phosphate solubilization, ammonia production, and nitrogen fixation. In addition, K. pneumoniae also exhibited high indoleacetic acid (IAA) production (195.66 ± 2.51 µg/ml) and potassium solubilization (2.13 ± 0.07 ppm). B. amyloliquefaciens and B. subtilis showed good extracellular enzyme production against cellulase, lipase, protease, and amylase. Both the isolates showed a broad spectrum of antimicrobial activity against the tested organisms. The optimization of IAA production by K. pneumoniae was done by the response surface methodology (RSM) tool. Characterization of IAA produced by the isolate was done by gas chromatography-mass spectrometry (GCMS) analysis. The enhanced plant growth-promoting ability of K. pneumoniae was also demonstrated using various growth parameters in a pot trial experiment using the seeds of Vigna unguiculata. ConclusionThe isolated bacterial endophytes reported in this study can be utilized as PGP promotion and biocontrol agents in agricultural applications, to enhance crop yield under salinity stress. The isolate K. pneumoniae may be used as a biofertilizer in sustainable agriculture and more work can be done to optimize the best formulations for its application as a microbial inoculant for crops.

Variety-strain interaction specificity of <i>Bacillus subtilis</i> with salt-stressed <i>Phaseolus vulgaris</i> L. plants

The effectiveness of crop inoculation using growth-stimulating bacteria can depend on the plant variety and environmental conditions. The reactions of three-week-old plants of the Ufimskaya and Zolotistaya green bean varieties to inoculation with strains 26D and 10-4 in normal conditions and under stress (1% NaCl 48 h) were analysed. Although the Zolotistaya variety formed less biomass and leaf area, it surpassed the Ufimskaya variety in terms of chlorophyll and root water content, as well as reacting to stress by reducing the content of photosynthetic pigments and root water content. Inoculation contributed to the preservation of these indicators at the level of non–stressed plants: the positive effect of strain 26D was expressed in the effect on the composition of pigments, while that of strain 10-4 was expressed in the hydration of roots. Under stress, the Ufinskaya variety improved the water status of the roots, on which inoculation had a weak or negative effect; however, the decrease in the level of synthetic pigments under stress was compensated by inoculation with both strains. According to the biomass of three-week-old plants, the Zolotistaya variety was shown to respond positively to inoculation with both strains both normally and under stress, while the Ufimskaya variety tended to react negatively to inoculation with strain 26D; under stress, the effect of inoculation with both strains was positive. Compared with the stress-induced control, the malondialdehyde content in the roots of inoculated plants of both varieties decreased in comparison with that of the uninoculated control both in normal conditions and under stress. The revealed differences in plant reactions to inoculation serve as a basis for further analysis of the effectiveness of variety-strain combinations of symbiotic partners.

Zinc solubilizing bacteria synergize the effect of zinc sulfate on growth, yield and grain zinc content of rice (Oryza sativa)

Zinc solubilizing bacteria inhabiting root endosphere possesses great potential to enhance plant yield by solubilizing the nutrients. The potential of Zn solubilizing bacteria Bacillus sp. SH-10 and Bacillus cereus SH-17 to improve yield and grain zinc content of rice was investigated under different regimes of individual and co-inoculation in the presence and absence of chemical fertilizer zinc sulfate (ZnSO4). The strains were applied to the rice varieties basmati 385 and super basmati under field conditions for two consecutive years. A significantly improved growth of rice plants, such as plant height (102–118 cm), number of tillers per plant (8.5–11.5), chlorophyll content (29.5–35.1), zinc requiring enzymes, i.e., superoxide dismutase (396–570 per gram fresh weight (g−1 FW)), carbonic anhydrase activity (CA) (10–15.06 U g−1 FW) and grain yield (3.0–3.8 tons ha−1), was observed in the plants inoculated with Bacillus sp. in the presence of chemical fertilizer (ZnSO4). Consortium of zinc solubilizing bacteria also caused higher grain Zn content (25.0–30.5 mg kg−1) of the rice varieties basmati 385 and super basmati as compared to that of un-inoculated plants. Hence, it can be concluded that Zn solubilizing bacteria has immense potential to be used as agricultural crop inoculants as they synergize the effect of chemical Zn, increase yield and improve the nutritional value of crops.

Extreme environments as sources of fungal endophytes mitigating climate change impacts on crops in Mediterranean‐type ecosystems

Societal Impact StatementClimate change is predicted to increase drought and soil salinity in Mediterranean‐type ecosystems (MTEs), posing a significant threat to global food security. Genetic modification of crops to counteract this threat is expensive and has not met with universal support, and alternatives are hence needed to enhance crop production in MTEs. Here, fungal endophytes from the Atacama Desert, High Andes and Antarctica inoculated onto three crops were found to alleviate the negative effects of drought and salinity on plant performance. The study concludes that extremophile endophytes might be used to enhance crop performance as the climate of MTEs changes over future decades.Summary Climate change will curtail the ability to provide sufficient food for our rapidly expanding population. Improvements to crop production in changing environments, particularly Mediterranean‐type ecosystems (MTEs), which are increasingly subjected to drought and salinisation, are hence urgently needed. Here, we explored the possibility that fungal endophytes from extreme environments can be used to enhance crop yield, survival and tolerance to environmental stresses. Plants of lettuce, tomato and bell pepper were inoculated with up to six species of endophytic fungi isolated from the Atacama Desert, the High Andes and Antarctica. They were then exposed in the field for up to 120 days in each of three summers to current climatic conditions or to a future climate scenario simulating increased drought and soil salinisation. Compared with uninoculated plants, the yield and survival of inoculated crops were increased by up to two‐fold under the future climate scenario. These effects were in part attributable to the improved water balance of inoculated crops exposed to drought and salinisation. The inocula also increased the concentrations of total phenols and proline in leaves and decreased lipid peroxidation when plants were subjected to increased aridity and salinity. A mixed inoculum of six endophytes from the extreme environments conferred the most beneficial effects on crop performance, with a commercially available inoculum having fewer positive effects on crops. We conclude that the inoculation of crops with endophytes from extreme environments may be a viable solution to sustaining crop production in MTEs exposed to rapid climate change.

Gas exchange and carbon assimilation of Bambara groundnut landraces co-inoculated with Bradyrhizobium japonicum and Bacillus subtilis under simulated drought stress

Currently, the world experiences unpredictable and severe climatic events that have led to a decline in the yield of especially crops grown in low-nutrients soils under rainfed conditions. Studies have shown that the growth, photosynthetic performance and yield of crops established in unfavourable conditions can be enhanced by inoculation with plant growth-promoting rhizobacteria. In particular, some authors have reported that the inoculation of crops with PGPR strains under drought conditions enhance their growth, yield and photosynthetic performance.This study assessed the effect of co-inoculation with Bradyrhizobium japonicum and Bacillus subtilis on the gas exchange measurements, shoot biomass and carbon assimilation of two Bambara groundnut (Vigna subterranea (L.) Verdc) landraces grown under simulated drought stress. The experiment was laid out in a 5 × 3 × 2 factorial arrangement of completely randomized design (CRD) with four replicates. Treatments included Bacillus subtilis BD234 strain (BA), Bradyrhizobium japonicum (BR), co-inoculation of B. subtilis BD234 and B. japonicum strain, ammonium nitrate (NH4-NO3) (positive control), and no inoculation (negative control). The simulated drought stress was divided into three levels namely 100% pot capacity (well-watered), 50% pot capacity (moderate stress), and 25% pot capacity (severe stress). Two landraces of Bambara groundnut, characterized by different seed colour (red and cream), were used. Significant variations were observed between the landraces and across the inoculation treatments. When grown under the drought stress levels and co-inoculated with B. japonicum and B. subtilis, the landraces of Bambara groundnut exhibited enhanced photosynthetic rate, transpiration rate, and intercellular CO2. Also, dual inoculation of the food crop grown under drought increased carbon accumulation. The red landrace revealed markedly improved growth and photosynthetic performance compared to its cream counterpart. Overall, co-inoculation of Bambara groundnut with B. japonicum and B. subtilis alleviated adverse effects under moderate and severe drought through improving the growth, photosynthetic performance, and carbon assimilation. Therefore, co-inoculation with B. japonicum and B. subtilis has a potential to combat negative effects of drought in Bambara groundnut.

System of pre-sowing seed inoculation

Pre-sowing inoculation of agricultural crops increases the parameters that affect the yield and quality of the crop, which has been proven by many Ukrainian and foreign researchers. The purpose of the study was to set the operating parameters of the injectors at different pressures, which allowed calculating the rate of discharge of the working solution during sowing to create a system of pre-sowing inoculation, which will simplify the process of seed treatment and increase the energy efficiency of farms. Methods of system and structural analysis, mathematical statistics, abstraction, and mathematical modelling based on the Euler-Lagrange equation, and using the foundations of theoretical mechanics, physics and machine theory were used for experimental research. The planning of the experiment met the current standards, and computer graphics systems and Microsoft Excel software suite were used for statistical data processing. Based on the conducted studies, the amount of liquid that one nozzle can pass in 1 min at pressures of 300, 400, and 500 kPA was determined. It was found that the lowest result was shown by a nozzle with a diameter of 0.1 mm with a pressure of 300 kPA – 10.493 ml/min, and the highest – a nozzle with a diameter of 0.8 mm and a pressure of 500 kPA – 146.379 ml/min. At the same time, injectors with a diameter of 0.4-0.6 mm used almost the same amount of liquid at pressures of 300 and 500 kPA. The amount of liquid that can be poured per 1 ha using a six-row seeding machine with a working width of 4.2 m per sowing unit of corn was calculated. The obtained data can be used to improve any systems that use similar nozzles, such as calculating the rate of discharge of agricultural sprayers or systems that allow cooling pig farms during the summer period

Evaluation of Growth Promotion Traits of Ridge Gourd in Vitro and In Vivo Conditions Using Soil Rhizobacteria as Green Bioinoculants

Abstract: Plant growth-promoting bacteria (PGPB) are now a days an important source of biofertilizers, due to increasing trend of organic fertilizers and ill effects of chemical fertilizers. PGPBs are efficient soil microbes which enhance the nutrient utilization efficiency, growth of several crops and controlling soil borne pathogens. Ridge gourd (Luffa acutangula L.) is a potential horticulture crop due to its high economic value and belongs to the family, Cucurbitaceae. In the present study, PGPB were isolated from the rhizospheric soil of 3 different crop fields (sugarcane, mustard and wheat) from Meerut, Uttar Pradesh were used to investigate their effect on growth pattern of ridge gourd. The isolates were screened for morphological, biochemical, and plant growth-promoting characterstics. Under in-vitro condition, inoculation of Ridge gourd with the P1, P2, B2, B3, B4, B5, R2, , R5, A2, A3, A5, A6, A7 showed a significant increase in seed germination and enhancement in elongation of root and shoot compared to control. Then isolated PGPB inoculated with Ridge gourd for Pot experiment and P1, P2, B2, B3, B4, B5, R2, R5, A2, A3, A4, A6, A7 showed the enhanced growth parameters as appearance of first leaf, flower and fruit as compared to the control. Hence, it can be concluded that application of PGPB has immense potential to be used as agricultural crop inoculants as they promote plant growth as well as improve the health and yield of the plants.

Impact of Sodium Hypochlorite Applied as Nutrient Solution Disinfectant on Growth, Nutritional Status, Yield, and Consumer Safety of Tomato (Solanum lycopersicum L.) Fruit Produced in a Soilless Cultivation

Soilless crop production is spread worldwide. It is a cultivating technique that enhances yield quality and quantity, thus contributing to both food safety and food security. However, in closed-loop soilless crops, the risk of spreading soil-borne pathogens through the recycled nutrient solution makes the establishment of a disinfection strategy necessary. In the current study, sodium hypochlorite was applied to the recycled nutrient solution as a chemical disinfectant to assess its impact on plant growth, leaf gas exchange, fruit yield, tissue mineral composition, and possible accumulation of chlorate and perchlorate residues in tomato fruits. The application of 2.5, 5, and 7.5 mg L−1 of chlorine three times at fortnightly intervals during the cropping period had no impact on plant growth or gas exchange parameters. Furthermore, the application of 2.5 mg L−1 of chlorine led to a significant increase in the total production of marketable fruits (total fruit weight per plant). No consistent differences in nutrient concentrations were recorded between the treatments. Moreover, neither chlorate nor perchlorate residues were detected in tomato fruits, even though chlorate residues were present in the nutrient solution. Therefore, the obtained tomatoes were safe for consumption. Further research is needed to test the application of chlorine in combination with crop inoculation with pathogens to test the efficiency of chlorine as a disinfectant in soilless nutrient solutions.

Control of White Rot Caused by Sclerotinia sclerotiorum in Strawberry Using Arbuscular Mycorrhizae and Plant-Growth-Promoting Bacteria

Sclerotinia sclerotiorum is a phytopathogenic fungus that causes wilting and white rot in several species such as strawberry. The overuse of agrochemicals has caused environmental pollution and plant resistance to phytopathogens. Inoculation of crops with beneficial microorganisms such as arbuscular mycorrhizae (AM), plant-growth-promoting rhizobacteria (PGPR), and their metabolites is considered as an alternative to agrochemicals. B.halotolerans IcBac2.1 (BM) and Bacillus TrujBac2.32 (B), native from Peruvian soils, produce antifungal compounds and are plant-growth-promoting rhizobacteria (PGPR). B. halotolerans IcBac2.1 and Bacillus TrujBac2 with or without G. intraradices mycorrhizal fungi (M) are capable of controlling S. sclerotiorum disease in strawberries. Inoculation of mycorrhiza alone decreases disease incidence as well. Treatments with chitosan (Ch), which is used to elicit plant defense responses against fungal pathogens, were used for comparison, as well as non-inoculated plants (C). Co-inoculation of mycorrhiza and bacteria increases plant shoot and root biomass. Our results show that the inoculation of arbuscular mycorrhiza and antifungal Bacillus are good biocontrols of S. sclerotiorum in strawberry.

Vertical migration of nutrients and water-soluble organic matter in the soil profile under pre-sowing seed treatment with plant growth promoting rhizobacteria

Studies conducted in a stationary lysimeter experiment in the conditions of the washing water regime have shown that the use of PGPR for pre-sowing seed inoculation of agricultural crops reduces vertical migration of biogenic nutrients and water-soluble organic matter down the soil profile. The effect of seed inoculation with PGPR on the reduction of nutrient losses was not specific to the type of rhizobacteria and was similar for crops grown on different mineral fertilizers backgrounds (spring barley and winter rye seeds were inoculated with the nitrogen-fixing bacteria—Azospirillum brasilense 410 and A. brasilense 18-2, respectively, while maize seeds were inoculated with the phosphate-mobilizing Paenibacillus polymyxa KB). Seed inoculation has decreased nitrogen leaching down the soil profile by 4–9 kg/ha, phosphorus compounds—by 0.5–3.0 kg/ha, potassium—by 0.6–3.0 kg/ha, calcium—by 6–42 kg/ha, magnesium—by 3.0–6.0 kg/ha, water-soluble organic matter—by 0.8–8.0 kg/ha, subject to crop and norms of mineral fertilizers. Maize seeds inoculated with phosphorous-mobilizing P. polymyxa KB under crop cultivation on the cattle manure background did not affect the intensity of nutrient migration. On the other hand, the combination of green manure (narrow-leaved lupine as an intermediate crop) with pre-sowing seed inoculation had significantly reduced nutrient losses beyond the root zone soil layer. It is concluded that the use of PGPR in crop production on mineral and green manure backgrounds contributes to the preservation of soil fertility by limiting biogenic nutrients and water-soluble organic matter leaching with the water drainage down the soil profile. Pre-sowing seed inoculation had no significant effect on the vertical migration of nutrients in the soil on the background of cattle manure, due to the highly competitive environment created with the introduction of microorganisms from organic fertilizer, preventing the establishment of close interactions between PGPR and plants.

Отзывчивость зернобобовых культур на различные элементы технологий их возделывания в условиях Волгоградской области

The importance of leguminous crops in the overall balance of grain in the country, as well as in the supply of biological nitrogen to the soil, is undeniable. The aim of the research was to study two methods – pre-sowing inoculation and pre-harvest desiccation of crops on the productivity and quality of the resulting soybean grain. The article presents observations and studies of individual elements in the technology of cultivation of rain-fed chickpeas and irrigated soybeans. The importance of pre-sowing seed treatment – inoculation, with modern preparations that can enhance their mobilization processes in the soil is considered. In practice, these leguminous crops are cultivated without presowing inoculation. As a result, a certain level of grain yield of these crops is obtained, but their main advantage of leguminous crops in the accumulation of biological nitrogen in the soil does not occur properly. Therefore, as a good precursor for subsequent crops, legumes lose their importance. As an inoculant, the biological preparation GeostimFit G (at a dosage of 5‑10 l / t) was used. Foliar fertilizing with biological products and a natural mineral – bilator, helps to increase the productivity of a legume plant and reduce its susceptibility to pathogens. By the end of the growing season, leguminous plants need to apply such a technique as pre-harvest desiccation for the simultaneous ripening of grain. As desiccants, an industrially produced chemical preparation was used – reglon at a dosage of 2 l/ha and a natural mineral mined in the territory of the Volgograd region – bischofite in a 30% concentration, which are applied two weeks in advance before the upcoming harvesting of leguminous crops. It is this use of a chemical substance (reglon) and a natural mineral (bischofite) that makes it possible to achieve simultaneous drying of all tiers of a leguminous plant to be harvested, which undoubtedly increases its productivity and improves the quality of the grain obtained.

Co-inoculation of multi-trait plant growth promoting rhizobacteria promotes growth and nutrient assimilation of transplant Aman rice (cv. BRRI dhan49)

BACKGROUND: Plant growth-promoting rhizobacteria (PGPR) are the rhizosphere bacteria that can enhance plant growth by a wide variety of mechanisms. This study was conducted to assess the effects of plant growth-promoting rhizobacteria on growth and nutrient assimilation of rice. METHODOLOGY: Seeds of transplant Aman rice (cv. BRRI dhan49) were collected from Bangladesh Rice Research Institute (BRRI). Pot experiment was conducted with rice plant inoculated with two PGPR isolates MQ1 (Zinc solubilizing, IAA producing, phosphate solubilizing and N2-fixing) and MQ2 (Zinc solubilizing, phosphate solubilizing and N2-fixing) with addition of three different levels of chemical fertilizers (FR0.0 no fertilizer, FR0.5 half of the recommended dose, FR1.0 full of the recommended dose of fertilizers) following Completely Randomized Design with three replications. Plant height at different days after transplanting, number of tillers hill-1 and biomass yield were recorded. Plant samples were analyzed for N, P, Ca, Mg, S, Fe, Zn, Mn, Cu and Cd contents. KEY FINDINGS: Rice plants inoculated with the PGPR both individually or in consortium along with different doses of fertilizers showed an improved plant growth and increased biomass production. Highest plant height (74.057±3.164 cm) and maximum number of tillers hill-1 (13.000±2.082) were recorded in PGPRMQ1RF1.0 treatment and the highest biomass production (10.275±0.541 t ha-1) was recorded in PGPRCONS.RF1.0. Nitrogen content and uptake of the individual PGPR treated rice plants was also found to be higher in comparison with the uninoculated control plants. Besides these iron and zinc content of the treated rice plants was also found to be higher in comparison with the uninoculated control plants. N (0.268±0.046), P (0.626±0.095), Fe (6.062094±A), Zn (1.237±0.197) and Mn (11.908±1.879) uptake were observed higher in PGPRMQ1RF1.0 treatment. CONCLUSION: PGPR inoculation has immense potential to be used as agricultural crop inoculants as they promote plant growth as well as nutrient assimilation of rice.

Isolation, Identification and Evaluation of the Plant Growth Promoting Activities of Endophytic Stenotrophomonas maltophilia to Stimulate Growth of Clover Plants under Salt Stress

Two endophytic bacterial isolates were obtained from root nodules of clover plants grown in salt affected clay soil of Egypt. The isolates were closely linked to Stenotrophomonas maltophilia strains IPR-Pv696 and 262XG2 based on the sequencing and phylogenetic analysis of 16S rRNA genes, and deposited in GenBank with accession numbers OM980221.1 (AM1) and OM980223.1 (AM2) respectively. The isolates were evaluated for their potential to promote plant growth. The results revealed that the two isolates of S. maltophilia strains (IPR-Pv696 and 262XG2) respectively exhibited production for indole-3- acetic acid (30.26 & 31.15 µg/ml), exopolysaccharides (13.57 & 13.68 g/l), nitrogen fixation activity and they solubilize the phosphate (278 & 208 mg/l) and potassium (33.5 & 32.9 µg/ml). In a field trial, these two isolates increased clover plant growth, chlorophyll, carbohydrates content and nutrients uptake while lowering proline levels. Hence this highlights its application to be exploited as biofertilizer by leading to sustainable agriculture. This could be a promising inoculant for many other crops.