Pea Rhizosphere Research Articles

Plant growth promoting rhizobacteria exploration on butterfly pea (Clitoria ternatea l) from North Maluku Indonesia

The Plant Growth Promoting Rhizobacteria (PGPR) is associated with the roots and nodules of butterfly peas (Clitoria ternatea L.). This study aims to explore the PGPR in the rhizosphere of butterfly peas and to study their potential for biofertilizer. Characterization of PGPR was based on their ability to phosphate dissolution, auxin production, and nitrogen fixation as well as synergistic and antagonistic tests, and molecular identification. A total of 11 phosphate solubilizing bacteria isolates were isolated from the rhizosphere of butterfly peas while two isolates were taken from nodules. The RTF2 isolate from the rhizosphere had the highest phosphate solubility index. Meanwhile, the RTDH5-1, F1.1, and F2.1 showed strong inhibition ability against the growth of the pathogenic Rhizoctonia solani. The nitrogenase activity of isolates F2.1 and F1.1 from nodules were 0.975 μmol mL-1 g-1 h-1; while the IAA production was 7.87 and 7.05 mg L-1, respectively. The F1.1 had 100% similarity with Bacillus aryabhattai while F2.1 was 99.84% similar with Rhizobium sp. Both isolates can be used in biofertilizer formulation for North Maluku butterfly peas.

Identification and characterization of Azotobacter sp. screened from different agro-climatic zones in Telangana.

Declining soil quality due to overexploited used of chemical-based fertilizers, pesticides and insecticides have deleterious effect on soil health. This has resulted in decreased productivity. The use of azotobacter sp. as an alternative to the chemical based Agri-practice can be a remedial step to increase soil healthiness and in turn productivity. For the proposed research, soil sample from rhizosphere of Pigeon pea cultivated at Mahabubnagar and Medchal agroclimatic zone of Telangana. The Azotobacter sp. were isolated and maintained on Ashby’s mannitol agar medium. The Azotobacter sp. were evaluated by morphological, biochemical and molecular attributes. Biochemical tests and 16s rRNA sequencing revealed identification of strains as Azotobacter beijerinckii strain (BKPOU06TS) and Azotobacter tropicalis strain (BKPOU08TS). The 16s rRNA sequences of Azotobacter beijerinckii strain (BKPOU06TS) and Azotobacter tropicalis strain (BKPOU08TS) were submitted to GenBank with accession ID- OP536202 and OP536206 respectively

Beneficial aluminium immobilizing microorganisms inhabiting the rhizosphere of pea

Acid soils contain elevated concentrations of mobile aluminium (Al) ions which are toxic for plants. Plants form symbioses with the rhizosphere microorganisms stimulating plant growth and affecting Al availability. Here, for the first time the approach based on the ability to immobilize Al in soil was applied for initial selection of beneficial rhizosphere microorganisms. Al-Immobilizing yeast Rhodotorula sp. AL1 and 12 bacterial strains assigned to various genera and species were isolated from the rhizosphere of pea cultivated in acid soils. Immobilization of Al was related to the increased pH of the environment and the formation of insoluble Al phosphates in soil. The strains differed in possessing beneficial properties such as modulation of the nutrient element (Ca, Fe, K, Mg, Mn, P) concentrations in soil, production of phytohormones (auxins, abscisic and gibberellic acids, ethylene), utilization of 1-aminocyclopropane-1-carboxylic acid and organic components typical for root exudates, acetylene reduction and antifungal activities. Eight strains promoted root elongation of radish seedlings by 30÷50 % with a maximal effect exerted by Cupriavidus basilensis strain D39. Taking together, the selected microorganisms are promising models to study the mechanisms of plant-microbe interactions in the presence of toxic Al and improving Al tolerance of plants in acid soils.

Characterization of phosphate solubilizing plant growth promoting rhizobacteria isolated from pea rhizosphere (Pisum sativa)

The rhizosphere soil is a source for a diversity of microorganisms which play a vital role in the enhancement of plant health through the mechanism of symbiotic interaction thereby influencing the plant growth. The present study aimed at isolating potential phosphate solubilizing rhizobacteria from pea (pisum sativa) crop for which, rhizosphere soil samples were collected from two pea growing districts of Kashmir valley viz. Srinagar and Baramulla. Isolates were cultured on nutrient agar medium followed by serial dilutions and different colonies with morphological variations were isolated from each dilution. A total of 80 bacteria were isolated and maintained as pure cultures. Out of the 80 isolates, 25 strains showed phosphate solubilizing ability and amongst them, 9 were highly potential which were subjected to morphological and biochemical characterization. Furthermore, the potential bacteria were analysed for Indole Acetic Acid (IAA) production, which was found to be directly proportional to the plant growth promotion. After screening the best nine isolates PGP1, PGP10, PGP28, PGP40, PGP49, PGP52, PGP60, PGP72 and PGP75 were selected for their effect on growth and yield in field conditions using pea as test crop.

Are native phosphate solubilizing bacteria a relevant alternative to mineral fertilizations for crops? Part I. when rhizobacteria meet plant P requirements.

Deployment of Phosphate Solubilizing Bacteria (PSB) can enhance plant P uptake through remobilization of recalcitrant forms of P in soil. In this study, bacterial strains isolated in the rhizospheric soil of rapeseed, winter pea and faba bean, with various P requirements, were screened for their PSB potential through the characterization of several interesting traits linked to P solubilization. In parallel, other Plant Growth Promoting Rhizobacteria (PGPR) traits of interest (indole-3-acetic acid (IAA) production or 1-aminocyclopropane-1-carboxylic acid (ACC) deaminase activity) were also determined for each isolate. An abundant proportion of PSB strains were successfully emphasized, mainly belonging to Pseudomonas and Bacillus genera. The present study also reveals for the first time the potential of phosphate solubilization of an isolate belonging to the species Sanguibacter inulinus. Interestingly, PSB isolated from rapeseed soil showed higher solubilization efficiency compared to those isolated from faba bean and winter pea rhizosphere. These results highlighted the great influence of plant to shape their associated microbiome in order to fit specific P requirement. Two distinct profiles of PSB isolates could be highlighted, deploying either direct or indirect processes. Plants seemed to preferentially enrich PSB populations presenting complementary characteristics to their own arsenal to favor P nutrition. Valuing native PSB potential, through artificial addition or through the legacy of previous crop for the further culture could represent a promising alternative to sustain plant growth in P-deprived situation.

Antagonistic activity of resident biological agents against wilt and root rot pathogens of pea in different culture media

Antagonistic potential of rhizospheric fungal and bacterial isolates evaluated against wilt and root-rot pathogens of pea exhibited significant effect on radial growth inhibition of pathogens in comparison to control. Two isolates of Trichoderma spp., one isolate of Aspergillus niger, one isolate of Penecillium oxalicum and three isolates of Pseudomonas were isolated from rhizosphere of pea and were evaluated for their antagonistic potential against three soil borne plant pathogens viz., Fusarium oxysporum f. sp, pisi, Rhizoctonia solani and Pythium ultimum using dual culture technique in different culture media (potato carrot agar, czapek dox agar, rose bengal chloramphenicol and czapek malt agar). Antagonistic potential of fungal and bacterial isolates were found to be significantly influenced in different culture media. All fungal and bacterial isolates preferred potato carrot agar and czapek dox agar media and resulted in maximum reduction in growth of test pathogen on the culture media.

Isolation and Molecular Identification Of Lactobacillus Bacteria and Evaluation of Their Efficacy In Inhibiting The Pathogenic Fungus Pythium aphanidermatum

Twenty-eight isolates of Lactobacillus were isolated from the rhizosphere of pea cultivated in the fields of five districts in Salah al-Din, which included: Tikrit, Al-Alam, Al-Sharqat, Samarra and Al-Baiji. The isolates identified according to molecular diagnosis using the analysis of the 16S rRNA sequences and were divided into five species: 7 Isolates of L. fermentum, 3 isolates of L. casei, 9 isolates of L. plantarum, 4 isolates of L. herbarum and 5 isolates of L. paralimentarius. Antagonism tests were conducted for these isolates against the pathogen Pythium aphanidermatum, the highest rate of inhibition was by isolates of bacteria L. paralimentarius 1981 reached 2.7 mm, followed by isolate L.plantarum 1982 with an inhibition rate of 2.5 mm. In the antagonism test using bacterial filtrate of L. paralimentarius 1981, the concentration of 30% was the highest in inhibiting the pathogenic fungus, as the fungus colony diameter reached 3.22 cm, followed by the concentration of 20 and 25%, as the colony diameter reached 4.47 and 3.68 cm, respectively. L. paralimentarius 1081 was recorded in the databases of the World Genetic Bank within the accession number MW149434.1. This is the first record of this bacteria in Iraq. L. paralimentarius 1081 showed the highest production of the antibacterial active substances including siderophores, total phenols and bacteriocin reached to 61.24%, 1.05 mg/ml and 18.02 mg/ml, respectively, as well as pH decreased to 4.5. The results also showed there are a strong correlation of pathogenic fungus inhibition with high concentrations of siderophores, total phenols, bacteriocin and low pH in the bacterial filtrate.

Response of Different Crop Cultivars to Micronutrient Fertilization and Relationship to Rhizosphere Soil Properties

ABSTRACT Five different cultivars each of wheat, pea, and canola were grown with and without copper (Cu), zinc (Zn), and boron (B) fertilization, respectively, in a greenhouse study to identify any crop cultivar and rhizosphere soil responses to micronutrient fertilization. The prairie agricultural surface soils (0–10 cm) used in the study were suspected to be micronutrient deficient according to soil extractable levels. Only durum wheat (CDC Fortitude) produced greater biomass from Cu fertilization compared to the other wheat cultivars. Cultivar dependent responses of pea and canola biomass yield to Zn and B fertilization were not significantly (P > .05) different. Boron concentration in whole plant canola tissue increased following fertilizer addition. Micronutrient fertilization increased concentrations and supply rates of available Cu, Zn, and B in post-harvest rhizosphere soil. Fertilizer Cu and Zn were distributed in labile soil solution-carbonate-exchangeable and oxyhydroxide fraction, whereas B was primarily found in the hot water-soluble fraction, specifically adsorbed and oxyhydroxide fractions. The composition of low molecular weight organic acids (formic, propionic, malic, and fumaric acid) in the rhizosphere soil varied among crops. Additionally, citric and tartaric acid were present in the pea and canola rhizosphere soils, respectively. The rhizosphere soil of durum wheat not fertilized with Cu contain higher levels of succinic acid compared to the other wheat cultivars. For pea and canola, there was no significant (P > .05) effect of cultivar on the amounts or forms of organic acids in the rhizosphere soils.

Phylogenetic diversity of indigenous Rhizobium trapped from the natural habitat of Pisum sativum L. in eastern and central Algeria

The nitrogen-fixing symbiosis fixation between legumes and Rhizobium helps the plant to survive and to compete effectively on nitrogen poor soils. The soil environment attached to the root system is characterized by intense microbial activity. This work aimed to study the diversity of indigenous rhizobia living in the rhizosphere of forage pea in eastern and central Algeria. Bacteria were trapped in vitro from collected soils. They were isolated from nodules by direct isolation or by bacterial trapping, and tested for nodulation. Further characterization was carried out to identify the isolates. Ninety-four isolates were obtained. Thirty-four were rhizobial strains that could, with two exceptions, establish root-nodule symbioses with the host plant. Different profiles of susceptibility to rhizobiophages indicated that the majority of isolates were likely to be members of the Rhizobium leguminosarum group of species. The strains revealed diverse plasmid profiles, and diverse restriction patterns of cpn60 gene amplicons and on Southern blot analysis of nodABC genes. Sequences of 16S rRNA gene showed that all isolates exhibited 99.85% identity with R. leguminosarum sv. viciae USDA 2370T, R. laguerreae FB206T and R. anhuiense CCBAU 23252T. Analysis of cpn60 sequences revealed two groups. One of them clustered with ≤99% identity with R. laguerreae FB403. The second was clustered with ≤99% identity with R. laguerreae FB206T. Our findings suggest that the isolates may belong to the species R. laguerreae.

Root rot alters the root-associated microbiome of field pea in commercial crop production systems

Pulses are important crops that have been used to diversify cropping rotations in the Canadian prairies. With increasing cultivation intensity, pulses are becoming more susceptible to root rots. Understanding how root-associated microbiomes are affected by plant health is vital for developing sustainable crop production systems. In this study, we investigated the effect of root rot on rhizosphere and root microbiomes of healthy and root-rot infected field pea (Pisum sativum L.) plants from nine commercial fields in Saskatchewan using amplicon metagenomic sequencing. Bacterial and oomycete α-diversity was higher in diseased root and rhizosphere samples than their healthy counterparts, while fungal diversity was higher in diseased rhizosphere samples. The community structure of root and rhizosphere microbiomes were also affected by the health status of the plants, with root bacterial communities exhibiting the strongest differences. Healthy samples were associated with a higher relative abundance of Rhizobium, Olpidium and Mortierella, and lower abundance of Fusarium and Pythium. Diseased samples had a higher number of indicator genera (42 in diseased vs. 11 in healthy) and more taxa exclusively detected in the diseased core microbiome. Results from this study revealed that root rot generally increased the diversity and altered the community structure and relative abundance of key taxa of the pea root-associated microbiome. This knowledge may aid in the development of microbiome-based disease management strategies, such as identification of key microbial taxa that could help commercial pea growers assess root rot risk.

АКТИВНІСТЬ РИЗОСФЕРНОЇ МІКРОБІОТИ ГОРОХУ ОЗИМОГО ЗА КОМБІНОВАНОЇ ДІЇ ГЕРБІЦИДУ І БІОЛОГІЧНИХ ПРЕПАРАТІВ

The article presents the results of studies the total number of bacteria, micromycetes and azotobacter in the rhizosphere of winter peas, depending on the use of different rates of herbicide MaxiMox (0,8; 0,9; 1,0 and 1,1 l / ha), separately and in tank mixes with plant growth regulator Agriflex Amino (1,0 kg/ha) on the background of bacterization seeds material with the microbial preparation Optimize Pulse (3,28 l/t) and without background. The obtained results showed the dependence of the functioning of the rhizosphere microbiota of winter peas on the application of different herbicide rates, but with the complex application of MaxiMox (0,8–1,0 l/ha) with the plant growth regulator Agriflex Amino (1,0 kg/ha) on the background of bacterization seeds material with the microbial preparation Optimize Pulse (3,28 l/t) was observed to reduce the negative impact of xenobiotics on the soil microbiota, which was manifested in an increase the total number of bacteria by an average of 3-21%, micromycetes - 42-73% and azotobacter - 2-9%

Pea (Pisum sativum l.) Plant Shapes Its Rhizosphere Microbiome for Nutrient Uptake and Stress Amelioration in Acidic Soils of the North-East Region of India.

Rhizosphere microbiome significantly influences plant growth and productivity. Legume crops such as pea have often been used as a rotation crop along with rice cultivation in long-term conservation agriculture experiments in the acidic soils of the northeast region of India. It is essential to understand how the pea plant influences the soil communities and shapes its rhizosphere microbiome. It is also expected that the long-term application of nutrients and tillage practices may also have a lasting effect on the rhizosphere and soil communities. In this study, we estimated the bacterial communities by 16S rRNA gene amplicon sequencing of pea rhizosphere and bulk soils from a long-term experiment with multiple nutrient management practices and different tillage history. We also used Tax4Fun to predict the functions of bacterial communities. Quantitative polymerase chain reaction (qPCR) was used to estimate the abundance of total bacterial and members of Firmicutes in the rhizosphere and bulk soils. The results showed that bacterial diversity was significantly higher in the rhizosphere in comparison to bulk soils. A higher abundance of Proteobacteria was recorded in the rhizosphere, whereas the bulk soils have higher proportions of Firmicutes. At the genus level, proportions of Rhizobium, Pseudomonas, Pantoea, Nitrobacter, Enterobacter, and Sphingomonas were significantly higher in the rhizosphere. At the same time, Massilia, Paenibacillus, and Planomicrobium were more abundant in the bulk soils. Higher abundance of genes reported for plant growth promotion and several other genes, including iron complex outer membrane receptor, cobalt-zinc-cadmium resistance, sigma-70 factor, and ribonuclease E, was predicted in the rhizosphere samples in comparison to bulk soils, indicating that the pea plants shape their rhizosphere microbiome, plausibly to meet its requirements for nutrient uptake and stress amelioration.

Soil Biological Properties in Rhizosphere of Pea (Pisum sativum L.) Improved by Magnetic Treatments

Soil Biological Properties in Rhizosphere of Pea (Pisum sativum L.) Improved by Magnetic Treatments

Shifts in the Active Rhizobiome Paralleling Low Meloidogyne chitwoodi Densities in Fields Under Prolonged Organic Soil Management.

Plants manipulate their rhizosphere community in a species and even a plant life stage-dependent manner. In essence plants select, promote and (de)activate directly the local bacterial and fungal community, and indirectly representatives of the next trophic level, protists and nematodes. By doing so, plants enlarge the pool of bioavailable nutrients and maximize local disease suppressiveness within the boundaries set by the nature of the local microbial community. MiSeq sequencing of specific variable regions of the 16S or 18S ribosomal DNA (rDNA) is widely used to map microbial shifts. As current RNA extraction procedures are time-consuming and expensive, the rRNA-based characterization of the active microbial community is taken along less frequently. Recently, we developed a relatively fast and affordable protocol for the simultaneous extraction of rDNA and rRNA from soil. Here, we investigated the long-term impact of three type of soil management, two conventional and an organic regime, on soil biota in fields naturally infested with the Columbian root-knot nematode Meloidogyne chitwoodi with pea (Pisum sativum) as the main crop. For all soil samples, large differences were observed between resident (rDNA) and active (rRNA) microbial communities. Among the four organismal group under investigation, the bacterial community was most affected by the main crop, and unweighted and weighted UniFrac analyses (explaining respectively 16.4% and 51.3% of the observed variation) pointed at a quantitative rather than a qualitative shift. LEfSe analyses were employed for each of the four organismal groups to taxonomically pinpoint the effects of soil management. Concentrating on the bacterial community in the pea rhizosphere, organic soil management resulted in a remarkable activation of members of the Burkholderiaceae, Enterobacteriaceae, and Pseudomonadaceae. Prolonged organic soil management was also accompanied by significantly higher densities of bacterivorous nematodes, whereas levels of M. chitwoodi had dropped drastically. Though present and active in the fields under investigation Orbiliaceae, a family harboring numerous nematophagous fungi, was not associated with the M. chitwoodi decline. A closer look revealed that a local accumulation and activation of Pseudomonas, a genus that includes a number of nematode-suppressive species, paralleled the lower M. chitwoodi densities. This study underlines the relevance of taking along both resident and active fractions of multiple organismal groups while mapping the impact of e.g. crops and soil management regimes.

Isolation and characterization of plant growth promoting rhizobacteria associated with pea rhizosphere in North Himalayan region

PGPR are naturally occurring soil bacteria which actively colonize plant root and benefit plants by promoting growth. They help in providing atmospheric nitrogen, increase supply of other nutrients, produce plant hormones, enhance other beneficial bacteria or fungi, control bacterial and fungal diseases and help in controlling insect pests. The purpose of this study was to investigate the diversity of bacteria associated with the roots of pea and to screen them for selection of most potential PGPR for application in pea crop. The study reveals the diversity of bacterial isolates from soils under pea cultivation in district Srinagar and Baramulla of J&K. The isolates were characterized morphological and physiologically to categorize and identify them. In all 80 different bacterial isolates were recovered from 16 fields of two districts of J&K. The characteristics of the bacterial isolates were determined using the colony morphology, gram staining, biochemical properties and plant growth promoting activities. On the basis of biochemical characterization, 55 isolates belonged to genus Bacillus, 12 to Pseudomonas, 4 to Micrococcus and 9 to Azotobacter. After screening the best nine isolates PGP1, PGP10, PGP28, PGP40, PGP49, PGP52, PGP62, PGP68 and PGP72 were selected for growth and yield in field conditions using pea as test crop.

Evaluation of antifungal activity of Bacillus spp. against Fusarium oxysporum and Rhizoctonia solani in Chick pea (Cicer arietinum L.)

Bacillus isolates were evaluated for their antagonistic activities against Fusarium oxysporum and Rhizoctonia solani from chick pea rhizosphere and their compatibility with Fusarium oxysporum and Rhizoctonia solani.Bacillus B1 isolate showed 53.3% inhibition and Bacillus N2(2) showed 41.7% inhibition against R. solani. Compatibility of fungicides with B1 and N2(2), Bacillus isolates was checked using turbidometric method, disc method and poisoned food method. Both isolates were found compatible with different fungicides concentration. Both isolates when incorporated as seed treatment, increased germination percentage, root/shoot length and vigour index. Out of 5 fungicides, maximum tolerance concentration and maximum inhibition centration was found to be more concentration by Carbendazim.

Bacterial microbiome associated with the rhizosphere and root interior of crops in Saskatchewan, Canada.

Rhizosphere and root associated bacteria are key components of plant microbiomes and influence crop production. In sustainable agriculture, it is important to investigate bacteria diversity in various plant species and how edaphic factors influence the bacterial microbiome. In this study, we used high-throughput sequencing to assess bacterial communities associated with the rhizosphere and root interior of canola, wheat, field pea, and lentil grown at four locations in Saskatchewan, Canada. Rhizosphere bacteria communities exhibited distinct profiles among crops and sampling locations. However, each crop was associated with distinct root endophytic bacterial communities, suggesting that crop species may influence the selection of root bacterial microbiome. Proteobacteria, Actinobacteria, and Bacteroidetes were the dominant phyla in the root interior, whereas Gemmatimonadetes, Firmicutes, and Acidobacteria were prevalent in the rhizosphere soil. Pseudomonas and Stenotrophomonas were predominant in the rhizosphere and root interior, whereas Acinetobacter, Arthrobacter, Rhizobium, Streptomyces, Variovorax, and Xanthomonas were dominant in the root interior of all crops. The relative abundance of specific bacterial groups in the rhizosphere correlated with soil pH and silt and organic matter contents; however, there was no correlation between root endophytes and analyzed soil properties. These results suggest that the root microbiome may be modulated by plant factors rather than soil characteristics.

Relationship between Mycoflora and Soil Functionality in Pigeon Pea (Cajanus cajan L.) in some Districts of Uttar Pradesh, India

India is the largest producer of pulses in the world, with 25% share in the global production. The leading pulse producing states are Madhya Pradesh, Maharashtra, Rajasthan, Uttar Pradesh, Karnataka and Andhra Pradesh. The important pulse crops are chickpea (48%), pigeon pea (15%), mung bean (7%), urdbean (7%) and lentil (5%). In the present communication, a survey was conducted from 2015 to 2016 of pigeon pea fields in eighteen locations at Agra, Prayagraj, Aligarh, Basti and Hardoi, districts. The pathogens isolated from pigeon pea plants were Fusarium udum., Sclerotinia rolfsii and Rhizoctonia solani mainly. Physically the textures of soil samples were found clay to sandy at several places among them sandy soil was dominating. Moisture content varied from 6.58 to 11.25%. During the course of study it became evident that pigeon pea (leguminous) plants were found to be wilting. It is also evident that the percent occurrence of wilted pigeon pea plants in different villages of the five districts was in the range of 6.03%-16.01%, whereas, the average wilting occurrence among the district varied from 9.03%-14.5%. Basti district showed maximum percentage of wilt occurrence (14.5%) while Agra, Prayagraj, Aligarh, and Hardoi showed 9.05%, 12.5%, 9.3% and 9.35%, respectively. It was also found that pH of the soil also affected diseases development. As in the fields having pH range of 6.5-8.0, the plants were found to be infected with wilt disease. However, at pH 5.0-6.5 the diseases could not be detected. In Basti, Prayagraj and Aligarh, due to alkaline pH (7.45-7.68) wilting disease on pigeon pea plants occurred frequently. Sandy loam favoured pigeon pea wilt. Sandy loams provide sufficient aeration in the rhizosphere of pigeon pea, which may be required for population build up of inoculum concentration of Fusarium leading to high incidence of wilt.

Microbiota of rhizosphere of peas under the influence of various technologies of crop cultivating

This article describes changes in the microflora depending on the variety of peas and its growing technologies. The microflora of rhizospheres of varieties Madonna and Starter under the influence of various technologies of cultivation of culture has been investigated. The risks of agroeconomy of peas during its vegetation are considered, which leads to increase in the number of phytopathogenic micromycetes in the rhizosphere of the plant. As a consequence, an increase in the spectrum of phytopathogenic fungi leads to the formation of epiphytoties that can accumulate toxins and mycotoxins. The development of epiphytotic species can lead to abrupt changes in the balance of its microbial and environmental pollution. Such violations substantially impair the composition of the soil. The systematic use of synthetic mineral fertilizers leads to depletion of the soil, changes in acidity, deterioration of functional bonds. Increased acidity of the soil prevents the activity of beneficial microorganisms, thus preventing the assimilation of leguminous crops of nitrogen resulting in impoverished soils. The degradation of soils is another negative consequence. The use of organic and biological technologies that increase and regulate microbial diversity in the rhizosphere of plant crops is an alternative methods. In addition, they do not pollute the environment. The regulating factor is an increase in saprotrophic fungi that inhibit the spread of pathogenic species. Saprotrophic species are involved in humus formation. The amount of phytopathogenic fungi in peas agrocenosis is substantially regulated by plants varieties and the technology of its cultivation. The changes of microbiodiversity of the rhizosphere, depending on the technologies of growing peas and varieties, are analyzed.

Influence of inoculation on photosynthesis and symbiotic parameters of pea and its crop yield in the conditions of the southern forest steppe of Western Siberia

The paper highlights the effect of inoculation by means of biological specimens on formation of photosynthetic parameters, nodule-forming capacities and yield of pea grain. The authors reveal the varieties which mostly respond to the tillage, effective specimens and methods of their application. The researchers explored two varieties of pea as Omskiy 9 and Omskiy 18 and two biological specimens (risotorphine and ruminatine). The study was conducted in the experimental fields of Omsk agricultural research center in 2016-2017 in the following variants: control (without inoculation), inoculation by means of risotorphine, inoculation by ruminatine and combined tillage. The researchers observed different meteorological conditions during the research. The experiments and calculations of the experimental data were carried out by means of general methodics. The positive effect of inoculation on increasing of such parameters as leaf surface index and photosynthetic potential is observed. Active symbiotic potential, number and weight of nodules rhizosphere of pea had a maximum value when being treated by biospecimen ruminatine and combined inoculation of seeds by risotorphine and ruminatine. The authors highlight significant positive relationship between photosynthetic and active symbiotic potential. Inoculation influenced the yield of pea varieties in a different way in the years of research. The results of variance analysis showed that conditions of experiment influenced the yield of varieties – 34.4 %, the proportion of inoculation effect was 25.0 % and genotype – 17,3 %. Omsk 18 variety was characterized by the highest rates of photosynthetic and symbiotic activity. Seed treatment with ruminatine and combined inoculation with risotorphine and ruminatine have impact when growing pea in the conditions of southern forest-steppe of Western Siberia.