Groundnut (Arachis hypogaea L.) growth and yield enhancement by consortium of diazotrophic and non-rhizobial root nodule endophytic bacteria

Groundnut (Arachis hypogaea L.) growth and yield enhancement by consortium of diazotrophic and non-rhizobial root nodule endophytic bacteria | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Research Article Groundnut ( Arachis hypogaea L.) growth and yield enhancement by consortium of diazotrophic and non-rhizobial root nodule endophytic bacteria Monday Ubogu, Afa Peter Abya, Esther E Ebah This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-6214229/v1 This work is licensed under a CC BY 4.0 License Status: Posted Version 1 posted You are reading this latest preprint version Abstract Modern agriculture rely heavily on costly and environmentally pernicious chemical fertilizers. To investigate possible alternatives to chemical fertilization in A. hypogaea cultivation, consortium of three plant growth promoting bacteria (PGPB): P. aeruginosa, A. chrococcum and A. faecalis were isolated from rhizosphere and root nodules of A. hypogaea using spread plate dilution method on Azotobacter chroococcum agar, and yeast extract manitol agar growth media. Isolates identified using cultural, morphological, biochemical and molecular characterization. Isolates were scaled-up, inoculated into 4000.0g of soil in pots at rate of 4.5 x 10 6 cfu/ml ( A. chrococcum ), 2.0 x 10 9 cfu/ml ( P. aeruginosa ), 1.5 x 10 9 cfu/ml ( A. faecalis ) in the following treatments: Uninoculated (control); NPK; Pseudomonas-Azotobacter; Pseudomonas-Alcaligenes; Pseudomonas-Alcaligenes-Azotobacter in triplicates. Seeds of A. hypogaea belonging to two varieties (SAMNUT 25 and 26) were propagated in treated soils in two separate sets. Growth enhancement parameters: germination time, percentage germination, shoot, root lengths growth, fresh plant and pods weights, pods and nodule numbers, and chemical properties of soils determined after 120 days. Results showed soils inoculated with PGPB enhanced all growth parameters over uninoculated (control) and NPK treated soils which were statistically significant for germination time, shoot, root lengths, fresh plant and pods weights, pods and nodule numbers (p < 0.5). Soil chemical properties: pH, P, N, CEC and SOM contents were maintained and enhanced. P. aeruginosa, A. chrococcum and A. faecalis soil inoculation offered effective alternative to chemical NPK fertilization. General Microbiology Diazotroph endophytes enhancement groundnut NPK fertilizer Figures Figure 1 Figure 2 Figure 3 Figure 4 Introduction Groundnut ( Arachis hypogaea L.) belong to the leguminous family, the third largest groups of flowering plants on earth (Madigan et al. 2012 ). The crop is cultivated in about 100 countries across the globe. While India, China, Nigeria and USA are the leading producers, Nigeria accounts for about 10% of total global production (Sogut et al. 2016 ). Current global annual groundnut production estimate stands at 54.2 million tonnes on 30.5 million hectares of land worldwide (Nepir and Tadesse 2024 ). A. hypogaea is the most important crop among the leguminous plants for edible vegetable oil production after soybean (Taphee et al. 2015 ; Upadhyaya and Dwivedi, 2015 ). The plant is highly valued as every parts of it is useful, providing food, requisite nutrition for human, animal, and financial security for growers. The seed is laden with high amount of quality vegetable oil (48–50%), protein (26–28% ), important minerals and vitamins (such as vitamin E, K and B complex), Fe, Mg, Ca, Zn, K, P), and dietary fibre (Janila et al., 2013 ; Girei et al. 2013 ; Abady et al. 2019 ; Gulluoglu et al. 2016 ). The haulms and residues serves as feedstocks for animals (Melesse et al. 2023 ). Modern agriculture relies heavily on the use of chemical fertilizers for improved growth and yield of crops (Rana et al. 2023 ). One hectare of A. hypogaea requires approximately 112.0 kg of N, 27.0 kg of P and 34.0 kg of K chemical fertilization for optimum growth (Misra 2017 ). Chemical fertilizers are both costly and environmentally pernicious. Excessive application of agrochemical nitrogen severely reduced soil fertility (Imran et.al. 2021 ), with unused nitrogen polluting surface and groundwater or emitted into the atmosphere (Sharma and Bali 2018 ). Nitrogen emissions (nitrous oxide, ammonia, nitrogen oxide etc.) play significant part in climate change as well as contributing particulate matter along with acid rain resulting in respiratory challenges, cancer, damage to forest and buildings (Imran et al. 2021 ). Not much attention has been focused on alternative natural sources of nitrogen for plant by the way of diazotrophs, the mini-nitrogen factories in the rhizosphere, rhizoplane and inside the root (Imran et al. 2021 ). For instance, inspite of favourable reports on plant growth promotion, very limited number of studies have delved into the possibility of supplementing chemical fertilizers with Azotobacter chroococcum , its application as biofertilizer have been reported to reduce chemical nitrogen fertilization by up to 50% in soil (Romero-Perdomo et al. 2017 ). As bioinocultants, these plant growth promoting rhizobacteria can offer a veritable alternative to chemical fertilization for the attainment of sustainable agriculture and ecosystem health. Biological nitrogen fixation by bacteria and archaea contributes about 40 to 100 teragram of nitrogen (Tg N) to terrestrial ecosystem annually ( Vitousek et. Al. 2023). Approximately one quarter of global annual nitrogen fixation occurs in the root nodules of legumes via symbiotic association with the diazotroph - Rhizobium (Madigan et al. 2012 ). An estimated 60 kg N/ha/yr is fixed into soil by free-living diazotrophs (Vadakattu et al. 2006 ; Reed et al. 2011 ). The non-symbiotic diazotroph, Azotobacter which is dominant in soil (Din et al. 2019 ) has the capacity to fix nitrogen at an average rate of 20 kg N/ha/year (Rawia et al., 2009 ) in addition to ensuring the availability of P in soil (Velmourougane et al. 2019 ). The nodulating diazotrophic Rhizobium do not exclusively occupy the root nodules of legumes but coexist with array of non-rhizobial endophytic microorganisms (Preyanga et al. 2021 ). Though a number of non-rhizobial root nodule endophytes have shown promise in the growth enhancement of legumes through biological nitrogen fixation, zinc and phosphorus solubilization, auxin, amonia, siderophore or phytohormones production (Zloch et al. 2016; Rana et al. 2023 ; Hnini and Aurag 2024 ), their roles remain insufficiently elucidated (Hnini and Aurag 2024 ). Endophytic nitrogen fixing bacteria are regarded superior to their rhizosphere and rizoplane counterpart as they deliver fixed nitrogen outrightly to their host plant (Cocking 2003 ). Furthermore, some of these non-rhizobial root nodule endophytic bacteria have also been reported to stimulate nodulation, protect against phytopathogens and enhance growth of legumes (Preyanga et al. 2021 ; Mustaq et al. 2023 ; Ge et al. 2023 ; Debnath et al. 2024). It is in furtherance of achieving sustainable agriculture via cost-effective and environmentally friendly biofertilization with plant growth promoting rhizobacteria that this study was carried out using non-symbiotic diazotroph ( Azotobacter chroococcum ) and non-rhizobial root nodule endophytes ( Pseudomonas aeruginosa and Alcaligenes faecalis ) for the growth and yield enhancement of A. hypogaea . Materials and Methods Isolation of non-symbiotic diazotroph ( Azotobacter chrocooccum ) and non-rhizobial root nodule endophytes ( Pseudomonas aeruginisa and Alcaligenes faecalis ) The non-symbiotic diazotroph, Azotobacter chrocooccum employed in this study was isolated from the rhizosphere of a four-month old A. hypogaea using the method adapted by Ikediugwu and Ubogu ( 2012 ), Akponah and Ubogu (2023). Ten grams of soil particles released from the rhizosphere after shaking uprooted A. hypogaea plants were homoginized. Thereafter 1.0 g of homogenized soil was weighed into sterile test tube containing 9.0 ml sterile physiological saline. From this, ten-fold serial dilutions (10 − 1 , 10 − 2 , 10 − 3 , 10 − 4 and 10 − 5 ) in physiological saline were made. Aliquote of 0.1 ml of serially diluted soil sample was then plated out in petri dishes containing Azotobacter chroococcum agar medium (composition of medium includes, K 2 HPO 4 , 1.0 g; CaCO 3 , 20.0 g; MgSO 4 .7H 2 O, 0.5 g; glucose, 20.0 g and agar, 20.0 g in 1000.0 ml of distilled water)(Atlas 2010 ), using the spread plate method. On the other hand, the non-rhizobial endophytes, Pseudomonas aeruginisa and Alcaligenes faecalis employed in this study were isolated from well-formed matured root nodules of a four-month old A. hypogaea using the method described by Ubogu et al. ( 2018 ). One gram of plucked root nodules was washed in tap water, thereafter surface-sterilized in 70% ethanol for 2.0 minutes and afterward rinsed using distilled sterile water. Sodium hypochlorite (3.5% v/v) was subsequently used to surface-sterilize nodules for 2.0 minutes and promptly rinsed with distilled sterile water thrice. The surface-sterilized root nodules were then aseptically crushed in Mac Cartney bottle with the addition of few drops of distilled sterile water. Following proper crushing, crushed nodules were made up to 10. 0 ml using physiological saline. From this, ten-fold serial dilutions (10 − 1 , 10 − 2 , 10 − 3 , 10 − 4 and 10 − 5 ) in physiological saline were made. Aliquote of 0.1 ml of serially diluted crushed sample was then plated out in petri dishes containing yeast extract manitol agar (YEMA) (YEMA composition includes, K 2 HPO 4 , 2.5 g; MgSO 4 , 0.1 g; NaCl, 0.13 g; manitol, 5.0 g; yeast extract, 0.5 g; agar powder, 20.0 g in 1000.0 ml of distilled water), using the spread plate method. All agar plates (TDC agar and YEMA) were incubated at 30.0 ± 2.0 ℃ (room temperature) for 72 h. Isolated colonies obtained were purified and stored in TDC agar and YEMA slants respectively for characterization of isolates and further studies. Characterization of bacterial isolates . The non-symbiotic diazotroph and non-rhizobial endophytic bacterial isolates used in this study were first presumptively identified based on their cultural, morphological and biochemical characteristics relying on Bergey’s Manual of Systemic Bacteriology (Brenner et al. 2005). Further confirmation of these isolates designated as OG1, OG2, OT1, OT2, OT3 and OT4 were done based on 16S rRNA conserved gene sequence. Following DNA extraction using ZR Fungal/Bacterial DNA MINIPREP ( manufactured by Zymo Research), targeted gene sequence of designated bacteria was amplified using standard PCR technique. The 16S rRNA gene fragments were amplified using forward (27F: AGAGTTTGATCMTGGCTCAG) and reverse (1525R: AAGGAGGTGWTCCARCCGCA) primer. The amplified fragments were verified on 1% agarose gel using agarose gel electrophoresis. Amplified fragments were sequenced using a Genetic Analyzer 3130xl sequencer (from Applied Biosystems) using manufacture’s manual. The sequencing kit used was that of BigDye terminator v3.1 cycle sequencing kit. Genetic analysis were carried out using Bio-Edit software and MEGA 12. NCBI GenBank database ( http://www.ncbi.nlm.nih.gov ) was employed for gene sequences comparison via Blastn search. Phylogenetic tree construction was carried out using the Maximum Likelihood method via Neighbour-Joining. Isolates OG2, OG1 and OT1 which were subsequently identified as A. chrocooccum, P. aeruginisa and A. faecalis respectively were subsequently selected for growth enhancement study of A. hypogaea. Determination of of soil physicochemical properties Experimental soil samples employed for this study were collected from a designated arable land area of Federal University of Agriculture Makurdi. Soil samples were collected in triplicates and first analyzed to ascertain its baseline physicochehemical properties to determine its suitability for the propagation of A. hypogaea before treatments and plant propagation. After treatments and propagation, the experimental set up was monitored for 120 days after which plants were harvested and the respective treated propagated soil samples were re-evaluated for any change in physicochemical properties. Soil samples were analyzed for its textural components of sand, silt and clay using the hydrometer method described by Aliyu and Oyeyiola ( 2011 ). Soil porosity was analyzed using the method of Ezzati et al. ( 2012 ). The method of Hendershot et al. ( 2006 ) was used to determine soil pH; while phosphorus (P) by the method of Skjemstad et al. (2006); nitrogen (N) by the procedure of micro-Kjeldahl (FAO 2021 ); soil organic matter (SOM) by Walkley-Black method (FAO 2020 ) and cation exchange capacity (CEC) by cation exchange capacity and exchangeable bases 1N ammonium acetate, pH 7.0 method (FAO 2022 ). Bacterial inoculants scale-up and soil inoculation The bacterial iosolates OG2, OG1 and OT1 which were subsequently identified as A. chrocooccum, P. aeruginisa and A. faecalis respectively were employed as microbial soil inoculants in the treatment of soil for plant propagation. The purified bacterial isolates were respectively scrapped from their agar slants using sterile wire loop into separate 200.0ml broth in sterile 500.0 ml conical flask. A. chroococcum was inoculated into A. chroococcum broth medium (composition of medium includes, K 2 HPO 4 , 1.0 g; CaCO 3 , 20.0 g; MgSO 4 .7H 2 O, 0.5 g and glucose, 20.0 g in 1000.0 ml of distilled water)(Atlas 2010 ), while P. aeruginosa and A. faecalis into yeast extract manitol broth (YEMB) (composition includes, K 2 HPO 4 , 2.5 g; MgSO 4 , 0.1 g; NaCl, 0.13 g; manitol, 5.0 g; yeast extract, 0.5 g in 1000.0 ml of distilled water). The respective flasks were then plugged with sterile cotton wool and incubated in a shaker at 30.0 ± 2.0 ℃ for five days. Thereafter, the content of flasks were respectively transferred into separate 2.0 L of broth of their respective growth medium in a 4.0 L jerrycan that have been sanitized previously using 70% alcohol. These were then incubated at 30.0 ± 2.0 ℃ for seven days with vigorous regular hand shaking for adequate aeration. Following the completion of incubation, aliquot of the 2.0 L broth cultures from the 4.0 L jerrycan were centrifuge at 4000 rev/minute for microbial cells recovery. Recovered bacterial cells were then transferred into a 4.0 L jerrycan (previously sanitized) containing 2.0 L normal physiological saline (0.85% NaCl). Selection and viability test of A. hypogaea seeds for propagation The two varieties of A. hypogaea seeds employed in this study, SAMNUT 25 and SAMNUT 26 were obtained from Institute of Agricultural Research (IAR) Samaru, Zaria, Nigeria. Before propagation, seeds were tested for viability adapting the flotation method of Suma and Srimathi ( 2014 ). Seeds were submerged in lukewarm water for 12.00 hours. Thereafter, seeds that remain submerged were selected for propagation as viable seeds while floated seeds were regarded as non-viable and discarded. Soil treatments and plant propagation Soil for plant propagation was collected within 15.0 cm of soil vertical profile from the designated arable land area at Federal University of Agriculture Makurdi. Four thousand grams (4000.0 g) of soil was collected and placed in each plastic pots measuring 25.0 cm width and 40.0 cm depth. Potted soils were subjected to five different treatments in triplicates. These treatments includes, Soil only (control), Soil + NPK fertilizer, Soil + Ps-Azo ( Pseudomonas-Azotobacter inoculants), Soil + Ps-Alc ( Pseudomonas- Alcaligenes inoculants), Soil + Ps-Azo-Alc ( Pseudomonas-Azotobacter-Alcaligenes inoculants). For soils with NPK fertilizer, fertilizer was applied at the rate of 5.0 g/4000.0 g of soil in pot. On the other hand, for soil with microbial inoculants, soils were inoculated with 250.0 ml of the respective bacterial isolates at the rate of 4.5 x 10 6 cfu/ml ( A. chroococcum ), 2.0 x 10 9 cfu/ml ( P. aeruginosa ) and 1.5 x 10 9 cfu/ml( A. faecalis ). With the aid of a sterile hand trowel, fertilizer and microbial inoculants were subsequently ploughed into soil thoroughly. Thereafter, soils with NPK fertilizer and microbial inoculants were allowed to stay for 14 days with regular watering before seed propagation. A. hypogaea plants were grown and monitored under green house condition. Seeds of SAMNUT 25 and SAMNUT 26 were respectively propagated three seeds per pot at depth of 2.0 cm for the various treatments. After germination, seedlings were monitored and thinned after two weeks leaving two seedlings per pot (selecting the best growths). Plants were then monitored for 120 days for relevant growth parameters with regular watering. Determination of the effects of various soil treatments on the growth and yield parameters of A. hypogaea The effects of soil treatments on A. hypogaea germination time was determined by taking note of the earliest emergence time of plant shoot from soil surface. While percentage germination was assessed using the formula: Percentage germination (%) = \(\:\frac{\text{N}\text{u}\text{m}\text{b}\text{e}\text{r}\:\text{o}\text{f}\:\text{g}\text{e}\text{r}\text{m}\text{i}\text{n}\text{a}\text{t}\text{e}\text{d}\:\text{s}\text{e}\text{e}\text{d}\text{s}}{\text{N}\text{u}\text{m}\text{b}\text{e}\text{r}\:\text{o}\text{f}\:\text{p}\text{r}\text{o}\text{p}\text{a}\text{g}\text{a}\text{t}\text{e}\text{d}\:\text{s}\text{e}\text{e}\text{d}\text{s}\:}\) × 100 Other growth and yield parameters such as shoot and root lengths, number of nodules, pods and fresh weights of pods were assessed after 120 days of plant propagation. To determine these, plants were first harvested by uprooting gently, ensuring no parts of leaves or roots were detached, damaged or stocked to the soil. Uprooted plants were washed to free roots of any adhering soils through slow flowing tap water. Plants were subsequently air-dry before evaluating growth and yield parameters. Shoot and root lengths were determined using calibrated measuring tape. Shoot height was measured from the base of plant to the tip of the tallest leaf. While root length from the base of the plant to the tip of the longest root. Fresh weight was determined using electronic weighing balance (Globe Scientific) after air-drying whole plant for 30 minutes. Fresh weight of pods per plant were determined after plucking pods from plant and taking weight using electronic balance. The number of pods and nodules per plant were determined by physical counting. Analysis of Data IBM SPSS Statistics Version 27 was employed in data analysis. Replicate data obtained from this study were analyzed using measure of central tendency and dispersion. The effect of various treatments on the growth and yield of A. hypogaea were evaluated using analysis of variance (ANOVA). Comparative performance of paired varieties of A. hypogaea (SAMNUT 25 and SAMNUT26) were analyzed using the students’ t -test. The level of significance for all analyzed data were placed at confident limits of P ˂ 0.05. Results Characterization of bacterial isolates Bacterial species employed for the growth and yield enhancement of A. hypogaea in this study were isolated from the rhizosphere and root nodules of A. hypogaea . These isolates OG1, OG2 and OT1 selected from among OG1, OG2, OT1, OT2, OT3 and OT4 were identified based on cultural, morphological, biochemical and molecular characterization (Table 1 and Figs. 1 , 2 and 3 ). The BLAST analysis of the retrieved 16S rRNA gene sequences indicated that OG1, OG2 and OT1 were closely related to P. aeruginosa strain M1(accession number LC094440.1), A. chroococcum strain ABA-1(accession number KF494187.1) and A. faecalis strain YZ19 (accession number MT579857.1) respectively on the NCBI data base. Baseline physicochemical properties of soil Reference data of the soil used for A. hypogaea propagation in this study indicates that the soil is sandy-loam (on the basis of its textural components), slightly alkaline, slightly low water holding capacity, SOM, N content and CEC with moderate P content(Table 2 and Fig. 6 ). Effects of different treatments on A. hypogaea growth and yield parameters Germination time differ significantly with the treatments applied for the two varieties of A. hypogaea (SAMNUT 25 and 26). However, while treatment Ps-Azo and Ps-Alc did not differ significantly from control, NPK and Ps-Azo-Alc treatments slowed down germination time in SAMNUT 25. On the other hand, all treatments except NPK treatment accelerated germination time in comparison to the control in SAMNUT 26. Comparatively, overall germination time for the two varieties of A. hypogaea (SAMNUT 25 and 26) in each paired treatments, except for the control were statistically the same ( p < 0.5) (Table 3 ). The germination rate was 100% irrespective of the treatments and variety (Table 4 ). The shoot lengths growths varied with the applied treatments for SAMNUT 25, with treatments Ps-Azo and Ps-Alc enhancing root lengths growth in comparison to other treatments and control. However, there were no significant difference in the shoot lengths growth among the various treatments applied for SAMNUT 26 including control. Comparatively, SAMNUT 25 recorded higher shoot lengths growth over SAMNUT 26 in each of the paired treatments including control, with the exception of treatment Ps-Azo-Alc where the shoot lengths growth of both varieties were statistically the same ( p < 0.5) (Table 5 ). The root lengths of plant was affected by the applied treatments for the two varieties under study. While the treatment effect was only statistically significant in treatments Ps-Azo and Ps-Alc in SAMNUT 25, significant root length increase only occurred in SAMNUT 26 with Ps-Alc and Ps-Azo-Alc. However, root lengths growth response for each paired applied treatment did not differ significantly among the two varieties of A. hypogaea ( p < 0.5) (Table 6 ). The fresh weight of the two varieties of A. hypogaea were affected by the applied treatments. For SAMNUT 25, all the treatments enhanced the fresh weight of the plant; however, weight increase for treatment Ps-Azo-Alc over that of the control was not statistically significant. Similarly, for SAMNUT 26, with the exception of NPK treatment, all the treatments enhanced the fresh weight of plant, though these weights increases were not statistically significant in comparison to the control. Comparatively, with the exception of NPK treatment, SAMNUT 25 and 26 fresh weight growth response to each of the applied treatments were statistically the same ( p < 0.5) (Table 7 ). The number of root nodules in the two varieties of A. hypogaea were greatly influenced by the applied treatments. With the exception of NPK treatment, all applied treatments significantly increased the number of root nodules in SAMNUT 25 and 26. With the exception of NPK treatment, the number of root nodules were higher in SAMNUT 25 than SAMNUT 26 including control; however, these increases were significantly higher in treatments Ps-Azo, Ps-Alc and Ps-Azo-Alc ( p < 0.5) (Table 8 ). The number of pods in both varieties of A. hypogaea were significantly influenced by the applied treatments. With the exception of NPK treatment, all other treatments significantly increased the number of pods in SAMNUT 25 and 26. The number of pods formed for each of the paired applied treatment among the two varieties were significantly the same ( p < 0.5) (Table 9 ). With the exception of NPK treatment, all the treatments enhanced the fresh weight of pods over the control, though this increases in weights were not statistically significant ( p < 0.5) (Table 10 ). Effects of different treatments on the chemical properties of soil propagated with A. hypogaea The chemical properties of soil propagated with one of the varieties of A. hypogaea (SAMNUT 25) was investigated immediately upon plant harvest and in comparison with the baseline chemical properties of the designated soil (Fig. 6 ). With the exception of NPK treatment which witnessed reduction in soil pH to a slightly acid status, there were no significant change in soil pH among the other treatments in comparison to the control and soil baseline pH which remain slightly alkaline ( p < 0.5) (Fig. 6 a). Save NPK treatment, there was an increase in soil organic matter (SOM) content for the other treatments over the control and baseline SOM ( p < 0.5) (Fig. 6 b). Though the N content of soil increased with all the treatments over the control and soil baseline N content, this increase was only statistically significant in comparison to the control ( p < 0.5) (Fig. 6 c). Comparative analysis of soil available P showed no significant difference among the various treatments, control and soil baseline P content ( p < 0.5) (Fig. 6 d). While there was increase in the soil cation ion exchange capacity (CEC) in all the treatments over the control, these increases were comparatively the same with the baseline CEC ( p < 0.5) (Fig. 6 e). Table 1 Cultural, morphological and biochemical characterization of bacterial isolates Bacterial Isolates Characteristics OG1 OG2 OT1 OT2 OT3 OT4 Shape rod rod rod rod rod rod Gram’s Reaction - - - - - - Colony Appearance Greenish-brown, smooth, circular grayish-brown, entire, low convex Non-pigmented, round, flat Greenish-brown, smooth, circular Non-pigmented, round, flat Greenish-brown, smooth, circular Motility + + + + + + Oxidase + + + + + + Urase - + - - - - Catalase + + + + + + Citrate + + + + + + Indole - - - - - - Glucose + + - + - + Fructose - + - - - - Lactose - + - - - - Maltose - + - - - - Sucrose - + - - - - Key: + (positive reaction); - (negative reaction) Table 2 Baseline textural components of soil and porosity Soil Particle Type % Occurrence (mean ± SD, n = 3) Classification Sand 78.80 ± 2.88 Sandy loam soil Silt 9.28 ± 1.03 Clay 11.92 ± 1.20 Porosity (%) 70.0 ± 2.64 Table 3 Effect of different treatments on germination time of two varieties (SAMNUT 25 and 26) of Arachis hypogaea Germination Time (Days) (mean ± SD, n = 3) Variety Control NPK Ps-Azo Ps-Alc Ps-Azo-Alc SAMNUT 25 4.3 ± 0.5 a* 6.0 ± 0.6 b* 4.2 ± 0.4 a* 4.3 ± 0.5 a* 5.0 ± 0.6 c* SAMNUT 26 5.2 ± 0.4 a** 6. 0 ± 0.6 b* 4.3 ± 0.5 c* 4.3 ± 0.5 c* 4.3 ± 0.5 c* Key: SAMNUT 25 and 26 = Two different varieties of Arachis hypogaea Ps-Azo = Pseudomonas aeruginosa + Azotobacter chroococcum ; Ps-Alc = Pseudomonas aeruginosa + Alcaligenes faecalis ; Ps-Azo-Alc = Pseudomonas aeruginosa + Azotobacter chroococcum + Alcaligenes faecalis *Values with the same superscript alphabet (a,b,c) along the same row, and Values with same number of asterisks(*) along same column did not differ significantly ( p < 0.5). Table 4 Effect of different treatments on percentage germination of two varieties (SAMNUT 25 and 26) of Arachis hypogaea Percentage Germination Rate (%) Variety Control NPK Ps-Azo Ps-Alc Ps-Azo-Alc SAMNUT 25 100.0 100.0 100.0 1000 100.0 SAMNUT 26 100.0 100.0 100.0 100.0 100.0 Key: SAMNUT 25 and 26 = Two different varieties of Arachis hypogaea Ps-Azo = Pseudomonas aeruginosa + Azotobacter chroococcum ; Ps-Alc = Pseudomonas aeruginosa + Alcaligenes faecalis ; Ps-Azo-Alc = Pseudomonas aeruginosa + Azotobacter chroococcum + Alcaligenes faecalis Table 5 Effect of different treatments on the shoot lengths of two varieties (SAMNUT 25 and 26) of Arachis hypogaea Shoot Length (cm)(mean ± SD, n = 6) Variety Control NPK Ps-Azo Ps-Alc Ps-Azo -Alc SAMNUT 25 53.5 ± 6.0 a** 58.4 ± 1.2 ab** 62.2 ± 4.3 b** 61.9 ± 3.1 b** 51.5 ± 7.9 a* SAMNUT 26 48.6 ± 4.6 a* 47. 4 ± 5.3 a* 54.6 ± 8.1 a* 49.5 ± 4.6 a* 53.6 ± 5.4 a* Key: SAMNUT 25 and 26 = Two different varieties of Arachis hypogaea Ps-Azo = Pseudomonas aeruginosa + Azotobacter chroococcum ; Ps-Alc = Pseudomonas aeruginosa + Alcaligenes faecalis ; Ps-Azo-Alc = Pseudomonas aeruginosa + Azotobacter chroococcum + Alcaligenes faecalis *Values with the same superscript alphabet (a,b) along the same row, and Values with same number of asterisks(*) along same column did not differ significantly (p < 0.5). Table 6 Effect of different treatments on the root lengths of two varieties (SAMNUT 25 and 26) of Arachis hypogaea Root Length (cm)(mean ± SD, n = 6) Variety Control NPK Ps-Azo Ps-Alc Ps-Azo-Alc SAMNUT 25 23.7 ± 5.4 a* 24.5 ± 1.0 a* 26.4 ± 5.0 ab* 31.9 ± 6.4 b* 24.5 ± 4.1 a* SAMNUT 26 22.7 ± 3.5 a* 19. 1 ± 4.2 a* 21.4 ± 5.5 a* 34.9 ± 2.5 b* 28.2 ± 6.5 c* Key: SAMNUT 25 and 26 = Two different varieties of Arachis hypogaea Ps-Azo = Pseudomonas aeruginosa + Azotobacter chroococcum ; Ps-Alc = Pseudomonas aeruginosa + Alcaligenes faecalis ; Ps-Azo-Alc = Pseudomonas aeruginosa + Azotobacter chroococcum + Alcaligenes faecalis *Values with the same superscript alphabet (a,b,c) along the same row, and Values with same number of asterisks(*) along same column did not differ significantly (p < 0.5). Table 7 Effect of different treatments on the fresh weights of two varieties (SAMNUT 25 and 26) of Arachis hypogaea Fresh weight of plant (g) (mean ± SD, n = 6) Variety Control NPK Ps-Azo Ps-Alc Ps-Azo-Alc SAMNUT 25 36.1 ± 5.1 a* 50.1 ± 5.8 b** 42.6 ± 6. 7 ab* 44.0 ± 8.3 b* 37.7 ± 7.6 a* SAMNUT 26 35.7 ± 5.1 a* 27. 1 ± 4.9 b* 40.5 ± 5.0 a* 41.6 ± 8.3 a* 42.7 ± 9.7 a* Key: SAMNUT 25 and 26 = Two different varieties of Arachis hypogaea Ps-Azo = Pseudomonas aeruginosa + Azotobacter chroococcum ; Ps-Alc = Pseudomonas aeruginosa + Alcaligenes faecalis ; Ps-Azo-Alc = Pseudomonas aeruginosa + Azotobacter chroococcum + Alcaligenes faecalis *Values with the same superscript alphabet (a,b) along the same row, and Values with same number of asterisks(*) along same column did not differ significantly (p < 0.5). Table 8 Effect of different treatments on the numbers of nodules of two varieties (SAMNUT 25 and 26) of Arachis hypogaea Number of Nodules (mean ± SD, n = 6) Variety Control NPK Ps-Azo Ps -Alc Ps-Azo-Alc SAMNUT 25 240.0 ± 53.2 a* 37.8 ± 9.6 b* 425.8 ± 68.8 c** 506.2 ± 73.3 d** 489.2 ± 143.5 c** SAMNUT 26 206.7 ± 29.0 a* 42. 8 ± 11.7 b* 321.0 ± 69.2 c* 282.7 ± 28.6 d* 384.3 ± 64.3 e* Key: SAMNUT 25 and 26 = Two different varieties of Arachis hypogaea Ps-Azo = Pseudomonas aeruginosa + Azotobacter chroococcum ; Ps-Alc = Pseudomonas aeruginosa + Alcaligenes faecalis ; Ps-Azo-Alc = Pseudomonas aeruginosa + Azotobacter chroococcum + Alcaligenes faecalis *Values with the same superscript alphabet (a,b,c,d) along the same row, and Values with same number of asterisks(*) along same column did not differ significantly (p < 0.5). Table 9 Effect of different treatments on the numbers of pods of two varieties (SAMNUT 25 and 26) of Arachis hypogaea Number of Pods (mean ± SD, n = 6) Variety Control NPK Ps-Azo Ps-Alc Ps-Azo -Alc SAMNUT 25 9.5 ± 2.2 a* 4.8 ± 1.2 b* 12.2 ± 1.1 c* 10.8 ± 2.0 ac* 10.5 ± 2.4 ac* SAMNUT 26 11.3 ± 1.2 a* 3. 3 ± 0.7 b* 12.7 ± 3.0 ac* 16.7 ± 6.3 c* 13.5 ± 4.8 ac* Key: SAMNUT 25 and 26 = Two different varieties of Arachis hypogaea Ps-Azo = Pseudomonas aeruginosa + Azotobacter chroococcum ; Ps-Alc = Pseudomonas aeruginosa + Alcaligenes faecalis ; Ps-Azo-Alc = Pseudomonas aeruginosa + Azotobacter chroococcum + Alcaligenes faecalis *Values with the same superscript alphabet (a,b,c) along the same row, and Values with same number of asterisks(*) along same column did not differ significantly (p < 0.5). Table 10 Effect of different treatments on the fresh weight of pods of two varieties (SAMNUT 25 and 26) of Arachis hypogaea Pod fresh weight (g) (mean ± SD, n = 6) Variety Control NPK Ps-Azo Ps-Alc Ps-Azo-Alc SAMNUT 25 9.9 ± 4.4 a * 6.7 ± 3.4 a** 13.9 ± 4.2 ab* 10.9 ± 4.4 a* 11.1 ± 4.0 a* SAMNUT 26 11.7 ± 0.9 a* 1. 9 ± 0.6 b* 12.7 ± 6.3 a* 13.4 ± 5.8 a* 14.4 ± 6.7 a* Key: SAMNUT 25 and 26 = Two different varieties of Arachis hypogaea Ps-Azo = Pseudomonas aeruginosa + Azotobacter chroococcum ; Ps-Alc = Pseudomonas aeruginosa + Alcaligenes faecalis ; Ps-Azo-Alc = Pseudomonas aeruginosa + Azotobacter chroococcum + Alcaligenes faecalis *Values with the same superscript alphabet (a,b) along the same row, and Values with same number of asterisks(*) along same column did not differ significantly (p < 0.5). Discussion The three bacterial isolates G1, G2 and T1 used as bioinoclulants for the growth and yield enhancement of A. hypogaea in this study were identified as Pseudomonas aeruginosa , Azotobacter chroococcum and Alcaligenes faecalis respectively. While A. chroococcum was isolated from the rhizosphere of A. hypogaea, P. aeruginosa and A. faecalis were isolated from the root nodules of A. hypogaea as endophytes. A. chroococcum is a non-symbiotic diazotroph that is highly dominant in tropical soil (Aasfar et al 2021 ). Previous studies lend credence to the existence of P. aeruginosa and Alcaligenes faecalis as root endophytes (Gupta et al. 2013 ; Omer 2016 ; Mastan et al. 2019 ; Singh et al. 2021 ; Verma et al. 2022 ; Khan et al. 2022 ; Fatema, et al. 2024 ) and diazotrophs (Gupta et al. 2013 ; Devi et al. 2017 ; Verma et al. 2022 ; Fatema, et al. 2024 ). Furthermore, these bacterial isolates ( P. aeruginosa , A. chroococcum and A. faecalis ) have been reported to enhance plant growth. The ability of these isolated rhizobacteria to enhance plant growth lies in their capacity to fix nitrogen, produce plant growth hormones [auxin, gibberelins, indole acetic acid (IAA), cytokinins], siderophores, solubilize inorganic phosphate and potassium, promote antioxidant traits of host plants and act as biocontrol agents (Sayyed et al. 2010 ; Wani et al. 2013 ; Gupta et al. 2013 ; Jnawali et al. 2015 ; Omer 2016 ; Devi et al. 2017 ; Romero-Perdomo et al. 2017 ; Mastan et al. 2019 ; Sumbul et al. 2020 ; Aasfar et al. 2021 ; Jia et al. 2022 ; Verma et al. 2022 ; Fatema, et al. 2024 ). In this study, the growth and yield of A. hypogaea were generally enhanced in soils inoculated with P. aeruginosa , A. chroococcum and A. faecalis over uninoculted soils. Irrespective of the fact that SAMNUT 26 germination rate was slower than that of SAMNUT 25 in the untreated control, the germination of SAMNUT 26 was accelerated with the inoculation of P. aeruginosa , A. chroococcum and A. faecalis . This finding is in tandem with previous reports. P. aeruginosa (Wang et al. 2021 ; Singh et al. 2024 ; Faisal 2024 ); A. chroococcum (Eklund 1970 ; Wani et al. 2016; Salhia 2013 ; Romero Perdomo et al. 2017; Yousefi et al. 2017 )d faecalis (Sayyed et a. 2010; Jia et al. 2022 ) were reported to enhance the germination of a number of plants such as groundnut ( A. hypogaea ), cabbage (Brassica oleracea), hopbush shrub ( Dodonaea viscosa L.), cotton ( Gossypium hirsutum ), cumcuber (Cucumis sativus), tomatoes (Lycopersicum esculentum), wheat ( Triticum aestivum ), barley ( Hordeum vulgare ), okra ( Abelmoschus esculentus ), onion ( Allium cepa ), and lettuce ( Lactuca sativa ). Similarly, the shoot length growth of SAMNUT 25 was significantly enhanced by soil inoculation of P. aeruginosa , A. chroococcum and A. faecalis consortium. Wang et al. ( 2021 ) and Singh et al. ( 2024 ), reported increased shoot growth in tomato with the inoculation of P. aeruginosa in soil. In the same vein, A. hypogaea (Sayyed et al. 2010 ) and bud shoot in cabbage (Jia et al. 2022 ) were reportedly enhanced with the inoculation of A. faecalis , while Romero-Perdomo et al. ( 2017 ) reported shoot growth enhancement in cotton with A. chroococcum inoculation. The two varieties of A. hypogaea employed in this study (SAMNUT 25 and 26) witnessed increased root lengths, fresh weight, number of nodules and pods with the inoculation of P. aeruginosa , A. chroococcum and A. faecalis consortium. Hindersah et al. ( 2024 ), reported increase in the numbers of nodules and pods in A. hypogaea as a result of A. chroococcum inoculation. Fresh weights and root lengths growth in a number of plants have also been reportedly enhanced by the inoculation of P. aeruginosa , A. chroococcum and A. faecalis ( Sayyed et al. 2010 ; Romero-Perdomo et al. 2017 ; Wang et al. 2021 ; Jia et al. 2022 ; Hindersah et al. 2024 ; Singh et al. 2024 ). It is worthy of note that the growth and yield of A. hypogaea were significantly enhanced by P. aeruginosa , A. chroococcum and A. faecalis inoculation over NPK fertilization for all the growth and yield parameters assessed, except for fresh weight in SAMNUT 25. The findings indicate that these microbial inoculants are comparatively effective alternative to NPK fertilization. NPK fertilization have been reported to increase vegetative growth of A. hypogaea (Orji et al. 2022 ; Hindersah et al. 2024 ), without proportionate increase in pod (seed) yields (Orji et al. 2022 ). Soils treated with high doses of NPK fertilizers have been reported to reduce nodulation (Haung et al. 2017 ; Aslani and Souri 2018 ; Zhao et al. 2020 ; Hindersah et al. 2024 ) due to nitrogen fixation inhibition (Zhao et al. 2020 ; Hindersah et al. 2024 ). The number of nodules in A. hypogaea in soils treated with P. aeruginosa , A. chroococcum and A. faecalis were overwhelmingly higher than that of NPK treated soils. Increased nodulation facilitate efficient nitrogen fixation (Zhao et al. 2020 ) which translate to higher pod (seed) numbers. Increased nodulation have been reported to correlate positively with pod numbers in A. hypogaea (Ubogu et al. 2017 ; Ubogu et al. 2018 ; Ubogu et al. 2019 ). SAMNUT 25 recorded a faster germination time (in the control), higher shoot lengths growth, fresh pod and plant weights (in treatment with NPK ), higher number of nodules in all the treatments (except NPK and control, where there were no variation) than SAMNUT 26. For other growth and yield parameters there were no variations. These suggest that SAMNUT 25 gave better growth and yield performance than SAMNUT 26 under the experimental conditions. Groundnut growth and yield have been reported to differ with variety (Galadima et al. 2017 ; Nwokwu 2020 ; Ibrahim et al. 2021 ). The slight differential responses of the two varieties of A. hypogaea (SAMNUT 25 and 26) to the applied treatments and control may be attributed to their inherent genetic make up and interaction with with their environment (Ibrahim et al. 2021 ). While the result of this study disagreed with that of Nwokwu ( 2020 ); Ibrahim et al. ( 2021 ), who reported that SAMNUT 26 performed better than SAMNUT 25; it is in agreement with that of Galadima et al., 2017 ; Ibrahim ( 2021 ); Ibrahim et al. ( 2022 ), who reported better growth and yield performance in SAMNUT 25 than 26. These discrepancies may be attributed to the locations and prevailing environmental conditions under which the studies were carried out. Ibrahim et al. ( 2021 ), reported differential responses of SAMNUT 25 and 26 varieties of A. hypogaea due to location of propagation. The baseline pH of the soil employed for the cultivation of A. hypogaea in this study showed that the soil is slightly alkaline (pH 7.34). However, with the exception of NPK treatment which reduced the soil pH to acidic level (pH 6.7), there were no significant changes in pH of soil inoculated with P. aeruginosa , A. chroococcum and A. faecalis as well as the control after plant harvest. Chemical NPK fertilizers have been reported to lower soil pH (Ge et al. 2018 ; Wang et al. 2019 ; Mose et al. 2022 ). Though, the optimum yield potential of groundnut occurs within pH 5.8 to 6.2 range (Chintu et al. 2021 ), the soil pH recorded in this study is suitable for groundnut cultivation. While the CEC and available P content of the soil were maintained in comparison to the baseline values after plant harvest in all the treatments, the inoculation of P. aeruginosa , A. chroococcum and A. faecalis in soil significantly improved the N and SOM contents over NPK treatment, control and baseline values. This is quite remarkable as the microbial inoculants do not only prevent soil chemical properties depletion but also resulted in its enhancement after plant harvest. SOM is no doubt the most essential soil component, impacting soil structure, stability, nutrient storage and turnover, water- and oxygen-holding capacity, creating the framework for soil health and fertility (Bullock 2005 ; FAO 2005 ; Hussain et al. 2023 ). Nitrogen is also a key nutrient for groundnut and every other plants. It is a vital ingredient for protein, chlorophyll and enzymes synthesis, promoting the absorption and utilization of other important nutrients such phosphorus, potassium etc., stimulating plant growth and productivity (Hofman and Cleemput 2004 ; Leghari et al. 2016 ). Conclusion The results of this study revealed that A. hypogaea growth and yield parameters such as germination time, shoot and root lengths growth, fresh weights of plant and pod, nodules and pod numbers were enhanced by the soil inoculation of P. aeruginosa , A. chroococcum and A. faecalis (isolated from the rhizosphere and root nodules of the plant) over uninoculated control and NPK fertilized soils. Soil chemical properties such as pH, P, N, CEC and SOM contents were also maintained and improved upon after propagation and harvest. 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Clin Biotechnol Microbiol 2(2):331–339 Ubogu M, Akponah E, Ejukonemu EF (2019) Response of Rhizobium to spent engine-oil contamination in the rhizosphere of legumes ( Arachis hypogaea and Phaseolus vulgaris ). Kuwait J Sci 46(4):83–92 Upadhyaya HD, Dwivedi SL (2015) Global perspectives on groundnut production, trade, and utilization: Constraints and opportunities, National Seminar on Technologies for Enhancing Oilseeds Production Through NMOOP (Hyderabad: PJTSAU) Vadakattu G, Roper M, Roget D (2006) Potential for non-symbiotic N-2- fixation in different agroecological zones of southern Australia. Aust J Soil Res 44:343–354. 10.1071/SR05122 Velmourougane K, Prasanna R, Chawla G, Nain L, Kumar A, Saxena AK (2019) Trichoderma– Azotobacter biofilm inoculation improves soil nutrient availability and plant growth in wheat and cotton. J Basic Microbiol 59:632–644. 10.1002/jobm.201900009 Verma S, Verma R, Fatima T, Arora NK (2022) Diazotrophic endophytic bacterium Alcaligenes sp. KA31 and its role in promoting the growth of wheat ( Triticum aestivum L.) under saline conditions. Int J Ecol Environ Sci 48: 585–596, 2022. https://doi.org/10.55863/ijees.2022.0585 Vitousek PM, Menge DN, Reed SC, Cleveland, CC (2013) Biological nitrogen fixation: rates, patterns and ecological controls in terrestrial ecosystems. Philos Trans R Soc Lond B Biol Sci 368:20130119 Wang X, Zhou X, Cai Z, Guo L, Chen X, Chen X, Liu J, Feng M, Qiu Y, Zhang Y, Wang AA (2021) A Biocontrol Strain of Pseudomonas aeruginosa CQ-40 Promote Growth and Control Botrytis cinerea in Tomato. Pathogens 10:22. https://doi.org/10.3390/pathogens10010022 Wang H, Xu J, Liu X, Zhang D, Li L, Li W, Sheng L (2019) Effects of long-term application of organic fertilizer on improving organic matter content and retarding acidity in red soil from China. Soil Tillage Res 195(2019): 104382. https://doi.org/10.1016/j.still.2019.104382 Wani SA, Chand S, Ali T (2013) Potential use of Azotobacter chroococcum in crop production: An overview. Curr Agric Res J 1(1):35–38 Yousefi S, Kartoolinejad D, Bahmani M, Naghdi R (2017) Effect of Azospirillum lipoferum and Azotobacter chroococcum on germination and early growth of hopbush shrub ( Dodonaea viscosa L.) under salinity stress. J Sustain For 36(2):107–120 Zhao Y, Liu X, Tong C, Wu Y (2020) Efect of root interaction on nodulation and nitrogen fxation ability of alfalfa in the simulated alfalfa/triticale intercropping in pots. Sci Rep (2020) 10:4269. https://doi.org/10.1038/s41598-020-61234-5 Złoch M, Thiem D, Gadzała-Kopciuch R, Hrynkiewicz K (2016) Synthesis of siderophores by plant-associated metallotolerant bacteria under exposure to Cd2+. Chemosphere 156:312–325. 10.1016/j.chemosphere.2016.04.130 Additional Declarations The authors declare no competing interests. Cite Share Download PDF Status: Posted Version 1 posted You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. We do this by developing innovative software and high quality services for the global research community. Our growing team is made up of researchers and industry professionals working together to solve the most critical problems facing scientific publishing. Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-6214229","acceptedTermsAndConditions":true,"allowDirectSubmit":true,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":427979655,"identity":"6de33302-e8c0-40ff-b68e-aa59516bd44c","order_by":0,"name":"Monday Ubogu","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAAt0lEQVRIiWNgGAWjYDACCTBpA2MAAQ9xWtJI13KYBC0Gt5uPbvi443xi/+zmgw8YamwYDM4cIKDlzrG0mzPP3E6ccedYsgHDsTQGg7MNBLTcyDG7zdt2O7EByJBgbDjMYHCekMMgWs4lzidVy4HEDXAthBwmCfZLW7LxxhtpyQYJx9J4JAl5n+9287EbH9vsZOfdSD744EONjRzfmQQCLoMCR7BrEoiISDiwJ1rlKBgFo2AUjDwAAD/mSrAsI1RpAAAAAElFTkSuQmCC","orcid":"","institution":"Federal University of Agriculture Makurdi","correspondingAuthor":true,"prefix":"","firstName":"Monday","middleName":"","lastName":"Ubogu","suffix":""},{"id":427979656,"identity":"6a2c01ef-5c84-46cf-be05-f4254ecff68b","order_by":1,"name":"Afa Peter Abya","email":"","orcid":"","institution":"Federal University of Agriculture Makurdi","correspondingAuthor":false,"prefix":"","firstName":"Afa","middleName":"Peter","lastName":"Abya","suffix":""},{"id":427979657,"identity":"768a3b23-2e44-44c5-8eb7-4350157a1c88","order_by":2,"name":"Esther E Ebah","email":"","orcid":"","institution":"Federal University of Agriculture Makurdi","correspondingAuthor":false,"prefix":"","firstName":"Esther","middleName":"E","lastName":"Ebah","suffix":""}],"badges":[],"createdAt":"2025-03-12 17:58:43","currentVersionCode":1,"declarations":{"humanSubjects":false,"vertebrateSubjects":false,"conflictsOfInterestStatement":false,"humanSubjectEthicalGuidelines":false,"humanSubjectConsent":false,"humanSubjectClinicalTrial":false,"humanSubjectCaseReport":false,"vertebrateSubjectEthicalGuidelines":false},"doi":"10.21203/rs.3.rs-6214229/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-6214229/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":78720727,"identity":"3ee948fa-d7b8-47fa-ac56-4eeb75c39cbd","added_by":"auto","created_at":"2025-03-18 04:32:18","extension":"png","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":60271,"visible":true,"origin":"","legend":"\u003cp\u003eGel image of high molecular weight DNA extracted from bacterial isolates (from the rhizosphere and root nodules of \u003cem\u003eA. hypogaea\u003c/em\u003e)\u003c/p\u003e","description":"","filename":"1.png","url":"https://assets-eu.researchsquare.com/files/rs-6214229/v1/23aabbdd666108a49bc159cc.png"},{"id":78721172,"identity":"1b9be90c-7271-406f-9343-573cb232f84a","added_by":"auto","created_at":"2025-03-18 04:48:18","extension":"png","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":110960,"visible":true,"origin":"","legend":"\u003cp\u003eGel image showing amplification of the 16S rRNA gene (of bacterial isolates from the rhizosphere and root nodules of \u003cem\u003eA. hypogaea) \u003c/em\u003eat about 1500bp. M is a 500bp DNA ladder\u003c/p\u003e","description":"","filename":"2.png","url":"https://assets-eu.researchsquare.com/files/rs-6214229/v1/02f40695d0318206dddae904.png"},{"id":78720966,"identity":"5e8b506a-9ce1-4f12-a3c6-664218943b4c","added_by":"auto","created_at":"2025-03-18 04:40:18","extension":"png","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":13727,"visible":true,"origin":"","legend":"\u003cp\u003ePhylogenetic tree of bacterial isolates (from the rhizosphere and root nodules of \u003cem\u003eA. hypogaea\u003c/em\u003e) constructed using the Maximum Likelihood method via Neighbour-Joining in MEGA 12\u003c/p\u003e","description":"","filename":"3.png","url":"https://assets-eu.researchsquare.com/files/rs-6214229/v1/4175d9fceb9bd3d9eb5c3662.png"},{"id":78720730,"identity":"7513dd1a-87c3-403b-b364-da56d9c621f6","added_by":"auto","created_at":"2025-03-18 04:32:18","extension":"png","order_by":4,"title":"Figure 4","display":"","copyAsset":false,"role":"figure","size":110467,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eFig. 6(a)\u003c/strong\u003e Effect of different treatments on soil pH after harvest of \u003cem\u003eA. hypogaea \u003c/em\u003e(SAMNUT 25)\u003c/p\u003e\n\u003cp\u003eKey: \u003cem\u003e\u0026nbsp;\u0026nbsp;\u003c/em\u003ePs-Azo = \u003cem\u003ePseudomonas aeruginosa\u003c/em\u003e+ \u003cem\u003eAzotobacter chroococcum\u003c/em\u003e; \u003cem\u003e\u0026nbsp;\u003c/em\u003e\u0026nbsp;\u0026nbsp;Ps-Alc = \u003cem\u003ePseudomonas aeruginosa\u003c/em\u003e + \u003cem\u003eAlcaligenes faecalis\u003c/em\u003e;\u003cem\u003e \u003c/em\u003ePs-Azo-Alc = \u003cem\u003ePseudomonas aeruginosa\u003c/em\u003e + \u003cem\u003eAzotobacter chroococcum + Alcaligenes faecalis\u003c/em\u003e\u003c/p\u003e\n\u003cp\u003e*Values with same alphabet did not differ significantly (p \u0026lt; 0.5).\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e(b)\u003c/strong\u003e Effect of different treatments on soil organic matter (SOM) after harvest of \u003cem\u003eA. hypogaea \u003c/em\u003e(SAMNUT 25)\u003c/p\u003e\n\u003cp\u003eKey: \u003cem\u003e\u0026nbsp;\u0026nbsp;\u003c/em\u003ePs-Azo = \u003cem\u003ePseudomonas aeruginosa\u003c/em\u003e+ \u003cem\u003eAzotobacter chroococcum\u003c/em\u003e; \u003cem\u003e\u0026nbsp;\u003c/em\u003e\u0026nbsp;\u0026nbsp;Ps-Alc = \u003cem\u003ePseudomonas aeruginosa\u003c/em\u003e + \u003cem\u003eAlcaligenes faecalis\u003c/em\u003e;\u003cem\u003e \u003c/em\u003ePs-Azo-Alc = \u003cem\u003ePseudomonas aeruginosa\u003c/em\u003e + \u003cem\u003eAzotobacter chroococcum + Alcaligenes faecalis\u003c/em\u003e\u003c/p\u003e\n\u003cp\u003e*Values with same alphabet did not differ significantly (p \u0026lt; 0.5)\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e(c)\u003c/strong\u003e Effect of different treatments on soil nitrogen (N) after harvest of \u003cem\u003eA. hypogaea \u003c/em\u003e(SAMNUT 25)\u003c/p\u003e\n\u003cp\u003eKey: \u003cem\u003e\u0026nbsp;\u0026nbsp;\u003c/em\u003ePs-Azo = \u003cem\u003ePseudomonas aeruginosa\u003c/em\u003e+ \u003cem\u003eAzotobacter chroococcum\u003c/em\u003e; \u003cem\u003e\u0026nbsp;\u003c/em\u003e\u0026nbsp;\u0026nbsp;Ps-Alc = \u003cem\u003ePseudomonas aeruginosa\u003c/em\u003e + \u003cem\u003eAlcaligenes faecalis\u003c/em\u003e;\u003cem\u003e \u003c/em\u003ePs-Azo-Alc = \u003cem\u003ePseudomonas aeruginosa\u003c/em\u003e + \u003cem\u003eAzotobacter chroococcum + Alcaligenes faecalis\u003c/em\u003e\u003c/p\u003e\n\u003cp\u003e*Values with same alphabet did not differ significantly (p \u0026lt; 0.5)\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e(d)\u003c/strong\u003e Effect of different treatments on soil available phosphorus (P) \u0026nbsp;after harvest of \u003cem\u003eA. hypogaea \u003c/em\u003e(SAMNUT 25)\u003c/p\u003e\n\u003cp\u003eKey: \u003cem\u003e\u0026nbsp;\u0026nbsp;\u003c/em\u003ePs-Azo = \u003cem\u003ePseudomonas aeruginosa\u003c/em\u003e+ \u003cem\u003eAzotobacter chroococcum\u003c/em\u003e; \u003cem\u003e\u0026nbsp;\u003c/em\u003e\u0026nbsp;\u0026nbsp;Ps-Alc = \u003cem\u003ePseudomonas aeruginosa\u003c/em\u003e + \u003cem\u003eAlcaligenes faecalis\u003c/em\u003e;\u003cem\u003e \u003c/em\u003ePs-Azo-Alc = \u003cem\u003ePseudomonas aeruginosa\u003c/em\u003e + \u003cem\u003eAzotobacter chroococcum + Alcaligenes faecalis\u003c/em\u003e\u003c/p\u003e\n\u003cp\u003e*Values with same alphabet did not differ significantly (p \u0026lt; 0.5)\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e(e)\u003c/strong\u003e Effect of different treatments on soil cation exchange (CEC) after harvest of \u003cem\u003eA. hypogaea \u003c/em\u003e(SAMNUT 25)\u003c/p\u003e\n\u003cp\u003eKey: \u003cem\u003e\u0026nbsp;\u0026nbsp;\u003c/em\u003ePs-Azo = \u003cem\u003ePseudomonas aeruginosa\u003c/em\u003e+ \u003cem\u003eAzotobacter chroococcum\u003c/em\u003e; \u003cem\u003e\u0026nbsp;\u003c/em\u003e\u0026nbsp;\u0026nbsp;Ps-Alc = \u003cem\u003ePseudomonas aeruginosa\u003c/em\u003e + \u003cem\u003eAlcaligenes faecalis\u003c/em\u003e;\u003cem\u003e \u003c/em\u003ePs-Azo-Alc = \u003cem\u003ePseudomonas aeruginosa\u003c/em\u003e + \u003cem\u003eAzotobacter chroococcum + Alcaligenes faecalis\u003c/em\u003e\u003c/p\u003e\n\u003cp\u003e*Values with same alphabet did not differ significantly (p \u0026lt; 0.5)\u003c/p\u003e","description":"","filename":"6.png","url":"https://assets-eu.researchsquare.com/files/rs-6214229/v1/96889d59ebabb32145cbd8c2.png"},{"id":78721811,"identity":"ea22c0e6-fdb0-40e7-8818-6670ca444302","added_by":"auto","created_at":"2025-03-18 05:04:24","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":1583763,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-6214229/v1/673b8a5d-4ee7-4c84-b1f3-9e92bce53a1f.pdf"}],"financialInterests":"The authors declare no competing interests.","formattedTitle":"\u003cp\u003eGroundnut (\u003cem\u003eArachis hypogaea\u003c/em\u003e L.) growth and yield enhancement by consortium of diazotrophic and non-rhizobial root nodule endophytic bacteria\u003cbr\u003e\n\u003c/p\u003e","fulltext":[{"header":"Introduction","content":"\u003cp\u003eGroundnut (\u003cem\u003eArachis hypogaea\u003c/em\u003e L.) belong to the leguminous family, the third largest groups of flowering plants on earth (Madigan et al. \u003cspan class=\"CitationRef\"\u003e2012\u003c/span\u003e). The crop is cultivated in about 100 countries across the globe. While India, China, Nigeria and USA are the leading producers, Nigeria accounts for about 10% of total global production (Sogut et al. \u003cspan class=\"CitationRef\"\u003e2016\u003c/span\u003e). Current global annual groundnut production estimate stands at 54.2 million tonnes on 30.5 million hectares of land worldwide (Nepir and Tadesse \u003cspan class=\"CitationRef\"\u003e2024\u003c/span\u003e).\u003c/p\u003e\n\u003cp\u003e\u003cem\u003eA. hypogaea\u003c/em\u003e is the most important crop among the leguminous plants for edible vegetable oil production after soybean (Taphee et al. \u003cspan class=\"CitationRef\"\u003e2015\u003c/span\u003e; Upadhyaya and Dwivedi, \u003cspan class=\"CitationRef\"\u003e2015\u003c/span\u003e). The plant is highly valued as every parts of it is useful, providing food, requisite nutrition for human, animal, and financial security for growers. The seed is laden with high amount of quality vegetable oil (48\u0026ndash;50%), protein (26\u0026ndash;28% ), important minerals and vitamins (such as vitamin E, K and B complex), Fe, Mg, Ca, Zn, K, P), and dietary fibre (Janila et al., \u003cspan class=\"CitationRef\"\u003e2013\u003c/span\u003e; Girei et al. \u003cspan class=\"CitationRef\"\u003e2013\u003c/span\u003e; Abady et al. \u003cspan class=\"CitationRef\"\u003e2019\u003c/span\u003e; Gulluoglu et al. \u003cspan class=\"CitationRef\"\u003e2016\u003c/span\u003e). The haulms and residues serves as feedstocks for animals (Melesse et al. \u003cspan class=\"CitationRef\"\u003e2023\u003c/span\u003e).\u003c/p\u003e\n\u003cp\u003eModern agriculture relies heavily on the use of chemical fertilizers for improved growth and yield of crops (Rana et al. \u003cspan class=\"CitationRef\"\u003e2023\u003c/span\u003e). One hectare of \u003cem\u003eA. hypogaea\u003c/em\u003e requires approximately 112.0 kg of N, 27.0 kg of P and 34.0 kg of K chemical fertilization for optimum growth (Misra \u003cspan class=\"CitationRef\"\u003e2017\u003c/span\u003e). Chemical fertilizers are both costly and environmentally pernicious. Excessive application of agrochemical nitrogen severely reduced soil fertility (Imran et.al. \u003cspan class=\"CitationRef\"\u003e2021\u003c/span\u003e), with unused nitrogen polluting surface and groundwater or emitted into the atmosphere (Sharma and Bali \u003cspan class=\"CitationRef\"\u003e2018\u003c/span\u003e). Nitrogen emissions (nitrous oxide, ammonia, nitrogen oxide etc.) play significant part in climate change as well as contributing particulate matter along with acid rain resulting in respiratory challenges, cancer, damage to forest and buildings (Imran et al. \u003cspan class=\"CitationRef\"\u003e2021\u003c/span\u003e).\u003c/p\u003e\n\u003cp\u003eNot much attention has been focused on alternative natural sources of nitrogen for plant by the way of diazotrophs, the mini-nitrogen factories in the rhizosphere, rhizoplane and inside the root (Imran et al. \u003cspan class=\"CitationRef\"\u003e2021\u003c/span\u003e). For instance, inspite of favourable reports on plant growth promotion, very limited number of studies have delved into the possibility of supplementing chemical fertilizers with \u003cem\u003eAzotobacter chroococcum\u003c/em\u003e, its application as biofertilizer have been reported to reduce chemical nitrogen fertilization by up to 50% in soil (Romero-Perdomo et al. \u003cspan class=\"CitationRef\"\u003e2017\u003c/span\u003e). As bioinocultants, these plant growth promoting rhizobacteria can offer a veritable alternative to chemical fertilization for the attainment of sustainable agriculture and ecosystem health. Biological nitrogen fixation by bacteria and archaea contributes about 40 to 100 teragram of nitrogen (Tg N) to terrestrial ecosystem annually ( Vitousek et. Al. 2023). Approximately one quarter of global annual nitrogen fixation occurs in the root nodules of legumes via symbiotic association with the diazotroph - \u003cem\u003eRhizobium\u003c/em\u003e (Madigan et al. \u003cspan class=\"CitationRef\"\u003e2012\u003c/span\u003e). An estimated 60 kg N/ha/yr is fixed into soil by free-living diazotrophs (Vadakattu et al. \u003cspan class=\"CitationRef\"\u003e2006\u003c/span\u003e; Reed et al. \u003cspan class=\"CitationRef\"\u003e2011\u003c/span\u003e). The non-symbiotic diazotroph, \u003cem\u003eAzotobacter\u003c/em\u003e which is dominant in soil (Din et al. \u003cspan class=\"CitationRef\"\u003e2019\u003c/span\u003e) has the capacity to fix nitrogen at an average rate of 20 kg N/ha/year (Rawia et al., \u003cspan class=\"CitationRef\"\u003e2009\u003c/span\u003e) in addition to ensuring the availability of P in soil (Velmourougane et al. \u003cspan class=\"CitationRef\"\u003e2019\u003c/span\u003e).\u003c/p\u003e\n\u003cp\u003eThe nodulating diazotrophic \u003cem\u003eRhizobium\u003c/em\u003e do not exclusively occupy the root nodules of legumes but coexist with array of non-rhizobial endophytic microorganisms (Preyanga et al. \u003cspan class=\"CitationRef\"\u003e2021\u003c/span\u003e). Though a number of non-rhizobial root nodule endophytes have shown promise in the growth enhancement of legumes through biological nitrogen fixation, zinc and phosphorus solubilization, auxin, amonia, siderophore or phytohormones production (Zloch et al. 2016; Rana et al. \u003cspan class=\"CitationRef\"\u003e2023\u003c/span\u003e; Hnini and Aurag \u003cspan class=\"CitationRef\"\u003e2024\u003c/span\u003e), their roles remain insufficiently elucidated (Hnini and Aurag \u003cspan class=\"CitationRef\"\u003e2024\u003c/span\u003e). Endophytic nitrogen fixing bacteria are regarded superior to their rhizosphere and rizoplane counterpart as they deliver fixed nitrogen outrightly to their host plant (Cocking \u003cspan class=\"CitationRef\"\u003e2003\u003c/span\u003e). Furthermore, some of these non-rhizobial root nodule endophytic bacteria have also been reported to stimulate nodulation, protect against phytopathogens and enhance growth of legumes (Preyanga et al. \u003cspan class=\"CitationRef\"\u003e2021\u003c/span\u003e; Mustaq et al. \u003cspan class=\"CitationRef\"\u003e2023\u003c/span\u003e; Ge et al. \u003cspan class=\"CitationRef\"\u003e2023\u003c/span\u003e; Debnath et al. 2024).\u003c/p\u003e\n\u003cp\u003eIt is in furtherance of achieving sustainable agriculture via cost-effective and environmentally friendly biofertilization with plant growth promoting rhizobacteria that this study was carried out using non-symbiotic diazotroph (\u003cem\u003eAzotobacter chroococcum\u003c/em\u003e) and non-rhizobial root nodule endophytes (\u003cem\u003ePseudomonas aeruginosa\u003c/em\u003e and \u003cem\u003eAlcaligenes faecalis\u003c/em\u003e) for the growth and yield enhancement of \u003cem\u003eA. hypogaea\u003c/em\u003e.\u003c/p\u003e"},{"header":"Materials and Methods","content":"\u003cp\u003e\u003cstrong\u003eIsolation of non-symbiotic diazotroph (\u003c/strong\u003e \u003cstrong\u003eAzotobacter chrocooccum\u003c/strong\u003e \u003cstrong\u003e) and non-rhizobial root nodule endophytes (\u003c/strong\u003e \u003cstrong\u003ePseudomonas aeruginisa\u003c/strong\u003e \u003cstrong\u003eand\u003c/strong\u003e \u003cstrong\u003eAlcaligenes faecalis\u003c/strong\u003e\u003cstrong\u003e)\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe non-symbiotic diazotroph, \u003cem\u003eAzotobacter chrocooccum\u003c/em\u003e employed in this study was isolated from the rhizosphere of a four-month old \u003cem\u003eA. hypogaea\u003c/em\u003e using the method adapted by Ikediugwu and Ubogu (\u003cspan class=\"CitationRef\"\u003e2012\u003c/span\u003e), Akponah and Ubogu (2023). Ten grams of soil particles released from the rhizosphere after shaking uprooted \u003cem\u003eA. hypogaea\u003c/em\u003e plants were homoginized. Thereafter 1.0 g of homogenized soil was weighed into sterile test tube containing 9.0 ml sterile physiological saline. From this, ten-fold serial dilutions (10\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e, 10\u0026thinsp;\u0026minus;\u0026thinsp;\u003csup\u003e2\u003c/sup\u003e, 10\u0026thinsp;\u0026minus;\u0026thinsp;\u003csup\u003e3\u003c/sup\u003e, 10\u0026thinsp;\u0026minus;\u0026thinsp;\u003csup\u003e4\u003c/sup\u003e and 10\u0026thinsp;\u0026minus;\u0026thinsp;\u003csup\u003e5\u003c/sup\u003e) in physiological saline were made. Aliquote of 0.1 ml of serially diluted soil sample was then plated out in petri dishes containing \u003cem\u003eAzotobacter chroococcum\u003c/em\u003e agar medium (composition of medium includes, K\u003csub\u003e2\u003c/sub\u003eHPO\u003csub\u003e4\u003c/sub\u003e, 1.0 g; CaCO\u003csub\u003e3\u003c/sub\u003e, 20.0 g; MgSO\u003csub\u003e4\u003c/sub\u003e.7H\u003csub\u003e2\u003c/sub\u003eO, 0.5 g; glucose, 20.0 g and agar, 20.0 g in 1000.0 ml of distilled water)(Atlas \u003cspan class=\"CitationRef\"\u003e2010\u003c/span\u003e), using the spread plate method.\u003c/p\u003e\n\u003cp\u003eOn the other hand, the non-rhizobial endophytes, \u003cem\u003ePseudomonas aeruginisa\u003c/em\u003e and \u003cem\u003eAlcaligenes faecalis\u003c/em\u003e employed in this study were isolated from well-formed matured root nodules of a four-month old \u003cem\u003eA. hypogaea\u003c/em\u003e using the method described by Ubogu et al. (\u003cspan class=\"CitationRef\"\u003e2018\u003c/span\u003e). One gram of plucked root nodules was washed in tap water, thereafter surface-sterilized in 70% ethanol for 2.0 minutes and afterward rinsed using distilled sterile water. Sodium hypochlorite (3.5% v/v) was subsequently used to surface-sterilize nodules for 2.0 minutes and promptly rinsed with distilled sterile water thrice. The surface-sterilized root nodules were then aseptically crushed in Mac Cartney bottle with the addition of few drops of distilled sterile water. Following proper crushing, crushed nodules were made up to 10. 0 ml using physiological saline. From this, ten-fold serial dilutions (10\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e, 10\u0026thinsp;\u0026minus;\u0026thinsp;\u003csup\u003e2\u003c/sup\u003e, 10\u0026thinsp;\u0026minus;\u0026thinsp;\u003csup\u003e3\u003c/sup\u003e, 10\u0026thinsp;\u0026minus;\u0026thinsp;\u003csup\u003e4\u003c/sup\u003e and 10\u0026thinsp;\u0026minus;\u0026thinsp;\u003csup\u003e5\u003c/sup\u003e) in physiological saline were made. Aliquote of 0.1 ml of serially diluted crushed sample was then plated out in petri dishes containing yeast extract manitol agar (YEMA) (YEMA composition includes, K\u003csub\u003e2\u003c/sub\u003eHPO\u003csub\u003e4\u003c/sub\u003e, 2.5 g; MgSO\u003csub\u003e4\u003c/sub\u003e, 0.1 g; NaCl, 0.13 g; manitol, 5.0 g; yeast extract, 0.5 g; agar powder, 20.0 g in 1000.0 ml of distilled water), using the spread plate method.\u003c/p\u003e\n\u003cp\u003eAll agar plates (TDC agar and YEMA) were incubated at 30.0\u0026thinsp;\u0026plusmn;\u0026thinsp;2.0 ℃ (room temperature) for 72 h. Isolated colonies obtained were purified and stored in TDC agar and YEMA slants respectively for characterization of isolates and further studies.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eCharacterization of bacterial isolates\u003c/strong\u003e .\u003c/p\u003e\n\u003cp\u003eThe non-symbiotic diazotroph and non-rhizobial endophytic bacterial isolates used in this study were first presumptively identified based on their cultural, morphological and biochemical characteristics relying on Bergey\u0026rsquo;s Manual of Systemic Bacteriology (Brenner et al. 2005). Further confirmation of these isolates designated as OG1, OG2, OT1, OT2, OT3 and OT4 were done based on 16S rRNA conserved gene sequence. Following DNA extraction using ZR Fungal/Bacterial DNA MINIPREP ( manufactured by Zymo Research), targeted gene sequence of designated bacteria was amplified using standard PCR technique. The 16S rRNA gene fragments were amplified using forward (27F: AGAGTTTGATCMTGGCTCAG) and reverse (1525R: AAGGAGGTGWTCCARCCGCA) primer. The amplified fragments were verified on 1% agarose gel using agarose gel electrophoresis. Amplified fragments were sequenced using a Genetic Analyzer 3130xl sequencer (from Applied Biosystems) using manufacture\u0026rsquo;s manual. The sequencing kit used was that of BigDye terminator v3.1 cycle sequencing kit. Genetic analysis were carried out using Bio-Edit software and MEGA 12. NCBI GenBank database (\u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttp://www.ncbi.nlm.nih.gov\u003c/span\u003e\u003c/span\u003e) was employed for gene sequences comparison via Blastn search. Phylogenetic tree construction was carried out using the Maximum Likelihood method via Neighbour-Joining. Isolates OG2, OG1 and OT1 which were subsequently identified as \u003cem\u003eA. chrocooccum, P. aeruginisa\u003c/em\u003e and \u003cem\u003eA. faecalis\u003c/em\u003e respectively were subsequently selected for growth enhancement study of \u003cem\u003eA. hypogaea.\u003c/em\u003e\u003c/p\u003e\n\u003cdiv id=\"Sec3\" class=\"Section2\"\u003e\n \u003ch2\u003eDetermination of of soil physicochemical properties\u003c/h2\u003e\n \u003cp\u003eExperimental soil samples employed for this study were collected from a designated arable land area of Federal University of Agriculture Makurdi. Soil samples were collected in triplicates and first analyzed to ascertain its baseline physicochehemical properties to determine its suitability for the propagation of \u003cem\u003eA. hypogaea\u003c/em\u003e before treatments and plant propagation. After treatments and propagation, the experimental set up was monitored for 120 days after which plants were harvested and the respective treated propagated soil samples were re-evaluated for any change in physicochemical properties.\u003c/p\u003e\n \u003cp\u003eSoil samples were analyzed for its textural components of sand, silt and clay using the hydrometer method described by Aliyu and Oyeyiola (\u003cspan class=\"CitationRef\"\u003e2011\u003c/span\u003e). Soil porosity was analyzed using the method of Ezzati et al. (\u003cspan class=\"CitationRef\"\u003e2012\u003c/span\u003e). The method of Hendershot et al. (\u003cspan class=\"CitationRef\"\u003e2006\u003c/span\u003e) was used to determine soil pH; while phosphorus (P) by the method of Skjemstad et al. (2006); nitrogen (N) by the procedure of micro-Kjeldahl (FAO \u003cspan class=\"CitationRef\"\u003e2021\u003c/span\u003e); soil organic matter (SOM) by Walkley-Black method (FAO \u003cspan class=\"CitationRef\"\u003e2020\u003c/span\u003e) and cation exchange capacity (CEC) by cation exchange capacity and exchangeable bases 1N ammonium acetate, pH 7.0 method (FAO \u003cspan class=\"CitationRef\"\u003e2022\u003c/span\u003e).\u003c/p\u003e\n\u003c/div\u003e\n\u003ch3\u003eBacterial inoculants scale-up and soil inoculation\u003c/h3\u003e\n\u003cp\u003eThe bacterial iosolates OG2, OG1 and OT1 which were subsequently identified as \u003cem\u003eA. chrocooccum, P. aeruginisa\u003c/em\u003e and \u003cem\u003eA. faecalis\u003c/em\u003e respectively were employed as microbial soil inoculants in the treatment of soil for plant propagation.\u003c/p\u003e\n\u003cp\u003eThe purified bacterial isolates were respectively scrapped from their agar slants using sterile wire loop into separate 200.0ml broth in sterile 500.0 ml conical flask. \u003cem\u003eA. chroococcum\u003c/em\u003e was inoculated into \u003cem\u003eA. chroococcum\u003c/em\u003e broth medium (composition of medium includes, K\u003csub\u003e2\u003c/sub\u003eHPO\u003csub\u003e4\u003c/sub\u003e, 1.0 g; CaCO\u003csub\u003e3\u003c/sub\u003e, 20.0 g; MgSO\u003csub\u003e4\u003c/sub\u003e.7H\u003csub\u003e2\u003c/sub\u003eO, 0.5 g and glucose, 20.0 g in 1000.0 ml of distilled water)(Atlas \u003cspan class=\"CitationRef\"\u003e2010\u003c/span\u003e), while \u003cem\u003eP. aeruginosa\u003c/em\u003e and \u003cem\u003eA. faecalis\u003c/em\u003e into yeast extract manitol broth (YEMB) (composition includes, K\u003csub\u003e2\u003c/sub\u003eHPO\u003csub\u003e4\u003c/sub\u003e, 2.5 g; MgSO\u003csub\u003e4\u003c/sub\u003e, 0.1 g; NaCl, 0.13 g; manitol, 5.0 g; yeast extract, 0.5 g in 1000.0 ml of distilled water). The respective flasks were then plugged with sterile cotton wool and incubated in a shaker at 30.0\u0026thinsp;\u0026plusmn;\u0026thinsp;2.0 ℃ for five days. Thereafter, the content of flasks were respectively transferred into separate 2.0 L of broth of their respective growth medium in a 4.0 L jerrycan that have been sanitized previously using 70% alcohol. These were then incubated at 30.0\u0026thinsp;\u0026plusmn;\u0026thinsp;2.0 ℃ for seven days with vigorous regular hand shaking for adequate aeration.\u003c/p\u003e\n\u003cp\u003eFollowing the completion of incubation, aliquot of the 2.0 L broth cultures from the 4.0 L jerrycan were centrifuge at 4000 rev/minute for microbial cells recovery. Recovered bacterial cells were then transferred into a 4.0 L jerrycan (previously sanitized) containing 2.0 L normal physiological saline (0.85% NaCl).\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eSelection and viability test of\u003c/strong\u003e \u003cstrong\u003eA. hypogaea\u003c/strong\u003e \u003cstrong\u003eseeds for propagation\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe two varieties of \u003cem\u003eA. hypogaea\u003c/em\u003e seeds employed in this study, SAMNUT 25 and SAMNUT 26 were obtained from Institute of Agricultural Research (IAR) Samaru, Zaria, Nigeria. Before propagation, seeds were tested for viability adapting the flotation method of Suma and Srimathi (\u003cspan class=\"CitationRef\"\u003e2014\u003c/span\u003e). Seeds were submerged in lukewarm water for 12.00 hours. Thereafter, seeds that remain submerged were selected for propagation as viable seeds while floated seeds were regarded as non-viable and discarded.\u003c/p\u003e\n\u003ch3\u003eSoil treatments and plant propagation\u003c/h3\u003e\n\u003cp\u003eSoil for plant propagation was collected within 15.0 cm of soil vertical profile from the designated arable land area at Federal University of Agriculture Makurdi. Four thousand grams (4000.0 g) of soil was collected and placed in each plastic pots measuring 25.0 cm width and 40.0 cm depth. Potted soils were subjected to five different treatments in triplicates. These treatments includes, Soil only (control), Soil\u0026thinsp;+\u0026thinsp;NPK fertilizer, Soil\u0026thinsp;+\u0026thinsp;Ps-Azo (\u003cem\u003ePseudomonas-Azotobacter\u003c/em\u003e inoculants), Soil\u0026thinsp;+\u0026thinsp;Ps-Alc (\u003cem\u003ePseudomonas- Alcaligenes\u003c/em\u003e inoculants), Soil\u0026thinsp;+\u0026thinsp;Ps-Azo-Alc (\u003cem\u003ePseudomonas-Azotobacter-Alcaligenes\u003c/em\u003e inoculants).\u003c/p\u003e\n\u003cp\u003eFor soils with NPK fertilizer, fertilizer was applied at the rate of 5.0 g/4000.0 g of soil in pot. On the other hand, for soil with microbial inoculants, soils were inoculated with 250.0 ml of the respective bacterial isolates at the rate of 4.5 x 10\u003csup\u003e6\u003c/sup\u003e cfu/ml (\u003cem\u003eA. chroococcum\u003c/em\u003e), 2.0 x 10\u003csup\u003e9\u003c/sup\u003e cfu/ml (\u003cem\u003eP. aeruginosa\u003c/em\u003e) and 1.5 x 10\u003csup\u003e9\u003c/sup\u003e cfu/ml(\u003cem\u003eA. faecalis\u003c/em\u003e). With the aid of a sterile hand trowel, fertilizer and microbial inoculants were subsequently ploughed into soil thoroughly. Thereafter, soils with NPK fertilizer and microbial inoculants were allowed to stay for 14 days with regular watering before seed propagation.\u003c/p\u003e\n\u003cp\u003e\u003cem\u003eA. hypogaea\u003c/em\u003e plants were grown and monitored under green house condition. Seeds of SAMNUT 25 and SAMNUT 26 were respectively propagated three seeds per pot at depth of 2.0 cm for the various treatments. After germination, seedlings were monitored and thinned after two weeks leaving two seedlings per pot (selecting the best growths). Plants were then monitored for 120 days for relevant growth parameters with regular watering.\u003c/p\u003e\n\u003cp\u003e\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eDetermination of the effects of various soil treatments on the growth and yield parameters of\u003c/strong\u003e \u003cstrong\u003eA. hypogaea\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe effects of soil treatments on \u003cem\u003eA. hypogaea\u003c/em\u003e germination time was determined by taking note of the earliest emergence time of plant shoot from soil surface. While percentage germination was assessed using the formula:\u003c/p\u003e\n\u003cp\u003ePercentage germination (%) = \u003cspan class=\"InlineEquation\"\u003e\u003cspan class=\"mathinline\"\u003e\\(\\:\\frac{\\text{N}\\text{u}\\text{m}\\text{b}\\text{e}\\text{r}\\:\\text{o}\\text{f}\\:\\text{g}\\text{e}\\text{r}\\text{m}\\text{i}\\text{n}\\text{a}\\text{t}\\text{e}\\text{d}\\:\\text{s}\\text{e}\\text{e}\\text{d}\\text{s}}{\\text{N}\\text{u}\\text{m}\\text{b}\\text{e}\\text{r}\\:\\text{o}\\text{f}\\:\\text{p}\\text{r}\\text{o}\\text{p}\\text{a}\\text{g}\\text{a}\\text{t}\\text{e}\\text{d}\\:\\text{s}\\text{e}\\text{e}\\text{d}\\text{s}\\:}\\)\u003c/span\u003e\u003c/span\u003e \u003cem\u003e\u0026times;\u003c/em\u003e 100\u003c/p\u003e\n\u003cp\u003eOther growth and yield parameters such as shoot and root lengths, number of nodules, pods and fresh weights of pods were assessed after 120 days of plant propagation. To determine these, plants were first harvested by uprooting gently, ensuring no parts of leaves or roots were detached, damaged or stocked to the soil. Uprooted plants were washed to free roots of any adhering soils through slow flowing tap water. Plants were subsequently air-dry before evaluating growth and yield parameters.\u003c/p\u003e\n\u003cp\u003eShoot and root lengths were determined using calibrated measuring tape. Shoot height was measured from the base of plant to the tip of the tallest leaf. While root length from the base of the plant to the tip of the longest root. Fresh weight was determined using electronic weighing balance (Globe Scientific) after air-drying whole plant for 30 minutes. Fresh weight of pods per plant were determined after plucking pods from plant and taking weight using electronic balance. The number of pods and nodules per plant were determined by physical counting.\u003c/p\u003e\n\u003ch3\u003eAnalysis of Data\u003c/h3\u003e\n\u003cp\u003eIBM SPSS Statistics Version 27 was employed in data analysis. Replicate data obtained from this study were analyzed using measure of central tendency and dispersion. The effect of various treatments on the growth and yield of \u003cem\u003eA. hypogaea\u003c/em\u003e were evaluated using analysis of variance (ANOVA). Comparative performance of paired varieties of \u003cem\u003eA. hypogaea\u003c/em\u003e (SAMNUT 25 and SAMNUT26) were analyzed using the students\u0026rsquo; \u003cem\u003et\u003c/em\u003e-test. The level of significance for all analyzed data were placed at confident limits of \u003cem\u003eP\u003c/em\u003e ˂ 0.05.\u003c/p\u003e"},{"header":"Results","content":"\u003cdiv id=\"Sec8\" class=\"Section2\"\u003e\n \u003ch2\u003eCharacterization of bacterial isolates\u003c/h2\u003e\n \u003cp\u003eBacterial species employed for the growth and yield enhancement of \u003cem\u003eA. hypogaea\u003c/em\u003e in this study were isolated from the rhizosphere and root nodules of \u003cem\u003eA. hypogaea\u003c/em\u003e. These isolates OG1, OG2 and OT1 selected from among OG1, OG2, OT1, OT2, OT3 and OT4 were identified based on cultural, morphological, biochemical and molecular characterization (Table \u003cspan class=\"InternalRef\"\u003e1\u003c/span\u003e and Figs. \u003cspan class=\"InternalRef\"\u003e1\u003c/span\u003e, \u003cspan class=\"InternalRef\"\u003e2\u003c/span\u003e and \u003cspan class=\"InternalRef\"\u003e3\u003c/span\u003e). The BLAST analysis of the retrieved 16S rRNA gene sequences indicated that OG1, OG2 and OT1 were closely related to \u003cem\u003eP. aeruginosa\u003c/em\u003e strain M1(accession number LC094440.1), \u003cem\u003eA. chroococcum\u003c/em\u003e strain ABA-1(accession number KF494187.1) and \u003cem\u003eA. faecalis\u003c/em\u003e strain YZ19 (accession number MT579857.1) respectively on the NCBI data base.\u003c/p\u003e\n\u003c/div\u003e\n\u003ch3\u003eBaseline physicochemical properties of soil\u003c/h3\u003e\n\u003cp\u003eReference data of the soil used for \u003cem\u003eA. hypogaea\u003c/em\u003e propagation in this study indicates that the soil is sandy-loam (on the basis of its textural components), slightly alkaline, slightly low water holding capacity, SOM, N content and CEC with moderate P content(Table \u003cspan class=\"InternalRef\"\u003e2\u003c/span\u003e and Fig. \u003cspan class=\"InternalRef\"\u003e6\u003c/span\u003e).\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eEffects of different treatments on\u003c/strong\u003e \u003cstrong\u003eA. hypogaea\u003c/strong\u003e \u003cstrong\u003egrowth and yield parameters\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eGermination time differ significantly with the treatments applied for the two varieties of \u003cem\u003eA. hypogaea\u003c/em\u003e (SAMNUT 25 and 26). However, while treatment Ps-Azo and Ps-Alc did not differ significantly from control, NPK and Ps-Azo-Alc treatments slowed down germination time in SAMNUT 25. On the other hand, all treatments except NPK treatment accelerated germination time in comparison to the control in SAMNUT 26. Comparatively, overall germination time for the two varieties of \u003cem\u003eA. hypogaea\u003c/em\u003e (SAMNUT 25 and 26) in each paired treatments, except for the control were statistically the same (\u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.5) (Table \u003cspan class=\"InternalRef\"\u003e3\u003c/span\u003e). The germination rate was 100% irrespective of the treatments and variety (Table \u003cspan class=\"InternalRef\"\u003e4\u003c/span\u003e).\u003c/p\u003e\n\u003cp\u003eThe shoot lengths growths varied with the applied treatments for SAMNUT 25, with treatments Ps-Azo and Ps-Alc enhancing root lengths growth in comparison to other treatments and control. However, there were no significant difference in the shoot lengths growth among the various treatments applied for SAMNUT 26 including control. Comparatively, SAMNUT 25 recorded higher shoot lengths growth over SAMNUT 26 in each of the paired treatments including control, with the exception of treatment Ps-Azo-Alc where the shoot lengths growth of both varieties were statistically the same (\u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.5) (Table \u003cspan class=\"InternalRef\"\u003e5\u003c/span\u003e).\u003c/p\u003e\n\u003cp\u003eThe root lengths of plant was affected by the applied treatments for the two varieties under study. While the treatment effect was only statistically significant in treatments Ps-Azo and Ps-Alc in SAMNUT 25, significant root length increase only occurred in SAMNUT 26 with Ps-Alc and Ps-Azo-Alc. However, root lengths growth response for each paired applied treatment did not differ significantly among the two varieties of \u003cem\u003eA. hypogaea\u003c/em\u003e (\u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.5) (Table \u003cspan class=\"InternalRef\"\u003e6\u003c/span\u003e).\u003c/p\u003e\n\u003cp\u003eThe fresh weight of the two varieties of \u003cem\u003eA. hypogaea\u003c/em\u003e were affected by the applied treatments. For SAMNUT 25, all the treatments enhanced the fresh weight of the plant; however, weight increase for treatment Ps-Azo-Alc over that of the control was not statistically significant. Similarly, for SAMNUT 26, with the exception of NPK treatment, all the treatments enhanced the fresh weight of plant, though these weights increases were not statistically significant in comparison to the control. Comparatively, with the exception of NPK treatment, SAMNUT 25 and 26 fresh weight growth response to each of the applied treatments were statistically the same (\u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.5) (Table \u003cspan class=\"InternalRef\"\u003e7\u003c/span\u003e).\u003c/p\u003e\n\u003cp\u003eThe number of root nodules in the two varieties of \u003cem\u003eA. hypogaea\u003c/em\u003e were greatly influenced by the applied treatments. With the exception of NPK treatment, all applied treatments significantly increased the number of root nodules in SAMNUT 25 and 26. With the exception of NPK treatment, the number of root nodules were higher in SAMNUT 25 than SAMNUT 26 including control; however, these increases were significantly higher in treatments Ps-Azo, Ps-Alc and Ps-Azo-Alc (\u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.5) (Table \u003cspan class=\"InternalRef\"\u003e8\u003c/span\u003e).\u003c/p\u003e\n\u003cp\u003eThe number of pods in both varieties of \u003cem\u003eA. hypogaea\u003c/em\u003e were significantly influenced by the applied treatments. With the exception of NPK treatment, all other treatments significantly increased the number of pods in SAMNUT 25 and 26. The number of pods formed for each of the paired applied treatment among the two varieties were significantly the same (\u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.5) (Table \u003cspan class=\"InternalRef\"\u003e9\u003c/span\u003e). With the exception of NPK treatment, all the treatments enhanced the fresh weight of pods over the control, though this increases in weights were not statistically significant (\u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.5) (Table \u003cspan class=\"InternalRef\"\u003e10\u003c/span\u003e).\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eEffects of different treatments on the chemical properties of soil propagated with\u003c/strong\u003e \u003cstrong\u003eA. hypogaea\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe chemical properties of soil propagated with one of the varieties of \u003cem\u003eA. hypogaea\u003c/em\u003e (SAMNUT 25) was investigated immediately upon plant harvest and in comparison with the baseline chemical properties of the designated soil (Fig. \u003cspan class=\"InternalRef\"\u003e6\u003c/span\u003e). With the exception of NPK treatment which witnessed reduction in soil pH to a slightly acid status, there were no significant change in soil pH among the other treatments in comparison to the control and soil baseline pH which remain slightly alkaline (\u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.5) (Fig. \u003cspan class=\"InternalRef\"\u003e6\u003c/span\u003ea). Save NPK treatment, there was an increase in soil organic matter (SOM) content for the other treatments over the control and baseline SOM (\u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.5) (Fig. \u003cspan class=\"InternalRef\"\u003e6\u003c/span\u003eb). Though the N content of soil increased with all the treatments over the control and soil baseline N content, this increase was only statistically significant in comparison to the control (\u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.5) (Fig. \u003cspan class=\"InternalRef\"\u003e6\u003c/span\u003ec). Comparative analysis of soil available P showed no significant difference among the various treatments, control and soil baseline P content (\u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.5) (Fig. \u003cspan class=\"InternalRef\"\u003e6\u003c/span\u003ed). While there was increase in the soil cation ion exchange capacity (CEC) in all the treatments over the control, these increases were comparatively the same with the baseline CEC (\u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.5) (Fig. \u003cspan class=\"InternalRef\"\u003e6\u003c/span\u003ee).\u003c/p\u003e\n\u003cp\u003e\u0026nbsp;\u003c/p\u003e\u0026nbsp;\u003ctable id=\"Tab1\" border=\"1\"\u003e\n \u003ccaption language=\"En\"\u003e\n \u003cdiv class=\"CaptionNumber\"\u003eTable 1\u003c/div\u003e\n \u003cdiv class=\"CaptionContent\"\u003e\n \u003cp\u003eCultural, morphological and biochemical characterization of bacterial isolates\u003c/p\u003e\n \u003c/div\u003e\n \u003c/caption\u003e\n \u003cthead\u003e\n \u003ctr\u003e\n \u003cth align=\"left\"\u003e\u0026nbsp;\u003c/th\u003e\n \u003cth align=\"left\" colspan=\"6\"\u003e\n \u003cp\u003eBacterial Isolates\u003c/p\u003e\n \u003c/th\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eCharacteristics\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eOG1\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eOG2\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eOT1\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eOT2\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eOT3\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eOT4\u003c/p\u003e\n \u003c/th\u003e\n \u003c/tr\u003e\n \u003c/thead\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eShape\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003erod\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003erod\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003erod\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003erod\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003erod\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003erod\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eGram\u0026rsquo;s Reaction\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e-\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e-\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e-\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e-\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e-\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e-\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eColony Appearance\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eGreenish-brown, smooth, circular\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003egrayish-brown, entire, low convex\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eNon-pigmented, round, flat\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eGreenish-brown, smooth, circular\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eNon-pigmented, round, flat\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eGreenish-brown, smooth, circular\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eMotility\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e+\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e+\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e+\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e+\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e+\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e+\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eOxidase\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e+\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e+\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e+\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e+\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e+\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e+\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eUrase\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e-\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e+\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e-\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e-\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e-\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e-\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eCatalase\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e+\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e+\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e+\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e+\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e+\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e+\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eCitrate\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e+\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e+\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e+\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e+\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e+\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e+\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eIndole\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e-\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e-\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e-\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e-\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e-\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e-\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eGlucose\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e+\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e+\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e-\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e+\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e-\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e+\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eFructose\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e-\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e+\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e-\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e-\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e-\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e-\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eLactose\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e-\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e+\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e-\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e-\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e-\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e-\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eMaltose\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e-\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e+\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e-\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e-\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e-\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e-\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eSucrose\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e-\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e+\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e-\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e-\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e-\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e-\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n \u003ctfoot\u003e\n \u003ctr\u003e\n \u003ctd colspan=\"7\"\u003eKey: + (positive reaction); - (negative reaction)\u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tfoot\u003e\n\u003c/table\u003e\n\u003cp\u003e\u003c/p\u003e\n\u003cp\u003e\u003cbr\u003e\u003c/p\u003e\n\u003cdiv class=\"gridtable\"\u003e\n \u003cdiv align=\"left\" class=\"colspec\"\u003e\u003cbr\u003e\u003c/div\u003e\u0026nbsp;\u003ctable id=\"Tab2\" border=\"1\"\u003e\n \u003ccaption language=\"En\"\u003e\n \u003cdiv class=\"CaptionNumber\"\u003eTable 2\u003c/div\u003e\n \u003cdiv class=\"CaptionContent\"\u003e\n \u003cp\u003eBaseline textural components of soil and porosity\u003c/p\u003e\n \u003c/div\u003e\n \u003c/caption\u003e\n \u003ccolgroup cols=\"3\"\u003e\u003c/colgroup\u003e\n \u003cthead\u003e\n \u003ctr\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eSoil Particle Type\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003e% Occurrence (mean\u0026thinsp;\u0026plusmn;\u0026thinsp;SD, \u003cem\u003en\u003c/em\u003e\u0026thinsp;=\u0026thinsp;3)\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eClassification\u003c/p\u003e\n \u003c/th\u003e\n \u003c/tr\u003e\n \u003c/thead\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eSand\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e78.80\u0026thinsp;\u0026plusmn;\u0026thinsp;2.88\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" rowspan=\"3\"\u003e\n \u003cp\u003eSandy loam soil\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eSilt\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e9.28\u0026thinsp;\u0026plusmn;\u0026thinsp;1.03\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eClay\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e11.92\u0026thinsp;\u0026plusmn;\u0026thinsp;1.20\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003ePorosity (%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e70.0\u0026thinsp;\u0026plusmn;\u0026thinsp;2.64\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n \u003c/table\u003e\n\u003c/div\u003e\n\u003cp\u003e\u003c/p\u003e\n\u003cdiv align=\"left\" class=\"colspec\"\u003e\u003cbr\u003e\u003c/div\u003e\u0026nbsp;\u0026nbsp;\u003ctable id=\"Tab3\" border=\"1\"\u003e\n \u003ccaption language=\"En\"\u003e\n \u003cdiv class=\"CaptionNumber\"\u003eTable 3\u003c/div\u003e\n \u003cdiv class=\"CaptionContent\"\u003e\n \u003cp\u003eEffect of different treatments on germination time of two varieties (SAMNUT 25 and 26) of \u003cem\u003eArachis hypogaea\u003c/em\u003e\u003c/p\u003e\n \u003c/div\u003e\n \u003c/caption\u003e\n \u003cthead\u003e\n \u003ctr\u003e\n \u003cth align=\"left\" colspan=\"6\"\u003e\n \u003cp\u003eGermination Time (Days) (mean\u0026thinsp;\u0026plusmn;\u0026thinsp;SD, \u003cem\u003en\u003c/em\u003e\u0026thinsp;=\u0026thinsp;3)\u003c/p\u003e\n \u003c/th\u003e\n \u003c/tr\u003e\n \u003c/thead\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eVariety\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eControl\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eNPK\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003ePs-Azo\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003ePs-Alc\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003ePs-Azo-Alc\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eSAMNUT 25\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e4.3\u0026thinsp;\u0026plusmn;\u0026thinsp;0.5\u003csup\u003ea*\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e6.0\u0026thinsp;\u0026plusmn;\u0026thinsp;0.6\u003csup\u003eb*\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e4.2\u0026thinsp;\u0026plusmn;\u0026thinsp;0.4\u003csup\u003ea*\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e4.3\u0026thinsp;\u0026plusmn;\u0026thinsp;0.5\u003csup\u003ea*\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e5.0\u0026thinsp;\u0026plusmn;\u0026thinsp;0.6\u003csup\u003ec*\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eSAMNUT 26\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e5.2\u0026thinsp;\u0026plusmn;\u0026thinsp;0.4\u003csup\u003ea**\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e6. 0\u0026thinsp;\u0026plusmn;\u0026thinsp;0.6\u003csup\u003eb*\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e4.3\u0026thinsp;\u0026plusmn;\u0026thinsp;0.5\u003csup\u003ec*\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e4.3\u0026thinsp;\u0026plusmn;\u0026thinsp;0.5\u003csup\u003ec*\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e4.3\u0026thinsp;\u0026plusmn;\u0026thinsp;0.5\u003csup\u003ec*\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n \u003ctfoot\u003e\n \u003ctr\u003e\n \u003ctd colspan=\"6\"\u003eKey: SAMNUT 25 and 26\u0026thinsp;=\u0026thinsp;Two different varieties of \u003cem\u003eArachis hypogaea\u003c/em\u003e Ps-Azo\u0026thinsp;=\u0026thinsp;\u003cem\u003ePseudomonas aeruginosa\u003c/em\u003e\u0026thinsp;+\u0026thinsp;\u003cem\u003eAzotobacter chroococcum\u003c/em\u003e; Ps-Alc\u0026thinsp;=\u0026thinsp;\u003cem\u003ePseudomonas aeruginosa\u003c/em\u003e\u0026thinsp;+\u0026thinsp;\u003cem\u003eAlcaligenes faecalis\u003c/em\u003e; Ps-Azo-Alc\u0026thinsp;=\u0026thinsp;\u003cem\u003ePseudomonas aeruginosa\u003c/em\u003e\u0026thinsp;+\u0026thinsp;\u003cem\u003eAzotobacter chroococcum\u0026thinsp;+\u0026thinsp;Alcaligenes faecalis\u003c/em\u003e\u003cbr\u003e\u003cem\u003e*Values with the same superscript alphabet (a,b,c) along the same row, and Values with same number of asterisks(*) along same column did not differ significantly (\u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.5).\u003c/em\u003e\u003cbr\u003e\u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tfoot\u003e\n\u003c/table\u003e\n\u003cp\u003e\u003c/p\u003e\n\u003cp\u003e\u0026nbsp;\u0026nbsp;\u003c/p\u003e\n\u003ctable id=\"Tab4\" border=\"1\"\u003e\n \u003ccaption language=\"En\"\u003e\n \u003cdiv class=\"CaptionNumber\"\u003eTable 4\u003c/div\u003e\n \u003cdiv class=\"CaptionContent\"\u003e\n \u003cp\u003eEffect of different treatments on percentage germination of two varieties (SAMNUT 25 and 26) of \u003cem\u003eArachis hypogaea\u003c/em\u003e\u003c/p\u003e\n \u003c/div\u003e\n \u003c/caption\u003e\n \u003cthead\u003e\n \u003ctr\u003e\n \u003cth align=\"left\" colspan=\"6\"\u003e\n \u003cp\u003ePercentage Germination Rate (%)\u003c/p\u003e\n \u003c/th\u003e\n \u003c/tr\u003e\n \u003c/thead\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eVariety\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eControl\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eNPK\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003ePs-Azo\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003ePs-Alc\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003ePs-Azo-Alc\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eSAMNUT 25\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e100.0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e100.0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e100.0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e1000\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e100.0\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eSAMNUT 26\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e100.0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e100.0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e100.0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e100.0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e100.0\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n \u003ctfoot\u003e\n \u003ctr\u003e\n \u003ctd colspan=\"6\"\u003eKey: SAMNUT 25 and 26\u0026thinsp;=\u0026thinsp;Two different varieties of \u003cem\u003eArachis hypogaea\u003c/em\u003e Ps-Azo\u0026thinsp;=\u0026thinsp;\u003cem\u003ePseudomonas aeruginosa\u003c/em\u003e\u0026thinsp;+\u0026thinsp;\u003cem\u003eAzotobacter chroococcum\u003c/em\u003e; Ps-Alc\u0026thinsp;=\u0026thinsp;\u003cem\u003ePseudomonas aeruginosa\u003c/em\u003e\u0026thinsp;+\u0026thinsp;\u003cem\u003eAlcaligenes faecalis\u003c/em\u003e; Ps-Azo-Alc\u0026thinsp;=\u0026thinsp;\u003cem\u003ePseudomonas aeruginosa\u003c/em\u003e\u0026thinsp;+\u0026thinsp;\u003cem\u003eAzotobacter chroococcum\u0026thinsp;+\u0026thinsp;Alcaligenes faecalis\u003c/em\u003e\u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tfoot\u003e\n\u003c/table\u003e\n\u003cp\u003e\u003c/p\u003e\n\u003cdiv class=\"gridtable\"\u003e\n \u003cdiv align=\"left\" class=\"colspec\"\u003e\u003cbr\u003e\u003c/div\u003e\u0026nbsp;\u003ctable id=\"Tab5\" border=\"1\"\u003e\n \u003ccaption language=\"En\"\u003e\n \u003cdiv class=\"CaptionNumber\"\u003eTable 5\u003c/div\u003e\n \u003cdiv class=\"CaptionContent\"\u003e\n \u003cp\u003eEffect of different treatments on the shoot lengths of two varieties (SAMNUT 25 and 26) of \u003cem\u003eArachis hypogaea\u003c/em\u003e\u003c/p\u003e\n \u003c/div\u003e\n \u003c/caption\u003e\n \u003ccolgroup cols=\"6\"\u003e\u003c/colgroup\u003e\n \u003cthead\u003e\n \u003ctr\u003e\n \u003cth align=\"left\" colspan=\"6\"\u003e\n \u003cp\u003eShoot Length (cm)(mean\u0026thinsp;\u0026plusmn;\u0026thinsp;SD, \u003cem\u003en\u003c/em\u003e\u0026thinsp;=\u0026thinsp;6)\u003c/p\u003e\n \u003c/th\u003e\n \u003c/tr\u003e\n \u003c/thead\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eVariety\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eControl\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eNPK\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003ePs-Azo\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003ePs-Alc\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003ePs-Azo -Alc\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eSAMNUT 25\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e53.5\u0026thinsp;\u0026plusmn;\u0026thinsp;6.0\u003csup\u003ea**\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e58.4\u0026thinsp;\u0026plusmn;\u0026thinsp;1.2\u003csup\u003eab**\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e62.2\u0026thinsp;\u0026plusmn;\u0026thinsp;4.3\u003csup\u003eb**\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e61.9\u0026thinsp;\u0026plusmn;\u0026thinsp;3.1\u003csup\u003eb**\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e51.5\u0026thinsp;\u0026plusmn;\u0026thinsp;7.9\u003csup\u003ea*\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eSAMNUT 26\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e48.6\u0026thinsp;\u0026plusmn;\u0026thinsp;4.6\u003csup\u003ea*\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e47. 4\u0026thinsp;\u0026plusmn;\u0026thinsp;5.3\u003csup\u003ea*\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e54.6\u0026thinsp;\u0026plusmn;\u0026thinsp;8.1\u003csup\u003ea*\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e49.5\u0026thinsp;\u0026plusmn;\u0026thinsp;4.6\u003csup\u003ea*\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e53.6\u0026thinsp;\u0026plusmn;\u0026thinsp;5.4\u003csup\u003ea*\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n \u003ctfoot\u003e\n \u003ctr\u003e\n \u003ctd colspan=\"6\"\u003eKey: SAMNUT 25 and 26\u0026thinsp;=\u0026thinsp;Two different varieties of \u003cem\u003eArachis hypogaea\u003c/em\u003e Ps-Azo\u0026thinsp;=\u0026thinsp;\u003cem\u003ePseudomonas aeruginosa\u003c/em\u003e\u0026thinsp;+\u0026thinsp;\u003cem\u003eAzotobacter chroococcum\u003c/em\u003e; Ps-Alc\u0026thinsp;=\u0026thinsp;\u003cem\u003ePseudomonas aeruginosa\u003c/em\u003e\u0026thinsp;+\u0026thinsp;\u003cem\u003eAlcaligenes faecalis\u003c/em\u003e; Ps-Azo-Alc\u0026thinsp;=\u0026thinsp;\u003cem\u003ePseudomonas aeruginosa\u003c/em\u003e\u0026thinsp;+\u0026thinsp;\u003cem\u003eAzotobacter chroococcum\u0026thinsp;+\u0026thinsp;Alcaligenes faecalis\u003c/em\u003e\u003cbr\u003e\u003cem\u003e*Values with the same superscript alphabet (a,b) along the same row, and Values with same number of asterisks(*) along same column did not differ significantly (p\u0026thinsp;\u0026lt;\u0026thinsp;0.5).\u003c/em\u003e\u003cbr\u003e\u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tfoot\u003e\n \u003c/table\u003e\n\u003c/div\u003e\n\u003cp\u003e\u0026nbsp;\u003c/p\u003e\u0026nbsp;\u003ctable id=\"Tab6\" border=\"1\"\u003e\n \u003ccaption language=\"En\"\u003e\n \u003cdiv class=\"CaptionNumber\"\u003eTable 6\u003c/div\u003e\n \u003cdiv class=\"CaptionContent\"\u003e\n \u003cp\u003eEffect of different treatments on the root lengths of two varieties (SAMNUT 25 and 26) of \u003cem\u003eArachis hypogaea\u003c/em\u003e\u003c/p\u003e\n \u003c/div\u003e\n \u003c/caption\u003e\n \u003cthead\u003e\n \u003ctr\u003e\n \u003cth align=\"left\" colspan=\"6\"\u003e\n \u003cp\u003eRoot Length (cm)(mean\u0026thinsp;\u0026plusmn;\u0026thinsp;SD, \u003cem\u003en\u003c/em\u003e\u0026thinsp;=\u0026thinsp;6)\u003c/p\u003e\n \u003c/th\u003e\n \u003c/tr\u003e\n \u003c/thead\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eVariety\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eControl\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eNPK\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003ePs-Azo\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003ePs-Alc\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003ePs-Azo-Alc\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eSAMNUT 25\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e23.7\u0026thinsp;\u0026plusmn;\u0026thinsp;5.4\u003csup\u003ea*\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e24.5\u0026thinsp;\u0026plusmn;\u0026thinsp;1.0\u003csup\u003ea*\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e26.4\u0026thinsp;\u0026plusmn;\u0026thinsp;5.0\u003csup\u003eab*\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e31.9\u0026thinsp;\u0026plusmn;\u0026thinsp;6.4\u003csup\u003eb*\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e24.5\u0026thinsp;\u0026plusmn;\u0026thinsp;4.1\u003csup\u003ea*\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eSAMNUT 26\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e22.7\u0026thinsp;\u0026plusmn;\u0026thinsp;3.5\u003csup\u003ea*\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e19. 1\u0026thinsp;\u0026plusmn;\u0026thinsp;4.2\u003csup\u003ea*\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e21.4\u0026thinsp;\u0026plusmn;\u0026thinsp;5.5\u003csup\u003ea*\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e34.9\u0026thinsp;\u0026plusmn;\u0026thinsp;2.5\u003csup\u003eb*\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e28.2\u0026thinsp;\u0026plusmn;\u0026thinsp;6.5\u003csup\u003ec*\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n \u003ctfoot\u003e\n \u003ctr\u003e\n \u003ctd colspan=\"6\"\u003eKey: SAMNUT 25 and 26\u0026thinsp;=\u0026thinsp;Two different varieties of \u003cem\u003eArachis hypogaea\u003c/em\u003e Ps-Azo\u0026thinsp;=\u0026thinsp;\u003cem\u003ePseudomonas aeruginosa\u003c/em\u003e\u0026thinsp;+\u0026thinsp;\u003cem\u003eAzotobacter chroococcum\u003c/em\u003e; Ps-Alc\u0026thinsp;=\u0026thinsp;\u003cem\u003ePseudomonas aeruginosa\u003c/em\u003e\u0026thinsp;+\u0026thinsp;\u003cem\u003eAlcaligenes faecalis\u003c/em\u003e; Ps-Azo-Alc\u0026thinsp;=\u0026thinsp;\u003cem\u003ePseudomonas aeruginosa\u003c/em\u003e\u0026thinsp;+\u0026thinsp;\u003cem\u003eAzotobacter chroococcum\u0026thinsp;+\u0026thinsp;Alcaligenes faecalis\u003c/em\u003e\u003cbr\u003e\u003cem\u003e*Values with the same superscript alphabet (a,b,c) along the same row, and Values with same number of asterisks(*) along same column did not differ significantly (p\u0026thinsp;\u0026lt;\u0026thinsp;0.5).\u003c/em\u003e\u003cbr\u003e\u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tfoot\u003e\n\u003c/table\u003e\n\u003cp\u003e\u003c/p\u003e\n\u003cp\u003e\u0026nbsp;\u003c/p\u003e\u0026nbsp;\u003ctable id=\"Tab7\" border=\"1\"\u003e\n \u003ccaption language=\"En\"\u003e\n \u003cdiv class=\"CaptionNumber\"\u003eTable 7\u003c/div\u003e\n \u003cdiv class=\"CaptionContent\"\u003e\n \u003cp\u003eEffect of different treatments on the fresh weights of two varieties (SAMNUT 25 and 26) of \u003cem\u003eArachis hypogaea\u003c/em\u003e\u003c/p\u003e\n \u003c/div\u003e\n \u003c/caption\u003e\n \u003cthead\u003e\n \u003ctr\u003e\n \u003cth align=\"left\" colspan=\"6\"\u003e\n \u003cp\u003eFresh weight of plant (g) (mean\u0026thinsp;\u0026plusmn;\u0026thinsp;SD, \u003cem\u003en\u003c/em\u003e\u0026thinsp;=\u0026thinsp;6)\u003c/p\u003e\n \u003c/th\u003e\n \u003c/tr\u003e\n \u003c/thead\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eVariety\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eControl\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eNPK\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003ePs-Azo\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003ePs-Alc\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003ePs-Azo-Alc\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eSAMNUT 25\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e36.1\u0026thinsp;\u0026plusmn;\u0026thinsp;5.1\u003csup\u003ea*\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e50.1\u0026thinsp;\u0026plusmn;\u0026thinsp;5.8\u003csup\u003eb**\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e42.6\u0026thinsp;\u0026plusmn;\u0026thinsp;6. 7\u003csup\u003eab*\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e44.0\u0026thinsp;\u0026plusmn;\u0026thinsp;8.3\u003csup\u003eb*\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e37.7\u0026thinsp;\u0026plusmn;\u0026thinsp;7.6\u003csup\u003ea*\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eSAMNUT 26\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e35.7\u0026thinsp;\u0026plusmn;\u0026thinsp;5.1\u003csup\u003ea*\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e27. 1\u0026thinsp;\u0026plusmn;\u0026thinsp;4.9\u003csup\u003eb*\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e40.5\u0026thinsp;\u0026plusmn;\u0026thinsp;5.0\u003csup\u003ea*\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e41.6\u0026thinsp;\u0026plusmn;\u0026thinsp;8.3\u003csup\u003ea*\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e42.7\u0026thinsp;\u0026plusmn;\u0026thinsp;9.7\u003csup\u003ea*\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n \u003ctfoot\u003e\n \u003ctr\u003e\n \u003ctd colspan=\"6\"\u003eKey: SAMNUT 25 and 26\u0026thinsp;=\u0026thinsp;Two different varieties of \u003cem\u003eArachis hypogaea\u003c/em\u003e Ps-Azo\u0026thinsp;=\u0026thinsp;\u003cem\u003ePseudomonas aeruginosa\u003c/em\u003e\u0026thinsp;+\u0026thinsp;\u003cem\u003eAzotobacter chroococcum\u003c/em\u003e; Ps-Alc\u0026thinsp;=\u0026thinsp;\u003cem\u003ePseudomonas aeruginosa\u003c/em\u003e\u0026thinsp;+\u0026thinsp;\u003cem\u003eAlcaligenes faecalis\u003c/em\u003e; Ps-Azo-Alc\u0026thinsp;=\u0026thinsp;\u003cem\u003ePseudomonas aeruginosa\u003c/em\u003e\u0026thinsp;+\u0026thinsp;\u003cem\u003eAzotobacter chroococcum\u0026thinsp;+\u0026thinsp;Alcaligenes faecalis\u003c/em\u003e\u003cbr\u003e\u003cem\u003e*Values with the same superscript alphabet (a,b) along the same row, and Values with same number of asterisks(*) along same column did not differ significantly (p\u0026thinsp;\u0026lt;\u0026thinsp;0.5).\u003c/em\u003e\u003cbr\u003e\u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tfoot\u003e\n\u003c/table\u003e\n\u003cp\u003e\u003c/p\u003e\n\u003cp\u003e\u0026nbsp;\u003c/p\u003e\u0026nbsp;\u003ctable id=\"Tab8\" border=\"1\"\u003e\n \u003ccaption language=\"En\"\u003e\n \u003cdiv class=\"CaptionNumber\"\u003eTable 8\u003c/div\u003e\n \u003cdiv class=\"CaptionContent\"\u003e\n \u003cp\u003eEffect of different treatments on the numbers of nodules of two varieties (SAMNUT 25 and 26) of \u003cem\u003eArachis hypogaea\u003c/em\u003e\u003c/p\u003e\n \u003c/div\u003e\n \u003c/caption\u003e\n \u003cthead\u003e\n \u003ctr\u003e\n \u003cth align=\"left\" colspan=\"6\"\u003e\n \u003cp\u003eNumber of Nodules (mean\u0026thinsp;\u0026plusmn;\u0026thinsp;SD, \u003cem\u003en\u003c/em\u003e\u0026thinsp;=\u0026thinsp;6)\u003c/p\u003e\n \u003c/th\u003e\n \u003c/tr\u003e\n \u003c/thead\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eVariety\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eControl\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eNPK\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003ePs-Azo\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003ePs -Alc\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003ePs-Azo-Alc\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eSAMNUT 25\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e240.0\u0026thinsp;\u0026plusmn;\u0026thinsp;53.2\u003csup\u003ea*\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e37.8\u0026thinsp;\u0026plusmn;\u0026thinsp;9.6\u003csup\u003eb*\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e425.8\u0026thinsp;\u0026plusmn;\u0026thinsp;68.8\u003csup\u003ec**\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e506.2\u0026thinsp;\u0026plusmn;\u0026thinsp;73.3\u003csup\u003ed**\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e489.2\u0026thinsp;\u0026plusmn;\u0026thinsp;143.5\u003csup\u003ec**\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eSAMNUT 26\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e206.7\u0026thinsp;\u0026plusmn;\u0026thinsp;29.0\u003csup\u003ea*\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e42. 8\u0026thinsp;\u0026plusmn;\u0026thinsp;11.7\u003csup\u003eb*\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e321.0\u0026thinsp;\u0026plusmn;\u0026thinsp;69.2\u003csup\u003ec*\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e282.7\u0026thinsp;\u0026plusmn;\u0026thinsp;28.6\u003csup\u003ed*\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e384.3\u0026thinsp;\u0026plusmn;\u0026thinsp;64.3\u003csup\u003ee*\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n \u003ctfoot\u003e\n \u003ctr\u003e\n \u003ctd colspan=\"6\"\u003eKey: SAMNUT 25 and 26\u0026thinsp;=\u0026thinsp;Two different varieties of \u003cem\u003eArachis hypogaea\u003c/em\u003e Ps-Azo\u0026thinsp;=\u0026thinsp;\u003cem\u003ePseudomonas aeruginosa\u003c/em\u003e\u0026thinsp;+\u0026thinsp;\u003cem\u003eAzotobacter chroococcum\u003c/em\u003e; Ps-Alc\u0026thinsp;=\u0026thinsp;\u003cem\u003ePseudomonas aeruginosa\u003c/em\u003e\u0026thinsp;+\u0026thinsp;\u003cem\u003eAlcaligenes faecalis\u003c/em\u003e; Ps-Azo-Alc\u0026thinsp;=\u0026thinsp;\u003cem\u003ePseudomonas aeruginosa\u003c/em\u003e\u0026thinsp;+\u0026thinsp;\u003cem\u003eAzotobacter chroococcum\u0026thinsp;+\u0026thinsp;Alcaligenes faecalis\u003c/em\u003e\u003cbr\u003e\u003cem\u003e*Values with the same superscript alphabet (a,b,c,d) along the same row, and Values with same number of asterisks(*) along same column did not differ significantly (p\u0026thinsp;\u0026lt;\u0026thinsp;0.5).\u003c/em\u003e\u003cbr\u003e\u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tfoot\u003e\n\u003c/table\u003e\n\u003cp\u003e\u003c/p\u003e\n\u003cp\u003e\u0026nbsp;\u003c/p\u003e\u0026nbsp;\u003ctable id=\"Tab9\" border=\"1\"\u003e\n \u003ccaption language=\"En\"\u003e\n \u003cdiv class=\"CaptionNumber\"\u003eTable 9\u003c/div\u003e\n \u003cdiv class=\"CaptionContent\"\u003e\n \u003cp\u003eEffect of different treatments on the numbers of pods of two varieties (SAMNUT 25 and 26) of \u003cem\u003eArachis hypogaea\u003c/em\u003e\u003c/p\u003e\n \u003c/div\u003e\n \u003c/caption\u003e\n \u003cthead\u003e\n \u003ctr\u003e\n \u003cth align=\"left\" colspan=\"6\"\u003e\n \u003cp\u003eNumber of Pods (mean\u0026thinsp;\u0026plusmn;\u0026thinsp;SD, \u003cem\u003en\u003c/em\u003e\u0026thinsp;=\u0026thinsp;6)\u003c/p\u003e\n \u003c/th\u003e\n \u003c/tr\u003e\n \u003c/thead\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eVariety\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eControl\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eNPK\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003ePs-Azo\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003ePs-Alc\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003ePs-Azo -Alc\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eSAMNUT 25\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e9.5\u0026thinsp;\u0026plusmn;\u0026thinsp;2.2\u003csup\u003ea*\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e4.8\u0026thinsp;\u0026plusmn;\u0026thinsp;1.2\u003csup\u003eb*\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e12.2\u0026thinsp;\u0026plusmn;\u0026thinsp;1.1\u003csup\u003ec*\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e10.8\u0026thinsp;\u0026plusmn;\u0026thinsp;2.0\u003csup\u003eac*\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e10.5\u0026thinsp;\u0026plusmn;\u0026thinsp;2.4\u003csup\u003eac*\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eSAMNUT 26\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e11.3\u0026thinsp;\u0026plusmn;\u0026thinsp;1.2\u003csup\u003ea*\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e3. 3\u0026thinsp;\u0026plusmn;\u0026thinsp;0.7\u003csup\u003eb*\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e12.7\u0026thinsp;\u0026plusmn;\u0026thinsp;3.0\u003csup\u003eac*\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e16.7\u0026thinsp;\u0026plusmn;\u0026thinsp;6.3\u003csup\u003ec*\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e13.5\u0026thinsp;\u0026plusmn;\u0026thinsp;4.8\u003csup\u003eac*\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n \u003ctfoot\u003e\n \u003ctr\u003e\n \u003ctd colspan=\"6\"\u003eKey: SAMNUT 25 and 26\u0026thinsp;=\u0026thinsp;Two different varieties of \u003cem\u003eArachis hypogaea\u003c/em\u003e Ps-Azo\u0026thinsp;=\u0026thinsp;\u003cem\u003ePseudomonas aeruginosa\u003c/em\u003e\u0026thinsp;+\u0026thinsp;\u003cem\u003eAzotobacter chroococcum\u003c/em\u003e; Ps-Alc\u0026thinsp;=\u0026thinsp;\u003cem\u003ePseudomonas aeruginosa\u003c/em\u003e\u0026thinsp;+\u0026thinsp;\u003cem\u003eAlcaligenes faecalis\u003c/em\u003e; Ps-Azo-Alc\u0026thinsp;=\u0026thinsp;\u003cem\u003ePseudomonas aeruginosa\u003c/em\u003e\u0026thinsp;+\u0026thinsp;\u003cem\u003eAzotobacter chroococcum\u0026thinsp;+\u0026thinsp;Alcaligenes faecalis\u003c/em\u003e\u003cbr\u003e\u003cem\u003e*Values with the same superscript alphabet (a,b,c) along the same row, and Values with same number of asterisks(*) along same column did not differ significantly (p\u0026thinsp;\u0026lt;\u0026thinsp;0.5).\u003c/em\u003e\u003cbr\u003e\u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tfoot\u003e\n\u003c/table\u003e\n\u003cp\u003e\u003c/p\u003e\n\u003cp\u003e\u003c/p\u003e\u0026nbsp;\u003ctable id=\"Tab10\" border=\"1\"\u003e\n \u003ccaption language=\"En\"\u003e\n \u003cdiv class=\"CaptionNumber\"\u003eTable 10\u003c/div\u003e\n \u003cdiv class=\"CaptionContent\"\u003e\n \u003cp\u003eEffect of different treatments on the fresh weight of pods of two varieties (SAMNUT 25 and 26) of \u003cem\u003eArachis hypogaea\u003c/em\u003e\u003c/p\u003e\n \u003c/div\u003e\n \u003c/caption\u003e\n \u003cthead\u003e\n \u003ctr\u003e\n \u003cth align=\"left\" colspan=\"6\"\u003e\n \u003cp\u003ePod fresh weight (g) (mean\u0026thinsp;\u0026plusmn;\u0026thinsp;SD, \u003cem\u003en\u003c/em\u003e\u0026thinsp;=\u0026thinsp;6)\u003c/p\u003e\n \u003c/th\u003e\n \u003c/tr\u003e\n \u003c/thead\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eVariety\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eControl\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eNPK\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003ePs-Azo\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003ePs-Alc\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003ePs-Azo-Alc\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eSAMNUT 25\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e9.9\u0026thinsp;\u0026plusmn;\u0026thinsp;4.4\u003csup\u003ea\u003c/sup\u003e*\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e6.7\u0026thinsp;\u0026plusmn;\u0026thinsp;3.4\u003csup\u003ea**\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e13.9\u0026thinsp;\u0026plusmn;\u0026thinsp;4.2\u003csup\u003eab*\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e10.9\u0026thinsp;\u0026plusmn;\u0026thinsp;4.4\u003csup\u003ea*\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e11.1\u0026thinsp;\u0026plusmn;\u0026thinsp;4.0\u003csup\u003ea*\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eSAMNUT 26\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e11.7\u0026thinsp;\u0026plusmn;\u0026thinsp;0.9\u003csup\u003ea*\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e1. 9\u0026thinsp;\u0026plusmn;\u0026thinsp;0.6\u003csup\u003eb*\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e12.7\u0026thinsp;\u0026plusmn;\u0026thinsp;6.3\u003csup\u003ea*\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e13.4\u0026thinsp;\u0026plusmn;\u0026thinsp;5.8\u003csup\u003ea*\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e14.4\u0026thinsp;\u0026plusmn;\u0026thinsp;6.7\u003csup\u003ea*\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n \u003ctfoot\u003e\n \u003ctr\u003e\n \u003ctd colspan=\"6\"\u003eKey: SAMNUT 25 and 26\u0026thinsp;=\u0026thinsp;Two different varieties of \u003cem\u003eArachis hypogaea\u003c/em\u003e Ps-Azo\u0026thinsp;=\u0026thinsp;\u003cem\u003ePseudomonas aeruginosa\u003c/em\u003e\u0026thinsp;+\u0026thinsp;\u003cem\u003eAzotobacter chroococcum\u003c/em\u003e; Ps-Alc\u0026thinsp;=\u0026thinsp;\u003cem\u003ePseudomonas aeruginosa\u003c/em\u003e\u0026thinsp;+\u0026thinsp;\u003cem\u003eAlcaligenes faecalis\u003c/em\u003e; Ps-Azo-Alc\u0026thinsp;=\u0026thinsp;\u003cem\u003ePseudomonas aeruginosa\u003c/em\u003e\u0026thinsp;+\u0026thinsp;\u003cem\u003eAzotobacter chroococcum\u0026thinsp;+\u0026thinsp;Alcaligenes faecalis\u003c/em\u003e\u003cbr\u003e\u003cem\u003e*Values with the same superscript alphabet (a,b) along the same row, and Values with same number of asterisks(*) along same column did not differ significantly (p\u0026thinsp;\u0026lt;\u0026thinsp;0.5).\u003c/em\u003e\u003cbr\u003e\u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tfoot\u003e\n\u003c/table\u003e\n\u003cp\u003e\u003c/p\u003e"},{"header":"Discussion","content":"\u003cp\u003eThe three bacterial isolates G1, G2 and T1 used as bioinoclulants for the growth and yield enhancement of \u003cem\u003eA. hypogaea\u003c/em\u003e in this study were identified as \u003cem\u003ePseudomonas aeruginosa\u003c/em\u003e, \u003cem\u003eAzotobacter chroococcum\u003c/em\u003e and \u003cem\u003eAlcaligenes faecalis\u003c/em\u003e respectively. While \u003cem\u003eA. chroococcum\u003c/em\u003e was isolated from the rhizosphere of \u003cem\u003eA. hypogaea, P. aeruginosa\u003c/em\u003e and \u003cem\u003eA. faecalis\u003c/em\u003e were isolated from the root nodules of \u003cem\u003eA. hypogaea\u003c/em\u003e as endophytes. \u003cem\u003eA. chroococcum\u003c/em\u003e is a non-symbiotic diazotroph that is highly dominant in tropical soil (Aasfar et al \u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2021\u003c/span\u003e). Previous studies lend credence to the existence of \u003cem\u003eP. aeruginosa\u003c/em\u003e and \u003cem\u003eAlcaligenes faecalis\u003c/em\u003e as root endophytes (Gupta et al. \u003cspan citationid=\"CR26\" class=\"CitationRef\"\u003e2013\u003c/span\u003e; Omer \u003cspan citationid=\"CR52\" class=\"CitationRef\"\u003e2016\u003c/span\u003e; Mastan et al. \u003cspan citationid=\"CR44\" class=\"CitationRef\"\u003e2019\u003c/span\u003e; Singh et al. \u003cspan citationid=\"CR60\" class=\"CitationRef\"\u003e2021\u003c/span\u003e; Verma et al. \u003cspan citationid=\"CR74\" class=\"CitationRef\"\u003e2022\u003c/span\u003e; Khan et al. \u003cspan citationid=\"CR41\" class=\"CitationRef\"\u003e2022\u003c/span\u003e; Fatema, et al. \u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e2024\u003c/span\u003e) and diazotrophs (Gupta et al. \u003cspan citationid=\"CR26\" class=\"CitationRef\"\u003e2013\u003c/span\u003e; Devi et al. \u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e2017\u003c/span\u003e; Verma et al. \u003cspan citationid=\"CR74\" class=\"CitationRef\"\u003e2022\u003c/span\u003e; Fatema, et al. \u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e2024\u003c/span\u003e). Furthermore, these bacterial isolates (\u003cem\u003eP. aeruginosa\u003c/em\u003e, \u003cem\u003eA. chroococcum\u003c/em\u003e and \u003cem\u003eA. faecalis\u003c/em\u003e) have been reported to enhance plant growth. The ability of these isolated rhizobacteria to enhance plant growth lies in their capacity to fix nitrogen, produce plant growth hormones [auxin, gibberelins, indole acetic acid (IAA), cytokinins], siderophores, solubilize inorganic phosphate and potassium, promote antioxidant traits of host plants and act as biocontrol agents (Sayyed et al. \u003cspan citationid=\"CR58\" class=\"CitationRef\"\u003e2010\u003c/span\u003e; Wani et al. \u003cspan citationid=\"CR78\" class=\"CitationRef\"\u003e2013\u003c/span\u003e; Gupta et al. \u003cspan citationid=\"CR26\" class=\"CitationRef\"\u003e2013\u003c/span\u003e; Jnawali et al. \u003cspan citationid=\"CR39\" class=\"CitationRef\"\u003e2015\u003c/span\u003e; Omer \u003cspan citationid=\"CR52\" class=\"CitationRef\"\u003e2016\u003c/span\u003e; Devi et al. \u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e2017\u003c/span\u003e; Romero-Perdomo et al. \u003cspan citationid=\"CR57\" class=\"CitationRef\"\u003e2017\u003c/span\u003e; Mastan et al. \u003cspan citationid=\"CR44\" class=\"CitationRef\"\u003e2019\u003c/span\u003e; Sumbul et al. \u003cspan citationid=\"CR66\" class=\"CitationRef\"\u003e2020\u003c/span\u003e; Aasfar et al. \u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2021\u003c/span\u003e; Jia et al. \u003cspan citationid=\"CR40\" class=\"CitationRef\"\u003e2022\u003c/span\u003e; Verma et al. \u003cspan citationid=\"CR74\" class=\"CitationRef\"\u003e2022\u003c/span\u003e; Fatema, et al. \u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e2024\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eIn this study, the growth and yield of \u003cem\u003eA. hypogaea\u003c/em\u003e were generally enhanced in soils inoculated with \u003cem\u003eP. aeruginosa\u003c/em\u003e, \u003cem\u003eA. chroococcum\u003c/em\u003e and \u003cem\u003eA. faecalis\u003c/em\u003e over uninoculted soils. Irrespective of the fact that SAMNUT 26 germination rate was slower than that of SAMNUT 25 in the untreated control, the germination of SAMNUT 26 was accelerated with the inoculation of \u003cem\u003eP. aeruginosa\u003c/em\u003e, \u003cem\u003eA. chroococcum\u003c/em\u003e and \u003cem\u003eA. faecalis\u003c/em\u003e. This finding is in tandem with previous reports. \u003cem\u003eP. aeruginosa\u003c/em\u003e (Wang et al. \u003cspan citationid=\"CR76\" class=\"CitationRef\"\u003e2021\u003c/span\u003e; Singh et al. \u003cspan citationid=\"CR62\" class=\"CitationRef\"\u003e2024\u003c/span\u003e; Faisal \u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e2024\u003c/span\u003e); \u003cem\u003eA. chroococcum\u003c/em\u003e (Eklund \u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e1970\u003c/span\u003e; Wani et al. 2016; Salhia \u003cspan citationid=\"CR61\" class=\"CitationRef\"\u003e2013\u003c/span\u003e; Romero Perdomo et al. 2017; Yousefi et al. \u003cspan citationid=\"CR79\" class=\"CitationRef\"\u003e2017\u003c/span\u003e)d \u003cem\u003efaecalis\u003c/em\u003e (Sayyed et a. 2010; Jia et al. \u003cspan citationid=\"CR40\" class=\"CitationRef\"\u003e2022\u003c/span\u003e) were reported to enhance the germination of a number of plants such as groundnut (\u003cem\u003eA. hypogaea\u003c/em\u003e), cabbage (Brassica oleracea), hopbush shrub (\u003cem\u003eDodonaea viscosa\u003c/em\u003e L.), cotton (\u003cem\u003eGossypium hirsutum\u003c/em\u003e), cumcuber (Cucumis sativus), tomatoes (Lycopersicum esculentum), wheat (\u003cem\u003eTriticum aestivum\u003c/em\u003e), barley (\u003cem\u003eHordeum vulgare\u003c/em\u003e), okra (\u003cem\u003eAbelmoschus esculentus\u003c/em\u003e), onion (\u003cem\u003eAllium cepa\u003c/em\u003e), and lettuce (\u003cem\u003eLactuca sativa\u003c/em\u003e). Similarly, the shoot length growth of SAMNUT 25 was significantly enhanced by soil inoculation of \u003cem\u003eP. aeruginosa\u003c/em\u003e, \u003cem\u003eA. chroococcum\u003c/em\u003e and \u003cem\u003eA. faecalis\u003c/em\u003e consortium. Wang et al. (\u003cspan citationid=\"CR76\" class=\"CitationRef\"\u003e2021\u003c/span\u003e) and Singh et al. (\u003cspan citationid=\"CR62\" class=\"CitationRef\"\u003e2024\u003c/span\u003e), reported increased shoot growth in tomato with the inoculation of \u003cem\u003eP. aeruginosa\u003c/em\u003e in soil. In the same vein, \u003cem\u003eA. hypogaea\u003c/em\u003e (Sayyed et al. \u003cspan citationid=\"CR58\" class=\"CitationRef\"\u003e2010\u003c/span\u003e) and bud shoot in cabbage (Jia et al. \u003cspan citationid=\"CR40\" class=\"CitationRef\"\u003e2022\u003c/span\u003e) were reportedly enhanced with the inoculation of \u003cem\u003eA. faecalis\u003c/em\u003e, while Romero-Perdomo et al. (\u003cspan citationid=\"CR57\" class=\"CitationRef\"\u003e2017\u003c/span\u003e) reported shoot growth enhancement in cotton with \u003cem\u003eA. chroococcum\u003c/em\u003e inoculation. The two varieties of \u003cem\u003eA. hypogaea\u003c/em\u003e employed in this study (SAMNUT 25 and 26) witnessed increased root lengths, fresh weight, number of nodules and pods with the inoculation of \u003cem\u003eP. aeruginosa\u003c/em\u003e, \u003cem\u003eA. chroococcum\u003c/em\u003e and \u003cem\u003eA. faecalis\u003c/em\u003e consortium. Hindersah et al. (\u003cspan citationid=\"CR29\" class=\"CitationRef\"\u003e2024\u003c/span\u003e), reported increase in the numbers of nodules and pods in \u003cem\u003eA. hypogaea\u003c/em\u003e as a result of \u003cem\u003eA. chroococcum\u003c/em\u003e inoculation. Fresh weights and root lengths growth in a number of plants have also been reportedly enhanced by the inoculation of \u003cem\u003eP. aeruginosa\u003c/em\u003e, \u003cem\u003eA. chroococcum\u003c/em\u003e and \u003cem\u003eA. faecalis\u003c/em\u003e ( Sayyed et al. \u003cspan citationid=\"CR58\" class=\"CitationRef\"\u003e2010\u003c/span\u003e; Romero-Perdomo et al. \u003cspan citationid=\"CR57\" class=\"CitationRef\"\u003e2017\u003c/span\u003e; Wang et al. \u003cspan citationid=\"CR76\" class=\"CitationRef\"\u003e2021\u003c/span\u003e; Jia et al. \u003cspan citationid=\"CR40\" class=\"CitationRef\"\u003e2022\u003c/span\u003e; Hindersah et al. \u003cspan citationid=\"CR29\" class=\"CitationRef\"\u003e2024\u003c/span\u003e; Singh et al. \u003cspan citationid=\"CR62\" class=\"CitationRef\"\u003e2024\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eIt is worthy of note that the growth and yield of \u003cem\u003eA. hypogaea\u003c/em\u003e were significantly enhanced by \u003cem\u003eP. aeruginosa\u003c/em\u003e, \u003cem\u003eA. chroococcum\u003c/em\u003e and \u003cem\u003eA. faecalis\u003c/em\u003e inoculation over NPK fertilization for all the growth and yield parameters assessed, except for fresh weight in SAMNUT 25. The findings indicate that these microbial inoculants are comparatively effective alternative to NPK fertilization. NPK fertilization have been reported to increase vegetative growth of \u003cem\u003eA. hypogaea\u003c/em\u003e (Orji et al. \u003cspan citationid=\"CR51\" class=\"CitationRef\"\u003e2022\u003c/span\u003e; Hindersah et al. \u003cspan citationid=\"CR29\" class=\"CitationRef\"\u003e2024\u003c/span\u003e), without proportionate increase in pod (seed) yields (Orji et al. \u003cspan citationid=\"CR51\" class=\"CitationRef\"\u003e2022\u003c/span\u003e). Soils treated with high doses of NPK fertilizers have been reported to reduce nodulation (Haung et al. \u003cspan citationid=\"CR27\" class=\"CitationRef\"\u003e2017\u003c/span\u003e; Aslani and Souri \u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e2018\u003c/span\u003e; Zhao et al. \u003cspan citationid=\"CR80\" class=\"CitationRef\"\u003e2020\u003c/span\u003e; Hindersah et al. \u003cspan citationid=\"CR29\" class=\"CitationRef\"\u003e2024\u003c/span\u003e) due to nitrogen fixation inhibition (Zhao et al. \u003cspan citationid=\"CR80\" class=\"CitationRef\"\u003e2020\u003c/span\u003e; Hindersah et al. \u003cspan citationid=\"CR29\" class=\"CitationRef\"\u003e2024\u003c/span\u003e). The number of nodules in \u003cem\u003eA. hypogaea\u003c/em\u003e in soils treated with \u003cem\u003eP. aeruginosa\u003c/em\u003e, \u003cem\u003eA. chroococcum\u003c/em\u003e and \u003cem\u003eA. faecalis\u003c/em\u003e were overwhelmingly higher than that of NPK treated soils. Increased nodulation facilitate efficient nitrogen fixation (Zhao et al. \u003cspan citationid=\"CR80\" class=\"CitationRef\"\u003e2020\u003c/span\u003e) which translate to higher pod (seed) numbers. Increased nodulation have been reported to correlate positively with pod numbers in \u003cem\u003eA. hypogaea\u003c/em\u003e (Ubogu et al. \u003cspan citationid=\"CR68\" class=\"CitationRef\"\u003e2017\u003c/span\u003e; Ubogu et al. \u003cspan citationid=\"CR69\" class=\"CitationRef\"\u003e2018\u003c/span\u003e; Ubogu et al. \u003cspan citationid=\"CR70\" class=\"CitationRef\"\u003e2019\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eSAMNUT 25 recorded a faster germination time (in the control), higher shoot lengths growth, fresh pod and plant weights (in treatment with NPK ), higher number of nodules in all the treatments (except NPK and control, where there were no variation) than SAMNUT 26. For other growth and yield parameters there were no variations. These suggest that SAMNUT 25 gave better growth and yield performance than SAMNUT 26 under the experimental conditions. Groundnut growth and yield have been reported to differ with variety (Galadima et al. \u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e2017\u003c/span\u003e; Nwokwu \u003cspan citationid=\"CR50\" class=\"CitationRef\"\u003e2020\u003c/span\u003e; Ibrahim et al. \u003cspan citationid=\"CR33\" class=\"CitationRef\"\u003e2021\u003c/span\u003e). The slight differential responses of the two varieties of \u003cem\u003eA. hypogaea\u003c/em\u003e (SAMNUT 25 and 26) to the applied treatments and control may be attributed to their inherent genetic make up and interaction with with their environment (Ibrahim et al. \u003cspan citationid=\"CR33\" class=\"CitationRef\"\u003e2021\u003c/span\u003e). While the result of this study disagreed with that of Nwokwu (\u003cspan citationid=\"CR50\" class=\"CitationRef\"\u003e2020\u003c/span\u003e); Ibrahim et al. (\u003cspan citationid=\"CR33\" class=\"CitationRef\"\u003e2021\u003c/span\u003e), who reported that SAMNUT 26 performed better than SAMNUT 25; it is in agreement with that of Galadima et al., \u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e2017\u003c/span\u003e; Ibrahim (\u003cspan citationid=\"CR34\" class=\"CitationRef\"\u003e2021\u003c/span\u003e); Ibrahim et al. (\u003cspan citationid=\"CR35\" class=\"CitationRef\"\u003e2022\u003c/span\u003e), who reported better growth and yield performance in SAMNUT 25 than 26. These discrepancies may be attributed to the locations and prevailing environmental conditions under which the studies were carried out. Ibrahim et al. (\u003cspan citationid=\"CR33\" class=\"CitationRef\"\u003e2021\u003c/span\u003e), reported differential responses of SAMNUT 25 and 26 varieties of \u003cem\u003eA. hypogaea\u003c/em\u003e due to location of propagation.\u003c/p\u003e \u003cp\u003eThe baseline pH of the soil employed for the cultivation of \u003cem\u003eA. hypogaea\u003c/em\u003e in this study showed that the soil is slightly alkaline (pH 7.34). However, with the exception of NPK treatment which reduced the soil pH to acidic level (pH 6.7), there were no significant changes in pH of soil inoculated with \u003cem\u003eP. aeruginosa\u003c/em\u003e, \u003cem\u003eA. chroococcum\u003c/em\u003e and \u003cem\u003eA. faecalis\u003c/em\u003e as well as the control after plant harvest. Chemical NPK fertilizers have been reported to lower soil pH (Ge et al. \u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e2018\u003c/span\u003e; Wang et al. \u003cspan citationid=\"CR77\" class=\"CitationRef\"\u003e2019\u003c/span\u003e; Mose et al. \u003cspan citationid=\"CR47\" class=\"CitationRef\"\u003e2022\u003c/span\u003e). Though, the optimum yield potential of groundnut occurs within pH 5.8 to 6.2 range (Chintu et al. \u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e2021\u003c/span\u003e), the soil pH recorded in this study is suitable for groundnut cultivation. While the CEC and available P content of the soil were maintained in comparison to the baseline values after plant harvest in all the treatments, the inoculation of \u003cem\u003eP. aeruginosa\u003c/em\u003e, \u003cem\u003eA. chroococcum\u003c/em\u003e and \u003cem\u003eA. faecalis\u003c/em\u003e in soil significantly improved the N and SOM contents over NPK treatment, control and baseline values. This is quite remarkable as the microbial inoculants do not only prevent soil chemical properties depletion but also resulted in its enhancement after plant harvest. SOM is no doubt the most essential soil component, impacting soil structure, stability, nutrient storage and turnover, water- and oxygen-holding capacity, creating the framework for soil health and fertility (Bullock \u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e2005\u003c/span\u003e; FAO \u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e2005\u003c/span\u003e; Hussain et al. \u003cspan citationid=\"CR32\" class=\"CitationRef\"\u003e2023\u003c/span\u003e). Nitrogen is also a key nutrient for groundnut and every other plants. It is a vital ingredient for protein, chlorophyll and enzymes synthesis, promoting the absorption and utilization of other important nutrients such phosphorus, potassium etc., stimulating plant growth and productivity (Hofman and Cleemput \u003cspan citationid=\"CR31\" class=\"CitationRef\"\u003e2004\u003c/span\u003e; Leghari et al. \u003cspan citationid=\"CR42\" class=\"CitationRef\"\u003e2016\u003c/span\u003e).\u003c/p\u003e"},{"header":"Conclusion","content":"\u003cp\u003eThe results of this study revealed that \u003cem\u003eA. hypogaea\u003c/em\u003e growth and yield parameters such as germination time, shoot and root lengths growth, fresh weights of plant and pod, nodules and pod numbers were enhanced by the soil inoculation of \u003cem\u003eP. aeruginosa\u003c/em\u003e, \u003cem\u003eA. chroococcum\u003c/em\u003e and \u003cem\u003eA. faecalis\u003c/em\u003e (isolated from the rhizosphere and root nodules of the plant) over uninoculated control and NPK fertilized soils. Soil chemical properties such as pH, P, N, CEC and SOM contents were also maintained and improved upon after propagation and harvest. Thus, these soil diazotrophs and non-rhizobial root endophytes can serve as effective alternative to the costly and environmentally pernacious chemical NPK fertilization for the attainment of sustainale agriculture and ecosystem health.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\u003cli\u003e\u003cspan\u003eAbady S, Shimelis H, Janila P, Mashilo J (2019) Groundnut (\u003cem\u003eArachis hypogaea\u003c/em\u003e L.) improvement in sub-Saharan Africa: a review, Acta Agric Scand Sect B Soil Plant Sci 69 (2019) 528\u0026ndash;545. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1080/09064710.2019.1601252\u003c/span\u003e\u003cspan address=\"10.1080/09064710.2019.1601252\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eAasfar A, Bargaz A, Yaakoubi K, Hilali A, Bennis I, Zeroual Y, Meftah KI (2021) Nitrogen fixing Azotobacter species as potential soil biological enhancers for crop nutrition and yield stability. 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Chemosphere 156:312\u0026ndash;325. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1016/j.chemosphere.2016.04.130\u003c/span\u003e\u003cspan address=\"10.1016/j.chemosphere.2016.04.130\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":true,"hideJournal":true,"highlight":"","institution":"Federal University of Agriculture Makurdi","isAcceptedByJournal":false,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true},"keywords":"Diazotroph, endophytes, enhancement, groundnut, NPK fertilizer","lastPublishedDoi":"10.21203/rs.3.rs-6214229/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-6214229/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003eModern agriculture rely heavily on costly and environmentally pernicious chemical fertilizers. To investigate possible alternatives to chemical fertilization in \u003cem\u003eA. hypogaea \u003c/em\u003ecultivation, consortium of three plant growth promoting bacteria (PGPB): \u003cem\u003eP. aeruginosa, A. chrococcum \u003c/em\u003eand \u003cem\u003eA. faecalis \u003c/em\u003ewere isolated from rhizosphere and root nodules of \u003cem\u003eA. hypogaea\u0026nbsp; \u003c/em\u003eusing spread plate dilution method on \u003cem\u003eAzotobacter chroococcum\u003c/em\u003e agar, and yeast extract manitol agar growth media. Isolates identified using cultural, morphological, biochemical and molecular characterization. Isolates were scaled-up, inoculated into 4000.0g of soil in pots at rate of 4.5 x 10\u003csup\u003e6\u003c/sup\u003e cfu/ml (\u003cem\u003eA. chrococcum \u003c/em\u003e), 2.0 x 10\u003csup\u003e9\u003c/sup\u003e cfu/ml (\u003cem\u003eP. aeruginosa\u003c/em\u003e), 1.5 x 10\u003csup\u003e9 \u003c/sup\u003ecfu/ml (\u003cem\u003eA. faecalis\u003c/em\u003e) in the following treatments: Uninoculated (control); NPK; \u003cem\u003ePseudomonas-Azotobacter; Pseudomonas-Alcaligenes; Pseudomonas-Alcaligenes-Azotobacter \u003c/em\u003ein triplicates. Seeds of \u003cem\u003eA. hypogaea\u003c/em\u003e belonging to two varieties (SAMNUT 25\u0026nbsp; and 26) were propagated in treated soils in two separate sets. Growth enhancement parameters: germination time, percentage germination, shoot, root lengths growth, fresh plant and pods weights, pods and nodule numbers, and chemical properties of soils determined after 120 days. Results showed soils inoculated with PGPB enhanced all growth parameters over uninoculated (control) and NPK treated soils which were statistically significant for germination time, shoot, root lengths, fresh plant and pods weights, pods and nodule numbers (p \u0026lt; 0.5). Soil chemical properties: pH, P, N, CEC and SOM contents were maintained and enhanced. \u003cem\u003eP. aeruginosa, A. chrococcum \u003c/em\u003eand\u003cem\u003e A. faecalis \u003c/em\u003esoil inoculation offered effective alternative to chemical NPK fertilization.\u003c/p\u003e","manuscriptTitle":"Groundnut (Arachis hypogaea L.) growth and yield enhancement by consortium of diazotrophic and non-rhizobial root nodule endophytic bacteria","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2025-03-18 04:32:13","doi":"10.21203/rs.3.rs-6214229/v1","editorialEvents":[{"type":"communityComments","content":0}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"cd9af754-70c6-4ed7-814d-40e1935832f1","owner":[],"postedDate":"March 18th, 2025","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"posted","subjectAreas":[{"id":45822052,"name":"General Microbiology"}],"tags":[],"updatedAt":"2025-03-18T04:32:13+00:00","versionOfRecord":[],"versionCreatedAt":"2025-03-18 04:32:13","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-6214229","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-6214229","identity":"rs-6214229","version":["v1"]},"buildId":"XKTyCvWXoU3ODBz1xrDgd","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}