MOBILIZATION OF POTASSIUM FROM WASTE MICA BY PLANT GROWTH PROMOTING RHIZOBACTERIA AND ITS ASSIMILATION BY MAIZE (ZEA MAYS) AND WHEAT (TRITICUM AESTIVUM L.): A HYDROPONICS STUDY UNDER PHYTOTRON GROWTH CHAMBER

A hydroponics study was carried out to evaluate the effect of three plant growth promoting rhizobacteria (PGPR) namely, Bacillus mucilaginosus, Azotobacter chroococcum, and Rhizobium spp. on their ability to mobilize potassium from waste mica using maize and wheat as the test crops under a phytotron growth chamber. Results revealed that PGPR significantly improved the assimilation of potassium by both maize and wheat, where waste mica was the sole source of potassium. This was translated into higher biomass accumulation, potassium content and uptake by plants as well as chlorophyll and crude protein content in plant tissue. Among the rhizobacteria, Bacillus mucilaginosus resulted in significantly higher mobilization of potassium than Azotobacter chroococcum and Rhizobium inoculation. Overall, inoculation of maize and wheat plants with these bacteria could be used to mobilize potassium from waste mica, which in turn could be used as a source of potassium for plant growth.     

Enhancement in Nutrient Accumulation and Growth of Oil Palm Seedlings Caused by PGPR Under Field Nursery Conditions

Abstract

Plant growth promoting rhizobacteria (PGPR) (e.g., Azospirillum and Bacillus spp.) have been reported to enhance growth and fix N₂ with several nonleguminous crops. These rhizobacteria have the potential to be applied to oil palm seedlings and, consequently, reduce the cost of nitrogenous fertilizer. The rhizobacteria are also known as a bioenhancer for the ability to increase root growth and enhanced water and nutrient absorption by the host plants. An experiment was carried out in the field nursery station, Federal Land Development Authorities (FELDA), Bukit Mendi, Pahang, Malaysia, to observe the effects of PGPR inoculation on enhanced nutrient accumulation and plant growth (tops and roots) of oil palm seedlings under field nursery conditions. The inoculation process showed positive response in enhancing higher accumulation of nitrogen (N), phosphorus (P), and potassium (K) in the plant tissues, enhanced root dry weight and top growth (dry matter and leaf chlorophyll content) of the host plants under field nursery conditions.     

The use of GUS-reporter gene to study the effect of Azospirillum-Rhizobium coinoculation on nodulation of white clover

 The gusA-marked Azospirillum lipoferum T1371, constructed by inserting transposon mTn5SSgusA20 from Escherichia coli S17-1 λ-pir into the genome of Azospirillum lipoferum 137, was used to evaluate its effect on nodulation of white clover with and without Rhizobium inoculation. When inoculated alone, Azospirillum colonized the tap roots, secondary roots and root hairs. The combined inoculation of white clover with Rhizobium leguminosarum bv trifolii and A. lipoferum enhanced the number of nodules by 2–3 times from 5 to 20 days after inoculation (DAI). The combined inoculation also enhanced acetylene reduction activity by 2.3–2.7 times at 20 DAI. Moreover, Azospirillum was observed colonizing the tap root, root hairs and sites near or on the nodules. These results suggest that the formation of additional infection sites by A. lipoferum, with a combined inoculation, may be the mechanism that will enhance nodulation and nitrogen fixation of white clover. Received: 23 July 1997     

Performance of wheat (Triticum aestivum) to incorporation of organic manure and bioinoculants

A field experiment was conducted to evaluate the effect of integrated use of farmyard manure and bio-inoculants on wheat productivity for two years in succession. Increasing levels of farmyard manure (FYM) up to 15 t ha^?1 significantly (p ≤ 0.05) improved the dry matter accumulation, effective tillers per m row length, and grain weight per spike in both the years. Application of 15 t ha^?1 FYM caused significant increase in spikelets per spike and grains per spike over control and 5 t ha^?1 during two consecutive years. Inoculation with MSX-9 strain of Azotobacter chroococcum produced significantly higher dry matter accumulation to 25.63, 13.33, 7.78 and 23.66, 8.35, 5.50% over uninoculation, Azospirillum brasilense (SP-7) and Azospirillum lipoferum (A-5) at harvest during 1999–2000 and 2000–2001, respectively. Incorporation of 15 t ha^?1 FYM significantly (p ≤ 0.05) enhanced grain and straw yield to 62.45 and 38.05%; 56.66 and 36.28%; 59.42 and 37.52% over control in 1999–2000, 2000–2001 and pooled analysis, respectively. The grain and straw yield of wheat significantly (p ≤ 0.05) enhanced to 26.51, 10.10, 7.54 and 14.45, 5.77, 3.16% through A. chroococcum (MSX-9), A. brasilense (SP-7) and A. lipoferum (A-5) over uninoculation.     

PLANT GROWTH PROMOTING RHIZOBACTERIA INCREASE GROWTH,YIELD AND NITROGEN FIXATION IN PHASEOLUS VULGARIS

Nitrogen (N) fixation by legume-Rhizobium symbiosis is important to agricultural productivity and is therefore of great economic interest. Growing evidence indicates that soil beneficial bacteria can positively affect symbiotic performance of rhizobia. The effect of co-inoculation with plant growth-promoting rhizobacteria (PGPR) and Rhizobium, on nodulation, nitrogen fixation, and yield of common bean (Phaseolus vulgaris L.) cultivars was investigated in two consecutive years under field conditions. The PGPR strains Pseudomonas fluorescens P-93 and Azospirillum lipoferum S-21 as well as two highly effective Rhizobium strains were used in this study. Common bean seeds of three cultivars were inoculated with Rhizobium singly or in a combination with PGPR to evaluate their effect on nodulation and nitrogen fixation. A significant variation of plant growth in response to inoculation with Rhizobium strains was observed. Treatment with PGPR significantly increased nodule number and dry weight, shoot dry weight, amount of nitrogen fixed as well as seed yield and protein content. Co-inoculation with Rhizobium and PGPR demonstrated a significant increase in the proportion of nitrogen derived from atmosphere. These results indicate that PGPR strains have potential to enhance the symbiotic potential of rhizobia.     

Enhancement of Nodulation and Yield of Chickpea by Co-inoculation of Indigenous Mesorhizobium spp. and Plant Growth–Promoting Rhizobacteria in Eastern Uttar Pradesh

We study the effect of plant growth–promoting rhizobacteria (PGPR) along with Mesorhizobium sp. BHURC02 on nodulation, plant growth, yield, and nutrient content of chickpea (Cicer arietinum L.) under field conditions. A similar study has been conducted for nodulation and plant growth of chickpea in pot experiment under glasshouse conditions. The treatment combination of Mesorhizobium sp. BHURC02 and Pseudomonas fluorescens BHUPSB06 statistically significantly increased nodule number plant^–1, dry weight of nodule plant^–1, and root and shoot dry weights plant^–1 over the control under a glasshouse experiment. The maximum significant increase in nodule number, dry matter, and nutrient content were recorded in co-inoculation of Mesorhizobium sp. BHURC02 and P. fluorescens BHUPSB06 followed by co-inoculation of Mesorhizobium sp., Azotobacter chroococcum, and Bacillus megatrium BHUPSB14 over uninoculated control in a 2-year field study. Hence, co-inoculation of Mesorhizobium sp. and P. fluorescens may be effective indigenous PGPR for chickpea production.     

Molecular characterization and PCR detection of a nitrogen-fixing Pseudomonas strain promoting rice growth

Nitrogen-fixing plant growth-promoting rhizobacteria (PGPR) from the genus Pseudomonas have received little attention so far. In the present study, a nitrogen-fixing phytohormone-producing bacterial isolate from kallar grass (strain K1) was identified as Pseudomonas sp. by rrs (16S ribosomal RNA gene) sequence analysis. rrs identity level was high with an uncharacterized marine bacterium (99%), Pseudomonas sp. PCP2 (98%), uncultured bacteria (98%), and Pseudomonas alcaligenes (97%). Partial nifH gene amplified from strain K1 showed 93% and 91% sequence similarities to those of Azotobacter chroococcum and Pseudomonas stutzeri, respectively. The effect of Pseudomonas strain K1 on rice varieties Super Basmati and Basmati 385 was compared with those of three non-Pseudomonas nitrogen-fixing PGPR (Azospirillum brasilense strain Wb3, Azospirillum lipoferum strain N4 and Zoogloea strain Ky1) used as single-strain inoculants. Pseudomonas sp. K1 was detected in the rhizosphere of inoculated plants by enrichment culture in nitrogen-free growth medium, which was followed by observation under the microscope as well as by PCR using a rrs-specific primer. For both rice varieties, an increase in shoot biomass and/or grain yield over that of noninoculated control plants was recorded in each inoculated treatment. The effect of Pseudomonas strain K1 on grain yield was comparable to those of A. brasilense Wb3 and Zoogloea sp. Ky1 for both rice varieties. These results show that nitrogen-fixing pseudomonads deserve attention as potential PGPR inoculants for rice.     

Maize genotype effects on the response to Azospirillum inoculation

Two field experiments were carried out in Northern Argentina, during the 1989–1990 and 1990–1991 growing seasons, on Argentinian and Brazilian maize genotypes. The inoculant consisted of a mixture of four Azospirillum brasilense strain isolated from surface-sterilized maize roots in Argentina and three A. lipoferum strains isolated from surface-sterilized maize or sorghum roots in Brazil. Establishment of the inoculated strains was confirmed by the antibiotic resistance of the strains in the highest dilution vials. In all treatments, numbers of Azospirillum spp. were increased and the inoculated strains were found in the highest dilutions. While grain yields of the different genotypes varied between 1700 and 7300 kg ha^-1, total N accumulation was much less variable. Significant inoculation effects on total N accumulation and on grain yields were consistently negative with one Argentinian genotype and positive with four Argentinian and two Brazilian genotypes. Significant inoculation effects on leaf nitrate reductase activity at the flowering stage, observed in the range-55% to +176%, indicated the presence of various interactions between the plant NO _inf3 ^sup- metabolism and Azospirillum spp. Three Brazilian and one Argentinian maize genotype showed significant decreases in leaf nitrate reductase due to inoculation while four Argentinian genotypes showed significant increases in leaf nitrate reductase activity. The results of the present study, were consistent over the two field experiments and strongly indicate that more detailed plant genotype-Azospirillum spp. strain interaction studies, taking the entire N metabolism in the plant into account, are needed to allow better inoculation results of cereal crops.     

The fate of markerAzospirillum lipoferum inoculated into rice and its effect on growth,yield and N2 fixation of plants studied by acetylene reduction,15N2 feeding and15N dilution techniques

Summary A spontaneous mutant ofAzospirillum lipoferum, resistant to streptomycin and rifampicin, was inoculated into the soil immediately before and 10 days after transplanting of rice (Oryza sativa L.). Two rice varieties with high and low nitrogen-fixing supporting traits, Hua-chou-chi-mo-mor (Hua) and OS4, were used for the plant bacterial interaction study. The effect of inoculation on growth and grain and dry matter yields was evaluated in relation to nitrogen fixation, by in situ acetylene reduction assay,¹⁵N₂ feeding and¹⁵N dilution techniques. A survey of the population of marker bacteria at maximum tillering, booting and heading revealed poor effectivety. The population of nativeAzospirillum followed no definite pattern. Acetylene-reducing activity (ARA) did not differ due to inoculation at two early stages but decreased in the inoculated plants at heading. In contrast, inoculation increased tiller number, plant height of Hua and early reproductive growth of both varieties. Grain yield of both varieties significantly increased along with the dry matter. Total N also increased in inoculated plants, which was less compared with dry matter increase.¹⁵N₂ feeding of OS4 at heading showed more¹⁵N₂ incorporation in the control than in the inoculated plants. The ARA,¹⁵N and N balance studies did not provide clear evidence that the promotion of growth and nitrogen uptake was due to higher N₂ fixation.     

Effects of Plant-Growth-Promoting Rhizobacteria on Yield,Growth, and Some Physiological Characteristics of Wheat and Barley Plants

In 2009 a greenhouse experiment was conducted to determine the effects of boron (B) and plant growth-promoting rhizobacteria (PGPR) treatments, applied either alone or in combination, on yield, plant growth, leaf total chlorophyll content, stomatal conductance, membrane leakage, and leaf relative water content of wheat (Triticum aestivum L. cv. Bezostiya) and barley (Hordeum vulgare L. cv. Tokak) plants. Results showed that alone or combined B (0, 1, 3, 6, 9 kg ha^?1) and PGPR (Bacillus megaterium M3, Bacillus subtilis OSU142, Azospirillum brasilense Sp245, and Raoultella terrigena) treatments positively affected dry weight and physiological parameters searched in both species. Statistically significant differences were observed between bacterial inoculation and B fertilizer on root and shoot dry weight under non-cold-stress (NCS) and cold-stress (CS) conditions. Leaf total chlorophyll content (LTCC), stomatal conductance (SC), leaf relative water content (LRWC), and membrane leakage (ML) were negatively affected by CS conditions and decreased with reduced temperatures of media, but B and PGPR application alleviate the low-temperature deleterious effect in both species. The greatest SC and LRWC, and the lowest ML, were obtained by 6 kg B ha^?1 combined with R. terrigena treatment. The greatest LTCC in both NCS and CS conditions was observed with B. megaterium M3 application alone.     

Field survival of the phytostimulator Azospirillum lipoferum CRT1 and functional impact on maize crop, biodegradation of crop residues, and soil faunal indicators in a context of decreasing nitrogen fertilisation

Heavy nitrogen fertilisation is often implemented in maize cropping systems, but it can have negative environmental effects. Nitrogen-fixing, phytohormone-producing Azospirillum plant growth-promoting rhizobacteria (PGPR) have been proposed as crop inoculants to maintain high yield when decreasing nitrogen fertilisation. In this context, agronomic and ecological effects of the inoculation of maize seeds with the PGPR Azospirillum lipoferum CRT1 were studied in two consecutive years. The inoculant was recovered from maize at 10⁵ CFU g⁻¹ root or higher. Inoculation enhanced root growth and development based on results of root biomass, rooting depth and/or parameters describing root system architecture, and a transient positive effect on shoot height was observed in the first year. Inoculation did not increase yield, but reducing mineral nitrogen fertilisation had only a minor effect on yield. This suggests that the lack of positive effect of the PGPR on yield was due to the fact that the whole field was heavily fertilised in years prior to the start of the experiment. Soil nitrogen levels decreased during the 2 years of the study, and the inoculant had no effect on residual soil nitrogen levels at harvest. Inoculation had no impact on Fusarium symptoms and concentration of the mycotoxin deoxynivalenol in maize kernels, but both were influenced by the interaction between inoculation and nitrogen fertilisation level. Inoculation did not influence meso/macrofaunal soil populations, but had a small but significant effect (smaller than the effect of added nitrogen) on decomposition, nitrogen mineralisation and mesofaunal colonisation of maize leaves (in litter bags). Overall, the ecological impact of seed inoculation with the PGPR A. lipoferum CRT1 was small, and its magnitude was smaller than that of chemical nitrogen fertilisation.     

Improving Strategic Growth Stage-based Drought Tolerance in Quinoa by Rhizobacterial Inoculation

ABSTRACT

Climate change is imposing high temperature resulting in prolonged drought episodes and shrinking of fresh water resources across the globe. In this scenario, even drought tolerant crops like quinoa are also losing significant yield. However, this study was planned to investigate the impact of drought on quinoa at critical growth stages and bacterial inoculation to improve drought tolerance. Drought was imposed by maintaining 25% pot water holding capacity (PWC) at multiple leaf, flowering, and seed filling stage (DSFS), while 80% PWC was considered as control. Three strains of plant growth promoting rhizobacteria (PGPR) named as: Bacillus licheniformis, Pseudomonas fluorescens, and Azospirillum brasilense were inoculated with quinoa seeds before sowing with respect to drought treatments. PGPR inoculation mitigated the drastic effects of drought by improving crop growth, net assimilation rate, water use efficiency, leaf chlorophyll, and phenolic contents, all of these ultimately contributed to improvement in grain yield and its contributing attributes. Moreover, PGPR markedly improves the grain quality attributes including protein, phosphorus, and potassium contents. Principal component analysis linked the different scales of study and demonstrated the potential of physio-biochemical traits to explain the quinoa yield variations under drought condition with response to PGPR inoculation. Among different PGPR, A. brasilense was found most effective both under normal and drought conditions. Overall, DSFS has more detrimental effects among critical growth stages of quinoa and A. brasilense can be used as a shotgun tactic to ameliorate drought stress in quinoa.     

Synergistic effects of plant-growth promoting rhizobacteria and Rhizobium on nodulation and nitrogen fixation by pigeonpea (Cajanus cajan)

Plant‐growth promoting rhizobacteria (PGPR), in conjuction with efficient Rhizobium, can affect the growth and nitrogen fixation in pigeonpea by inducing the occupancy of introduced Rhizobium in the nodules of the legume. This study assessed the effect of different plant‐growth promoting rhizobacteria (Azotobacter chroococcum , Azospirillum brasilense, Pseudomonas fluorescens, Pseudomonas putida and Bacillus cereus) on pigeonpea (Cajanus cajan (L) Milsp.) cv. P‐921 inoculated with Rhizobium sp. (AR‐2–2 k). A glasshouse experiment was carried out with a sandy‐loam soil in which the seeds were treated with Rhizobium alone or in combination with several PGPR isolates. It was monitored on the basis of nodulation, N₂ fixation, shoot biomass, total N content in shoot and legume grain yield. The competitive ability of the introduced Rhizobium strain was assessed by calculating nodule occupancy. The PGPR isolates used did not antagonize the introduced Rhizobium strain and the dual inoculation with either Pseudomonas putida, P. fluorescens or Bacillus cereus resulted in a significant increase in plant growth, nodulation and enzyme activity over Rhizobium‐inoculated and uninoculated control plants. The nodule occupancy of the introduced Rhizobium strain increased from 50% (with Rhizobium alone) to 85% in the presence of Pseudomonas putida. This study enabled us to select an ideal combination of efficient Rhizobium strain and PGPR for pigeonpea grown in the semiarid tropics.     

Inoculation of Earthworms and Plant Growth–Promoting Rhizobacteria (PGPR) for the Improvement of Vegetable Growth via Enhanced N and P Availability in Soils

A pot trial was conducted to investigate the single, dual, and triple inoculation of earthworms or plant growth–promoting rhizobacteria (PGPR), including nitrogen-fixing bacteria (NFB) (Azotobacter chroococcum HKN-5) and phosphate-solubilizing bacteria (PSB) (Bacillus megaterium HKP-1), on the growth of Brassica parachinenesis and nitrogen (N) and phosphorus (P) availability in soils. All of the five inoculation treatments significantly (P < 0.05) increased the shoot growth of B. parachinenesis. The greatest shoot and root biomass were recorded in the triple inoculation of earthworm, NFB, and PSB. All of the five inoculation treatments significantly (P < 0.05) increased the concentrations of ammonium (NH₄ ⁺)-N, NO_x-N, and sodium bicarbonate (NaHCO₃)–extractable P in soils. Based on plant growth and availability of N and P in soils, the present study suggested that the triple inoculation may be a promising approach for reducing the need for chemical fertilizers in growing vegetables.     

Interactions of some nematicides with Azospirillum lipoferum and the growth of Zea maize

The possible interaction of four nematicides (Terbufos, Carbofuran, Fenamiphos, and Aldicarb) with Azospirillum lipoferum and growth of two Zea maize cultivars was studied in a greenhouse experiment. Application of nematicides, Fenamiphos in particular, resulted in higher plant length, dry matter production and N yield over the nematicide-untreated plants. Azospirillum spp. inoculation stimulated the growth of nematicide-treated Z. maize. Among the nematicides used, Carbofuran and Aldicarb inhibited the nitrogenase activity on plant roots more seriously than Fenamiphos and Terbufos. Generally, the inhibition percentages in acetylene reducing activity in soil of inoculated treatments were lower (14.4 - 61.8%) than those reported for the uninoculated ones (21.4 - 73.9%). Soil, irrespective of treatment, regained a part of its normal N₂-ase activity with time. Field concentrations of all nematicides showed different inhibitory effects on N₂-ase activity of Azospirillum spp. in culture medium, such effects increased with increased doses (10- and 100- fold) and incubation periods (10 days). The contribution of Azospirillum spp. to the N economy of soil treated with nematicides is discussed.     

Microbial Dynamics,Root Colonization,and Nutrient Availability as Influenced by Inoculation of Liquid Bioinoculants in Cultivars of Apple Seedlings

The present study investigates the performance of recommended doses of chemical fertilizer (RDF) and locally isolated strains of Azotobacter, Azospirillum, and arbuscular mycorrhizal fungi (AMF) inoculated either solely or in combination with seedlings of Red Delicious and Lal Ambri cultivars. The RDF (T₇) treatment recorded significantly greater vegetative growth and leaf nitrogen (N), phosphorus (P), and potassium (K) contents over multi-inoculation of Azotobacter + Azospirillum + AMF (T₆) but root colonization and microbial counts decreased significantly. Inoculation of Azotobacter + Azospirillum + AMF (T₆) was superior over sole and dual inoculation with respect to vegetative growth and nutrient contents in leaves and soil but had significant greater counts of Azotobacter, Azospirillum, and Pseudomonas than RDF. Greatest root colonization (34.0 and 35.1%) was recorded in Azotobacter + Azospirillum + AMF (T₆) followed by AMF (T₄) treatment (29.3 and 32.0%) in Red Delicious and Lal Ambri seedlings, respectively. Overall, it can be inferred that multiinoculation of synergistically interacting bioinoculants may be helpful in the establishment of healthy organic apple orchards.     

Grain yield response of Zea mays (hybrid AE 703) to Azotobacter chroococcum H23

Summary Field experiments were conducted during 1985 and 1986 to examine the effect of Azotobacter chroococcum on the grain yield of maize. Application of 40 kg N ha^–1 plus A. chroococcum caused a significant increase in maize yield. Azotobacter inoculation was more efficient at lower doses (40 kg N ha^–1) than at high doses (80 kg N ha^–1) of urea.     

Potential for enhancement of root growth and nodulation of soybean co-inoculated with Azospirillum and Bradyrhizobium in laboratory systems

The potential enhancement of root growth and nodulation in vegetable soybean (AGS190) was studied with application of Azospirillum brasilense (Sp7) and A. lipoferum (CCM3863) co-inoculated with two Bradyrhizobium japonicum strains (TAL102 and UPMR48). Significant root growth stimulation and nodulation were observed in Azospirillum as well as during its co-inoculation with Bradyrhizobium. Nodule formation is linked with the initiation of new roots; nodules were almost absent even in Bradyrhizobium inoculated plant due to the absence of new roots development in clipped rooted seedlings. Total root length, root number, specific root length, root dry matter, root hair development and shoot dry matter were significantly increased by Azospirillum alone and its co-inoculum. Co-inoculated plants significantly influenced the number of nodules and its fresh weight. A. brasilense seemed to perform better in root growth and nodule development compared to A. lipoferum.     

Impact of inoculation with the phytostimulatory PGPR Azospirillum lipoferum CRT1 on the genetic structure of the rhizobacterial community of field-grown maize

The phytostimulatory PGPR Azospirillum lipoferum CRT1 was inoculated to maize seeds and the impact on the genetic structure of the rhizobacterial community in the field was determined during maize growth by Automated Ribosomal Intergenic Spacer Analysis (ARISA) of rhizosphere DNA extracts. ARISA fingerprints could differ from one plant to the next as well as from one sampling to the next. Inoculation with strain CRT1 enhanced plant-to-plant variability of the ARISA fingerprints and caused a statistically significant shift in the composition of the indigenous rhizobacterial community at the first two samplings. This is the first study on the ecological impact of Azospirillum inoculation on resident bacteria done in the field and showing that this impact can last at least one month.     

Investigating the effect of Azospirillum brasilense and Rhizobium pisi on agronomic traits of wheat (Triticum aestivum L.)

ABSTRACT

Plant growth-promoting rhizobacteria (PGPR) play an important role in improving crop growth but have not been studied sufficiently. A wire house experiment was conducted in Pakistan to determine the combined effect of inoculating wheat seeds with PGPR on the subsequent growth and yield of the wheat. The experiment included four treatments: T_{0 –} no-inoculation (control), T₁ – Azospirillum brasilense inoculation, T₂ – Rhizobium pisi inoculation and T₃ – co-inoculation with A. brasilense and R. pisi. Development and growth attributes, as well as final yield of wheat, were studied. Co-inoculation of seeds with both strains increased significantly wheat grain yield, the number of grains per plant and 1000-grain weight by 36%, 11% and 17%, respectively, compared to non-inoculated control. While crop growth rate increased for, respectively, 5.5% and 33% at tillering and flag leaf stages, corresponding values for T₃ were about 9% and 14% higher than values for sole inoculations in T₁ and T₂. Co-inoculation also significantly increased leaf epicuticular wax and relative water content as compared to the control treatment. Thus, inoculation of wheat seeds with A. brasilense and R. pisi and their combination is a promising method to improve growth, yield and quality of wheat.