Effect of Different Phosphorus Levels on Growth and Yield of Wheat under Water Stress Conditions

Water stress and low phosphorus availability are the limiting factors for growth and yield of wheat. Five different phosphorus levels (P = 0, 30, 60, 90, 120 kg ha-1) with three water stress levels (I1 = well-irrigated, I2 = water stress at reproductive stage and I3 = water stress both at vegetative + reproductive stages) were applied to check their effects on growth and yield of wheat. Higher application of phosphorus with optimum irrigation showed significant effect on growth of wheat. Higher phosphorus application rate compensate the effect of water stress conditions both at vegetative and reproductive stages. Drought stress at vegetative + reproductive stages was more drastically affected as compared to stress at reproductive stage. Lower phosphorus application rate with water stress caused maximum reduction in plant height, number of tillers, spike length, number of grains spike-1, 1000 grains weight, grain yield and straw yield. It was concluded that application of phosphorus at higher rate could compensate drastic effect of water stress. On overall performance, application of phosphorus at the rate of 120 kg ha-1 showed better results under water stress conditions as compared to other phosphorus levels. Keywords: - wheat, water stress, phosphorus, growth, yield

Co-inoculation with Rhizobium and plant growth promoting rhizobacteria (PGPR) for inducing salinity tolerance in mung bean under field condition of semi arid climate

Salinity stress severely affects the growth, nodulation and yield of mung bean (Vigna radiata L.). However, its growth can be improved under salinity stress by inoculation/co-inoculation with rhizobia and plant growth promoting rhizobacteria (PGPR) containing 1-Aminocyclopropane-1-carboxylic acid (ACC) deaminase enzyme. ACC-deaminase containing bacteria regulate the stress induced ethylene production by hydrolyzing the ACC (immediate precursor of ethylene) into ammonia and ketobutyric acid, thus improve plant growth by lowering the ethylene level. A study was conducted under salt affected field conditions where pre-isolated strains of Rhizobium and PGPR were used alone as well as in combination for mitigating the salinity stress on growth, nodulation and yield of mung bean by following the randomized complete block design (RCBD). The data were recorded and analyzed statistically to see the difference among treatments

Preliminary study on phosphate solubilizing Bacillus subtilis strain Q3 and Paenibacillus sp. strain Q6 for improving cotton growth under alkaline conditions

Background Low phosphorus availability limits crop production in alkaline calcareous soils in semi-arid regions including Pakistan. Phosphate solubilizing bacteria may improve crop growth on alkaline calcareous soils due to their ability to enhance P availability. Methods Twenty rhizobacterial isolates (Q1–Q20) were isolated from rhizosphere of cotton and characterized for their growth promoting attributes in vitro. The selected phosphate solubilizing isolates were further screened for their ability to improve cotton growth under axenic conditions (jar trial). The phosphorus solubilization capacities of selected strains were quantified and these strains were identified through 16S rDNA sequencing. Results Isolates Q2, Q3, Q6, Q7, Q8, Q13 and Q14 were able to solubilize phosphate from insoluble sources. Most of these isolates also possessed other traits including catalase activity and ammonia production. The growth promotion assay showed that Q3 was significantly better than most of the other isolates followed by Q6. Maximum root colonization (4.34 × 106 cfu g−1) was observed in case of isolate Q6 followed by Q3. The phosphorus solubilization capacities of these strains were quantified, showing a maximum phosphorus solubilization by Q3 (optical density 2.605 ± 0.06) followed by the Q6 strain. The strain Q3 was identified as Bacillus subtilis (accession # KX788864) and Q6 as Paenibacillus sp. (accession # KX788865) through 16S rDNA sequencing. Discussion The bacterial isolates varied in their abilities for different growth promoting traits. The selected PGPR Bacillus subtilis strain Q3 and Paenibacillus sp. strain Q6 have multifarious growth promoting traits including ability to grow at higher EC and pH levels, and phosphorus solubilizing ability. These strains can efficiently colonize cotton roots under salt affected soils and help plants in phosphorus nutrition. It is concluded that both strains are potential candidates for promoting cotton growth under alkaline conditions, however further investigation is required to determine their potential for field application

Perspectives of Microbial Inoculation for Sustainable Development and Environmental Management

How to sustainably feed a growing global population is a question still without an answer. Particularly farmers, to increase production, tend to apply more fertilizers and pesticides, a trend especially predominant in developing countries. Another challenge is that industrialization and other human activities produce pollutants, which accumulate in soils or aquatic environments, contaminating them. Not only is human well-being at risk, but also environmental health. Currently, recycling, land-filling, incineration and pyrolysis are being used to reduce the concentration of toxic pollutants from contaminated sites, but too have adverse effects on the environment, producing even more resistant and highly toxic intermediate compounds. Moreover, these methods are expensive, and are difficult to execute for soil, water, and air decontamination. Alternatively, green technologies are currently being developed to degrade toxic pollutants. This review provides an overview of current research on microbial inoculation as a way to either replace or reduce the use of agrochemicals and clean environments heavily affected by pollution. Microorganism-based inoculants that enhance nutrient uptake, promote crop growth, or protect plants from pests and diseases can replace agrochemicals in food production. Several examples of how biofertilizers and biopesticides enhance crop production are discussed. Plant roots can be colonized by a variety of favorable species and genera that promote plant growth. Microbial interventions can also be used to clean contaminated sites from accumulated pesticides, heavy metals, polyaromatic hydrocarbons, and other industrial effluents. The potential of and key processes used by microorganisms for sustainable development and environmental management are discussed in this review, followed by their future prospects

Inducing salinity tolerance in red pepper (Capsicum annuum L.) through exogenous application of proline and L-tryptophan

Deterioration of agricultural lands due to salinity is one of the serious threats in irrigated areas of the world. Confronting the influence of salinization in agriculture is a key for achieving food security. Red pepper (Capsicum annuum L.) is not only economically but also nutritionally, important for human diet. A study was conducted to ameliorate the effect of salinity on the production and quality of red pepper by exogenous application of osmolytes. Two potential osmolytes i.e. proline and L- tryptophan were exogenously applied solely and in combination (@ 50 mM and 0.12 mM, respectively). There were three salinity levels i.e. ECe; 0.6, 4.04 and 6.11 dS m-1. Results showed that plant height, root length, plant biomass and yield were significantly decreased, while significant increase in Na+ and Na+/K+ ratio was observed with increasing level of salinity. A significant improvement in growth, yield and quality was observed when both osmolytes were exogenously applied under salinity stress. The combined use of proline and L-tryptophan was more effective for reducing the inhibitory effect of salinity as compared to sole application of these osmolytes. It is concluded that the combined application of proline and L-tryptophan (@ 50 mM and 0.12 mM, respectively) was more effective for improving growth of red pepper under normal conditions as well as salinity stressed conditions

Short Communication <br>Synergistic effect of rhizobia and plant growth promoting rhizobacteria on the growth and nodulation of lentil seedlings under axenic conditions

Plant growth promoting rhizobacteria (PGPR) containing ACC-deaminase in combination with rhizobia can improve the growth and nodulation in plants by suppressing the endogenous level of ethylene. In the present study, ten strains, each of PGPR and rhizobia from the previously screened cultures were tested for their effect as co-inoculants on growth and nodulation of lentil in growth pouches under axenic conditions. Results showed that most of the combinations improved the lentil growth as compared to the un-inoculated control. Maximum increase in shoot length (1.87 fold), root length (1.97 fold) and total biomass (1.98 fold) over the un-inoculated control was observed in the treatment where the lentil seedlings were inoculated with the combination Z24P10. Co-inoculation also improved the nodulation in lentil and the maximum number of nodules plant-1 (24 nodules) were observed in the combination Z22P10. However, there was no nodulation in few combinations. It is concluded that the co-inoculation with rhizobia and PGPR containing ACC-deaminase has improved the growth and nodulation in lentil under axenic conditions and the selected combinations may be evaluated in pot and field trial

Biochemical analysis of fruiting bodies of Volvariella volvacea strain Vv pk, grown on six different substrates

A local strain of Volvariella volvacea Vv pk, locally known as Chinese mushroom was cultivated on six different agricultural wastes including paddy straw, cotton waste, banana leaves, corn stovers, sugarcane baggasse and pulses straw. The study was conducted to know that how much a substrate contributes in the nutritional value of the fruiting bodies of the mushroom harvested from such substrate and to recommend the best substrate for the commercial cultivation of the mushroom with high levels of protein, crude fibre and certain other elements. The biochemical analysis of the fruiting bodies harvested from the substrates was done to estimate the moisture percentage, crude fat, protein, fiber, and ash contents. Maximum protein (34.17%), ash (10.8) and crude fiber percentage (11.9%) was observed in the fruiting bodies harvested from cotton waste. So, cotton waste is recommended as an effective substrate to grow Chinese mushroom on commercial scale

Field evaluation of multistrain biofertilizer for improving the productivity of different mungbean genotypes

Mungbean can successfully be grown in the small slots present in the existing cropping systems that may increase the farmer income and can also restore soil fertility. The inoculation of crop plants with bacterial inoculants has the potential to increase crop productivity even under different soil and climatic conditions. A field experiment was conducted to evaluate the effectiveness of multi-strain biofertilizer prepared through combined use of Rhizobium phaseoli and Pseudomonas fluorescens and Bacillus subtilis for enhancing the growth, nodulation and productivity of ten mungbean genotypes under field conditions, and effect of inoculation on total bacterial DNA (population) in soil. The experiment was laid out in randomized complete block design (RCBD) with factorial arrangements and three replications. Results revealed that inoculation with multistrain biofertilizer increased the nodule numbers, growth, and yield under different mungbean genotypes when compared with their respective uninoculated control. The genotypes showed different productive potentials either with or without inoculation under field conditions. The genotype NCM 2015 yielded more but inoculation was more effective with genotypes NM 17, NM 19 and NCM-252- 10 under field conditions of Bahawalpur. Results of 16S rRNA analysis showed a higher number of gene copies in the rhizosphere of inoculated plants of all mungbean genotypes than those of uninoculated plants. Maximum total bacterial population was observed in the rhizosphere of inoculated plants in NM 11 that was significantly better than un-inoculated control plants of the same mungbean line but non-significant when compared with other lines under inoculation. It is concluded that the use of multistrain biofertilizer prepared through combined use of Rhizobium and PGPR strains containing ACC-deaminase could be an effective approach to improve growth, nodulation and yield of mungbean genotypes. The response of different genotypes to the inoculation varied significantly. So, research for the development of inoculum for different advanced genotypes should be continued and more emphasis should be deployed to develop biofertilizers with efficient strains to use them under different climate and soil conditions