Impact of Plant Growth Promoting Rhizobacteria (PGPR) on Nitrogen Uptake and Yield of Palu Local Shallots

Optimization of Plant Growth Promoting Rhizobacteria (PGPR) Concentration for Enhanced Growth and Biomass of Pakcoy Brassica rapa L.) in Wick System Hydroponic Cultivation

This study aimed to determine the effect of Plant Growth Promoting Rhizobacteria (PGPR) concentrations on the growth of pakcoy Brassica rapa L.) cultivated hydroponically. The experiment was conducted in Toabo Village, Papalang Subdistrict, Mamuju Regency, West Sulawesi Province, from March to April 2024. The research employed a Randomized Block Design with five PGPR concentration treatments: control (no PGPR), 15 ml/L, 20 ml/L, 25 ml/L, and 30 ml/L, each replicated three times. The observed parameters included plant height, number of leaves, edible weight, root weight, and total plant weight. The results showed that PGPR application significantly affected plant height, root weight, and total plant weight, but had no significant effect on the number of leaves and edible weight. The best treatment was obtained with 30 ml/L PGPR, yielding an average plant height of 27.83 cm, root weight of 22.06 g, and total plant weight of 76.67 g. This study recommends the application of 30 ml/L PGPR to improve the growth and yield of hydroponically grown pakcoy.

Effect of plant growth promoting rhizobacteria on the growth promotion of Mustard CS61 (Brassica juncea)

Plant growth-promoting rhizobacteria (PGPR) help plants grow and develop by protecting them from abiotic and biotic stresses, thereby increasing biochemicals synthesis that promote growth and nutrients uptake. Soil salinity is a major global constraint on crop productivity, and salt-tolerant PGPR offer a promising mitigation strategy. This study represents the use of PGPR consortia in the growth and augmentation of Mustard CS61 (Brassica juncea) under saline conditions. Mangrove rhizosphere soils collected from Koparkhairane (19.1045° N, 73.0033° E) to Belapur (19.0168° N, 73.0455° E), Navi Mumbai, Maharashtra, India. A total of 1,263 bacterial isolates were obtained, of which 168 isolates were screened for halotolerance. Further on the basis of purity, morphological characteristics, and PGPR traits three isolates were selected. These isolates produced significant amounts of IAA with concentrations of 59.27–81.63 µg mL⁻¹, and prominent CMC activity with hydrolysis zones of 2–5 mm. Molecular identification by 16 S rRNA sequencing revealed the potential isolates as Micrococcus luteus (Accession No. PX974661), Microbacterium barkeri (Accession No. PX974662) and (Accession No. PX974663). Plant growth promotion studies with consortia on salt tolerant variety Mustard CS61 (Brassica juncea L.) under 1% saline conditions showed 100% germination, improved seedling vigour, and increased growth. Future studies using metagenomic approaches are needed to explore the wider uncultured microbial diversity, to discover novel genes associated with stress tolerance and plant growth–promoting traits.

Interactive effects of plant growth-promoting rhizobacteria and drought stress on the growth and yield of shallot (Allium ascalonicum L.) cultivated in saline soil

This study evaluated the effects of plant growth-promoting rhizobacteria (PGPR) and drought-stress timing on the growth, yield, and physiological responses of shallot ( Allium ascalonicum L.) cultivated in saline soil. The experiment was conducted using a factorial randomized block design with PGPR concentrations of 0, 20, and 40 mL L⁻¹ and drought-stress timing consisting of no stress, early growth stress (1–14 DAP), vegetative stress (15–28 DAP), and bulb formation stress (29–42 DAP). The final soil EC reached 6 dS m⁻¹, while soil moisture during drought periods declined to 30–50%. PGPR improved plant length, leaf area, tiller number, plant dry weight, and net assimilation rate. PGPR at 40 mL L⁻¹ was more effective for vegetative growth, whereas 20 mL L⁻¹ tended to enhance proline and flavonoid accumulation. Drought during early and vegetative phases caused the greatest reductions in growth and yield. These findings indicate that PGPR supports shallot performance in saline soil, but its effectiveness depends strongly on water availability during critical growth phases.

Response of Planting Spatial and PGPR (Plant Growth Promoting Rhizobacteria) Concentration of Bamboo Roots on The Growth and Yield of Sweet Corn

The productivity of sweet corn must be continuously improved to meet increasing market demand. Inorganic fertilizers may reduce soil fertility. The application of (PGPR) derived from bamboo roots, which function as biofertilizers and biostimulants by enhancing nutrient availability and stimulating plant growth. Appropriate plant spacing is also an important agronomic practice for optimizing the use of light, water, nutrients, and growing space. This study aimed to evaluate the interaction between plant spacing and bamboo root PGPR concentration on the growth and yield of sweet corn. The experiment was conducted in Potroyudan Village, Jepara from December 2024 to March 2025 using a two-factor Randomized Complete Block Design (RCBD). The first factor consisted of three plant spacings (75 × 40 cm, 75 × 30 cm, and 75 × 20 cm), while the second factor included three PGPR concentrations (0, 25, and 50 ml L⁻¹). Data were analyzed using analysis of variance (ANOVA) followed by Duncan's Multiple Range Test (DMRT) at the 5% significance level. The interaction between plant spacing and PGPR concentration significantly affected plant height only at 6 weeks after planting. Plant spacing significantly influenced stem diameter, cob weight with husk, and cob length without husk. The 75 × 40 cm spacing produced the highest cob weight (276.48 g) and longest cob length (19.44 cm). PGPR concentration showed no significant effect, although 25 ml L⁻¹ tended to produce better growth and yield. Overall, plant spacing contributed more to sweet corn productivity than bamboo root PGPR under the conditions of this study.

Effect of Biofertilization with Plant Growth-Promoting rhizobacillus (PGPR) on Growth and Productivity of maize (Zea mays L.) Compared to Chemical Fertilization

Background: Maize (Zea mays L.) is one of the world's most important cereal crops, and improving its productivity while reducing dependence on chemical fertilizers has become a major goal of sustainable agriculture. The potential role of plant growth promoting rhizobacteria (PGPR) as a biofertilizer evolved as appropriate substitute to neutralize adverse environmental impacts wielded by manmade agrochemical. Objective: This study aimed to evaluate the effects of Pseudomonas fluorescens and Bacillus subtilis, individually and in combination, on the growth and yield of maize compared with conventional NPK fertilization. Methods: A field experiment was conducted during the 2025 growing season at the Field Crops Research Station, College of Agriculture, University of Samarra, using a Randomized Complete Block Design (RCBD) with three replicates. Six treatments were evaluated: Untreated control (T1), Pseudomonas fluorescens (T2), Bacillus subtilis (T3), combined inoculation (P. fluorescens + B. subtilis) (T4), combined inoculation with NPK fertilizer (T5), and NPK fertilizer (20:20:20) only (T6). Vegetative growth and yield-related traits were recorded and statistically analyzed. Results: Inoculation of plants with PGPR bacteria resulted in a significant improvement in both vegetative growth and yield compared to the untreated control group. Pseudomonas fluorescens (T2) exhibited the highest vegetative growth rate, recording the highest plant height (148.00 cm), leaf area (365.00 cm²), leaf area index (2.63), and number of grains per spike (688 grains) compared control group recorded (92.33 cm), (10.67 plant⁻¹), (151.73 cm²), (0.70) respectively. Bacillus subtilis (T3), achieved the highest productivity, producing the largest number of spikes per plant (2.67 spikes) and the highest spike weight (283.50 g) compared control group recorded (2.00) and (161.60 g). Conclusion: The use of PGPR, and especially Pseudomonas fluorescens and Bacillus subtilis as potential biofertilisation agents is a promising sustainable alternative to chemical fertilisation that can enhance maize growth and production, while decreasing dependence on mineral fertilisers.

Combined microbial inoculation improves plant growth, nutrient acquisition, and soil biological functioning in Opuntia ficus-indica under water deficit