Rajesh Kaushal

Productivity of Capsicum as Influenced by Conjoint Application of Isolated Indigenous PGPR and Chemical Fertilisers

ABSTRACT Inorganic fertilizers alone cannot sustain high levels of productivity. This study was conducted to determine whether higher productivity of capsicum could be achieved by conjoint application of chemical fertilizers and plant growth promoting rhizobacteria (PGPR). Four PGPR isolates (RS2, RS3, RS4, and RS7) from capsicum roots and rhizosphere were evaluated at Solan, Himachal Pradesh (India), during 2009–2012. Two best performers: RS2 and RS7 were tried singly or in consortium with different levels of chemical fertilizers under field conditions, Randomized Block Design, replicated thrice. The conjoint use of 100% recommended nitrogen, phosphorus, and potassium (NPK) doses through chemical fertilizers (RDF) plus PGPR significantly increased fruit yield, plant height, and biomass by 37%, 20%, and 30%, respectively, over sole application of 100% RDF (control). Further, response of capsicum to 80% RDF plus PGPR was statistically comparable with control. The results, therefore, indicate the potential of isolated PGPR strains to substitute about 20% NP fertilizers besides enhanced productivity of capsicum.

Effect of conjoint application of indigenous PGPR and chemical fertilizers on productivity of maize (Zea mays L.) under mid hills of Himachal Pradesh

ABSTRACT The present study was conducted to work out the conjoint application of indigenous PGPR (plant growth promoting rhizobacteria) and chemical fertilizers levels on the productivity of maize (Zea mays L.). Three best PGPR isolates (B1N1, MAT1 and DHK) having maximum PGP (plant growth promoting) traits were screened at different recommended doses (80%, 60% and 40%) of NP (Nitrogen and Phosphorous) under net house conditions, and finally two isolates (B1N1 and MAT1) along with optimum dose i.e. 80% of NP were selected for field experimentation, which was performed for two years consecutively i.e. 2013–2015 under random block design (RBD). Conjoint application of 80% recommended doses of NP with PGPR (B1N1) significantly increased maize yield (11.7%), plant height (12.9%) and biomass (17.9%), over control (100% recommend dose of fertilizer (RDF) of chemical fertilizer). Therefore, the results revealed the potential of indigenous PGPR isolates to supplement about 20% NP fertilizers without hampering the productivity of maize.

Efficacy of indigenous plant growth promoting rhizobacteria on capsicum yield and soil health

Screening of plant growth promoting rhizobacteria (PGPR) was carried out by isolating 56 bacterial isolates from rhizosphere and roots of capsicum. The isolates were grouped on morphological similarities (RS1 to RS10), characterized biochemically and evaluated for various plant growth promoting (PGP) traits. Among all, six best isolates (RS2, RS3, RS4, RS7, RS8 and RS10) were evaluated for their effect on seed germination and seedling growth of capsicum under controlled conditions. Out of six, four best performers (RS2, RS3, RS4 and RS7) were evaluated for their effect on growth and yield of capsicum under net house conditions. Among which RS2 isolate possessed maximum P-solubilization (80.0%) and auxin production (29.67 μg/ml). However, RS7 isolate possessed maximum siderophore production (83.3%) and antagonism against Pythium spp. (41.7%), Phytophthora spp. (42.5%) and Colletotrichum spp. (40.1%). Seed bacterization with RS7 isolate (Bacillus sp.) showed maximum increase in shoot length (48.0%), shoot biomass (43.7%), root length (50.0%), root biomass (42.1%), yields (33.7%) and nutrient uptake N (40.0%), P (36.8%) and K (23.6%) over control which was statistically at par with treatment receiving RS2 isolate (Bacillus subtilis). Hence, the two bacterial isolates (RS2 and RS7) were strong to be used as biofertilizer and biocontrol agent for capsicum under mid-hill conditions of northwestern Himalayan region.

Plant Growth-Promoting Rhizobacteria of Medicinal Plants in NW Himalayas: Current Status and Future Prospects

Plant species are considered to be one of the most important factors in shaping rhizobacterial communities and driving plant–microbe interactions in the rhizosphere. Based on their effects on the plant, the microbes interacting with plants can be pathogenic, saprophytic or beneficial. In recent years, there is much interest in the conservation of economically important and endangered medicinal plants in order to meet the great demand of biologically active compounds used by food, pharmaceutical and health-care industries. Plant growth-promoting rhizobacteria (PGPRs) have been used as cost-effective, eco-friendly inoculants for sustainable agricultural practice, but their role as a supplement to improve the growth and yield of medicinal plants has not evinced much interest. PGPRs are able to improve plant growth by improving seed germination, speeding up seedling emergence, minimizing the adverse effects of abiotic stresses and protecting plants from soil-borne pathogens and diseases. This chapter provides methods for the exploitation of beneficial microorganisms occurring in the rhizosphere as biofertilizer or bioprotectant. The review covers the studies published so far on the improvement of growth of endangered and economically important medicinal plants through the use of PGPRs and emphasizes some researchable issues for future attention.

Integrated Nutrient Management for Improved Cauliflower Yield and Soil Health

ABSTRACT Nutrient management in Cauliflower (Brassica oleracea var. botrytis L.) cultivation is in part dependent on the microbial population in the rhizosphere. Fertilizer must be applied to support plant growth and development. Whether fertilizer usage in cauliflower can be reduced needs to be determined. Rhizospheric isolates of cauliflower, obtained from soil around the roots and from their roots, in the low and mid-hills agro-ecological zones of India were tested for their efficacy to support cauliflower productivity. The plant growth–promoting rhizobacteria SB5, SB8, SB10, and SB11 exhibited the best plant growth–promoting traits with antagonism against soilborne pathogens compared to the reference strain Bacillus pumilus (JN559852). Application of SB11 (Bacillus spp.) exhibited the most plant growth–promoting attributes in field trials at 75% N and P and increased yield by 33% over the uninoculated control at 100% N and P. The isolate SB11 exhibited P solubilization, siderophore production, indole acetic acid production, hydrocyanic acid (HCN) production, and antifungal activity that may be developed as a plant growth–promoting rhizobacteria (PGPR) to enhance crop productivity and sustain soil health while saving 25% usage of chemical fertilizers.

Impact of Plant Growth–Promoting Rhizobacteria on Vegetable Crop Production

ABSTRACT Biological approaches for improving crop production are becoming the norm for agronomists and environmentalists using integrated plant nutrient management systems. Plant growth–promoting rhizobacteria (PGPR) are among the most effective, and most studied, soil microorganisms that can promote plant performance. Ongoing research is exploring a wide range of rhizobacteria possessing novel traits, including heavy metal detoxifying potential, pesticide degradation/tolerance, salinity tolerance, and biological control of phytopathogens besides the normal plant growth–promoting properties, such as phytohormone, siderophore, 1-amino-cyclopropane-1-carboxylate, hydrogen cyanate, ammonia production, nitrogenase activity, and phosphate solubilization. This review examines the rhizosphere bacteria and the benefits of their use as inoculum with vegetable crops.

Indigenous plant-growth-promoting rhizobacteria and chemical fertilisers: impact on wheat (Triticum aestivum) productivity and soil properties in North Western Himalayan region

High levels of crop productivity cannot be sustained by chemical fertiliser application alone. In order to mitigate this, a 2-year study was conducted to test the effects of combined application of indigenous plant-growth-promoting rhizobacteria (PGPR) and chemical fertilisers on productivity of wheat and soil properties. Ten morphologically distinct indigenous PGPR isolates from wheat roots and rhizosphere were evaluated at Solan, Himachal Pradesh, India, during 2013–14. Three PGPR isolates (B2, SIR1 and BIS2) with maximum PGP traits were screened at different doses of nitrogen (N) and phosphorus (P) (80%, 60% and 40% of recommended fertiliser dose, RFD) under net-house conditions. Two isolates, B2 (Serratia sp.) and SIR1 (Bacillus subtilis), along with the optimum NP dose (i.e. 80% RFD) were selected for field experimentation, which was performed over two consecutive years, 2014–16. Combined application of 80% RDF of NP with PGPR (B2) significantly increased wheat yield by 9.4%, number of tillers per plant by 28.03%, grain number per spike by 19.61%, 1000-grain weight by 10.5%, and biomass by 9.2% relative to the uninoculated control with 100% RFD. Soil properties in the terms of available N, P and potassium, microbial biomass carbon, soil enzyme activities and population of phosphate-solubilising bacteria in the wheat crop were significantly increased by the combined application of bacterial inoculants with 80% RFD of NP in both years over the uninoculated control. Therefore, the results revealed the potential of indigenous PGPR isolates to supplement ~20% of NP fertilisers without hampering the soil fertility and productivity of wheat.