Veena Khanna

Yield enhancement and phosphorus economy in lentil (Lens culinaris Medikus) with integrated use of phosphorus, Rhizobium and plant growth promoting rhizobacteria

ABSTRACT The study evaluated the effects of phosphorus (0, 20, 30, and 40 kg P2O5 ha−1) and biofertilizers [Rhizobium (Rhizobium leguminosarum bv viciae), plant growth promoting rhizobacteria (PGPR) (Pseudomonas fluorescens), Rhizobium + PGPR, and uninoculated control] in lentil. Application of 40 kg P2O5 ha−1 resulted in the highest number of nodules, nodule dry weight, leghemoglobin content in nodules, chlorophyll content, yield attributes, and grain yield. Coinoculated treatment performed better than uninoculated control, and individual inoculations of Rhizobium and PGPR in terms of all above mentioned parameters. Application of 20 kg P2O5 ha−1 + Rhizobium inoculation gave statistically similar and 20 kg P2O5 ha−1 + Rhizobium + PGPR inoculation gave significantly higher grain yield than that by 40 kg P2O5 ha−1 alone. The use of Rhizobium alone and Rhizobium + PGPR consortium can save not only 20 kg P2O5 ha−1 but also increase the grain yield of lentil.

Symbiotic parameters, growth, nutrient accumulation, productivity and profitability as influenced by integrated nutrient management in lentil (Lens culinaris)

ABSTRACT Field experiments evaluated the effects of integrated nutrient management on symbiotic parameters, growth, nutrient accumulation, productivity and profitability of lentil (Lens culinaris Medikus). Application of recommended dose of nutrients (RDN, 12.5 kg N ha−1 + 40 kg P2O5 ha−1) + 25 kg ZnSO4 ha−1 + seed inoculation with biofertilizers [Rhizobium + phosphate solubilizing bacteria (PSB) + plant growth promoting rhizobacteria (PGPR)] + 1.0 g ammonium molybdate kg−1 seed recorded the highest number & dry weight of nodules, leghaemoglobin content, root & shoot dry weight, plant height, number of pods plant−1 and 100-seed weight. The next best treatment was RDN + seed inoculation with biofertilizers + 1.0 g ammonium molybdate kg−1 seed. On the basis of mean of three-year data, the treatment of RDN + 25 kg ZnSO4 ha−1 + seed inoculation with biofertilizers + 1.0 g ammonium molybdate kg−1 seed proved the best in realizing the highest grain yield (34.0%), gross returns (34.0%) and net returns (54.8% higher over control). Nitrogen, phosphorus and potassium in the grains and straw were significantly improved where RDN was applied in combination with seed inoculation, basal application of ZnSO4 and seed treatment with 1 g ammonium molybdate than their single applications.

Abiotic Stress Mitigation Through Plant-Growth-Promoting Rhizobacteria

Abiotic and biotic stresses highly impacts production of principal crops all around the world. Due to climate change, extreme abiotic factors like high and low temperatures, droughts, salinity, osmotic stress, heavy rains, floods and frost damages are posing grave threats to crop production. There is a dire need to mitigate these stresses, so in order to cope with such impacts, microorganisms can be employed as best alternatives to chemical inputs by exploiting their unique properties of tolerance to extreme environments, their ubiquity, their genetic diversity and their interaction with crop plants and by developing methods for their successful employment in agriculture production. Plant-growth-promoting rhizobacteria (PGPRs) mitigate abiotic stresses on plants most effectively through degradation of ACC, the ethylene precursor by bacterial ACC-deaminase and through biofilm and exopolysaccharide production. Alleviation of environmental stresses in crop plants using these microorganisms opens new and emerging applications in sustainable agriculture.

INDUCTION OF SYSTEMIC RESISTANCE AND WILT MANAGEMENT IN CHICKPEA BY ANTAGONISTIC RHIZOBACTERIA CO-INOCULATED WITH MESORHIZOBIUM CICERIS.

Suman kumari. The use of PGPR as an inducer of systemic resistance in crop plants is relatively novel, cheaper and appropriate method to provide resistance against a broad spectrum of pathogens via production of defense related proteins. This study has reported the potential of five native rhizobacterial antagonists (2B, 7B, 28P, 34Pand 38P) alone and in combination with Mesorhizobium to control the disease severity and to boost the defense enzymes in chickpea plants (variety GPF-2) against Fusarium oxysporum f. sp. ciceris under glass house conditions. Selected antagonists were observed for the production of Salicylic and Gibberellic acid. Gibberellic acid production ranged from (242.4377.3 μg/ml). Maximum Salicylic (72.9 μg/ml) and Gibberellic acid (377.3 μg/ml) production was shown by 38P. Seed bacterization with 38 P and 34P along with Mesorhizobium, efficiently controlled the disease (76.8 % and 75.4 %) than the fungicide treatment (69.2%) and rhizobacterial isolates alone indicating the synergistic effect. Estimation of the Pathogenesis related proteins from the root tissues of chickpea revealed that maximum production of phenolic, Peroxydase and Polyphenol oxidase was also observed in 34P and 38P in combination with Mesorhizobium. PR proteins play important role in disease resistance and also help the plant to adapt to the environmental stress. This study reveals that PGPRs co-inoculation with specific rhizobia not only enhance the growth rate or protect the plants from pathogens via antagonism, but also help to induce enhanced systemic resistance i.e. plant defence mechanism by the induction of phenolic and several pathogenesis related proteins.

Integration of pre-and post-emergence herbicides for weed management in pigeonpea

Pigeonpea is an important pulse crop of India. During 2012-13, it was cultivated in an area of 3.69 million hectares with a production of 2.75 million tonnes and productivity of 753 kg/ha (Indiastat 2014). Pigeonpea is a long duration and widely spaced row crop having slow initial growth rate. The crop canopy does not cover the inter row space during initial phase of growth due to which weeds compete with pigeonpea for available moisture, nutrients and light. The crop suffers from early weed infestation. Therefore, it is necessary to keep the crop weed-free during the early growth period (4-6 weeks). In pigeonpea, weeds cause yield reduction up to 80% (Talnikar et al. 2008). Only pre-emergence herbicides are available for weed control in pigeonpea. Among the pre-emergence herbicides, pendimethalin has been found promising in controlling weeds and improving grain yield (Reddy et al. 2007, Singh et al. 2010a, Singh et al. 2010b). However, it is effective only up to about a month and thereafter weeds may pose a problem. Furthermore, weeds emerge in different flushes due to rainy season. Also, one of the important benefits of growing any legume crop is its ability to fix atmospheric nitrogen to plant usable forms, thus, it becomes imperative to assess any possible effects of herbicide application on its symbiotic efficiency. So, there was a need to study the effect of integrated use of pre-emergence and post-emergence herbicides in pigeonpea.