Janardan Yadav
Banaras Hindu University, India
Title: Impact of plant probiotics and Frankia on revival of soil and promotion of growth and yield of tomato (Solanum lycopersicum L.) in cold regions of Himalayas, India
Biography
Biography: Janardan Yadav
Abstract
The soils of arid temperate regions of Leh valley, situated an elevation of more than 3000m in J&K, India, are poorly developed under influence of climatic factors (where mean monthly temperature varies from of 27.8 0C to – 14.3 0C and sometimes falls to -30 0C), geomorphic processes aided by glacial drift and geolithology. Most of the soils of this valley have more than 35% coarse fragments (skeletal), calcareous, neutral to alkaline in reaction, very low content of organic carbon, available N and P and classified as Sandy-skeletal (calcareous) Typic Eutrocypts. Under such circumstances, microbial activities and nutrients cycling of added organic manure / fertilizers in soil are very poor and consequently grown vegetable crop give less response to nutrients. By principle, dynamic properties of soils can be improved by application of beneficial microbes. Therefore, efforts were made to revive the soils of Leh valley by isolation, selection and application of quality plant probiotics (plant growth promoting rhizobacteria) with cultivation of vegetables particularly tomato (Solanum lycopersicum L.). Selection of effective plant probiotic strains of Pseudomonas trivialis (JY-01, JY-05), Pseudomonas sp. (JY-02, 03, 04, 07, and JY -11), Pseudomonas aeruginosa (BHUPSB-02), P.fluorescens (BHUPSB-06) and Bacillus subtilis (BHUPSB-13) was done on the basis of biochemical, plant growth promoting properties and molecular characterization of many rhizosphere bacteria isolated from the soils of Leh valley. Further, isolation and selection of Frankia strain FL-1(symbiotic N2-fixer) was done from the root nodules of non-leguminous Seabuckthorn (Hippophae spp.) shrubs wildly grown in Leh valley. This strain of Frankia was showing plant growth promoting properties and synergistic relationship with above plant probiotic strains. During the interaction study, Frankia isolate (FL-1) and B. subtilis (BHUPSB-13) were showing inhibitory effect on both Ralstonia solanacearum ( causing root wilt) and Fusarium oxysporum lycopersici (causing stem wilt) in tomato under in-vitro condition. Therefore, based on Theory of Koch Pastulate, a pot experiment was conducted on tomato Var. Kashiamrit with 12 treatments in triplicate under CRBD at Banaras Hindu University, Varanasi during kharif 2014-15 to see the effect of P. fluorescens, B. subtilis and Frankia, separately and in combination, to control the infestation of wilt causing pathogen and promotion of growth and yield. Observation after 10 days of infestation showed that the plants without pretreated with PGPR were showing much more infestation and few of plants died completely in separate or combined treatments of bacterial and fungal pathogens. Though, B. subtilis, P. fluorescens and Frankia (FL-1) were effective, separately or in combination, to control the infestation of both pathogens but B. subtilis was more effective to control bacterial pathogen while, Frankia isolate (FL-1) was effective not only to controlling both pathogens but also for higher plant growth and early flowering in the tomato plant. However, combined effect of B. subtilis and Frankia had given significantly better performance of disease control, growth and fruit yield of tomato in comparison of individual inoculants.
These strains of plant probiotics are now being used by different agricultural laboratories and other stakeholders involved in cultivation of tomato and other vegetables in Leh valley. Though, there is need of further study but results of improvement in rhizosphere microflora, soil microbial biomass carbon, hydrogenase and phosphtase enzymic activities high yield of tomato under inoculated conditions conferred that the plant probiotic consortium of Pseudomonas trivialis (JY-01, JY-05), Pseudomonas sp. (JY-02, 03, 04, 07, and JY -11), Pseudomonas aeruginosa (BHUPSB-02), P.fluorescens (BHUPSB-06) and Bacillus subtilis (BHUPSB-13) would be useful to revive the soils of Leh valley for cultivation of tomato as well as other vegetables.