Prospecting of multitasking strain with potential of biofertilization, biostimulation and biocontrol of Turcicum leaf blight of maize
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Date
2020
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DRPCAU, Pusa
Abstract
Rhizobacteria have vital role in agriculture as they enhance the plant growth, biomass, yield, nutrient content and suppress the phytopathogens. These multitasking abilities of rhizobacteria were exploited to see their role in maize crop. A total 48 rhizobacterial isolates were isolated from soil samples collected from different regions of Bihar and were screened for various biofertilizing, biostimulating and biocontrolactivities viz., nitrogen fixation, phosphorus solubilization, potassium solubilisation, Zn solubilization, Siderophore production, HCN production, Ammonia production, IAA production, chitinase production and antagonistic ability against Turcicum leaf blight i.e., Exserohilum turcicum. Out of 48 rhizobacterial isolates,10 isolates showed nitrogen fixation, 37 were positive for P-solubulization, 22 were positive for K-solubulization, 33 were positive for Zn-solubulization, 29 showed siderophore production, 27 showed IAA production, 11 showed HCN production, 17 showed ammonia production, 19 showed chitinase production and 9 isolates showed antagonistic ability against Exserohilum turcicum. Among all these screened isolates, only two isolates i.e., AK-9 and AK-21were
positive for all the activities. So, these two isolates were selected as multitasking strains and further used in pot experiments against maize crop. Two pot experiments were conducted. First pot experiment was conducted in maize variety-Shaktiman-5 to evaluate the biofertilization and biostimulation ability of these multitasking strains along with different levels of chemical fertilizers (N, P, K, Fe, Zn) on plant growth parameters (shoot length, root length, shoot fresh and dry weights, root fresh and dry weights), yield parameters (Number of grains per cob, 100 seed weight and yield per pot) and nutrient contents (N, P, K, Fe and Zn) of grain and plant. All these parameters were enhanced when multitasking strains were used in combination with different dosages of chemical fertilizer as compared to control and 100% RDF. Maximum enhancement was recorded in treatments containing 100%RDF+Fe+Zn+AK-9 followed by treatment containing 100%RDF+Fe+Zn+AK-21. Second pot experiment was conducted to evaluate the biocontrol ability of these multitasking strains along with different levels of fungicide in maize variety-Shaktiman-5 along with one susceptible variety CML-186 and plant growth and yield parameters, nutrient content and disease severity index were analysed. It was observed that there was enhancement in the crop growth, yield and nutrient contents and decrease in disease severity index in both the maize varieties when multitasking strains along with fungicide were applied as compared to control and 100 % fungicide.Disease severity index of the treatment containing Pathogen inoculation+50% Fungicide+AK-9/ AK-21was on par with the treatment containing Pathogen inoculation+100% Fungicide.Therefore, these two isolates AK-9 and AK-21, having multitasking ability, can play a significant role in biofertilization, biostimulation and biological control of maize crop against Turcicum leaf blight disease.