Induction of Systemic Resistance against Phytophthora Blight in Pigeonpea Through the Interaction of Plant Growth Promoting Rhizobacteria: In vivo and in vitro Study

Background: Phytophthora blight (PB), caused by Phytophthora drechsleri f. sp. cajani, is soil borne disease of pigeonpea (Cajanus cajan L.). The use of plant growth promoting rhizobacteria (PGPR) in agriculture leads to alternative disease management of crop in a sustainable ecofriendly way. Methods: In vitro and in vivo experimentation was conducted at fields of Punjab Agricultural University, Ludhiana during kharif season of 2017-18 to study the percentage of blight inhibition by rhizobacteria and production potential in pigeonpea. The present study consisted of 6 treatments of dual inoculation of antagonistic bacteria with recommended rhizobium of PAU (LAR-06). Result: The selected rhizoisolates were studied against Phytophthora drechsleri caused stem blight of pigeonpea. The allelochemicals and plant growth promoting rhizobacteria traits involved in antagonistic behavior significantly inhibited the growth of the test fungus. Scanning electron microscopy between potential rhizoisolates and test fungus revealed intumescent hyphae with irregular cell surface morphology. The synergistic effects of LAR-06 + S-2 and LAR-06+ S-18 were found to be the most potent ones in inhibiting the radial growth of the test pathogen with increased yield production in the field as well as greenhouse conditions.