Comparative analysis of cow dung microflora of different cow breeds for plant growth promoting traits and antifungal properties for prospective use in organic and natural farming system

Abstract

Abstract In the present study, cow dung from different breeds of cow were explored for its microbial population, plant growth promoting (PGP) traits and antagonistic activity against six fungal phytopathogens. Physico-chemical analysis of cow dung showed highest N, P, K, EC and pH in indigenous Himachali Pahari non-lactating cow. The microbial population of cow dung was enumerated for a period of 7 days and maximum microbial count was found in Himachali Pahari lactating cow. A total of 32 morphologically different cow dung bacterial isolates were selected for further characterization. Cow dung isolates i.e., PL2, PL3 from Himachali Pahari lactating and PD3, PD5 from non-lactating cow; SL1, SL2, SL5 from Sahiwal lactating cow and SD3 from non-lactating cow; JL1 from Jersey lactating cow and JD1, JD2 from non-lactating cow were found positive for all PGP activities except HCN production. Quantitative estimation showed Jersey non-lactating isolate (JD3) best in phosphate solubilisation (127.79 µg/ml) and JD4 for siderophore production (98.42%) whereas, Himachali Pahari lactating (PL2) was found best in IAA production (80.03 µg/ml). Bacterial isolates were checked for antifungal activity against six fungal pathogens viz., Rhizoctonia solani, Sclerotonia sclerotiorum, Pythium aphanidermatum, Phytopthora sp., Alternaria alternata and Fusarium oxysporum. Maximum antifungal activity was found in Jersey lactating isolates (JL1, JL2 and JL4) and Jersey non-lactating (JD1), against all tested fungal phytopathogens. Thirteen bacterial isolates were selected on the basis of PGP and antifungal activities for biochemical and molecular identification. PD3, SL1, JL1, JL2, JL4 and JD1 were identified as Bacillus subtilis, SL2 as Bacillus sp., SD3 and JL3 as Escherichia coli, SL5 as Arthrobacter gandavensis, PL2 as Stenotrophomonas maltophilia and PL3 as Microbacterium thalassium.