Effect of Phyllosphere Consortia on Growth and Nutrient Uptake of Radish (Raphanus sativus L.)

Abstract

This study aimed to develop microbial consortia for foliar application to enhance the growth and yield of radish. The study was conducted in 2022-2023 at University of Agricultural Sciences, Dharwad, Karnataka. Microbial isolates were collected from Institute of Organic Farming, UAS, Dharwad, and evaluated for plant growth promoting (PGP) traits through biochemical and functional tests. The results showed that among 11 PGP bacterial isolates (i e, 6 actinobacteria, 2 PPFM, 3 Lactic acid bacteria), all six actinobacteria and two PPFM isolates showed positive results for oxidase, catalase, HCN and siderophore production, while all three LAB isolates were positive only for HCN production. Among 11, 4 isolates showed the highest production of IAA, GA, invitro N2 fixation and were having multiple traits, are selected for further study.  All 4 isolates were found to be compatible. Further 11 liquid formulations were prepared, including 7 consortia with multiple isolates and 4 individual formulations. These formulations were tested for their effect on radish growth. The results revealed that Treatment T13 (RDF + phyllosphere consortia) significantly improved radish growth, with the highest plant height (42.2 cm), leaf length (31.57 cm), number of leaves (14.33), chlorophyll content (45.23), and fresh and dry weights of leaves and roots. Highest nutrient uptake was observed in T13 with nitrogen (0.82 g plant⁻¹), phosphorus (0.29 g plant⁻¹), and potassium (0.88 g plant⁻¹). T12 was found to be on par with T13 in all parameters i e, consortia with four and eleven strains were equally effective. This study achieved effective microbial inoculants with fewer strains, multiple functions, and high bioefficacy.