Effect of Plant Growth Promoting Rhizobacteria on the Growth and Yield of Foxtail Millet (Setaria italica L. Beauv)

Abstract

The use of plant growth-promoting rhizobacteria (PGPR) is a sustainable way for efficient absorption and utilization of nutrients by crop species to enhance growth and yield and persistence against biotic and abiotic stresses. However, the use of PGPRs in drought tolerant crops such as foxtail millet is limited because of the low adaptability of PGPRs to the low moisture conditions. In this study, PGPRs acclimatised to low moisture conditions, were isolated from the rhizosphere of sorghum and their growth and yield promoting effect on foxtail millet was studied. Four isolates, Pseudomonas putida, Bacillus subtilis, Bacillus cereus, and Pantoea Stewart were isolated from the rhizosphere of sorghum cultivated on black soils. Further their identity was confirmed by sequencing 16S rDNA. Foxtail millet seeds were inoculated with the newly isolated PGPR strains and evaluated for their effect on shoot and root growth under greenhouse conditions. Effect of PGPRs on yield related traits such as ear-head weight, grain weight, fodder weight, and ear-head length were assessed under field conditions. Newly isolated PGPRs boosted average root and shoot length when seeds were inoculated with Bacillus cereus (19.33 cm) and Pseudomonas putida (28.66 cm), respectively. On the other hand, among the four bacterial cultures, Bacillus subtilis enhanced grain weight (40.42%), ear-head weight (30.19%), fodder weight (49.72%) and ear-head length (42.56%) compared to the control group under field conditions. When considered collectively, the empirical evidence suggests that PGPR can improve crop growth and yield under greenhouse and field conditions.