Effective zinc mobilization to rice grains using rhizobacterial consortium

Low Zn in staple food grains like rice is closely related to large scale Zn malnutrition in many countries of the World. Zinc biofortification of rice grains by some cost effective agronomic method is important for low income farmers. To explore the possibility of enhancing the bioavailability of Zn in rice grains besides higher yields of two cultivars, the combinations of varying Zn fertilizer doses with or without inoculation of rhizobacteria consortium under split plot design set up were evaluated in two years field trials. Microbial inoculation + 5 kg Zn ha-1 to I year rice crop resulted in the highest number of effective tillers, grain yields, Zn concentration and uptake in grains and straw and total Zn uptake in both years. Grain yield of rice during two years increased by 19.7-27.9 and 17.1-20.4 percent over control under treatments receiving microbial inoculation + 5 kg Zn ha-1 to I year rice and 5 kg Zn ha-1 alone to I year rice crop, respectively. The highest concentration of Zn (10.9-19.1 mg kg-1) and the lowest concentration of phytic acid (18.5-25.3 g kg-1) in dehulled rice grains were recorded with soil application of 5 kg Zn ha-1; however, the values were at par with those observed under microbial inoculation + 5 kg Zn ha-1 (12.0-17.0 mg Zn kg-1 and 19.2-26.9 g phytic acid kg-1). The percent utilization of soil applied Zn increased with microbial inoculation in both the years and it was relatively higher in NDR 359 as compared to PD 16.