The potential of irradiated inoculants consortium for zinc accumulation in rice mutant lines

Abstract

Some of the microorganisms in soil play important roles in plant performance by improving mineral nutrition. Zinc (Zn) is an essential micronutrient that has various important functions and is only obtained by the intake of foods. Rice is a staple food for Indonesian people. Increasing Zn concentration in rice through fertilization and gamma irradiated inoculants consortium is an effective way to accumulate Zn in rice grains. The objective of this research was to utilize gamma-irradiated inoculants and enhancement of Zn content in rice mutant lines. This study used inoculants consortium from potential microorganisms consisting of Aspergillus niger, Azotobacter sp, Bacillus circulants, and Trichoderma harzianum. They can be used to solubilize metals or minerals that are accumulated in part of the plants. The irradiation of the inoculant was conducted by 250 Gy gamma rays. Seven Mira-1 rice mutant lines together with their wild type, Inpari Nutri Zinc rice variety, were used. Treatment combinations, i.e., Control, T1, T2, T3, T4, and T5 were applied to the rice materials randomized block experimental design with three replications. Agronomic characteristics at the vegetative phase were observed and Zn content in rice grain was measured by atomic absorption spectrophotometry. The result shows significant differences in agronomic characteristics from different treatments. Zn content in rice mutant lines was higher than their wild type, and the irradiated inoculants consortium was very effective in enhancing Zn content in rice grains. The best treatment for accumulation of Zn in rice grain was irradiated inoculants consortium combined with 10 kg/ha zinc sulfate (treatment T4), resulting in a grain Zn content of 72.19 ppm in the 82 rice mutant line.