Efficacy of Biological Products of Bacillus siamensis RRK1–Rif for Reducing Sheath Blight and Dirty Panicle of Rice

Abstract

Efficacy of Baciilus siamensis RRK1–Rif bioproduct for reducing sheath blight and dirty panicle of rice was evaluated in small plot (1 × 3 m2) condition. The results revealed that all treatments using bioproduct as seed soaking (Sk) and plant spray (Ps) (three–times) or applying during soil preparation (Sp) significantly reduced sheath blight severity and disease incidence caused by Rhizoctonia solani when compared with a pathogen inoculated control. At 14 and 21 days after pathogen inoculation, bioproduct of B. siamensis RRK1–Rif effectively reduced sheath blight by 49.80–60.14% and 32.55–62.78%, respectively when compared to a pathogen inoculated control. Moreover, this bioproduct also reduced discolored seed disease on panicles due to natural fungal pathogen infection by 35.26–55.53%, increased the percentages of fertile seeds by 6.36–11.71%, reduced the dirty panicle infected seeds by 3.78–23.19% and reduced empty seed by 9.01–43.40% when compared with the control treatment. The bioproduct of RRK1–Rif promoted plant growth by increasing the tiller number per plant, the number of panicles per plant. This product also increased yield by 20.60–54.45% and increased quality by increasing whole kernels and reducing broken rice of milled brown rice. B. siamensis RRK1–Rif colonized roots of rice plants from seedling to harvesting stages and could be detected on the leaves by 63.33–93.33% at 24 hrs after spaying bioproduct RRK1–Rif on the rice plant.