Enhancement of Rice Seed Performance Using Rhizobacterial Agents and Molecular Characterization of Isolates from Paddy Rhizosphere

Study aims to evaluate the effect of two rhizobacterial isolates on the germination and vigor of rice seeds and to identify the strains through molecular characterization. A factorial completely randomized design was used, involving concentrations of rhizobacterial (0%, 25%, 50%, 75%, and 100%) and soaking durations (1 and 4 hours), with three replications, totaling 30 experimental units. Variables included seed viability and seed vigor. Diversity is assessed by Shannon and Simpson Diversity Index. Molecular identification used 16S rRNA gene sequences. Phylogenetic trees were constructed using the NeighborJoining method, and evolutionary distances were calculated with the Kimura 2-parameter model. The results showed that soaking duration of 4 hours significantly enhanced seed vigor, the average vigor index from 76.80% to 92.07%, and growth rate from 51.88% to 72.53%, regardless of rhizobacterial concentration. The highest maximum growth potential (100%) was recorded 25% concentration and 4-hour soaking. Shannon Diversity Index for two species is: 0.693 and Simpson Diversity Index 0,5. Molecular analysis identified Isolate 1 related to Bacillus cereus strain ATCC 14579 with 95% identity. Isolate 2 showed 88% similarity, suggesting potential novelty. These findings support rhizobacteria as bioenhancement, increasing ecologically important diversity and strengthening their relevance in sustainable rice cultivation.