<![CDATA[Ultisol soils are widely distributed in Southeast Sulawesi and are characterized by low fertility, acidic pH, low organic matter content, and limited availability of essential nutrients. These constraints contribute to the low productivity of local upland rice and require sustainable technologies that can improve plant growth with lower dependence on synthetic inputs. This study aimed to evaluate the effectiveness of seed biopriming using indigenous rhizobacterial isolates from the rhizosphere of upland rice on the growth of local upland rice cultivated on Ultisol soil. The experiment was arranged in a randomized block design consisting of ten treatments: nine rhizobacterial isolates, namely KNW01, KNW03, KNW05, KNW09, KNW12, BTN15, KNS8, MN06, and BMB01, and a non-inoculated control. Each treatment was replicated three times. The observed variables included plant height, number of leaves, leaf area, number of tillers, root length, plant dry weight, and relative growth rate. The results showed that seed biopriming with indigenous rhizobacteria improved the growth performance of upland rice compared with the control. Isolate KNW05 consistently produced the best response across most growth variables, including plant height of 120.7 cm, leaf area of 1,622 cm², root length of 37.9 cm, plant dry weight of 24.3 g, and relative growth rate of 2.5 g/g/week. KNW05 also increased the number of tillers by 87% compared with the control. These findings indicate that indigenous rhizobacteria, particularly isolate KNW05, have potential as biofertilizer candidates to support sustainable upland rice cultivation on Ultisol soil.]]>
