Screening of Plant Growth Promoting Bacteria for Rice from Rhizosphere Soil of Gomphrena celosioides Mart.

Abstract

The objective of this research was to isolate plant growth promoting bacteria from rhizospheric soil of Gompherna celosioides Mart. and test their basic properties of plant growth promoters on rice seedling, which is an important economic crop of Thailand. Forty-four bacteria isolates were isolated including 32 isolates of gram negative, 10 isolates of gram positive, and 2 isolates of actinobacteria. Plant growth promoting properties were tested such as nitrogen fixation, siderophore production, phosphate solubilization and indole-3-acetic acid production. After that 8 isolates were selected for studying of root colonization and plant growth promoting properties on rice including GCWR 8, GCSR 12, GCSR  15, GCMR 18, GCSR  33, GCSR  38, GCMR 43 และ GCMR 44. The results showed that soaking rice seed with cell suspension of GCSR 33 before planting have the most seed germination with 66.67%. Detection of bacteria from rhizoplane, seven days after seeding, GCMR 43 was the most recovering with 9.9×10⁹ cfu/1 gram of root. As for the isolation from the rhizosphere soil, it was found that all isolate increasing bacteria concentration. Measuring root lengths and stems, found that the GCSR 33 had the highest root length of 4.44 cm, but the highest stem length was GCMR 43 with 3.41 cm. However, further studies are needed to obtain the most effective bacteria to promote plant growth.