Development of Rapid Method for Screening of Plant Growth Promoting Rhizobacteria in Rice

Abstract

Plant growth promoting rhizobacteria (PGPR) is a group of rhizobacteria which have abilities to promote plant growth and plant health though various mechanisms. Among 523 rhizosphere bacterial isolates of rice collected from the northern, northeastern, central and southern regions of Thailand, 107 isolates had at least two plant growth promoting properties of nitrogen fixation, indole acetic acid production, phosphate solubilization, and siderophore production were selected for testing the rapid plant growth screening method. By using growth pouch system, 32 isolates were selected based on significant growth promoting out performance of 107 tested isolates within 7 days. These 32 selected isolates were further confirmed their growth promoting property under greenhouse condition by using pot experiment. Twenty-eight out of 32 isolates (87.5%) gave similar results on significant increasing the total dry weight of 30 days-old rice seedlings which agreed with the growth pouch results. The results indicated that screening of PGPR by combining of PGPR properties test and growth pouch system is an effective method which efficiently selected PGPR isolates from a large number of tested isolates in a short period of time, using a limited space, and less labor than the previously reported methods.