Production of IAA by Bradyrhizobium sp.

Abstract

The objective of thts research was to detemtine the potency of indigenous acid-aluminium 1olerant Bradyrhizob1um japomcum as producer of tndole acetic acid (IAA) and applied it as mtrogen fixation on local soybeans viz Anjasmoro, Tanggamus (yellow soybean seeds), and Detam (black soybean seed). Three isolates of acid-aluminium tolerant 8radyrhizobium japonicum (BJ) were used in this research, i.e. BJ II (wt), BJ 11 (19) - BJ I l{wt) mutant, and USDA 110 as a reference isolate. All of isolates lested to produce the !AA by using Solkow~ky method. Effect of IAA producuon by each of 8. japomcum was tested on growth pouch and greenhouse using three vancties of soybean All isolates could grow '~ell and produce IAA on yeast mannitol broth (YMB) medium in the presence of 0.5 mM L-uyptophan. BJ 11 (19) produced the highest of IAA at 4 days mcubation compared to BJ 11 (wt) and USDA 110. All 1ested ISOiates of 8radyrh1zobium japomcum have showed effect on stimulating the fonnation of root nodules in soybean varieties grown on Leonard bottle. The concentralion of JAA on root nodules of soybean symbiotic with 8. japonicum was significantly different with control, except on the treatment using Tanggamus soybean.