Effect of inoculation with selected Beadyrhizobium spp. on the survival and growth of Acacia mangium saplings after 20 months in the field

Abstract

This work was designed to test the long-term effect of the inoculation of Acacia mangium seedlings with 10 selected strains of Bradyrhizobium spp. The percentage of survival of seedlings inoculated with any of the Bradyrhizobium strains was increased by 10% as compared to the control plants. However, out of the 10 Bradyrhizobium strains tested, only 3 strains, Aust 13c, Lu 4 and Tel 8, belonging to the phylogenetic group 1, significantly enhanced the growth of A. mangium after 20 months in the field. For the first time, inoculation with indigenous Malaysian strains Bradyrhizobium such as Tel 8 and Lu 4 at the seedling stage is reported to produce enhanced and sustained growth and development of A. mangium in the field. We propose that in the future, it may be best to isolate and select local strains from each reforestation plot using a simple screening to determine their phylogenetic group, and conducting a simple nursery inoculation test to assess their competitivity and efficiency when associated with A. mangium seedlings.