Selection for the Effective Species of Vesicular-Arbuscular Mycorrhizal Fungi on Soybean Root Infection and Growth Enhancement

Abstract

The selection for the effective species of vesicular-arbuscular mycorrhizal fungi (VAMF) was conducted in the greenhouse of Soil Science Department, Kasetsart University at Kamphaengsaen Campus. Nine VAMF species, from pot production in Yangtalard soil, consisted of Acaulospora dilatata, Acaulospora scrobiculata, Entrophospora colombiana, Gigaspora sp. No 2, Glomus aggregatum, G. claroideum, G. geosporium, G. tenuis and Scutellospora sp. were inoculated to SJ5 soybeans grown in a 6–litre clay pots with sterilized sand medium. The results revealed that various VAMF had different abilities to infect soybean roots. The VAMF species having fast infection rate and high intensities of root colonization were E. colombiana, A. scrobiculata, G. aggregatum, G. geosporium and Scutellospora sp. The intensities of root colonization were 96.75, 95.25, 93.75, 90.50 and 89.25 %, respectively. The ability of VAMF on hyphal development in soil were differed among species. G. aggregatum, G. geosporium, Scutellospora sp. and E. colombiana had greater hyphal development than the rest while their lengths of extraradical hyphae at harvest period were 168.33, 137.37, 134.85 and 128.90 cm, respectively. Finally, high yield and high mycorrhizal dependency were found in plants inoculated with Scutellospora sp., E.
colombiana, G. aggregatum and G. geosporium. These VAMF species showed high potential to enhance soybean growth and should be further examined with different levels and kinds of phosphorus fertilizer in various conditions.