Isolation and Selection of Arbuscular Mycorrhizal Fungal Community Enhancing The Growth and Development of Maize (Zea mays L.)

The study was conducted under the greenhouse condition with an aim to select a mycorrhizal fungal community enhancing growth and development of maize (Zea mays L.) by reducing 1/5 phosphorus fertilizer. Seven VAM communities from rhizosphere of maize plants (CĐB4, CĐB5, CĐB6, CĐB7, CĐB8, CĐB9, CĐB10) and two VAM communities from rhizosphere of sesame plants (CĐM2 and CĐM4) were collected at maize and sesame fields in Can Tho city. The number of mycorrhizal spores from the VAM communities inoculated into maize plant was 25 spores/100g dry soil. Treatments of the VAM communities responded well to maize growth were further selected and inoculated into maize plant under reducing 1/5 phosphorus fertilizer. Results from the field survey showed that more than 66% of sesame and maize roots were colonized by VAM. There were three types of colonization including arbuscules, vecicles and fine fungal mycellia inside the roots. Glomus, Acaulospora, Gigaspora and Entrophosphora were also identified in soil samples. The spore density of each community varied from 66 to 391 spores/100g dry soil. The results from the greenhouse experiment showed that maize grown in the treatments inoculated with the CĐB4, CĐB7, CĐB9 and CĐB10 had improved weight of corn, increased the percent root colonization and the number of VAM pores in comparison with the control treatment. The results from the reduction of 1/5 phosphorus fertilizer application showed that maize grown in the treatment inoculated with either CĐB7 or CĐB9 as well as CĐB10 had more than 90% of root infected by VAM community, increased the sporulation of VAM from 4,032 to 5,656% as well as weight of corn up to 53.63g/tree in compared with the control treatment (40.78g/tree). Our results identified the CĐB7, CĐB9 and CĐB10 VAM communities which had potential to be applied to the maize field under reducing phosphorus fertilizer.