Mineral nutrition and yield of sorghum inoculated with microbe strains under two agroenvironments

Abstract

Microbial inoculants have great ecological and economic importance in agriculture. We assessed the agrobiological effectiveness of inoculating microbial strains in sorghum (D-47) grown under irrigated and dryland conditions. Six experimental strains of arbuscular mycorrhizal fungi were evaluated [3 (Funneliformis mosseae), 20 (Gigaspora albida), 32 (F. mosseae), 35 (F. mosseae), 39 (F. mosseae) and 55 (Gigaspora albida)], as well as a consortium of growth promoting bacteria [Pseudomonas spp. (Bacterial 2709)] (Ba), INIFAP arbuscular mycorrhiza (Rhizophagus intraradices) (M) and a fertilized control (TF). The doses used were 60‑40-00 and 120-40-00 for dryland and irrigation, respectively. Chlorophyll (SPAD), nitrogen (N), phosphorus (P), iron (Fe) and foliar zinc (Zn), and radical biomass, grain yield and mycorrhizal colonization were quantif ied. Microbial strains influenced the characteristics of sorghum planted in the agroenvironments differently. In general, sorghum had better response in irrigated conditions. Content of Zn, radical biomass and mycorrhizal colonization were not influenced by moisture conditions. Under irrigation, the highest rates of chlorophyll were found in TF and M; N uptake highlighted TF, M, and strains 3 and 32; the highest values of P were observed for strain 35; for Fe, strain 32 excelled. In irrigation, the bacterial consortium 2709 increased Zn, whereas in dryland it was strain 39. Greater mycorrhizal colonization occurred in M and strains 55, 39 and 35. In grain yield, M and strains 39 and 3 were competitive with TF and outperformed the rest of the treatments. Results showed that the expression of the potential of microbial inoculants on nutrition and sorghum yield, varied in function of the strain used.