Species composition of native arbuscular mycorrhizal fungal consortia influences growth and nutrition of poblano pepper plants (Capsicum annuum L.)

The influence of agronomic management of poblano pepper crops on the composition and effectiveness of arbuscular mycorrhizal fungi (AMF) was determined based on growth promotion and nutrition of Capsicum annuum plants. Mycorrhizal colonization, spore number, and AMF-species composition in the rhizosphere soil of C. annuum were determined from six agroecosystems with different agronomic management: a) San Martinito (SM) with little management, b) Santa María Zacatepec (SMZ), Juárez Coronaco I and II (JCI and JCII) with moderate management, and c) San Mateo Capultitlan I and II (SMCI and SMCII) with intense management. From each agroecosystem an AMF consortium was obtained for evaluating its effectiveness on plant growth. A completely randomized design with seven treatments and 10 replicates was set. Plant growth parameters and leaf content (N, P, and K) were determined after 90 days of AMF-inoculation; in addition, AMF colonization, spore number, and mycorrhizal dependence were determined. The AMF-species composition in consortia from agroecosystems with low and moderate management was different from that obtained from agroecosystems with intensive management. The SMZ consortium, isolated from the agroecosystem with moderate management, significantly increased the stem diameter, plant height, and leaf area; in contrast, the SMCI consortium, isolated from the agroecosystem with intense management, showed the lowest values in all growth parameters. All AMF-consortia increased the leaf content of N and K; however, only the SMZ consortium had significant effects on P content. Plants inoculated with the SMCII and SMZ consortia showed highest mycorrhizal dependence for shoot biomass and nutrient content, respectively. The isolation and utilization of native AMF consortia may promote the growth and nutrition of poblano pepper plants, and be an important biological component for sustainable pepper cropping.