Fungal spore diversity of arbuscular mycorrhizal fungi associated with spring wheat: effects of tillage.

We investigated the influence of tilling, N fertilization and crop stage on arbuscular mycorrhizae (AM) fungal species diversity in a wheat monoculture in the Pampa region of Argentina. Glomalean spores were isolated by wet sieving and decanting from conventionally tilled and nontilled soils cropped with wheat with or without N fertilization, at three phenological stages of the crop (tilling, flowering and grain filling) and fallow. Morphological characterization yielded at least 24 AM fungi taxa in the field samples, belonging to six genera of AMF: Acaulospora Archaeospora, Entrophospora, Gigaspora, Glomus and Scutellospora. Tilling and fertilization treatments did not result in decreased spore biodiversity. Wheat phenology influenced AM communities, with highest spore biodiversity during grain filling.