Cultivar Variation In Spring Wheat Inoculated with Arbuscular Mycorrhizal Fungi.

In 50-130 years, mineable phosphorus resources across the earth are predicted to run out. Arbuscular mycorrhizal fungi (AMF) are well established to assist in phosphorus and water uptake, as well provide protection from pathogens, to improve plant performance. Field trials have been conducted in five locations across Washington State over two years to test the responsiveness of five spring wheat (Triticum aestivum L.) cultivars to a commercial inoculum consisting of four arbuscular mycorrhizal species. These sites, representing conventional, organic and no-till management, are found in the extreme dryland production regions and high rainfall zones of eastern Washington. Each site consisted of two inoculation treatments, two fertilizer treatments, and five cultivars arranged in split-split plot design with four replicates. Data on multiple agronomic traits were gathered over each field season during tillering, heading, grain fill and senescence. These traits include phosphorus leaf and seed content, plant height, SPAD chlorphyll readings and yield, among others. Mycorrhizal colonization of plant roots during 2009 was highest in the no-till site. Mycorrhizal colonization resulted in increased phosphorus uptake during early and mid-season growth, increased yield, reduced severity of stripe rust (Puccinia striiformis f. sp. tritici) infection in susceptible cultivars and increased chlorophyll content for specific cultivar by environment combinations. These results indicate that this AMF inoculum can exert cultivar-dependent effects, both positive and parasitic, on spring wheat grown in Washington.