Mycorrhizal responsiveness of cultivars and wild varieties of switchgrass, Panicum virgatum L.

Abstract

This study focuses on switchgrass, Panicum virgatum L., a North American tallgrass prairie species that has been used in agriculture for only 50 years. We hypothesized that wild variants of this species are more mycorrhizal dependent than the cultivars due to selection against mycorrhizae in agricultural conditions. Mycorrhizae, naturally occurring associations between roots and symbiotic fungi, are known to benefit plants in most environments. These associations have been proposed as a means for crop improvement in agriculture. However, current agricultural practices tend to diminish the potential for crops to benefit from mycorrhizae. Two greenhouse experiments with a factorial design were performed using switchgrass inoculated or not with Glomus intraradices Schenck and Smith. In the first experiment, four wild varieties (PH, ONP, Ojibway and Pterophylla) and six cultivars (Forestburg, Summer, Shelter, Caddo, NU and Trailblazer) were grown for 12 weeks. From those, 3 wild types (PH, ONP and Ojibway) and 3 cultivars (Forestburg, Caddo and NU) were chosen for the second experiment. Switchgrass plants were analyzed for various physiological, root and mineral parameters in order to assess their overall mycorrhizal dependency (MD). (Abstract shortened by UMI.)