Enhancing native grass productivity by cocultivating with endophyte-laden calli

The influence native endophytes have on grass establishment and productivity was evaluated by cocultivating Bouteloua eriopoda (Torr.) Torr. (black grama) or Sporobolus cryptandrus (Torr.) Gray (sand dropseed) seedlings with endophyte-laden calli from three of four native grass and shrub species: Atriplex canescens (Pursh) Nutt. (fourwing saltbush), S. cryptandrus, Sporobolus airoides (Torr.) Torr. (alkali sacaton), and B. eriopoda in vitro. Following cocultivation, grass seedlings were hardened and transferred to three replicate field plots, each containing 16 grass plants of a single species that had been cocultivated with a single callus species. Plant establishment rates, heights, crown diameters, aboveground biomass, seed yields, and seed quality were compared. In B. eriopoda (black grama), significant increases in plant biomass were not observed. However, early plant heights and crown diameters, establishment rates, and stolon production were higher in some callus treatments. In S. cryptandrus (sand dropseed), all variables were positively influenced by one or more of the endophyte treatments. Biomass increases ranged from 2.5- to threefold over untreated plants, and harvested seed increased 5.9-fold in plants treated with endophytes from A. canescens (fourwing saltbush). Seed quality, determined by purity, germination rates, and tetrazolium assays, did not differ across endophyte treatments for either grass. There is evidence that endophyte transfer is responsible for the altered vigor of treated plants.