Rhizome and Herbage Production of Endophyte‐Removed Tall Fescue Clones and Populations

Abstract Grass endophytes alter the morphology and growth of their hosts. The endophyte ( Acremonium coenophialum Morgan‐Jones and Gams) benefits the tall fescue ( Festuca arundinacea Schreb.) plant by increasing dry matter production and drought tolerance. Rhizomatous tall fescue was also found to be more persistent and competitive in mixed swards, but the effect of endophyte infection on rhizome expression is unknown. This study was conducted to determine the effect of endophyte removal on rhizome and herbage production of clones and populations of tall fescue. Six clones and four populations (‘Kentucky 31,’ Georgia‐5, Georgia‐Jesup, and Georgia‐Jesup Improved), infected with A. coenophialum and the same clones and populations with the endophyte removed were evaluated for rhizome production, tillering, and herbage and root yield after 12 wk of growth in the greenhouse. No differences in rhizome production were detected between either infected and noninfected clones or populations. However, endophyte infection increased tillering, herbage growth and root growth by 12, 18, and 25%, respectively. A significant (P < 0.01) interaction was detected between endophyte infection and populations for herbage growth with infection increasing herbage growth in Kentucky 31 but decreasing growth in Georgia‐Jesup. Interaction between populations and endophyte infection suggest that the data obtained should not be extrapolated to other germplasm or environmental conditions.