TALL FESCUE DEVELOPMENT IN RESPONSE TO ACREMONIUM-COENOPHIALUM AND SOIL ACIDITY

The fungal endophyte Acremonium coenophialum Morgan-Jones and W. Gams can modify productivity and stress tolerance of tall fescue (Festuca arundinacea Schreber). Clonal populations of five tall fescue genotypes were used in a glasshouse experiment to assess the effect of endophyte infection and soil pH on plant yield, demography, and development. Genotypes differed for most measured parameters, and a general lack of interactions among endophyte infection, genotype, and lime allowed use of treatment means to identify trends that may be reflected in larger populations. Infected plants had 13% greater shoot mass and 11% greater root mass than uninfected plants due primarily to increased tiller size. Larger size may increase tiller longevity and competitive ability. Endophyte did not affect relative tiller appearance rate as reduced relative leaf appearance rates were compensated by increased site usage. Liming of an acid soil (pH 4.3 for unamended soil) resulted in a 32% increase in dry matter production and increased root to shoot ratios of high-yielding genotypes. Root to shoot ratio was affected by the interaction of lime and genotype; high-yielding genotypes had greater root to shoot ratios when limed compared with nonlimed genotypes, while low-yielding genotypes were not affected by liming. This increase was associated with greater site usage and tiller production; relative leaf appearance rate and tiller mass were unaffected. Endophyte modified the resource allocation patterns with resultant increase in phenotypic plasticity and potential competitive ability.