ERGOVALINE VARIABILITY IN ACREMONIUM-INFECTED TALL FESCUE DUE TO ENVIRONMENT AND PLANT GENOTYPE

Competitiveness and persistence of tall fescue (Festuca arundinacea Schreb.) is superior when infected with the endophyte, Acremonium coenophialum Morgan-Jones and Gams. Acremonium derived ergopeptine alkaloids impair animal productivity, and if reduced or eliminated would improve animal performance. This study was conducted to determine: (i) environmental influence on ergovaline concentration in A. coenophialum infected tall fescue genotypes, and (ii) the extent that plant genotype influences ergovaline production by the endophyte. A field experiment evaluated five endophyte-infected tall fescue genotypes grown at three locations (environments) during 2 yr. Plant genotypes, harvested every 28 d, differed in ergovaline concentration (P < 0.05) during spring months. Rank correlations of genotypes were high among harvest dates, locations, and years. A greenhouse experiment was used to evaluate ergovaline concentration among progeny from a reciprocal cross between a high- and a low-ergovaline tall fescue genotype. Parents differed in ergovaline concentration by 630 mu g kg(-1) but produced similar F-1 progeny means that were not different from the midparent (415 mu g kg(-1)). Both F, populations had similar ranges for ergovaline (122-938 mu g kg(-1)). Although subject to environmental influence, ergovaline production by tall fescue-Acremonium associations was partially dependent upon plant genotype.