Viability of Acremonium coenophialum in tall fescue seed after ionizing radiation treatments.

Planting tall fescue (Festuca arundinacea Schreb.) seed free of the endophyte Acremonium coenophialum Morgan-Jones & Gams allows establishment of swards free of the fungus. Eradication of the fungal endophyte from infected tall fescue seeds containing 130 g kg −1 moisture using ionizing radiation was investigated. Three sources of radiation were used: gamma rays ( 60 Co source), neutron particles ( 252 Cf source), and a thermal neutron beam. The percent germination of tall fescue seeds among gamma doses did not differ significantly (P 90%. percent seed germination of tall fescue and high levels of radiation were negatively correlated for both sources of neutrons. Gamma radiation was shown to reduce (P<0.01) the percent of the viable endophyte to ≃10% of control. The 252 Cf and thermal neutrons reduced the percent of tall fescue infected by the endophyte to ≃30% without deleterious effects on seed germination