Detection of Somaclonal Variation in Tissue Culture Regenerants of Tall Fescue

Abstract

Clones of tall fescue (Festuca arundinacea Schreb.) regenerated from tissue culture are required for examining interactions between the endophyte, Acremonium coenophialum Morgan‐Jones and Gams, and its host. Somaclonal variation is common among regenerated plants, and could limit the utility of this technology to study the interactions of tall rescue and its endophyte. Various methods are used to detect somaclonal variation, but there is little agreement as to the relative advantages of each. Therefore, the objectives of this study were to determine (i) whether somaclonal variation exists among tall fescue plants regenerated from somatic embryos, and (ii) whether pollen viability, yield, morphological traits, or phenological development give consistent estimates of somaclonal variation. Seven regenerants from non‐infected tall fescue genotype PDN2 and a non‐regenerated PDN2 control were planted in the field in five replications. Plants were screened for somaclonal variation by phenological development, vegetative and flag leaf width/length ratios, total biomass, seed yield, and pollen viability over 2 yr. Although regeneration protocols were designed to minimize somaclonal variation, somaclonal variation of quantitative traits was observed. Total biomass and seed yield of regenerants, used together, were most consistent in detecting somaclonal variation. When using tissue culture to insert endophytes into tall rescue, we found multiple regenerants need to be infected with each isolate of endophyte to ascertain whether differences among response variables are due to endophyte or somaclonal variation.