Preliminary Evaluation of Locations for Conducting Selection for Resistance to Ergot (Claviceps purpurea) in Rye

Abstract

Plant breeders conduct selection for resistance in environments that maximize disease development. We studied
ergot resistance in rye to assess the suitability of locations as selection environment including one very favourable
location for disease development. Sixty-five populations and 245 full-sib families were evaluated in six environments
across three agro-climatically diverse locations (Eckartsweier, Kleinhohenheim, Oberer- indenhof [OLI]) and 3 years.
Significant genotypic and genotype-environment interaction variations were observed for ergot severity. We further
partitioned interaction variation due to linear regression of environments (b, genotypic mean at a test location regressed
onto average over all environments) and remainder, and also computed simple correlation (r) and coefficient of
determination (r2) between these two variables. The b and r2 were used as measures of discrimination ability (DA)
and prediction ability (PA) of test locations; respectively. Differences due to heterogeneity among b’s were significant
in all experiments except one. Ergot severity was distinctly highest at OLI. But OLI had lowest DA and PA whereas
Kleinhohenheim had highest values. Our study showed that OLI having higher ergot development, was not the
best selection environment. More information encompassing a larger number of environments is needed.