2021 journal article
Genetic variation and inheritance of susceptibility to Neonectria neomacrospora and Christmas tree traits in a progeny test of Nordmann fir
Annals of Forest Science, 78(1).
Pronounced additive genetic variation and high narrow-sense heritability for lesion length caused by Neonectria neomacrospora were found in a Nordmann fir progeny test. Significant inbreeding depression was detected in traits important for Christmas tree production. Recurrent selection for multiple traits would be successful for Christmas tree quality traits. The fungal pathogen N. neomacrospora causes severe damage in Nordmann fir Christmas trees in Denmark. Family variation in disease susceptibility in the species has not been investigated before. This is the first combined genetic analysis of susceptibility to N. neomacrospora and Christmas tree traits in Nordmann fir. Evaluate the genetic variation of susceptibility to N. neomacrospora and five Christmas tree traits in Nordmann fir. Five Christmas tree traits were measured on 2413 trees in a progeny test. Artificial inoculation was conducted on detached twigs of full-sib progenies with a N. neomacrospora isolate to assess the resistance/susceptibility. Observed variation was partitioned into genetic and environmental causes to understand the heritable control of the traits. Pronounced additive genetic variation was observed in susceptibility to N. neomacrospora and Christmas tree traits. Narrow-sense heritability for susceptibility to N. neomacrospora was 0.63. Significant differences between selfings and outcrossed trees were detected for all traits. Significant improvement for Christmas tree quality could be observed in the breeding process. Resistance to N. neomacrospora disease and other Christmas tree characteristics can be improved through recurrent selection.