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Efficiency of breeding strategy where grandparents — but not parents — contribute equally to the breeding population

Efficacité de la stratégie de sélection où les grands-parents — mais pas les parents — contribuent également à l’amélioration de la population

Abstract

  • • The objective was to optimise the strategy for maintaining the genetic balance in long-term breeding where the grandparents contribute equally to the breeding population, but the parents do not.

  • • The annual genetic progress under a budget constraint was compared for a number of scenarios. The factors considered were: genetic parameters, recruitment population size, mating number per grandparent, cost of plants and parents, selection age and time components. Phenotypic selection forward was assumed. Using more parents than grandparents affects the testing population only, thus, gene diversity loss and breeding population size remain constant.

  • • Using larger number of parents than grandparents was a superior strategy at all scenarios tested. The strategy with 6 parents per grandparent and 1% of the tested plants selected on their phenotype at age 15 for further mating is recommendable. The strategy to choose 6 parents per grandparent was robust over a heritability range 0.05 to 0.2. At a higher heritability, the optimum number of parents per grandparent was 2 to 4.

  • • Using larger number of parents than grandparents has the potential to improve annual genetic gain in the magnitude of 50% compared to the strategies currently used for Scots pine in Sweden.

Résumé

  • • L’objectif était d’optimiser la stratégie pour le maintien de l’équilibre génétique dans une sélection à long terme où les grands-parents, mais pas les parents, contribuent également à l’amélioration de la population.

  • • Le progrès génétique annuel sous une contrainte budgétaire a été comparé pour un certain nombre de scénarios. Les facteurs considérés sont les suivants : les paramètres génétiques, la taille de la population de recrutement, le nombre de croisements par grand-parent, le coût des plants et des parents, l’âge de sélection et les composantes temporelles. La sélection phénotypique précoce a été prise en charge. Utiliser plus de parents que de grands-parents a seulement un effet sur la population d’essai, donc, la perte de la diversité génétique et la taille de la population améliorée restent constantes.

  • • L’utilisation d’un plus grand nombre de parents que de grands-parents est une stratégie supérieure pour tous les scénarios testés. La stratégie avec 6 parents par grands-parents et par 1 % des plants testés sur leur phénotype à l’âge de 15 ans par croisement supplémentaire est recommandable. La stratégie du choix de 6 parents par grand-parent a été robuste sur une échelle d’héritabilité de 0,05 à 0,2. Lors d’une héritabilité plus élevée, le nombre optimal de parents par grand-parent était de 2 à 4.

  • • L’utilisation d’un plus grand nombre de parents que de grands-parents a le potentiel d’améliorer le gain génétique annuel de l’ordre de 50 % par rapport aux stratégies utilisées actuellement pour le pin sylvestre en Suède.

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Correspondence to Darius Danusevičius.

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Danusevičius, D., Lindgren, D. Efficiency of breeding strategy where grandparents — but not parents — contribute equally to the breeding population. Ann. For. Sci. 67, 404 (2010). https://doi.org/10.1051/forest/2009124

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Keywords

  • balanced selection
  • long-term breeding
  • gene diversity
  • optimising
  • Pinus sylvestris

Mots-clés

  • sélection équilibrée
  • sélection à long terme
  • diversité génétique
  • optimisation
  • Pinus sylvestris