The role of relatedness within a neighborhood in plant-to-plant interaction: effect on height growth and rust damage inPopulus nigra

Abstract

Selfish individuals might prevail in the wild, but they often cause waste of nutritional resources and decrease the population yield in breeding schemes. Re-orienting past evolution towards less competitive paths (e.g., group selection) can limit negative interactions between elite material and leads to a more efficient transformation of resources into economically interesting traits. In particular, there are reasons to believe that, in the presence of kin, individuals either will cooperate (kin selection) or over-compete (niche partitioning). In either case, local relatedness might reveal interaction that can enhance the predictive abilities of genomic models when accounted for. However, recurrent family selection during domestication can have blurred the effect of relatedness on neighbors' phenotypes. To overcome this difficulty, we analyzed data from the French breeding program of Populus nigra L., where 1,452 genotypes were replicated six to eight times, each time encountering a different neighborhood. We assessed local relatedness and investigated genomic estimated breeding values on tree height and rust vulnerability with a single-step GBLUP incorporating local relatedness as a covariate. We found that, when surrounded by related individuals, rust damage is significantly more important, whereas no interaction was visible on tree height.