Garden, greenhouse or climate chamber? Experimental conditions influence whether genetic differences are phenotypically expressed

Abstract

Common-environment experiments are important to study genetically-based phenotypic variation within and among plant populations. Such experiments can be performed in an experimental garden, greenhouse or climate chamber. However, phenotypic expression may be strongly affected by the environmental conditions and influenced by parental and storage effects. Hence, it is unclear if results from common-environment experiments are reproducible across multiple experimental setups.In this study, we assessed the effects of three different growth facilities – outdoor garden, greenhouse, and climate chamber –, on phenotypic expression. We compared ancestral and descendant genotypes of the same population ofLeontodon hispidus. We also evaluated differences in phenotypic expression between plants grown after one (F1) vs. two (F2) intermediate generations.We observed strong differences among plants growing in different growth facilities. Furthermore, we found that descendants had larger rosettes than ancestors only in the greenhouse and they flowered later than ancestors exclusively in the climate chamber. We did not find significant differences between intermediate generations within the growth facilities.Overall, our study demonstrates that environmental variation among growth facilities can dictate the presence and magnitude of phenotypic differences. This implies that absence of evidence for phenotypic differences is not evidence of absence. Experimental systems should be carefully designed to provide meaningful conditions related to the research question. Finally, growing a second intermediate generation did not impact the genetic differences of ancestors and descendants within the facilities, supporting that only one intermediate generation may be sufficient to reduce detectable parental and storage effects.