Data from: Nonlinear phenotypic variation uncovers the emergence of heterosis in Arabidopsis thaliana

Heterosis describes the phenotypic superiority of hybrids over their parents in traits related to agronomic performance and fitness. Understanding and predicting nonadditive inheritance such as heterosis is crucial for evolutionary biology as well as for plant and animal breeding. However, the physiological bases of heterosis remain debated. Moreover, empirical data in various species have shown that diverse genetic and molecular mechanisms are likely to explain heterosis, making it difficult to predict its emergence and amplitude from parental genotypes alone. In this study, we examined a model of physiological dominance initially proposed by Sewall Wright to explain the nonadditive inheritance of traits like metabolic fluxes at the cellular level. We evaluated Wright's model for two fitness-related traits at the whole-plant level, growth rate and fruit number, using 450 hybrids derived from crosses among natural accessions of A. thaliana. We found that allometric relationships between traits constrain phenotypic variation in a nonlinear and similar manner in hybrids and accessions. These allometric relationships behave predictably, explaining up to 75% of heterosis amplitude, while genetic distance among parents at best explains 7%. Thus, our findings are consistent with Wright's model of physiological dominance and suggest that the emergence of heterosis on plant performance is an intrinsic property of nonlinear relationships between traits. Furthermore, our study highlights the potential of a geometric approach of phenotypic relationships for predicting heterosis of major components of crop productivity and yield.S1_DataThis file contains trait values measured (1) on accessions and hybrid individuals of Arabidopsis thaliana, as well as (2) on a set of 334 plant species obtained from the study of Niklas and Enquist (PNAS 2001; 98: 2922-2927). These data are used in the article entitled Non-linear phenotypic variation uncovers the emergence of heterosis in Arabidopsis thaliana, published in 2019 by Vasseur and colleagues in PLOS Biology. For A. thaliana data, traits were measured with the same protocol in two experiments that took place at the Max Planck Institute for Development Biology (Tübingen, Germany) between 2013 and 2015. idExp represents experiment identifier: GT01, which is the first experiment and which contains 451 accessions (n=2), and GT05, the second experiment which contains 450 hybrids (n=4) and 16 accessions (n=4). The GT01 experiment has also been described and analyzed by Vasseur and colleagues. (PNAS 2018; 115: 3416-3421). Identifier numbers are 1001 Genomes identifiers (http://1001genomes.org/). Detailed protocol for trait measurement can be found in Image-based methods for phenotyping growth dynamics and fitness in Arabidopsis thaliana (Vasseur et al., Plant Methods 2018; 14: 63; https://doi.org/10.1101/208512). Units of traits measured: Age at reproduction: duration in days between the emergence of the first two leaves and the end of reproduction, when fruits are drying. FruitNumber: total number of fruits (siliques) per individual, measured at the end of reproduction. GrowthRate: Average growth rate (mg d-1), measured as the ratio of final rosette dry mass over age at reproduction. VegetativeDryMass: rosette dry mass (mg) measured at the growth inflection point (when growth rate is maximum), which was estimated by fitting a sigmoid growth curve on plant dry mass over time