DOI: 10.5061/dryad.stqjq2cfb
title: Experimental demonstration of allometric invariance of plant response to density over the course of wheat domestication

description: Crop domestication and breeding have led to phenotypic changes,
 particularly in plant size. Allometric relationships – the link between
 trait and size– have been repeatedly described as invariant across taxa,
 suggesting strong constraints on phenotypic evolution. By analogy,
 artificial selection during domestication and breeding might have been
 strongly constrained by plant allometry, but an experimental test is
 lacking. We used 39 genotypes representative of the four key stages (wild,
 first domesticated, landrace, and elite) of the evolutionary history of
 durum wheat. We grew them in pots as monogenotypic cultures, with
 increasing density from one to ten individuals. We measured biomass
 components and functional traits involved in plant competition to assess
 the response of genotypes to density. In response to density,
 wheat genotypes reduced their tillers number and flowered earlier.
 However, we showed invariant biomass-based responses to density across the
 different stages. Furthermore, allometric relationships between vegetative
 biomass and reproductive biomass did not vary across stages, despite
 phenotypic changes. Our findings contribute to strengthening empirical
 knowledge of the phenotypic changes in the aerial compartment over the
 course of plant domestication. Moreover, they reinforce the interest in
 using the allometric framework to better understand constraints on crop
 phenotype and productivity.
description: # Experimental demonstration of allometric invariance of plant response to
 density over the course of wheat domestication Dataset DOI:
 [10.5061/dryad.stqjq2cfb](10.5061/dryad.stqjq2cfb) ## Description of the
 data and file structure We explore changes in size-density relationships
 and traits that contributed to increased productivity during domestication
 and breeding. We used a collection of 39 genotypes representative of the
 four key stages (wild, first domesticated, landrace and elite) of the
 evolutionary history of durum wheat. We grew them in pots as monogenotypic
 culture, with increasing density from one to ten individuals. We measured
 biomass components and functional traits involved in plant competition
 (height, tillers number, heading date) to assess the response of genotypes
 to density. ### Files and variables #### File:
 density\_database\_wheat.xlsx **Description:**  ##### Variables *
 Genotype_number corresponds to INRAE number genotype. * Compartment
 corresponds to the different compartments in the domestication and
 breeding history of the tetraploid wheat *Triticum turgidum.* There are
 four compartment modalities (Wild = dicoccoides; First domesticated =
 dicoccum; Landraces = durum_landrace*; elite varieties = durum_*elite). *
 The block_number corresponds to the three repetitions of the experiment. *
 Density corresponds to the density of individuals in the pot (From one to
 ten plants in the pot). * Density\_ind_m2 corresponds to the estimated
 density of individuals per m². * Tiller_number_plot_level corresponds to
 the number of the total number of tillers per pot on all the plants in the
 pot. * Tiller_number_individual_level corresponds to the number of the
 number of tillers per individual (Total number of tillers per pot divided
 by the density). * Plant_vegetative_height_cm corresponds to the height
 between the soil and the highest leaf in the pot, without stretching in
 centimeter. * Heading_date_degree_day corresponds to the date at which
 spikes were visible for 50% of the plants in a pot, converted in degree
 day using a 0 °C base temperature. * Vegetative_biomass_plot_level_g
 corresponds to vegetative (leaves and stems) biomass in g at the pot level
 (all the individuals in the pot). * Vegetative_biomass_individual_level_g
 corresponds to vegetative biomass in g measured at pot level divided by
 the density in the pot to obtain individual measurements. *
 Reproductive_biomass_plot_level_g corresponds to reproductive (spikes with
 grains) biomass in g at the pot level (all the individuals in the pot). *
 Reproductive_biomass_individual_level_g corresponds to reproductive
 biomass in g measured at pot level divided by the density in the pot to
 obtain individual measurements. * Total_biomass_plot_level_g corresponds
 to total biomass at the pot level in g which corresponds to the sum of
 vegetative biomass and reproductive biomass at the pot level. *
 Total_biomass_individual_level_g corresponds to total biomass at the
 individual level in g which corresponds to total biomass at the pot level
 divided by the density of individuals in the pot. *
 Ratio_reproductive_biomass_total_biomass corresponds to the reproductive
 effort as the ratio of spike biomass divided by the sum of vegetative
 biomass and spike biomass measured at pot level. * “NA” corresponds to
 missing values in the dataset. ## Code/software All statistical analyses
 were performed with R version 4.4.0 (R Core Team, 2024). We used the
 package ggplot2, cowplot, performance, lme4, lsmeans, emmeans and smatr.