DOI: 10.5061/dryad.w3r2280wr
title: Weak local adaptation to drought in seedlings of a widespread conifer

description: Tree seedlings from populations native to drier regions are often assumed
 to be more drought tolerant than those from wetter provenances. However,
 intraspecific variation in drought tolerance has not been well
 characterized despite being critical for developing climate change
 mitigation and adaptation strategies, and for predicting the effects of
 drought on forests. We used a large-scale common-garden drought-to-death
 experiment to assess range-wide variation in drought tolerance measured by
 decline of photosynthetic efficiency, growth, and plastic responses to
 extreme summer drought in seedlings of 73 natural populations of the two
 main varieties of Douglas-fir (Pseudotsuga menziesii var. menziesii and
 var. glauca). Local adaptation to drought was weak in var. glauca
 and nearly absent in menziesii. Var. glauca showed higher tolerance to
 drought but slower growth than var. menziesii. Clinal variation in drought
 tolerance and growth species-wide was mainly associated with temperature
 rather than precipitation. A higher degree of plasticity for growth was
 observed in var. menziesii in response to extreme drought. Genetic
 variation for drought tolerance in seedlings within varieties is
 maintained primarily within populations. Selective breeding within
 populations may facilitate adaptation to drought more than assisted gene
 flow.
description: # Weak local adaptation to drought in seedlings of a widespread conifer
 This dataset contains the
 raw phenotypic data of individual plants from the drought experiment
 conducted for the study. The data includes height growth, visual damage,
 and Fv/Fm measurements collected at five different time points. For the
 manuscript by Candido-Ribeiro and Aitken (2024), only the 73 provenances
 from "natural" origin and varieties *glauca* and *menziesii*
 were used. Provenances from "orchard" origin and the species
 *Pseudotsuga* *macrocarpa* (in the variety column as
 "*macrocarpa*") were excluded from the analysis. **Description
 of the dataset (columns):** * box = the boxes used in the experiment with
 90 active plants ("subplot" column). In total, there were 16
 boxes (8 for "Dry" treatment and the other 8 for "Wet
 treatment"). * block = Each block contains 2 boxes (1 for
 "Dry" treatment and 1 for "Wet" treatment). There were
 8 blocks in total. * provenance = provenance (population) number. the
 provenance number matches the number in Table S1 and Fig. 1 of the
 manuscript. * treatment = two treatments used in the experiment (details
 of the experiment can be found in the manuscript). * wide-plot = the two
 boxes within a block. * subplot = sequential position of each plant within
 a box (from 1 to 90). * seed_id = unique identification of each plant in
 the experiment. Each seed_id consists of the provenance number and a
 unique number within that provenance separated by "_". *
 y_treatment = y position of the plant in a tratment. * x_treatment = x
 position of the plant in a tratment. * y_experiment = y position of the
 plant in the whole experiment. * x_experiment = x position of the plant in
 the whole experiment. * variety = two *Pseudotsuga menziesii* varieties
 ("*glauca"* and "*menziesii"*) plus one provenance
 (99) of *Pseudotsuga macrocarpa* ("*macrocarpa*") (excluded from
 the analysis). * origin = either "natural" when seeds were
 collected from natural stands or "orchard" when seeds were
 generated and collected from breeding programs (with cycles of selection).
 "Orchard" seedlots were excluded from the analysis. * group =
 general region where seedlots came from. For more details, see Table S1. *
 date = date when phenotypes were measured. * measurement = 1-5 measurement
 time points. * exp_day = day of experiment since establishment. * VWC =
 volumetric water content (%) in each box. * h = height (cm). * h_max =
 maximum height reached at the time (regardless of survival state). *
 cumul_grow = cumulative height increment * h_increment = height at
 measurement t minus height at measurement t-1. * visual damage = 0 (0%); 1
 (1% to 25%); 2 (26% to 50%); 3 (51% to 75%); and 4 (76% to 100% canopy
 damage). * fv_fm = Fv/Fm (dark adapted chlorophyll fluorescence).