2.2 Growth and phenotyping.
We conducted the net house experiments in the Agricultural Research
Organization - Volcani (ARO) Center, Israel following similar sowing and
transplanting as described previously for water limitation experiments
by (Merchuk-Ovnat et al., 2018) . Due to the sensitivity of wild
barley to day-length conditions, we preferred to achieve mild higher
temperature conditions by warming the nethouse rather than late sowing
conducted for example for tomato (Bineau et al., 2021). The
thermal differences between HT and AT is depicted in Figure S1 ,
with a mean increase of 3.9 °C and 2.8 °C during day and night time and
maximum delta of mean 7.5 °C between AT to HT.
We obtained the life history traits phenotype for the ASHER population
lines during winter of 2017-2018 in six replicates per treatment. The
reciprocal hybrids lines population were grown during winter of
2019-2020. We began phenotyping by measuring Tiller height (TH), that is
the length of the longest tiller from ground level to the last fully
expended leaf in th at tiller. Tiller number (TN) is the number of
tillers per plant and it was determined about one month after
transplanting the plants. TH and TN ware measured once (_1) or twice
(_2) with 14 days apart. We calculated TH rate by suspecting TH_2 with
TH_1 and dividing with the number of days between these two
measurements. We determined the number of days to flowering (DTF) based
on the date when the first awns appear in the main tiller. During grain
filling we measured five spikes per plant for spike length (SL) and
later to obtain SLCV. In addition, during grain filling we measured
plant height (PH) from ground to the start of the toolset spike. We then
cached the five and whole spikes of each plant in separate paper and
nylon bags, respectively. Plants were left to dry for several weeks
after irrigation was terminated. We harvested dry plants by cutting at
soil level and placing them in the nylon bags. Weight of the nylon bag
with the plant is the total dry matter (TDM). We collected dispersal
units from bag and weighted them. We calculated average spike dry weight
(ASDW) based on weighing the five spikes that we cached in the paper
bag. We then summed the weight of spikes (dispersal units) in the
plastic and paper bags to obtain spikes dry weight (SpDW). Vegetative
dry weight (VDW) is the reduction of SpDW from TDM.
We measured circadian clock amplitude and period in high-throughput
SensyPAM (SensyTIV, Aviel, Israel) custom-designed to allow Fluorescence
measurements under optimal temperature of 22ºC (OT) or high temperature
of 32ºC (HT) as previously described (Bdolach et al. , 2019).