Figure 1- Circadian variation in 191 naturally occurring accessions from Sweden
Delayed fluorescence rhythms were characterised by period, phase and RAE and show significant variation (A-C). Colours represent the 10 most extreme accessions for each phenotype which we use as tail groups for further analysis. Some accessions belong to multiple tail groups as is shown in D. This reflects the strong correlation between circadian characteristics (See Supplementary Figure 4). Number of individual wells contributing to the mean of each accession ranged from 4 to 18, with each well representing the mean rhythms of approximately 15 seedlings.
Figure 2- Period phenotypes are linked by both the geography and the genetic relatedness of accessions across Sweden
Figure A shows the location of origin of the 10 accessions with the shortest (red triangles) and longest (blue triangles) periods. The longest periods are found near the city of Malmo where day length and temperature fluctuates less throughout the year than in Ornskoldsvik where periods tend to be shorter (B,C). Day-length and temperature averages were downloaded from timeanddate.com and are based on predictions for 2019 (Thorsen, 1995).
PC analysis revealed a sub-clade within the Southern Swedish accessions; PC.C coloured light blue in plots D-F. This was used to distinguish accessions with significantly longer period phenotype than in the other PC groups; PC.A which represents the remaining southern accessions in yellow and PC.B which represents the northern accessions in red. Map figures were created using the ggmaps package in R using Google maps (accessed 2018) (Kahle & Wickham, 2013).