<i>ELF3</i> controls trait heterogeneity by tuning the rate of maturation in Arabidopsis and barley

Abstract Trait heterogeneity in a population increases the likelihood that some individuals will survive an unpredictable environmental stress. Individual plants mature at different rates due to genetics, environmental factors, and random chance. All of this contributes to trait heterogeneity. EARLY FLOWERING3 ( ELF3 ), a core circadian clock component, determines developmental timing, and here we tested the hypothesis that it would shape trait heterogeneity. We developed a model predicting that faster-growing populations exhibit greater heterogeneity during development but reduced heterogeneity at maturity, while slower-growing populations show the opposite pattern. Experiments in Arabidopsis elf3 and barley Hvelf3 mutants supported this prediction. In Arabidopsis, ELF3 controlled hypocotyl elongation variability via maturation rate rather than direct regulation. Bolting time heterogeneity also decreased in faster-growing plants. In barley, Hvelf3 altered growth heterogeneity, but this was initially masked by germination timing differences. Finally, smaller barley plants were found to be more resilient to osmotic stress, suggesting that ELF3 -driven trait heterogeneity may contribute to bet hedging. These findings highlight how modifying developmental rates influences population-level trait distributions and stress resilience.