Interacting effects of genetic variation for seed dormancy and flowering time on phenology, life history, and fitness of experimental Arabidopsis thaliana populations over multiple generations in the field

Abstract

Major alleles for seed dormancy and flowering time are well studied, and can interact to influence seasonal timing and fitness within generations. However, little is known about how this interaction controls phenology, life history, and population fitness across multiple generations in natural seasonal environments. To examine how seed dormancy and flowering time shape annual plant life cycles over multiple generations, we established naturally dispersing populations of recombinant inbred lines of Arabidopsis thaliana segregating early and late alleles for seed dormancy and flowering time in a field experiment. We recorded seasonal phenology and fitness of each genotype over 2 yr and several generations. Strong seed dormancy suppressed mid-summer germination in both early- and late-flowering genetic backgrounds. Strong dormancy and late-flowering genotypes were both necessary to confer a winter annual life history; other genotypes were rapid-cycling. Strong dormancy increased within-season fecundity in an early-flowering background, but decreased it in a late-flowering background. However, there were no detectable differences among genotypes in population growth rates. Seasonal phenology, life history, and cohort fitness over multiple generations depend strongly upon interacting genetic variation for dormancy and flowering. However, similar population growth rates across generations suggest that different life cycle genotypes can coexist in natural populations.

Spatio-temporal variation in fitness responses to contrasting environments inArabidopsis thaliana

“…Although it is not a straightforward task, future research should also focus on field experiments evaluating the extent of varying selection on both key A. thaliana ’s life‐history traits simultaneously (see Taylor et al. ) under contrasting environmental scenarios.…”

“…Here, we hypothesize that north-western early-flowering accessions will generally outperform late-flowering ones in southern environments. The rationale behind this expectation is based on previous studies of phenotypic selection in A. thaliana indicating a general trend for higher fitness for early-flowering accessions, in spite of the geographic and environmental variation accounting for changes in the intensity and direction of selection on lifehistory traits detected in these studies (Fournier-Level et al 2013;Agren et al 2017;Taylor et al 2017). Specifically, we address the following questions to better understand the evolutionary and plastic response of A. thaliana to novel environments.…”

“…; Taylor et al. ). Specifically, we address the following questions to better understand the evolutionary and plastic response of A. thaliana to novel environments.…”

Phenological and fitness responses to climate warming depend upon genotype and competitive neighbourhood in Arabidopsis thaliana

“…When the focal plant had fully senesced, it was harvested at the base, oven‐dried and weighed. This reproductive biomass was taken as a proxy measurement of fitness, as previous data indicated that dry biomass correlates strongly to silique number ( R 2 > 0.83), a direct fitness metric, across a variety of seasonal and competitive conditions (Taylor et al, ). We then calculated relative interaction intensity (RII) of fitness ( w ) for each focal plant with neighbours ( +N ) relative to focal plants without neighbours (− N ) as…”

Diverse paths to hybrid incompatibility in Arabidopsis

“…In recent years, in addition to studying Arabidopsis in controlled growth conditions, an increasing number of field studies have been performed and local collections of Arabidopsis have been established to enhance our understanding of plant adaptation in nature (e.g. Leinonen et al ., ; Ågren and Schemske, ; Savolainen et al ., ; Rellstab et al ., ; Taylor et al ., ; Frachon et al ., ). In the past decade, in addition to molecular and genetic mechanisms of plant adaptation, both inter‐ and intraspecific crosses in the Arabidopsis genus have been investigated to understand the mechanisms underlying hybrid incompatibilities.…”