Abstract Detail

Reproductive Processes

Steinecke, Christina [1], Friedman, Jannice [1].

Selection and genetic constraints on clonal investment in a perennial plant.

Many plant species can reproduce both clonally (for example, via stolons or corms) and sexually via flowers and seed. The question, then, is why some plants invest resources into both, and whether phenotypic and genetic correlations exist when investing in traits associated with one mode or the other. The relative importance of the two modes of reproduction likely vary in different ecological conditions, but to what extent can selection drive different investment strategies? A population’s ability to respond to selection on clonal investment might impact its capacity to respond to environmental change. Furthermore, genetic correlations between traits can either facilitate or constrain evolutionary responses depending on the direction and strength of selection. Here, we investigate the capacity for clonal investment to respond to high or low truncation selection in a perennial population of Mimulus guttatus. The aims of our research are to first quantify the magnitude of phenotypic responses to artificial selection on clonal growth, and then to identify traits that respond in concert due to underlying genetic correlations. To address these aims, we first established an outbred population from field collected seed in a greenhouse, and then imposed four generations of divergent, truncation selection on clonal growth for two replicate high lines, two low lines, and a control line. We used quantitative genetics and pedigree analyses to investigate additive genetic variance, heritability, and the response of clonal growth through time. We then investigated genetic correlations among life history traits measured throughout the life cycle to identify whether genetic constraints might constrain evolutionary trajectories. Our results showed that selection elicited the predicted divergent response in clonal growth; however, low-clonal lines respond more strongly to selection compared to high-clonal lines. Decreased clonal growth was also negatively correlated with a suite of traits including overall size, flower number, and flowering time. These findings suggest unequal additive genetic variance in the low-clonal and high-clonal lines, and indicate that populations have greater capacity to reduce clonality in the face of selection, and that increases in clonal investment might be more difficult. This study tests a classic, yet unresolved, evolutionary question and suggests populations harbour sufficient standing genetic variation to respond rapidly to selection but that the underlying genetic architecture and trait covariation could constrain evolutionary trajectories and adaptive divergence.

1 - Queen's University, Biology Department, 116 Barrie Street, Kingston, ON, K7L 3N6, Canada

life history
quantitative genetics
asexual reproduction

Presentation Type: Oral Paper
Number: RP1002
Abstract ID:797
Candidate for Awards:None

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