Plant Genome Size Is Associated With Fine‐Scale Spatial Variation in Soil Depth, but Not Climatic Conditions, in the Grass Festuca ovina.

Trinder, Sarah; Hidalgo, Oriane; Fay, Michael F.; Askew, Andrew P.; McAllister, Hugh; Whitlock, Raj

Plant Genome Size Is Associated With Fine‐Scale Spatial Variation in Soil Depth, but Not Climatic Conditions, in the Grass Festuca ovina.

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Ecology_and_Evolution_-_2025_-_Trinder_-_Plant_Genome_Size_Is_Associated_With_Fine_Scale_Spatial_Variation_in_Soil_Depth_.pdf

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637.12 KB

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Journal article

Creator (person)

Trinder, Sarah

Hidalgo, Oriane

Fay, Michael F.

Askew, Andrew P.

McAllister, Hugh

Whitlock, Raj

Date published

November 27, 2025

Abstract

Genome size varies among individuals within plant species and their populations. Interspecific variation in plant genome size isassociated with phenology, climate, and latitude and longitude—suggesting that genome size may be linked with environmentaladaptation—but the evolutionary significance of intraspecific variation in genome size remains unresolved. In particular, littleis known regarding how selection under different climatic and micro-environmental conditions shapes intraspecific variationin genome size. We measured genome size within Festuca ovina populations collected from grassland plots exposed to 16 yearsof experimental drought treatment at the Buxton Climate Change Impacts Laboratory. We assessed whether genome size wasassociated with either drought treatment or fine-scale heterogeneity in soil depth within grassland plots. Genome size varied byup to 1.28-fold among F. ovina individuals, but was not associated with either drought treatment or plant phenotypes (cell size,flowering time, and biomass). Genome size was, however, negatively associated with fine-scale variation in soil depth, implyingthat abiotic and biotic conditions linked with soil depth impose either direct or indirect selection on genome size. We suggest thatthe higher nutrient availability and reduced competition associated with shallow soils enable individuals with larger genomesto persist locally within the grassland.