Genetic diversity and domestication of hazelnut (Corylus avellana) in Turkey

Abstract

O_LIAssessing and describing genetic diversity in crop plants is a crucial first step towards their improvement. The European hazelnut, Corylus avellana, is one of the most economically important tree nut crops worldwide. It is primarily produced in Turkey where rural communities depend on it for their livelihoods. Despite this we know little about hazelnuts domestication history and the genetic diversity it holds.\nC_LIO_LIWe use double digest Restriction-site Associated DNA (ddRAD) sequencing to produce genome-wide dataset containing wild and domesticated hazelnut. We uncover patterns of population structure and diversity, determine levels of crop-wild gene flow and estimate the timing of key divergence events.\nC_LIO_LIWe find that genetic clusters of cultivars do not reflect their given names and that there is limited evidence for a reduction in genetic diversity in domesticated individuals. Admixture has likely occurred multiple times between wild and domesticated hazelnut. Domesticates appear to have first diverged from their wild relatives during the Mesolithic.\nC_LIO_LIWe provide the first genomic assessment of Turkish hazelnut diversity and suggest that it is currently in a partial stage of domestication. Our study provides a platform for further research that will protect this crop from the threats of climate change and an emerging fungal disease.\nC_LI