Extensive variation between chromosomes of North American and European hop.

Abstract

Hop is an essential ingredient in brewing, providing beer with its characteristic bitterness and aroma. Most modern hop cultivars are hybrids between European and North American hop lineages, but how these ancestries contribute to bitter acid content, the most important trait in hop breeding, remains unclear. Here, we report chromosome-scale, haplotype-resolved assemblies of the hybrid hop cultivar Apollo, assign European and North American ancestry across the genome, and identify varying levels of recombination suppression between chromosomes of either origin. Using this reference, we uncover genetic and chemical diversity in core bittering pathways between European and North American hops. We further show additive effects of beneficial European and North American alleles on bitter acid content, providing a foundation for genomics-assisted hop breeding.