The haplo-diplont life cycles of brown and red seaweeds allow sexual and asexual propagation of the organisms. In our study models, Gracilaria chilensis, asexual reproduction has dominated its production. To determine the genetic consequences that different crossbreeding strategies will have on the efficiency of selection of this seaweed, we will combine experiments of manipulation of progenitors and their clonality rate, with genomic approaches and inference methods based on coalescence theory.

Most kelp breeding strategies target hybrid vigor, but often from a limited number of parental sporophytes, allowing yield increases and phenotypic homogeneity of the production but reducing genetic variation and selection efficiency in further attempts to modify traits, an evolutionary dead end for domestication. MASH will explore alternative breeding strategies prioritizing the obtention of landraces, by introgressing high value hybrids with local genotypes and selecting target traits. We expect such landraces to be hybrid only at the genomic regions underlying specific traits of interest, while retaining substantial diversity at the genome scale including alleles involved in local adaptations to environmental conditions.

In parallel, we will explore the possibility that selection operates at the scale of the seaweed holobiont, using experimental approaches for the manipulation of microorganisms and different phases of the life cycle of model organisms.