POPULATION CONNECTIVITY OF SUGAR KELP Saccharina spp. IN THE NORTHWEST ATLANTIC FOR CULTIVATION AND BREEDING

An understanding of g enetic diversity of natural  kelp  populations is  critical for making  recommendations  for  breeding and cultivation efforts of the growing seaweed aquaculture  sector in the US . A n important component of the ARPA-E's MARINER project is selectively breeding Saccharina  spp.  in  the Northwest Atlantic in order  to improve  overall productivity for biofuels, feeds and food. Historical  records indicate the presence of  regional kelp ecotypes based on physiological tolerance, specifically temperature . We made collections of 13 wild Saccharina spp. populations  via SCUBA along the New England coast.  These parental populations were also used to make over 300 hybrid crosses that were planted at several farm locations .  We  then  used genome-wide single nucleotide polymorphism data to identify the finer population structure of the kelp in the Gulf of Maine and Long Island Sound.

An assessment of the sequence diversity revealed d istinct genetic variation between the Gulf of Maine and Southern New England, confirming that Cape Cod acts as a barrier to  kelp gene flow. Furthermore, based on the analysis of molecular variance (AMOVA), we fou nd the largest variance (58%)  within  sites. We also observed  admixture  among  five sub-populations (Figure 1) and isolation by distance in the Gulf of Maine .

Future steps for this project include skim sequencing the haploid phase of the kelp life cycle to identify trait heritability and phenotypic diversity observed for both morphological traits and tissue composition. Furthermore, we plan to place our  sequence  data into a larger context to include samples from sites in Europe and Asia.