Genetic determinants of heat tolerance and growth in the sugar kelp Saccharina latissima

Summary

The sugar kelp Saccharina latissima plays a vital role in coastal ecosystems of Europe and North America. Rising sea temperatures cause severe heat stress, threatening kelp populations. Developing methods to enhance heat tolerance and growth of sugar kelp is crucial for restoration efforts. This study explores the relationship between genetic and phenotypic variation in heat tolerance and growth. It assesses the impact of inbreeding vs. outbreeding on both traits, their heritability between life stages, and identifies genetic markers linked to enhanced trait values. Fourteen sporophyte families were created by crossing gametophyte cultures from Svalbard. Their growth at 10°C was measured for two months. Sporophytes and their gametophyte parents were then exposed to a 23°C heatwave to assess survival. Whole-genome sequencing was used to identify genetic markers linked to superior performance. Our findings support breeding efforts to develop more heat tolerant S. latissima cultivars.