Kelp breeding in China: Challenges and opportunities for solutions

Breeding has played an important role in the mariculture and industrialization of kelp in China. However, the current kelp breeding systems in China have encountered some problems relating to germplasm diversity, management, technological innovations, and regional co-operation. This review summarizes the main challenges, such as top-down and fragmented management of germplasm libraries, as well as private industry breeding without government regulations, inter-cultivar accidental admixing and genetic erosion, loss of heterozygosity due to repeated selection and self-crossing. We outline multiple potential approaches to breed cultivars with improved qualitative/quantitative traits which can be subjected to changing environments, for example: (i) establishing a national germplasm repository to enhance integrative collection and preservation of kelp resources; (ii) planning and implementing kelp breeding programmes according to strategic priorities and goal-orientations; (iii) optimizing a hybridization-based breeding pipeline to produce robust cultivars through the introgression of novel alleles and thus the expression of hybrid vigour; (iv) enriching the high-quality annotated reference genomes and functional analysis of trait-associated markers/loci to develop DNA-based breeding technologies; (v) developing new priming-based (e.g., thermal and disease resistance) bio-engineering breeding strategies to meet future unpredictable climate change; and (vi) breeding towards an ecological kelp-microbiome interaction-based technique to produce cultivars with enhanced performance and adaptability to environmental scenarios. Collectively, the lessons learned from kelp breeding in China and the solutions proposed here may not only potentially improve or re-invigorate the Chinese kelp industry, but will also assist other developing countries in taking corrective actions to develop a sustainable future kelp farming industry.