Recently, the seaweed culture collection team led by Prof. PANG Shaojun from the Institute of Oceanology of the Chinese Academy of Sciences (IOCAS), along with collaborators, reported challenges of genetic homogeneity in aquaculture of the kelp Saccharina japonica.
The study was published in Aquaculture Reports on May 27.
The study highlights a prevalent issue of genetic homogeneity in farmed kelp (Saccharina japonica) cultivars across China. Initially identified in Rongcheng, Shandong Province—a major kelp cultivation region—the researchers conducted a decade-long follow-up investigation. They discovered that among the six main kelp cultivars analyzed, five maintained persistent genetic uniformity, with only one hybrid cultivar exhibiting significant genetic diversity.
Employing molecular marker technologies and open-sea cultivation trials, the team pinpointed standardized parental selection and uniform seedling production processes as primary factors contributing to genetic uniformity. However, introducing genetically distinct external germplasm through targeted hybridization breeding significantly enhanced genetic diversity and productivity. Notably, a newly developed cultivar, "205–24," showed improved resistance to early sporulation, reducing sori formation rates from 70% to 28% at harvest, thus substantially enhancing its economic value.
The researchers emphasized that genetic uniformity increases susceptibility to diseases and environmental stress, exemplified by a severe kelp mortality event in Rongcheng during 2021–2022, where only a few hybrid cultivars survived. This underscores the critical need for maintaining genetic diversity in kelp aquaculture.
"We suggest that kelp farming enterprises establish independent, sustainable breeding systems and parental management processes, enhance genetic monitoring, and strategically introduce diverse external germplasm," said Prof. PANG. Such measures can help mitigate genetic drift and inbreeding risks, ensuring the long-term sustainable development of China's kelp industry.
Full stage-covered Saccharina seedlings and cultivation production cycle in China. (Image by IOCAS)
Li, Xiaodong, Chang, L., Han, F., Li, Xia, Xiao, L., Huang, E., Yang, Y., Su, L., Pang, S. (2025). Challenges of genetic homogeneity in aquaculture of the kelp Saccharina japonica: Insights from China in ten year's retrospect. Aquaculture Reports, 43, 102904.
(Text by LI Xiaodong)
Media Contact:
ZHANG Yiyi
Institute of Oceanology
E-mail: zhangyiyi@qdio.ac.cn
(Editor: ZHANG Yiyi)