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Development of a new cultivar with high yield and high-temperature tolerance by crossbreeding of Undaria pinnatifida (Laminariales, Phaeophyta)
- Niwa, Kyosuke, Kobiyama, Atsushi
- Aquaculture 2019 v.506 pp. 30-34
- Undaria pinnatifida, climate change, crossing, cultivars, farms, females, gametophytes, males, new variety, seawater, sporophytes, stress tolerance, temperature, zoospores, Sea of Japan
- Recent production of the marine crop Undaria pinnatifida has become unstable due to rising temperatures caused by global climate change. The cultivar HGU-1 was bred in a previous study to achieve early cultivation. A new cultivar, NW-1, was bred for improved yield and stress tolerance. This was achieved by crossbreeding using male and female gametophytes, each isolated from a single zoospore. To evaluate whether the cultivar NW-1 is superior to the previous cultivar HGU-1, we compared their growth characteristics in an Undaria farm, in the eastern Seto Inland Sea of Japan. Despite the early start of nursery cultivation, due to a high seawater temperature of 24.5 °C, many young sporophytes of NW-1 grew on strings wound around the collector, whereas most of the HGU-1 sporophytes fell from the strings. After nursery cultivation, seawater temperature during rope cultivation was remarkably higher than usual. Nevertheless, the mean total length and weight of NW-1 were 115.5 cm and 140.1 g, respectively, at the end of December. In contrast, the mean total length and weight of HGU-1, at the corresponding time, were 85.4 cm and 58.1 g, respectively. Moreover, the growth and weight of the NW-1 sporophytes were significantly higher than those of HGU-1 throughout experimental cultivation. These results demonstrate that NW-1 is an excellent cultivar with a high yield and high-temperature tolerance.