2023 Volume 71 Issue 1 Pages 9-22
In this study, a laboratory-selected high-temperature resistant strain of Undaria pinnatifida obtained from crossbreeding was evaluated for growth and productivity under three outplanting periods of varying water temperature levels: high (September 29, 2021; 25.4°C), middle (October 15, 2021; 24.4°C) and low (October 31, 2021; 22.2°C), in a cultivation site in the Shimane Peninsula. Our results showed that seedlings were lost significantly for the conventionally used strain (the control strain NT2♂NT2♀; CS) outplanted during the high-temperature period. On the other hand, the high-temperature resistant strain (IS1♂NT2♀; RS) grew well, suggesting the possibility of early shipment. Cultivation of this strain yielded shipping size U. pinnatifida with an average weight of over 100 g per individual upon harvest in early January, a period when the trading price of fresh U. pinnatifida is high. Furthermore, the January to March harvests showed that the RS outplanted during the high and middle-temperature periods produced harvest amounts that were 1.8 to 3.3 times higher than that of the CS outplanted during the low-temperature period. The use of the RS in U. pinnatifida cultivation sites is therefore expected to make a stable and improved production.
