Cultivation of a hybrid of free-living gametophytes between Undariopsis peterseniana and Undaria pinnatifida: morphological aspects and cultivation period

The kelp Undariopsis peterseniana is warm-water-tolerant, and consequently, there is currently considerable interest in developing commercial cultivation techniques for this species in Korea. U. peterseniana plants have been successfully transferred to the northern coast of Korea beyond their original habitat in Jeju Island (33°30′08.65″N, 126°55′39.02″E). In this study, we cultured a hybrid kelp consisting of a cross between free-living gametophytes of U. peterseniana and U. pinnatifida in an attempt to extend the culture period of Undaria which is an important species for both the abalone industry and for commercial seaweed mariculture for human food applications. Morphological characters and cultivation period were compared between the parent thalli and the hybrid. The cultivation experiment was conducted in Wando, on the southern coast of Korea (34°26′18.68″N, 127°05′43.88″E). The morphological characteristics of the hybrid thalli were intermediate between the two species having shallow pinnated blades and a reduced reproductive organ. Hybrid thalli showed faster growth rates, 1.5 times greater biomass, and a longer cultivation period than the parent thalli. The hybrid strain possessed characteristics that indicate it could be used as an alternative kelp source to supply the abalone feed industry.