Existence of an intact male life cycle offers a novel way in pure-line crossbreeding in the brown alga Undaria pinnatifida
Hermaphroditic gametophyte production and an intact male life cycle were investigated in Undaria pinnatifida. Zoospore-derived hermaphroditic gametophyte could give rise to male sporophytes which showed the same morphological appearance but with smaller biomass than normal cultivated sporophytes. Male sporophytes were shown to discharge only male zoospores. In this investigation, male spores derived from the male sporophytes and female spores derived from female parthenosporophytes were crossed to produce the hybrid sporophytic offspring. The latter contained both alleles of homozygous parental sporophytes when analyzed by use of eight polymorphic microsatellite markers, further confirming the success of cross. Thus, line crossing by use of unisexual sporophytes will be expected to replace unisexual gametophyte line crossing in breeding practice in the future in this commercially farmed seaweed.
KeywordsBreeding method Unisexual zoospores Parentage analysis Undaria pinnatifida, Phaeophyceae
This research was supported by projects from the National Natural Science Foundation of China (No. 41476141 and 41676128), the Sino-German Science Center (GZ 1080), the scientific and technological innovation project from Qingdao National Laboratory for Marine Science and Technology (No. 2015ASKJ01), and the National Infrastructure of Fishery Germplasm Resource (2016DKA30470). The authors wish to thank Su Qin Gao for maintaining the cultures in the laboratory.
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