The edible brown seaweed Alaria esculenta (Phaeophyceae, Laminariales): hybridization, growth and genetic comparisons of six Irish populations

Alaria esculenta populations from six different geographical locations on the Irish coast were examined for hybridization abilities, growth rates and genetic make-up with a view towards identifying a fast-growing strain suitable for aquaculture. Hybridization experiments under laboratory conditions with the three most geographically dispersed populations showed that all cross combinations were interfertile, although differences were found in survival, and in blade and hapteron morphology. A comparison of relative growth rates showed significant differences amongst the self-crosses and hybrids. The data of the hybridization experiments and growth rates under laboratory conditions show that the best population for the purpose of seaweed aquaculture are the Slea Head and Corbet Head self-crosses and their hybrids. Genetic fingerprinting of the internal transcribed spacer of the ribosomal DNA of five A. esculenta isolates from geographically separated populations in Ireland revealed no restriction length polymorphisms between the tested isolates and show that the A. esculenta populations around the Irish coast are clearly genetically homogenous in respect of the DNA region examined. The genetic analysis, interfertility of the populations, morphology and growth rates are discussed with a view to potential cultivation.