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

Abstract

Alaria esculenta populations from six differentgeographical locations on the Irish coast wereexamined for hybridization abilities, growth rates andgenetic make-up with a view towards identifying afast-growing strain suitable for aquaculture.Hybridization experiments under laboratory conditionswith the three most geographically dispersedpopulations showed that all cross combinations wereinterfertile, although differences were found insurvival, and in blade and hapteron morphology. Acomparison of relative growth rates showed significantdifferences amongst the self-crosses and hybrids. Thedata of the hybridization experiments and growth ratesunder laboratory conditions show that the bestpopulation for the purpose of seaweed aquaculture arethe Slea Head and Corbet Head self-crosses and theirhybrids. Genetic fingerprinting of the internaltranscribed spacer of the ribosomal DNA of five A. esculenta isolates from geographically separatedpopulations in Ireland revealed no restriction lengthpolymorphisms between the tested isolates and showthat the A. esculenta populations around theIrish coast are clearly genetically homogenous inrespect of the DNA region examined. The geneticanalysis, interfertility of the populations,morphology and growth rates are discussed with a viewto potential cultivation.