Intraspecific diversity of the gracilarioid algae (Gracilariales, Rhodophyta)

Abstract

The strain selection in seaweeds is a recent activity and it is restricted to oriental countries. In Brazil, many attempts of mariculture have failed; one of the reasons would be the absence of previous studies in laboratory. Recent approaches that include strain selection in gracilarioid algae (Gracilariales, Rhodophyta) in the Laboratório de Algas Marinhas (IBUSP) have shown promising results and can contribute to agarophyte mariculture. In this project, we will focus on two species: Gracilaria birdiae and G. caudata. Strains of G. birdiae have already shown satisfactory performance in laboratory and at sea (Ubatuba, SP); however, they have never been evaluated in localities where its populations occur (Northeastern Brazil). We intend to study the potential of strain cultivation at sea for future mariculture projects that will benefit communities and promote a better utilization of this economic resource. Moreover, we intend to evaluate the population dynamics. Other approaches will employ laboratory culture techniques in G. caudata for the analysis of intraspecific diversity caused by intrinsic characteristics in many rhodophythes that, although with a triphase life-history, show two isomorphic phases, haploid and diploid, that are present in the same population. Moreover, these studies will produce results about the occurrence of ecotypes in this species, since we intend to evaluate individuals from two populations in regions 20° of latitude apart. The integration of this information will allow interpretations about the adaptive advantages in maintaining haplo-diploid history cycles and will enable strain selection that will be utilized in practical applications. (AU)