Cultivation potential of the tropical carrageenophyte Eucheumatopsis isiformis (Solieriaceae, Rhodophyta) from Yucatán, Mexico.

The production of tropical red seaweeds, collectively referred to as eucheumatoids, has stagnated or declined over the past decade. This trend is primarily attributed to limited availability of high-quality planting material, increased incidence of diseases, and insufficient genetic exchange between cultivated stocks and wild populations. Consequently, enhancing species diversification in commercial seaweed farming through the controlled management of reproductive strategies remains a significant global challenge. Eucheumatopsis isiformis is a native eucheumatoid from the tropical Atlantic Ocean that contains a high proportion of iota-carrageenan with a kappa-iota-nu carrageenan hybrid structure and represents a promising candidate for diversification of commercial crops. This study reports the first successful induction of sporulation in this species, thereby expanding current knowledge of its reproductive phenology and supporting its potential cultivation from spores. Molecular analyses confirmed the identity of E. isiformis across the three morphotypes examined, which exhibited comparable carrageenan yields. Collectively, these findings establish a robust methodological foundation for the development of spore-based production systems for this species. Sporulation was successfully induced after 5 and 10 days of acclimatization, with the highest carpospore densities obtained under treatment with putrescine at 10-3 M. Optimal spore development was observed at a light intensity of 40 µmol·m-2·s-1. These findings highlight the potential for advancing the cultivation of E. isiformis through consolidation of selective breeding and domestication protocols, which may also be applicable to other eucheumatoid species.