Comparative analysis of morphometric traits of farmed sugar kelp and skinny kelp, Saccharina spp., strains from the Northwest Atlantic

Abstract

Our team has initiated a selective breeding program for regional strains of sugar kelp, Saccharina latissima, to improve the competitiveness of kelp farming in the United States. Within our breeding program, we also include an endemic putative species, Saccharina angustissima, locally referred to as skinny kelp. We crossed uniclonal gametophyte cultures derived from 37 wild-collected blades representing five sugar kelp strains and one skinny kelp strain to produce 104 unique crosses. Each cross was outplanted on a near-shore research farm located in the Gulf of Maine (GOM). After the first farming season, our results indicated that sugar kelp and skinny kelp were interfertile, and produced mature and reproductively viable sporophytes. Morphological traits of individual blades varied depending on the parental contribution (sugar vs. skinny), with significant differences found in progeny blade length, width, thickness, and in stipe length and diameter. Despite these differences, wet weight and blade density per plot showed no statistical differences regardless of the cross. Given their published genetic similarity and their interfertility shown here, S. angustissima and S. latissima may not be different species,

Simulation of sugar kelp (Saccharina latissima) breeding guided by practices to accelerate genetic gains

“…A second isolation is performed approximately 2–4 months later when GPs develop into tufts large enough (>100 µm), to be sexed and moved to individual Petri dishes for regular periodic filament fragmentation. Once sufficient uniclonal biomass is achieved (∼10 mg to cover 1 m plots), which can take up to another 4 months, crosses are made by mixing female and male GPs at a 2:1 ratio ( Umanzor et al 2021 ; Fig. 1 ).…”

“…Within a cross, each SP has the same genotype, resulting in genetically uniform 1-m line “plots” in the farm. In our breeding work, we have measured various traits at plot and individual blade levels ( Umanzor et al 2021 ). At harvest time for the 2019 and 2020 seasons, the farm-grown SPs were phenotyped and sampled.…”

“…We initiated a sugar kelp breeding program in 2018, and our primary breeding goal is to improve biomass-related traits including wet weight and ash free percentage dry weight, and to reduce biomass ash content. With 3 years of breeding experience, we have identified limiting factors to our breeding effort and the investments that might be exerted to overcome those limitations ( Umanzor et al 2021 ). To guide the research effort objectively, the extent of accelerated gain from different possible investments and interventions needs to be assessed via simulation.…”

The SeaCoRe system for large scale kelp aquaculture: a plug-and-play, compatible, open-source system for the propagation and transport of clonal gametophyte cultures

“…The second method is called the controlled reproductive method (CRM), as it offers a more direct control on gametophyte reproduction because of the in vitro environment where gametophyte growth and reproduction take place (Zhang et al 2008). Gametophyte reproduction can be induced in a controlled setting and the subsequent cultures with juvenile sporophytes can then be attached to twine strings using techniques like paintbrush-seeding (Hwang et al 2006;Redmond et al, 2014;Umanzor et al 2021), or direct seeding (Kerrison et al 2020;Forbord 2020). However, using CRM as a primary cultivation method is still considered risky, more labor-intensive than URM, and showing a higher detachment from the seed strings when applied (Xu et al 2009).…”

Seaweed aquaculture—From historic trends to current innovation

“…Understanding the genetic diversity of wild seaweed populations is vital not only for preserving biodiversity but also for breeding and commercialization of strains that are thermally tolerant, high yielding, adapted to low nutrient conditions, and disease resistant (Mao et al, 2020;Wade et al, 2020). Observation of heritability of genetic and phenotypic traits over many generations allows for selecting and identifying seaweed best suited for production on both land-based and off-shore farm performance (Augyte, Yarish, Redmond, & Kim, 2017;Umanzor et al, 2021;Zertuche-González et al, 2021). Various techniques can be implemented to improve harvesting and extend the growing season for seaweeds (Grebe et al, 2021).…”