Putative QTLs for six economic traits on the MapMaker linkage map.

<p>Putative QTLs for six economic traits on the MapMaker linkage map.</p

Principal component analysis of the different communities in the tested BTFs.

<p>Principal component analysis of the different communities in the tested BTFs.</p

Summary of genetic linkage maps constructed by MapMaker software.

<p>Summary of genetic linkage maps constructed by MapMaker software.</p

Frequency distribution of the phenotypic value of six traits “Frond Length”, “Frond Width”, “Frond Fascia Width”, “Frond Thickness”, “Raw Weight” and “Base Shape” in F₂ population.

<p>Frequency distribution of the phenotypic value of six traits “Frond Length”, “Frond Width”, “Frond Fascia Width”, “Frond Thickness”, “Raw Weight” and “Base Shape” in F₂ population.</p

Genetic Map Construction and Quantitative Trait Locus (QTL) Detection of Six Economic Traits Using an F₂ Population of the Hybrid from <i>Saccharina longissima</i> and <i>Saccharina japonica</i>

<div><p><i>Saccharina</i> (<i>Laminaria</i>) is one of the most important economic seaweeds. Previously, four genetic linkage maps of <i>Saccharina</i> have been constructed and five QTLs have been identified. However, they were not enough for its breeding. In this work, <i>Saccharina longissima</i> (♀) and <i>Saccharina japonica</i> (♂), which showed obvious differences in morphology and genetics, were applied in hybridization to yield the F₂ mapping population with 102 individuals. Using these 102 F₂ hybrids, the genetic linkage map of <i>Saccharina</i> was constructed by MapMaker software based on 37 amplified fragment length polymorphisms (AFLPs), 22 sequence-related amplified polymorphisms (SRAPs) and 139 simple sequence repeats (SSRs) markers. Meanwhile, QTL analysis was performed for six economic traits. The linkage map constructed in this research consisted of 422 marker loci (137 AFLPs, 57 SRAPs and 228 SSRs), which formed 45 linkage groups (LGs) with an average marker space of 7.92 cM; they spanned a total length of 2233.1 cM, covering the whole estimated genome size. A total of 29 QTLs were identified for six economic traits, which explained 1.06 to 64.00% of phenotypic variation, including three QTLs for frond length (FL) and raw weight (RW), five QTLs for frond width (FW), two QTLs for frond fascia width (FFW) and frond thickness (FT), and fourteen QTLs for base shape (BS). The results of this research will improve the breeding efficiency and be beneficial for marker-assisted selection (MAS) schemes in <i>Saccharina</i> breeding.</p></div

Schematic diagram of the biotrickling filter.

<p>(1) H₂S cylinder, (2) Mixing chamber, (3,4) Gas flowmeter, (5) Air compressor, (6) NaOH dosing pump, (7,8) Nutrient tank, (9,10) pH probe, (11,12) Peristaltic pump, (13–15) BTFa-u/m/b port for sampling packing materials, (16–18) BTFn-u/m/b port for sampling packing materials.</p

Putative 29 QTLs and their genetic effect for six economic traits in <i>Saccharina</i>.

<p>Putative 29 QTLs and their genetic effect for six economic traits in <i>Saccharina</i>.</p

The relative abundances of main bacterial phylum.

<p>The relative abundances of main bacterial phylum.</p

The heat map of the dominant genus in the two BTFs.

<p>The heat map of the dominant genus in the two BTFs.</p

Phenotypic traits of <i>Saccharina</i> and four types (cuneate, round, round flat, and heart-shaped) of base shape.

<p>Phenotypic traits of <i>Saccharina</i> and four types (cuneate, round, round flat, and heart-shaped) of base shape.</p