Fatty acids and their composition in seeds determine oil value for nutritional or industrial purposes and also affect seed germination as well as seedling establishment. To better understand the genetic basis of seed fatty acid biosynthesis in oilseed rape (Brassica napus L.) we applied a genome-wide association study, using 91,205 single nucleotide polymorphisms (SNPs) characterised across a mapping population with high-resolution skim genotyping by sequencing (SkimGBS). We identified a cluster of loci on chromosome A05 associated with oleic and linoleic seed fatty acids. The delineated genomic region contained orthologs of the Arabidopsis thaliana genes known to play a role in regulation of seed fatty acid biosynthesis such as Fatty acyl-ACP thioesterase B (FATB) and Fatty Acid Desaturase (FAD5). This approach allowed us to identify potential functional genes regulating fatty acid composition in this important oil producing crop and demonstrates that this approach can be used as a powerful tool for dissecting complex traits for B. napus improvement programs.

Brassica napus (L.), winter oilseed rape (WOSR) or canola, is one of the most important oilseed crop species of the moderate climate zone. Improving the seed quality and yield makes the main target in breeding programs worldwide. In this study, we examined the genotype-by-environment (G×E) interaction with respect to six seed traits among 25 WOSR genotypes. The plant material included the registered canola cultivars, our newly developed mutant breeding lines and the Ogura F1 hybrids and their parental components, in addition to our domestic breeding lines including two semi-resynthesized (semi-RS) lines. The 25 genotypes were examined in field trials at two locations, in three growing seasons. Seed oil and protein content, total glucosinolates (GLS) content in seed meal and C18 unsaturated fatty acid (oleic, linoleic and linolenic) composition in seed oil were examined. The additive main effects and multiplicative interaction (AMMI) analyses revealed significant effects of both, genotype (G) and environment (E) as well as the G×E interaction regarding the analyzed seed traits. In our study, two Ogura F1 hybrids, a CMS line and a new high oleic mutant breeding line revealed high stability and good average values for most of the analyzed seed traits, thus making a valuable source of starting materials for further improvement.

Resynthesized (RS) oilseed rape (Brassica napus L.) is potentially of great interest for hybrid breeding. However, a major problem with the direct use of RS B. napus is the quality of seed oil (high level of erucic acid) and seed meal (high glucosinolate content), which does not comply with double-low quality oilseed rape. Thus, additional developments are needed before RS B. napus can be introduced into breeding practice. In this study, RS oilseed rape was obtained through crosses between B. rapa ssp. chinensis var. chinensis and B. oleracea ssp. acephala var. sabellica. RS plant was then crossed with double-low (00) winter oilseed rape lines containing the Rfo gene for Ogura cytoplasmic male sterility (CMS ogu) system. Populations of doubled haploids (DH) were developed from these F1 hybrids using the microspore in vitro culture method. The seeds of semi-RS DH lines were analyzed for erucic acid and glucosinolate content. Among the populations of semi-RS DHs four 00-quality lines with the Rfo gene were selected. Using 344 AFLP markers to estimate genetic relatedness, we showed that the RS lines and semi-RS lines formed clusters that were clearly distinct from 96 winter oilseed rape parental lines of F1 hybrids.