**4. Prospects and Future Directions**

Although conventional breeding methods are an integral part of crop improvement, modern molecular genetics and gene technologies have accelerated progress and enabled the incorporation of genetic resources across species and genera in canola. These technologies, especially gene editing, allow more detailed observations on functions of the genome compartments, as well as major genetic factors controlling biological and biochemical processes in canola, from which the obtained knowledge facilitates e ffective manipulation of the genetic resources towards enhancement of canola varieties. Contributions of modern genetic and gene technologies towards shaping current canola varieties are summarized in Figure 2.

As the current major market for canola crops are food, feed, and biofuel industries [17], the improvement targets prioritize oil yield and quality [9,36], and further reduction of GSL content and other antinutritional compounds [104], while simultaneously enhancing resistance against the major pathogens and tolerance to abiotic stress and herbicides [31,69,116,117,132,134,148,173–175]. The approval for commercial release of DHA canola [86,87] is the most recent achievement in canola improvement and exploits natural resources in fatty acid biosynthesis, where modern genetic and gene technologies play a crucial role in the success. Glucosinolates, which have been long time avoided in canola meal, are now found useful for diverse bioactivities which facilitate plant defense against non-adapted pathogen and insect pests [132,176], cancer treatment [177], and nutritional quality of canola meal [104]. Knowledge on GSL biosynthesis and their roles in physiological and biological processes of *B. napus* are being made more specific by genomic and transcriptomic approaches [100,177]. Improvement of pathogen resistance or herbicide tolerance need continued attention as pathogens and weeds can overcome these resistances after introduction of the pathogen resistant or herbicide tolerant varieties, with the pace depending on the managemen<sup>t</sup> and rotation of those varieties in combination with other managemen<sup>t</sup> practices [156,158,171]. The application of genomics and gene technologies in *Brassica* species have validated hypotheses and incorporated new knowledge on the evolution and the genetic diversity of *B. napus*, and explored the genetic layout of the complex genome of amphidiploid canola [63]. Genomic studies in rapeseed which used to be challenged by the complexity of the genome, are now facilitated by "omic" and gene technologies, enabling more insights about factors controlling 1,trait development and further enhancement of ca [80,100,107,134].

Facing climate change, rapid evolution of phyto-pathogens and weeds and an increasing world population, canola is assumed as an economical e ffective "multiple-purposes" crop fitting a broad range of markets, industries, and sustainable development policies [36]. The choice of technological approach for developing and enhancing canola varieties, such as GM canola, is a ffected by local legislation, research investment, and improvement targets. Although current GM canola varieties benefit in enhancement values of canola products and reducing labor costs (HT canola), the transgenes might a ffect performance of other genomic compartments Therefore, eliminating unessential transgenes from GM canola, environmental impact assessment and obtaining legislative approvals for commercial release of these varieties are requirements to developing a GM variety of which procedure prolongs the time reaching their markets. The world's largest canola importer, EU, has imposed strict regulations on GM organisms, which a ffects technological choices in improving canola. Taking environmental and legislation perspectives, gene editing tools, such as CRISPR/Cas, are the most promising technology for enhancement of canola for commercial purpose [178]. With the advance of genomics and pan-genomics, the genetic architecture underlying response to the major pathogens and abiotic stresses such as salinity and drought need to be further dissected. Cytoplasmic genomes are attracting more interest as the new source for maximizing oil content in canola [90]. Considering factors shaping modern canola varieties, genetic and gene editing technologies are proven powerful tools for achieving new breeding targets, allowing thorough exploration and exploitation of *B. napus* genes which are largely unknown.

**Figure 2.** Contributions of the modern genetic and gene technologies to the understanding of the genetic architecture of the major traits of Brassica oilseed crop, adapted from Mackay [179] suggestions, and achievements in canola variety research and development. GWAS, Genome-Wide Association Study; CRISPR/Cas, the clustered regularly interspaced short palindromic repeat; GO, gene ontology; NGS, next-generation sequencing technique; SMRT, single molecule real time; SNP, single nucleotide polymorphism; QTL, quantitative trait loci; MAS, marker-assisted selection; GSL, glucosinolate; GM, genetically modified; (\*) molecular biology fundamentals of these mechanisms is being established; (\*\*) products from experimental studies.

**Author Contributions:** Conceptualization, L.B.T. and T.X.N.; writing—original draft preparation, L.B.T. and T.X.N; writing—reviewing and editing, J.B.; visualization, L.B.T.; funding acquisition, J.B. All authors have read and agreed to the published version of the manuscript.

**Funding:** This work was funded by Australian Research Council Projects DP1601004497, LP160100030.

**Acknowledgments:** We acknowledge The University of Western Australia's support through a 'UWA International Fee Scholarship and University Postgraduate Award'.

**Conflicts of Interest:** The authors declare no conflict of interests.
