Genetic Improvement of Oil Yield and Quality in Brassica Crops under Climate Stress

Abstract

Brassica oilseed crops (B. napus, B. juncea, B. rapa, B. carinata) rank as the world’s second-largest source of vegetable oil, supplying 12–14% of global production and supporting food, biofuel, and industrial sectors valued at over US$67 billion. However, escalating climate stresses terminal heat, drought, salinity, and waterlogging severely impair reproductive success, seed filling, and oil biosynthesis, reducing yield and altering fatty-acid profiles toward less desirable compositions. This review synthesizes the genetic and physiological basis of oil yield and quality under stress, highlighting the polyploid complexity of U’s Triangle genomes, key QTL hotspots (e.g., A09 for oil content, A06 for pod shatter resistance), and master regulators such as WRI1 and FAD genes. Advances in high-throughput genomics, GWAS, and multi-omics have pinpointed stable marker-trait associations and candidate genes, while CRISPR/Cas9-mediated editing (e.g., BnFAD2 and BnaEOD3 knockouts) has already delivered high-oleic and higher-seed-weight lines. Exploitation of crop wild relatives and landraces, combined with marker-assisted pyramiding, accelerated breeding platforms, and AI-driven predictive modeling, offers a clear pathway to climate-resilient, high-oil Brassica varieties. Recent releases such as Pusa Mustard 26 and double-zero B. juncea lines demonstrate that integrated genomic strategies can simultaneously enhance stress tolerance, oil content, and nutritional quality. Continued convergence of genome editing, spatial omics, and epigenome engineering will be essential to secure stable oil production under future climate scenarios.