QTL Mapping of Seed Fatty Acid Contents in Camelina sativa Under Heat Stress

Heat stress alters oil quality in oilseed crops, yet its genetic underpinnings in Camelina sativa remain unclear. This study investigated the genetic basis of heat-induced changes in seed fatty acids using a recombinant inbred line (RIL) population derived from a cross between Suneson and Pryzeth. In the RIL population, exposure to high temperature led to increased proportions of C16:0, C18:0 and C18:1, whereas C18:3, total unsaturated fatty acids (UFA) and the PUFA/MUFA ratio decreased, consistent with inhibition of the C18:1→C18:2→C18:3 desaturation pathway and a shift toward membrane-stabilizing lipids. A high-density linkage map (4,981 bins across 20 chromosomes) was built and used to detect 25 QTLs for fatty acids, with hotspots on chromosomes 1, 9, 12, 13, 16 and 20. A major QTL on chromosome 1 (~ 80 cM) explained the largest variance component for PUFA/MUFA under heat. Three desaturase genes ( FAD2 , FAD7 , FAD8 ) were located within key QTL intervals, nominating them as candidates for modulating unsaturation under elevated temperature. These results provide a genetic basis for fine mapping and functional validation, supporting future molecular and breeding efforts to stabilize oil quality under warming conditions.