QTL mapping and epistatic interactions for improved seed oil quality in safflower

Safflower oil with high oleic is an important source of oil due to its oxidative stability and nutritional value as well as its industrial benefits.

Identification of molecular markers associated with oil quality traits may aid in genotype selection in breeding efforts of safflower. To determine the genetic basis of seed oil, oleic acid, and linoleic acid content in safflower seeds, a recombinant inbred population was developed from a cross between Goldasht (low oleic line) and Mex 22–191 (high oleic line) by individual self-pollinated plants in each generation (from F2 to F9). Fatty acid components were detected by gas chromatography and subsequently analyzed by QTL analysis. The high variability in fatty acid composition was demonstrated and the first high-oleic safflower genotype was generated. A new linkage map with 69 AFLP and 45 ISSR polymorphic markers was made, covering 1472,441 cM of the safflower genome. A total of 63 individual QTLs and 238 epistatic QTLs, related to oil quality, were detected in 14 genomic regions. Some major QTLs with phenotypic variation greater than 10% were identified for the measured traits. These results demonstrate that major QTL may play an important role in increase the oleic acid of the genetic material used. Furthermore, the larger number of minor QTLs and epistatic QTLs, both of which have additive effects, indicates that the expression of these traits is also influenced by interactions between multiple genes. Our results provide additional genetic resources that can be used to precisely breed these traits in the future.