Marker-assisted selection for fast-track breeding of high oleic lines in safflower (Carthamus tinctorious L.)

Safflower is grown primarily for edible oil rich in unsaturated fatty acids. Due to higher stability and longer shelf life, the oil with high oleic acid content is preferred for food and other industrial applications. Safflower cultivars with high oleic acid content (>70%) have been developed and commercially successful. Incorporation of the high oleic trait through conventional breeding techniques has been a slow process due to recessive inheritance and difficulties associated with phenotyping by biochemical methods. DNA based marker-assisted selection (MAS) for high oleic trait would help speed up the breeding efforts in safflower. In this study, a set of high oleic varieties were found to carry the same mutation in the fatty acid desaturase 2-1 gene, CtFAD2-1, which is presumed to be the 'ol' allele associated with high oleic acid content in safflower. Genotypic assays namely Kompetitive Allele Specific PCR (KASP (R)) and the Amplifluor (TM) SNPs Genotyping System (Amplifluor (R)) were designed for the prediction of high oleic trait based on the mutation in the CtFAD2-1. The assays were thoroughly validated in segregating populations derived from crosses between low and high oleic parents. Through marker-assisted backcrossing scheme, the high oleic allele, 'ol' from the exotic variety, Montola-2000 was incorporated into the background of popular Indian linoleic type variety, Bhima and a set of promising high oleic lines (75.2%- 81.8%) were developed. The MAS-derived lines showed consistent expression of high oleic acid content over seasons and comparable seed/oil yield performance with the local check varieties. The genotypic assays reported in this study were robust, non-destructive, co-dominant and accurately predicted high oleic trait in segregating populations; thus, recommended for fast-track breeding of high oleic cultivars in safflower.