Inheritance of very high oleic acid content and its relationship with several morphological and physiological traits

Safflower oil with high oleic acid content has a great value for both food and non-food uses. The trait is mainly controlled by recessive alleles at the Ol locus, although the influence of modifying genes has been suggested. The objective of the present research was to study the inheritance of very high oleic acid content (>85%) and its relationship with other traits such as nuclear male sterility (NMS), flowering time, presence of spines, and corolla colour. The line CR-9, characterized by very high oleic acid content, male fertility, early flowering, absence of spines, and orange corolla, was crossed to the line CL2, characterized by conventional fatty acid profile, NMS, late flowering, presence of spines, and white corolla. The analysis of the F2 seed and plant (F3 seeds averaged) generation confirmed monogenic inheritance of very high oleic acid content, although the presence of modifying genes produced a reduction of oleic acid content in the high oleic acid class to minimum values of 81%, 74%, and 68% at the F2 seed, F2 plant, and F3 seed level, respectively. NMS and white corolla were recessive and controlled by a single gene. The presence of spines was monogenic and dominant. Oleic acid content segregated independently from the other traits evaluated. The results confirmed the great effect of modifying genes on the expression of very high oleic acid content and revealed that the Ol locus is not closely linked to genes involved in the expression of the traits evaluated.