Inheritance of very high linoleic acid content and its relationship with nuclear male sterility in safflower

Safflower (Carthamus tinctorius L.) possesses the highest amount of linoleic acid among the 10 major vegetable oil crops of the world. Very high linoleic acid content is controlled by recessive alleles at a single locus Li. However, deviated segregations from the expected monogenic inheritance have been observed in crosses involving nuclear male-sterile (NMS) lines. The present research was undertaken to study the inheritance of very high linoleic acid content in safflower and its relationship with nuclear male sterility. F₁, F₂, F₃, BC₁F₁ and BC₁F₂ seed generations were evaluated in a cross between CR-142 (a line with very high linoleic acid content, 88%) and CL1 (an NMS line with wild-type linoleic acid content, 74%). The genetics of linoleic acid content in male-sterile plants was determined by testcrossing with CR-142. The results confirmed monogenic inheritance. The analysis of the F₃ and BC₁F₂ to CL1 seed generations demonstrated a repulsion-phase linkage between Li and Ms loci, the latter conferring the NMS trait. The recombination rate between Li and Ms was estimated to be 0.09.