Inheritance of High Stearic Acid Content in the Sunflower Mutant CAS‐14

Abstract

A sunflower (Helianthus annuus L.) oil with high concentration of stearic acid has important applications in the food industry. Two sunflower mutants with high stearic acid content, CAS‐3 and CAS‐14, have been developed. In contrast to CAS‐3, high stearic acid expression in CAS‐14 seeds is temperature dependent and nonuniformly distributed in the seed. The trait in CAS‐3 has been found to be governed by two genes, Es1 and Es2. The objective of the present research was to study the inheritance of high stearic acid content in CAS‐14 through crosses with P21, a nuclear male sterile (NMS) line with a wild‐type fatty acid profile, and CAS‐3. The genetic analysis included the evaluation of the F1, F2, F3, BC1F1, and BC1F2 seed generations. Crosses between P21 and CAS‐14 revealed that the high stearic acid trait was recessive and controlled by a single gene, designated Es3. The analysis of the F3 and BC1F2 to P21 generations demonstrated a repulsion‐phase linkage between the Es3 and the Ms loci, the latter conferring the NMS trait. The frequency of recombination between Es3 and Ms was estimated to be 0.09. Crosses between CAS‐3 and CAS‐14 demonstrated that both lines possess alleles for high stearic acid content at different loci, as transgressive segregants with low stearic acid content were observed in all generations. Genetic recombination of es1 and es3 alleles did not result in an increment of the maximum stearic acid content in the seeds compared with the maximum levels produced by the es3 alleles alone.