Inheritance of high palmitic acid content in the seed oil of sunflower mutant CAS-5

Sunflower genotypes with increased levels of palmitic acid (C16:0) in the s eed oil could be useful for food and industrial applications. The objective of the present study was to determine the inheritance of the high C16:0 co ntent in the sunflower mutant line CAS-5 (> 25% of the total oil fatty acid s). This mutant was reciprocally crossed with the lines HA-89 (5.7% C16:0) and BSD-2-691 (5.4% C16:0), the latter being the parental line from which C AS-5 was isolated. No maternal effect for the C16:0 content was observed fr om the analysis of Fl seeds in any of the crosses. The inheritance study of the C16:0 content in F-1, F-2 and BC1F1 seeds from the crosses of CAS-5 wi th its parental line BSD-2-691 indicated that the segregation fitted a mode l of two alleles at one locus with partial dominance for the low content. T he analysis of the fatty acid composition in the Fz populations from the cr osses with HA-89 revealed a segregation fitting a ratio 19:38:7 for low(<7. 5%), middle (7.5-15%, and high (>25%)C16:0 content, respectively. This segr egation was explained on the basis of three loci (P1, P2, P3 each having tw o alleles showing partial dominance for low content. The genotypes with a h igh C16:0 content were homozygous for the recessive allele pi and for at le ast one of the other two recessive alleles, p2 or p3. This model was furthe r confirmed with the analysis of the F-3 and the BC1F1 generations. It was concluded that both the recessive alleles p2 and p3 were already present in the BSD-2-691 line, the allele p1 bring the result of a mutation from P1. This genetic study will facilitate breeding strategies associated with the incorporation of the high C16:0 trait into agronomically acceptable sunflow er hybrids.