Inheritance of medium stearic acid content in the seed oil of a sunflower mutant CAS-4
2002
Perez-Vich, B. | Garces, R. | Fernandez-Martinez, J.M.
The sunflower (Helianthus annuus L.) line CAS-4 obtained by mutagenesis has an increased stearic acid (C18:0) content in its seed oil (130 g kg(-1)), which is desired for some food products. The objectives of this study were to determine (i) the inheritance of medium C18:0 content in CAS-4, (ii) the relationship between CAS-4 and the high C18:0 mutant CAS-3, and (iii) if recombinants with higher C18:0 content than CAS-3 could be obtained. CAS-4 was reciprocally crossed with its original parental line RDF-1-532 (80 g kg(-1) C18:0), HA-89 (standard low 50 g kg(-1) C18:0), and CAS-3 (250 g kg(-1) C18:0). The fatty acid content of the F1, F2, BC1F1 to both parents, and F3 seeds was analyzed by gas-liquid chromatography (GLC). Alleles controlling low C18:0 exhibited partial dominance to those for medium C18:0, and these were partially dominant to those for high C18:0. Segregation patterns fit a two-loci model for the HA-89 x CAS-4 cross and one-locus model for the RDF-1-532 x CAS-4 and the CAS-3 x CAS-4 crosses. We concluded that medium C18:0 content of CAS-4 was controlled by alleles at the Es1 and Es2 loci previously identified in CAS-3, or at tightly linked loci. The CAS-4 alleles at the Es2 locus are those present in CAS-3 (es2es2), whereas the alleles at the Es1 locus are different from those of CAS-3 (es1es1) and have been designated es1bes1b. The proposed genotype (C18:0 content) of CAS-4 is es1bes1bes2es2. The continuous distribution observed in the HA-89 crosses with CAS-4 indicated that minor genes and environmental effects also are important in the expression of C18:0 content in CAS-4.
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