GENETIC-LINKAGE BETWEEN THE TRIGENIC MALE-FEMALE STERILITY AND OIL QUALITY ALLELES IN SAFFLOWER

Several studies have shown that the proportions of oleic and linoleic acid in the seed oil of safflower (Carthamus tinctorius L.) are govern ed by two alleles at the ol locus. In some studies, however, fewer pla nts than expected had the olol genotype. The deviation from the expect ed ratio could have been caused by a genetic linkage between sterility and oleic or linoleic acid content. Although male-female sterile plan ts appeared in the F2 of such studies, sterile plants were not used in measurements of fatty acid composition. The objective of this investi gation was to detect possible genetic association between sterility an d oil quality genes. We examined data from a cross of US-10 with genot ype 0101 (high linoleic acid) to 57-147, an introduction from India wi th genotype olol (high oleic acid). This cross gave sterile plants in the F2. We measured the iodine value (IV) in bulk seeds from 217 selfe d, fertile F1 plants and found a distorted ratio due to fewer than exp ected plants with low IV (genotype olol). Using the half-seed techniqu e to determine the fatty acid composition of 342 (fertile and sterile) F2 seeds from selfed F1 plants, there was no deficiency in the expect ed number of olol genotypes. The difference in the ratios of the F2 pl ants grown from half-seeds and those used in fatty acid measurements i ndicate linkage between sterility and the ol locus. Of the genes invol ved in sterility, where sterile genotypes are s1s1s2s2S3-, s1s1S2-s3s3 , and s1s1s2s2s3s3, a statistically significant deviation was detected due to linkage between the s1 and ol loci. This information should be considered by breeders of safflower who systematically use introducti ons from a multitude of gene centers in their breeding programs