An assessment of phenotype selection for linolenic acid using genetic markers

Marker assisted selection (MAS) procedures potentially can make breeding more efficient, as genotypes can be identified before pollination allowing breeders to cross or backcross only suitable materials. Our objective was to assess the accuracy of our phenotypic selections in soybean [Glycine max (L.) Merr.] for linolenic acid using molecular markers specific for mutations in two fatty acid desaturase genes, GmFAD3A and GntFAD3C. The markers were not available earlier in the selection process and were used retrospectively to determine that phenotypic selection for seed linolenic acid <= 35 g kg(-1)oil was successful in capturing genotypes homozygous for mutant alleles at both loci, but phenotypic selection was not perfect. Chemical analysis for seed linolenic acid concentration was not an accurate predictor of genotype. The advancement of heterozygotes reduced the selection efficiency relative to what would have been possible using molecular markers specific for mutations in the two fatty acid desaturase genes. Errors are thought to have derived from inaccurate sample tracking or identification, contamination, or errors in chemical analyses. Use of mutation-specific molecular markers to identify F, lines homozygous for mutant alleles in GmFAD3A and GmFAD3C, combined with diligence in reducing sampling errors, would eliminate the need for chemical testing for linolenic acid content in subsequent generations where screening can emphasize other traits.