Location: Soybean and Nitrogen Fixation ResearchTitle: Agronomic effects of mutations in two soybean Stearoyl-ACP-Desaturases) Author
Submitted to: Crop Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/6/2013
Publication Date: 7/1/2013
Citation: Ruddle, P., Cardinal, A., Upchurch, R.G., Arellano, C., Miranda, L.M. 2013. Agronomic effects of mutations in two soybean Stearoyl-ACP-Desaturases. Crop Science. 53:1-7. Interpretive Summary: Stearic acid is a saturated fat that can be used to replace imported solid fats high in palmitic acid content. Unlike palmitate, stearic acid consumption has no detrimental health effects on cholesterol levels. Increasing steric acid content of soybean oil is a highly desirable breeding goal that could only be realized by developing high stearic lines with good agronomic performance. Our research evaluated the agronomic effects of high stearic acid mutant alleles for two different Delta–stearoyl-acyl carrier protein-desaturase genes, SACPD-B and SACPD-C. We determined that there was no detrimental effect of the SACPD-C mutation on all the traits studied but the SACPD-B mutant lines suffered from a decreased seedling growth rate, were shorter at maturity, had smaller seed size and yielded significantly less than the wild-type lines. These differences were attributed to the fact that unlike the SACPD-C mutation, the SACPD-B locus not only affects seed fatty acid profiles but also vegetative tissues.
Technical Abstract: Soybean [Glycine max (L.) Merr.] oil normally contains 2-4% stearic acid. Oil with higher levels of stearic acid is desired for use in the baking industry, for both its chemical properties and human health benefits. Several lines with increased stearic acid have been identified; however, the agronomic consequences of high seed stearic acid are poorly understood on agronomic performance. Fifty F2-derived lines developed in a previous study were evaluated in a germination chamber and two field environments. Lines were either homozygous for the SACPD-C fasnc allele previously identified in FAM94-41, homozygous for the SACPD-B fas2nc allele from the induced ‘Holladay’ mutant TCJWB03-806-7-19, homozygous for both mutant genes or homozygous wild-type for both genes. SACPD-C mutant lines were agronomically indistinguishable from the wild-type lines and yielded as well (3534 kg ha-1 vs. 3414 kg ha-1). SACPD-B mutant lines suffered from a decreased seedling growth rate, were 15% shorter at maturity, had a 4% seed size reduction and yielded 6% less than the wild-type lines. The different agronomic performance between SACPD-C and SACPD-B mutant lines was attributed to altered fatty acid composition in vegetative tissues of the SACPD-B mutant lines.