Molecular mapping genes conditioning reduced palmitic acid content in N87-2122-4 soybean

Palmitic acid is one of the two major saturated fatty acids of soybean [Glycine max (L.) Merr.] oil that is closely related to nutritional quality of soybean oil. Reduction of palmitic acid content would lower the total saturated fatty acid content of soybean oil and improve the oil quality for human consumption. Several mutant lines with reduced palmitic acid content have been developed in which the genes conditioning palmitic acid content are located at different loci. The objective of this research was to map the genes conferring reduced palmitic acid from N87-2122-4 on the public soybean genetic linkage map with simple sequence repeat (SSR) markers. Four near-isogenic lines with normal and reduced palmitic acid content and the F-2 and F-2:3 generations of a population derived from the cross of 'Cook' x N87-2122-4 were used to perform the SSR mapping of the genes conditioning reduced palmitic acid. The results indicated that a major gene with an allele for reduced palmitic acid contributed by N87-2122-4 is located near the top of Linkage Group (LG) A1. A SSR marker, Satt684 in that region accounted for 38% of variation in palmitic acid content in the F2 generation and 31% of variation in the F-2:3 generation. On LG-M, Satt175 accounted for 8% of the variation in the F-2 and 9% of the variation in the F-2:3 generation. This minor gene on LG-M had a significant interaction with the gene on LG-A1 in the F-2 generation. When combined in a multiple regression equation, these markers explained 51% of total phenotypic variation for palmitic acid content in the F-2 and 43% of the variation in the F-2:3 generations.