Genotypic Variation for Fatty Acid Content in Selected Glycine max × Glycine Soja Populations

Modifications in the fatty acid composition of soybean [Glycine max (L.) Merr.] oil may extend its utility to industrial markets currently serviced by other vegetable-, mineral-, or fossil-based oils. However, extension into new markets depends on the development of soybean oils with increased concentrations of saturated, monounsaturated, or polyunsaturated fatty acids. Three wild soybean (G. soja Siebold & Zucc.) accessions possessing unique fatty acid profiles were intercrossed with the reduced saturate and polyunsaturate fatty acid germplasm, N87-2122-4, to produce widely segregating populations. Random F₂ and F₂:₃ families from each population were grown, and seed fatty acid contents of individuals within families were analyzed. Genotypic differences for oil quality were significant among populations and families within populations. Individual families produced >140 and 175 g kg⁻¹ palmitic and total saturated fatty acid contents, respectively. No family produced greater oleic acid content than N87-2122-4. Some families produced >640 g kg⁻¹ linoleic acid and total polyunsaturates exceeding 720 g kg⁻¹, while selected individuals produced >750 g kg⁻¹ total polyunsaturates in both the F₂:₃ parental and F₂:₄ progeny generations. High narrow-sense heritability estimates for palmitic (h² = 0.67 to 0.98) and linoleic (h² = 0.44 to 0.80) acid contents suggested that individual F₂ plants can be selected for either trait. However, the smaller heritabilities for oleic (h² = 0.36 to 0.66) and linolenic (h² = 0.10 to 0.47) acid contents necessitate selection based on family means. Analyzing these selected wild soybean crosses has demonstrated G. soja may be a useful source of genes to extend genotypic variation for linoleic and total polyunsaturated fatty acid contents. Genes for greater saturate content in PI 424031 may extend variation currently available in mutant soybean germplasm. However, it appears unlikely that G. soja would be useful for increasing oleic acid content above levels in existing soybean mutants.