Agronomic performance, seed characteristics, and stability of soybean lines containing mid oleate content and molecular analysis for diversity in the FAD2-1B gene
Soybean [Glycine max (L.) Merr.] lines with increased levels of oleate content may be useful for the food industry. Iowa State University has used the mutant soybean line, M23, developed by Saga University in Japan, to develop lines that contain mid-oleate content combined with 10 g kg -1 linolenate (MO/LLN), low saturated fatty acids (MO/LS), and both low saturated fatty acids and 10 g kg-1 linolenate (MO/LS/LLN). The first objective of the research was to determine the stability of oleate content across four Iowa environments and one Missouri environment in two years for the three types of lines. For environmental stability based on either the evaluation of the range of oleate content over the environments or a regression on an environmental index, the MO/LLN lines on average were the most stable followed by the MO/LS/LLN lines and the MO/LS lines. When stability was based on the frequency with which a line would exceed 500 g kg-1 oleate, the lines with the highest mean oleate in each type had the greatest stability. The second objective of this research was to determine the effect of the ol allele that controls increased oleate content in M23 on agronomic and seed characteristics. The performance of 27 MO/LLN lines from each of three populations was compared to that of 27 lines with conventional oleate content (CO/LLN) from the same population. The MO/LLN lines had 12% lower yield on average than the CO/LLN lines. For the other traits, many of the MO/LLN lines were comparable to the CO/LLN lines indicating that it would be possible to develop MO/LLN cultivars with similar agronomic and seed characteristics as CO/LLN cultivars. The third objective of this research was to evaluate a mutated population of soybean for polymorphisms in the FAD2-1B gene. A total of 1452 M2 families were screened and 32 M2 families were selected that could potentially have changes in the FAD2-1B gene. When M3 progeny from the 32 families were evaluated in the field, none of them had elevated oleate content and they had the same sequence for the FAD2-1B gene as Williams 82, the wild-type progenitor.