Method for Early Generation Soybean Population Selection Using F 2 High-Parent Heterosis Testing

The germplasm pool for North American soybean [Glycine max (L.) Merr.] is narrow, and identifying novel and useful genetic diversity is time consuming and expensive. The objective of this research was to develop an early-generation population screening method to select diversity ' elite populations. The F-2 high-parent heterosis (F-2 heterosis) was used as a tool to identify populations with the greatest potential for producing high-yielding lines in subsequent generations. For Set 1 populations, six populations were selected for significantly positive F-2 heterosis, and six were selected for significantly negative F-2 heterosis. When these populations were advanced into plant row yield trials, five out of six populations with positive F-2 heterosis had the highest average yield for the top 5% of the lines, and five out of six populations with negative F-2 heterosis had the lowest average yield for the top 5% of the lines. For Set 2, two populations with the highest positive F-2 heterosis value had significantly higher average population yield and average top 5% selection yield compared with two populations with negative F-2 heterosis. Differences in combining ability were evident in both sets of populations, as two populations with one parent in common may have opposite classifications for F-2 heterosis. Using F-2 heterosis as an early-generation population selection tool may enable the focus of resources to identify which populations have the best opportunity to develop high-yielding lines with unique diversity. These data will need to be verified in replicated yield testing over multiple years and locations.