Evaluation of marker-assisted introgression of yield QTL alleles into adapted soybean

Genetic diversity is limited in southern elite soybean [Glycine max (L.) Merrill]. Introgression of diverse alleles for yield may increase the rate of yield improvement. Beneficial yield alleles at three quantitative trait loci (QTL) from the northern cultivar Archer have been tagged with molecular markers. The objective of this research was to assess the value of the three Archer alleles for increased yield in southern environments and genetic backgrounds. Four sets of near isogenic lines (NIL) for each quantitative trait locus (QTL) were derived from heterozygous F-6 plants identified from the crosses of Archer X Asgrow A5403 and Archer X Pioneer 9641. The NIL sets were tested at four environments across 2 yr. Data was collected on yield, height, and maturity. None of the marker effects were significant for any of the three QTL for any trait, when averaged over all sets or for individual sets. The results suggest that the Archer alleles are not superior to the southern alleles when tested in southern environments. Archer has low relative yield in the South, while in the original mapping study Archer was the high-yield adapted parent. The superior genetic value assigned to the Archer yield QTL may not be readily transported to populations or environments where Archer is inferior. Recombination and epistasis may also have affected the ability of the Archer markers and QTL to improve yield. Our results indicate that it may be difficult to capture the value assigned to QTL alleles derived from diverse parents with variable relative genetic value when the alleles are introgressed into populations with different genetic backgrounds, or when tested in different environments.