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

Genetic diversity is limited in southern elite soybean [Glycine max (L.) Me rrill]. Introgression of diverse alleles for yield may increase the rate of yield improvement. Beneficial yield alleles at three quantitative trait lo ci (QTL) from the northern cultivar Archer have been tagged with molecular markers. The objective of this research was to assess the value of the thre e Archer alleles for increased yield in southern environments and genetic b ackgrounds. Four sets of near isogenic lines (NIL) for each quantitative tr ait locus (QTL) were derived from heterozygous F-6 plants identified from t he 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 individu al sets. The results suggest that the Archer alleles are not superior to th e southern alleles when tested in southern environments. Archer has low rel ative yield in the South, while in the original mapping study Archer was th e high-yield adapted parent. The superior genetic value assigned to the Arc her yield QTL may not be readily transported to populations or environments where Archer is inferior. Recombination and epistasis may also have affect ed 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 alle les derived from diverse parents with variable relative genetic value when the alleles are introgressed into populations with different genetic backgr ounds, or when tested in different environments.