Direct application of QTL discoveries may improve realised gain from selection in open-pollinated forages such as white clover (Trifolium repens). White clover (2n=4x=16) exhibits complex inheritance for traits underpinning animal productivity, animal health, pasture persistence, and seed production. Seed yield (SY) exhibits moderate to high heritability in forage legumes and may be a constructive case-study for application of marker-assisted selection (MAS) in white clover improvement. The objectives of this research were to assess marker:trait associations in complex breeding populations, using markers sourced from genome regions exhibiting QTL effects for SY and its components: inflorescence density (ID) and seed yield per inflorescence (YI). Marker loci linked to a QTL conditioning SY and ID on linkage group C2, or to a QTL conditioning SY and YI on linkage group D2 were used to survey complex, multi-parent breeding populations (>160 plants per population). SY field testing of each population followed standard practice in forage legume breeding programmes: i.e. a single year, unreplicated spaced-plant trial conducted in an arable environment as a SY ‘finishing selection' among genotypes which had been extensively tested and selected in mixed sward pastoral environments. A survey of potential parent plants in breeding population ‘C23759' using these marker loci revealed alleles significantly (p<0.01) associated with SY, exhibiting mean performance differences of up to 39% between allele present and allele absent genotypic classes at a locus. Selections were made on phenotypic or genotypic criteria for subsequent poly-crossing and testing to determine the value of phenotypic selection versus MAS in terms of realised gain from selection. Genotypic selections were made using marker loci with one or more alleles at 30-70% frequency in the population and with the allele present phenotype significantly (p<0.01) greater than the allele absent phenotype for SY. These strategies and initial results indicate opportunity for MAS in forage species.