Marker‐assisted parentage analysis reveals high individual selfing rates in tetraploid red clover genotypes selected for seed yield

Seed yield is a major breeding target in tetraploid red clover. We investigated if marker-assisted parentage analysis can identify progeny plants with two high seed-yielding parents in tetraploid red clover and if this technique is more advantageous than traditional half-sib selection. Parentage analysis was successfully performed on the progeny from the 10% highest seed-yielding genotypes from a second-cycle family selection trial: 16.0% of progeny were identified with a high seed-yielding father. However, progeny plants with two high seed-yielding parents did not produce more seeds than traditionally selected progeny (27.3 g vs. 30.7 g/plant, respectively). The 10% highest seed-yielding genotypes displayed on average 2% self-fertilization. Four genotypes were self-fertile with individual selfing rates up to 20%. Our results discourage the use of marker-assisted parentage analysis to improve seed yield in tetraploid red clover when the material has been preselected for seed yield. Breeders should be aware that intensive selection for seed yield in tetraploid red clover may inadvertently lead to selection for increased self-fertility, which may increase inbreeding in the long term.