Variation for Concentrations of Various Phytoestrogens and Agronomic Traits Among a Broad Range of Red Clover (Trifolium pratense) Cultivars and Accessions

Agronomic characteristics and phytoestrogen concentrations were measured on 17 cultivars and 47 accessions of red clover (Trifolium pratense). These accessions included a range of currently recommended cultivars—from Australia and overseas—and germplasm accessed from genetic resource collections. All lines were grown in the field at Hamilton Vic in 2000 and 2001. Significant genetic variation was detected for key agronomic parameters such as growth habit, leaf shape and markings, leaf area, herbage yield, flowering time, and prolificacy. Significant variation in the concentration of the four main phytoestrogens was found; total isoflavone concentration ranged from 0.14–1.45% DM. Maximum concentrations of daidzein, genistein, formononetin, and biochanin were 0.06, 0.08, 0.86, and 0.91% DM respectively. Multivariate analysis showed that the accessions grouped into 10 distinct clusters that had between 1 and 10 members. Several accessions were superior to existing cultivars—notably Mediterranean accessions with regard to cool season vigour—and valuable for breeding programs to develop high yielding cultivars with either high (for possible medicinal purposes) or low (for grazing) phytoestrogen concentrations.