Varietal and environmental variations in isoflavone concentrations in subterranean clover (Trifolium subterraneum L.)

Abstract

The concentrations of formononetin, genistein, and biochanin A in leaves of 151 lines belonging to three subspecies of T. subterraneum L. and of 8 lines of T. israeliticum D. Zoh. & Katzn, were measured from plants grown in the field at Perth and Canberra, and in a glasshouse at Perth. The average concentrations did not differ significantly between locations, but did between sampling dates.

The components of variance were greater for subspecies, and for varieties within subspecies, than for environmental variables other than error. Interactions were negligible, although some were greater than zero. The component correlations between concentrations of different isoflavones were generally positive where determined by environment, but tended to be negative where determined by genotype, especially that between genistein and biochanin A.

Differences among subspecies In level and pattern of isoflavone concentration could be of limited value for taxonomic classification. Differences among varieties within subspecies are sufficient to promise progress in selection for low levels of individual isoflavones by conventional techniques of plant breeding. Selection for low levels of total isoflavones would be hindered, but not prevented, by the negative genotypic correlations between concentrations of genistein and biochanin A.