Variation of condensed tannins in roundhead lespedeza germplasm

Abstract

Roundhead lespedeza, Lespedeza capitata Michx., is a deeprooted, perennial legume native to the eastern and central USA and is relatively common on remnant upland prairies throughout the Midwest. Information on condensed tannin (CT) concentrations from different plant parts is needed for cultivar development and also to provide data for developing management and feeding strategies. The objectives of this study were to determine variation of CT concentrations in roundhead lespedeza leaves, stems, and inflorescences; evaluate genotype variation over environments; and select germplasm lines that could be used for breeding parents and/or bulked into a synthetic variety. Thirty-nine roundhead lespedeza plant introductions (PI) were sampled from replicated nurseries grown in two environments in 1996. Plant shoots were collected at flowering and seed filling. Each plant shoot sample was divided into leaf, stem, and inflorescence. Condensed tannin concentrations were determined by means of a modified vanillin-HCl method. We found that variation due to the environment was low, variation due to genotype was high, and variation due to genotype × environment interaction was high. Of these 39 plant introductions, we selected eight that were common to both environments and had low CT concentrations in leaves at flowering. The CT content of these plant introductions, however, was still relatively high when compared with sericea lespedeza [Lespedeza cuneata (Dumont) G. Don] that was bred for low tannin content. Collections should be made from a larger geographical region to look for germplasm with lower CT concentrations.