Morphology and agronomic performance of white clover with increased flowering and condensed tannin concentration

Abstract

High tannin (HT) white clover (Trifolium repens), bred for increased floral condensed tannin (CT) and flowering prolificacy, was assessed under dairy grazing in the Waikato region of New Zealand. HT and ‘Grasslands Huia’ white clover monocultures sown in April 2001 were monitored until November 2003. HT grew 1 t DM ha^–1 less than ‘Huia’ each year and both had similar CT concentrations in flower heads across sampling dates (13–80 g kg^–1 DM). HT had more flowers per plant and per node than ‘Huia’, but similar numbers of stolon branches per node. Higher flower densities in HT than ‘Huia’ swards from October 2001 to January 2003 resulted in higher clover CT concentrations, reaching 12 g kg^–1 clover DM, but contamination of HT swards by clover plants arising from the seedbank reduced treatment differences. Future attempts to increase CT concentration in white clover should involve CT expression in foliage rather than flowers to maintain agronomic performance.

Key words:

• condensed tannin
• cyanogenesis
• flowering
• morphology
• stolon branching
• Trifolium repens
• white clover