Paclobutrazol and white clover seed production: a non-fulfilled potential

Abstract

Seed yield in white clover depends largely on the number of ripe inflorescences per unit area, and the plant growth regulator paclobutrazol has been used in an attempt to both increase and concentrate inflorescence production, and hence increase seed yield. However results reported from both New Zealand and Europe have been inconsistent, with seed yield responses ranging from highly significant increases to no effects. The current high cost of the chemical ($1280/ha) requires a seed increase of over 300 kg/ha to ensure an economic return. Similarly no consistent effects of paclobutrazol on white clover vegetative and reproductive growth and development have been established. Possible reasons for this variable response of white clover to paclobutrazol application are presented and discussed. Keywords: inflorescence production, Parlay, reproductive growth, seed yield components, Trifolium repens, vegetative growth