The role of allelopathy in legume decline in pastures. III. Tolerance of subterranean clover lines to the allelopathic compounds released from Phalaris residues

Abstract

The tolerance of 126 lines of subterranean clover (Trifolium subterraneam L.) to allelochemicals released in cold water leachate from dry herbage of phalaris (Phalaris aquatica L. cv. Australian) was examined and compared. The lines were 112 accessions from grassy associations in the Mediterranean region and 14 Australian cultivars. Measures of germination, radicle length, nodulation and root length in seedlings exposed to three concentrations of extract relative to those obtained from seedlings exposed to distilled water only were obtained. A performance index for each line was derived from these measures. Large differences between lines for these four parameters were evident. On the basis of these comparisons, scope exists to select and recommend lines of subclover which are tolerant to these allelochemicals and thus are capable of higher production and greater persistence in long-term perennial phalaris pastures.