Sward tests of some morphological-agronomic groups of Stylosanthes accessions in dry tropical environments

Abstract

An experiment is described in which 33 accessions of Stylosanthes, comprising 12 morphological–agronomic groups of six species, were grown with an associated grass Urochloa mosambicensis for 3 years in small mown swards at nine different dry tropical environments in northern Australia. Pattern analysis was used to elucidate the major differences in sward performance between accessions and sites and to classify the 33 accessions defined by 54 sward attributes (6 measurements x 9 sites) over 3 years. There was a close relation between the classification of the accessions defined by sward data with a previous morphological-agronomic classification based on spaced-plant data.

Among the morphological-agronomic groups tested, S. hamata M–A 28 was outstanding at most sites. However, at the extreme ranges of adaptability, S. scabra M–A 18 was more productive at sites with a growing season of 24–30 weeks, and S. scabra M–A 17 was more productive at sites with one of less than 10 weeks.