Assessment of the genetic potential for pasture purposes of the Psoralea eriantha - patens complex, a native legume of the semi-arid zone

Abstract

Four accessions of Psoralea were grown under favourable conditions in a simulated sward trial at the University of Queensland Research Farm, Redland Bay. The accessions, selected on the basis of growth habit, were A1 8, prostrate; A1 5 and A1 13, semi-erect; and A1 84, erect. These were compared with lucerne and Siratro as controls. Dry matter and nitrogen determinations were made at three different harvest intervals and plant densities for a twelve month period. Yields of the Psoralea accessions reflected markedly the harvest regimes to which they were subjected. Highest yields of the prostrate A1 8 come from the six week harvest interval, A1 13 from the three month interval and A1 5 and A1 84 from the six month harvest interval. Highest yields in most cases were obtained from the highest planting density. When the most favorable cutting regimes were compared for each entry, the two highest Psoralea accessions, A1 84 and A1 13, gave yields at the end of the first six months comparable to the lucerne control and greater than Siratro. A184 behaved as an annual and did not recover after cutting at the six month harvest interval. Other accessions showed greater ability to recover after cutting. A1 13 at the 12 month harvest was the highest yielding Psoralea, producing less than lucerne and more than Siratro. The nitrogen content of leaves of A1 13 was less (P < 0.05) than lucerne, but not significantly less than Siratro. Leaf dry matter as percentages of the total were comparable with the two controls.