Volume 25, 1

Tropical Grasslands (1991) Volume 25, 1–11

Sward evaluation of fifteen Stylosanthes hamata accessions in twenty dry tropical environments

L.A. EDYE¹, T.J. HALL², C.H. MIDDLETON², W.B. MESSER¹, C.M. PIGGIN,³, A.C. SCHLINK⁴ and N.M. KLEPACKI⁵

¹Division of Tropical Crops and Pastures, CSIRO, Townsville;
²Pasture Management Branch, QDPI, Mareeba and Rockhampton;
³Livestock Development Project, Timur (Indonesia);
⁴Division of Tropical Animal Production, CSIRO, Townsville;
⁵WA Department of Agriculture, Derby, Australia.

Abstract

Forty-four S. hamata accessions were grown in association with volunteer species (mainly native grasses) for 3 to 5 years in small swards in 20 dry tropical environments, 18 of which were considered marginal for the existing cultivar Verano because of low rainfall (8), cool temperatures (5) or soil type (5).
The objectives were to find accessions superior to Verano for marginal environments. Results are presented for the 15 S. hamata tetraploids which were grown in all environments, and for the diploid CPI 61670 which was grown in 10 environments.
In spite of low rainfall, the stylos established and survived in 15 of the 20 environments. The stylos were adapted to a wide range of soil types including solodics and red and yellow earths but not grey cracking clays and a shallow solodic with impeded drainage.
Cultivar Amiga (CPI 55822) was significantly better than Verano in perenniality in 2 out of 3 years and dry matter yield in 2 out of 4 years when averaged over all environments, and maintained higher seedling densities than Verano. In Timur, CPI 61670 showed marked environmental specificity and gave higher yields than Amiga and Verano on an alkaline clay soil with pH 8.6 and an average annual rainfall of 1200 mm.