STYLOSANTHES SP. AFF. SCABRA, A NEW STYLO FOR HEAVY SOILS
P.I. Jansen and L.A. Edye
CSIRO Division of Tropical Crops & Pastures, Davies Lab, PMB, PO Aitkenvale, Qld 4814

INTRODUCTION

In 1988, a new species of Stylosanthes was discovered as a contaminant in a field trial of S. scabra. Maass and Schulze-Kraft (2) refer to this morphotype as S. sp. aff. scabra, because of its close similarity to S. scabra. It has some unique morphological and agronomic features, including its ability to perform well on heavy soils. This paper gives a brief overview of its most important features.

MATERIALS AND METHODS

Seventeen S. sp. aff. scabra lines were grown in spaced plant trials on weed matting at the CSIRO Lansdown Research Station near Townsville, Queensland and on heavy soils in regional sward trials near Emerald, Theodore, Gayndah, Mundubbera and Roma and on light soils near Charters Towers. Morphological characters were studied at Lansdown and yield and perennial plant and seedling numbers were recorded at the regional sites.

RESULTS AND DISCUSSION

Stylosanthes sp. aff. scabra outperformed S. scabra to a considerable degree on the heavy soils of central and southern Queensland. The results of the fourth year's sampling at the Brigalow Research Station are given as an example (Table 1). Performance on the light soils of northern Queensland was less or similar to S. scabra.

Table 1. Mean density of Seca (S. scabra) and two S. sp. aff. scabra lines: perennials and seedlings (no/m²) and yield (kg/ha) on Brigalow Grey Clay (Theodore) in year 4.

Accession	Perennials (no/m2)	Seedlings (no/m2)	Yield (kg/ha)
Seca	2.7	21.7	693
104710	8.7	252.7	3328
110361	9.7	561.0	3865

Stylosanthes sp. aff. scabra lines differed morphologically from S. scabra in their more elongate, hairless leaflets, the presence of stipule horn lateral bristles and thinner stems. Date et al. (1) have provided evidence that the S. sp. aff. scabra population belongs to a new, distinct species, which is, however, closely related to S. scabra.

REFERENCES

1. Date, R.A., Edye, L.A. and Liu, J.C. 1995. Proc. 5th Trop. Grassl. Conf. (in press).
2. Maass, B.L. and Schulze-Kraft, R. 1993. Proc. XVII Int. Grassl. Cong., pp. 2151-2153.