L.A. EDYE¹ and BRIGITTE L. MAASS²

¹CSIRO Tropical Agriculture, Townsville, Queensland, Australia
²Centro Internacional de Agricultura Tropical, Cali, Colombia

Abstract

Three species "new" to agriculture, viz. S. hamata allotetraploids, S. scabra and "Stylosanthes seabrana", have been recognised following the classification and evaluation of Stylosanthes collections, and cultivars have been developed.
S. hamata is indigenous to the drier habitats of the Caribbean Islands, southern Florida, Colombia and Venezuela. Diploid (2n = 20) and allotetraploid (2n = 40) races are recognised currently. The diploids, from predominantly alkaline soils, require specific rhizobia from similar soils. The allotetraploids occur only in Colombia and Venezuela on acid–neutral soils and nodulate freely.
S. scabra is an allotetraploid, widespread in South and central America. Accessions nodulate freely and show morphological and agronomic variation, which reflects the different geographic and climatic environments of their origin.
"Stylosanthes seabrana" is a diploid closely related to S. scabra originating from Bahia, Brazil. It has a specific Bradyrhizobium requirement, and occurs at altitudes of 400–1050 m in regions with 400–1190 mm annual rainfall and a 2–7 month dry season. This diploid is a potential forage plant for northern Australia.