D.F. CAMERON¹, R.M. TREVORROW² and C.J. LIU¹

¹CSIRO Tropical Agriculture, St Lucia, Queensland, Australia
²CSIRO Tropical Agriculture, c/- QDPI, Mareeba, Queensland, Australia

Abstract

The considerable diversity in virulence within the population of Colletotrichum gloeosporioides causing anthracnose on Stylosanthes contributes to the ability of the pathogen to overcome resistance in the host. Therefore, breeding programs aim to include a diversity of resistance genes in a cultivar to produce broad-based, durable resistance. Breeding strategies with S. scabra include the use of genotype mixtures and recurrent selection for partial resistance to anthracnose. Current work with DNA markers linked to major resistance genes should enable the development of cultivars with pyramided genes for resistance. S. scabra breeding programs also aim to improve winter survival, leafiness, dry matter and seed yield, flowering time and resistance to other diseases. Accessions of S. hamata generally exhibit strong field resistance to anthracnose, and improvements in resistance to date have been sought through the introduction and evaluation of further accessions. Since S. guianensis is less important in Australia and there is potential to import cultivars developed through South American breeding programs, breeding for anthracnose resistance in this species has not been continued in Australia. The possible contribution of "Stylosanthes seabrana" to pastures on clay soils has been recognised recently, and 2 new cultivars have been released.