RECENT ADVANCES IN STUDIES OF ANTHRACNOSE OF STYLOSANTHES - II - APPROACHES TO BREEDING FOR ANTHRACNOSE RESISTANCE IN STYLOSANTHES IN AUSTRALIA

The considerable diversity in virulence within the population of Colle totrichum gloeosporioides causing anthracnose on Stylosanthes contribu tes 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. Breed ing strategies with S. scabra include the use of genotype mixtures and recurrent selection for partial resistance to anthracnose. Current wo rk with DNA markers linked to major resistance genes should enable the development of cultivars with pyramided genes for resistance. S. scab ra breeding programs also aim to improve winter survival, leafiness, d ry matter and seed yield, flowering time and resistance to other disea ses. Accessions of S. hamata generally exhibit strong field resistance to anthracnose, and improvements in resistance to date have been soug ht through the introduction and evaluation of further accessions, Sinc e 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 con tinued in Australia. The possible contribution of ''Stylosanthes seabr ana'' to pastures on clay soils has been recognised recently, and 2 ne w cultivars have been released.