THE DEVELOPING RELATIONSHIP BETWEEN STYLOSANTHES AND ANTHRACNOSE AFTER 14 YEARS IN A NORTH QUEENSLAND PASTURE .3. DIVERSITY IN THE PLANT-POPULATION

Host-plant diversity in a mixed accession Stylosanthes spp. pasture 14 years after establishment was demonstrated in families derived from s eed and in cuttings obtained from the pasture. Glasshouse examination of the progeny from 181 field plants inoculated with 4 different patho genicity strains of Colletotrichum gloeosporioides indicated the wides t possible spread of diversity in disease reaction. The progeny exhibi ted wider variation in resistance to the disease than the originally s own accessions, and when transplanted to a field site, plant phenotypi c variability became increasingly evident as the progenies matured. Of 1339 transplanted progeny, 369 were not able to be conclusively categ orised according to the descriptions of the originally sown accessions , indicating that outcrossing had occurred. The demonstrated plant var iability is, arguably, encouraging for the management of anthracnose u sing genotype mixtures in the vast areas of low-input beef pastures in northern Australia.