Myrtaceae species resistance to rust caused by Puccinia psidii

Seeds from different species and provenances of Myrtaceae, collected from wild populations in Australia, were screened for resistance to rust caused by Puccini psidii. Seedlings were inoculated with a suspension of rust inoculum and incubated in a mist chamber in the dark for 24 h. Subsequently, the plants were transferred to a growth chamber and rust reaction was evaluated 12 days later. Inter-and intra-specific variability was observed among and within the myrtaceae species. Independent of the provenance, the most resistant species were: Corymbia calophylla 'rosea', C. tesselaris, Melaleuca ericifolia, Eucalyptus tereticornis, E. resinifera, E. scias subsp. scias, E. paniculata, E. pellita and C. intermediata. In contrast, M. nesophila, M. alternifolia, M. cajuputi subsp. cajuputi, M. leucadendra, M. quinquenervia, E. cloeziana, E. diversicolor, E. regnans and E. grandis displayed the highest number of susceptible plants. Among those additional myrtaceaceous genera which were tested for their reaction to rust the most resistant were Asteromyrtus dulcia, A. tenuifolia, Gossia fragrantissima, Lophostemon confertus, Syzygium australe, S. wilsonii subsp. cryptophlebium, Archirhodomytus beckleri, Acmena smithii and Syzygium alatoramulum. Pericalymma ellipticum, Kunzea baxteri, Astartea heteranthera, Regelia ciliata, Rhodomyrtus psidioides and Syncarpia glomulifera were the most susceptible species.