Genotype x environment effects on selection for rust resistance in sugarcane

Successful variety selection depends on reliable estimates of economically important characters. The effect of sugarcane rust (Puccinia melanocephala H. and P. Syd.) on varieties in an advanced selection trial within the Herbert River district was examined in 1979 (Symington, 1981). Reliability of rust ratings within the trial was high, but caution was expressed in relation to the degree of development of the symptoms and the likelihood of variation from trial to trial. After the initial outbreak, low levels of infection were observed until 1983. However, since 1983 this species of rust has appeared on many of the local commercial varieties during September-February with the possibility of small, but increasing, crop losses. The aim of this study was to assess the importance of locations and years effects on the reliability of rust ratings.