Orange rust resistance screening in parent canes at BSES Meringa 2000-2008.
Orange rust (Puccinia kuehnii) is one of the most important leaf diseases affecting the yield of commercial crops in Queensland. An epidemic in 2000-2001 in the susceptible variety Q124 caused widespread yield losses throughout the industry and highlighted the need for resistance screening in parent varieties. Since then the most important parents have been assessed for resistance at BSES Meringa. A selection of varieties (standards) with known field reaction to orange rust were selected and assessed for disease severity each year (except 2005) through to 2008. Their average disease infestation level over that period was used to apply standard ratings and, in turn, these ratings were used to apply resistance ratings to other parent clones/varieties. This paper describes the consistency of reaction of these standards in each year of disease assessment. In general, orange rust resistance screening is reliable and the standard varieties selected in 2000 provide a suitable range in disease resistance, allowing the application of reliable ratings to other parent varieties.