DETERMINING PLANT RATINGS WITHOUT FIELD TRIALS-PREDICTION OF CLONAL DISEASE RATINGS FOR FIJI LEAF GALL USING NIR SPECTROSCOPY AND CHEMOMETRIC TECHNIQUES

FIJI leaf gall is one of Australia?s most serious diseases of sugarcane and represents a significant problem in almost half of the total area under sugarcane production. Rating sugarcane clones for resistance/susceptibility is difficult and expensive, due to the nature of field-based methods and variable infection levels of trials. Despite the recent development of glasshouse methods to evaluate clones, there are still issues with throughput, quarantine and the timescale to yield final results. We investigated NIR spectroscopy as an alternative means to rate clones without requiring specific field trials and can successfully predict resistance ratings for a set of traditional standard clones from leaf NIR spectra. Further research intends to develop this into a tool for use within the plant breeding and selection program to screen at an earlier stage(s) for resistance, thereby providing cost savings, productivity benefits and increased numbers of resistant clones to later selection stages. The primary advantages of this method are the timescale to produce ratings (potentially hours as opposed to months) and that requirements of specific field trials and quarantine will be minimal. Other prospects exist to develop improved understanding of the basis of resistance to Fiji leaf gall and similar screening technologies for other pest/disease resistance issues that are either difficult or expensive under traditional techniques.