ARS | Publication request: Breeding for Resistance to Orange Rust of Sugarcane Caused by Puccinia kuehnii

Submitted to: American Phytopathological Society Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: December 14, 2011
Publication Date: December 15, 2012
Citation: Glynn, N.C. 2012. Breeding for Resistance to Orange Rust of Sugarcane Caused by Puccinia kuehnii. American Phytopathological Society Abstracts. P175.

Technical Abstract: Orange rust of sugarcane caused Puccinia kuehnii is an economically important disease in many parts of the world. Orange rust was first reported in Florida in 2007. A 2009 survey showed that over 80% of the commercial sugarcane acreage is moderately susceptible or highly susceptible to the disease representing potentially millions of dollars in losses. Host resistance provides the most efficient long-term method for controlling orange rust. A comprehensive approach has been developed to improve our understanding of orange rust resistance in sugarcane and to support sugarcane breeding and cultivar development in Florida. Naturally occurring inoculum and artificial inoculation experiments were use to determine the orange rust reactions of germplasm used for breeding. In replicated field experiments, 34% of 500 clones tested were found to be highly resistant to orange rust and 27% highly susceptible, this information is being used to design crosses aimed at improving the resistance among progeny selected in the Canal point program. A seedling inoculation test was developed and applied to screen progeny of crosses made using combinations of resistant and susceptible parents to explore the genetics of orange rust resistance. Susceptible progeny could easily be identified in flats and the heritability of orange rust resistance was found to be moderate-high. Restriction-site Associated DNA Sequencing and gene expression studies are being applied to sugarcane clones contrasting in orange rust reactions in order to identify potential markers associated with orange rust resistance and to understand genes involved in the orange rust resistance mechanisms.