|Davidson, Wayne -|
Submitted to: American Society of Sugar Cane Technologists
Publication Type: Abstract Only
Publication Acceptance Date: May 4, 2009
Publication Date: July 1, 2009
Citation: Comstock, J.C., Glynn, N.C., Davidson, W.R. 2009. Sugarcane Brown and Orange Rusts: Their Impact in Florida and the USDA-ARS Sugarcane field Station. American Society of Sugar Cane Technologists. Volume 29:82 Technical Abstract: Sugarcane brown rust has been present in Florida since 1978 and orange rust, caused Puccinia kuehnii, was confirmed in Florida in 2007 by morphological and molecular techniques. Both brown and orange rusts have impacted both the commercial production and cultivar development programs in Florida. Since the July 2007, orange rust caused severe symptoms on CP 80-1743, a cultivar that occupied 25 % of the acreage. CP 72-2086, occupying 4 % of the acreage was also moderately susceptible. Furthermore, the high orange rust spore load threatens CP 89-2143 a major cultivar that did not have orange rust symptoms originally but P. kuehnii pustules are now occurring on the variety. A status of the impact of brown and orange rusts on the selection and cultivar development program will be given. In the 2008 crossing season, approximately 45 % of the parental clones were resistant to either orange or brown rust. The overall 30% of the clones in Stage II were resistant to both sugarcane rust pathogens but depending on the specific female parent the resistance of their progeny varied dramatically. Rust resistance of clones advanced to Stage III improved in 2008 compared to those of 2007. The level of rust resistance of clones in Stage IV and the increase program appears to be improving. Changes in the program to develop rust resistant progeny will be discussed.