|Del Blanco, Isabel|
|Gilbert, Robert -|
|Davidson, Wayne -|
Submitted to: Sugar Journal
Publication Type: Abstract Only
Publication Acceptance Date: May 10, 2010
Publication Date: June 18, 2010
Citation: Comstock, J.C., Del Blanco, I.A., Edme, S.J., Zhao, D., Glynn, N.C., Glaz, B.S., Gilbert, R., Davidson, W. CP-Cultivar Development Program: Challenges and Responses. Sugar Journal. Technical Abstract: The goal of the CP-Cultivar Development Program is to release high-yielding, stress- tolerant cultivars for the Florida sugarcane industry. To meet this goal, two major challenges have recently emerged: 1. it has become increasingly apparent that brown and orange sugarcane rusts are having a major impact on the program, and 2. the program needs to improve its ability to identify productive cultivars for sand soils. The objective of this presentation is to describe the CP program’s progress in addressing these challenges. More intense selection pressure for rust resistance has been implemented by modifying screening procedures in the earlier stages of the program. All clones in the first clonal selection stage (Stage I) are now rated for their reaction to rust in August and all clones with a rating of 2 and above on a 4 point scale are eliminated. Likewise, all Stage II, III, and IV clones are rated at least twice for their sugarcane rust reactions based on natural infection in the regular cultivar development plots and in separate plantings using whorl inoculation. For the first time since orange rust was detected in Florida in 2007, all clones advanced to Stage III in November 2009 had a rating of 1 or less for rust susceptibility. To improve the selection of clones for sand soils, one Stage IV test site on organic soil was moved to a sand location thereby increasing the number of sites with sand soil from two to three. Also, previously this program advanced the same clones from Stage III to all Stage IV locations, regardless of soil type. Now, selection is conducted independently for sand and muck soils. The result has been that about one-third of the clones in Stage IV are tested on both soil types, with one-third tested on sand only, and one-third tested on muck only. Early indications are that this is increasing the number of clones released for sand. Finally, a scientist has been added to the team who will spend substantial time studying how we can genetically improve sugarcane tolerance to the stresses when it is exposed to on sand soils, and other scientists have ongoing or recently completed research projects that aim at improving our selection on sand soils. The CP program modifications have been with the sugar industry partnership and cooperation.