2010 Annual Report
1a.Objectives (from AD-416)
1. Develop more efficient breeding and selection methodologies for cultivar development and to produce seed of selected sugarcane germplasm for use in Florida, Louisiana, and Texas.
2. Develop better agronomic practices for the Florida sugarcane industry.
3. Identify alleles or genes that can be used in molecular marker-assisted selection to complement the conventional approach of sugarcane cultivar development.
4. Identify agronomic and physiological relationships of sugarcane with stress tolerance to improve sugarcane cultivar development.
1b.Approach (from AD-416)
Development of new cultivars with disease resistance, freeze tolerance, and high sucrose content will be advanced through genetic and genomics approaches. These will involve the utilization of a sugarcane genetic map with quantitative trait loci (QTL) and the identification of variation in candidate genes through gene expression profiling, and in some cases through developing markers for gene insertions. To improve cultivar development on sand soils, genetic studies will compare selection efficiencies on organic and sand soils and repeatability between selection stages, and agronomic research will seek useful traits for identifying high-yielding genotypes on sand soils. Agronomic research will also seek useful traits for identifying tolerance to shallow water tables on organic soils, and will examine sampling procedures for estimating fiber content.
Production of older cultivars is reduced as new diseases and new races of current diseases infect previously resistant cultivars. The most recent challenge facing Florida sugarcane growers is the introduction of orange rust. However, production remains high across the industry due to the availability of new cultivars.
True seeds, developed from crosses at Canal Point, FL were sent to the ARS cultivar development program in Louisiana, and the Texas A&M program in Texas. About 106,104 seeds from 483 crosses were sent to Louisiana; about 49,900 seeds from 197 crosses were sent to Texas; and it is estimated that 319,985 seeds from 956 crosses remained in Florida.
Cultivars developed by ARS occupy more than 92.8% of the sugarcane acreage in Florida. This breeding and selection program develops sugarcane cultivars for sand and organic (muck) soils in Florida. In 2010, a growers’ meeting was held to report on newly released sugarcane cultivars in Florida and on promising sugarcane varieties being evaluated in the CP (Canal Point) program. Presentations reported that CP 03-1912 and CPCL 00-4111 were the most promising new varieties in the program. CP 03-1912 is recommended for sand soils and CPCL 00-4111 for muck soils. It was also reported that the CP program has made recent improvements in identifying higher yielding sugarcane varieties for sand soils in Florida. In addition to CP 03-1912, two recently released varieties, CP 00-1101 and CP 01-1372, are being expanded rapidly by growers with sand soils, and it was reported that the CP program has three varieties in the pipeline that may be released next year, all of which are promising for sand soils. Also, it was reported that the CP program has changed strategies on selecting varieties with resistance to two rust diseases, and that while the effectiveness of these new strategies will not be known with certainty for several years, early indications are positive.
Managing Floods in Sugarcane. Sugarcane growers in Florida face strict regulations that limit phosphorus export from their fields to the natural Everglades. To comply, sugarcane must often be flooded or grown with below-ground water tables near the soil surface. In lysimeter research conducted by ARS researchers at the Sugarcane Field Station in Canal Point, FL, sugarcane yields were not reduced by repeated flood durations of 2 weeks if these floods were followed by drainage to 18 inches below the soil surface for 1 week. Drainage to only 9 inches resulted in substantial yield losses compared with a constant 18-inch water-table depth. These findings helped develop a new theory that while sugarcane roots can withstand being inundated for up to 2 weeks, the presence of constant shallow water tables inhibits new root growth. This new theory will be used by researchers to try to develop practices that help sugarcane growers optimize yields while also contributing positively to Everglades restoration.
Release of Two High Yielding Sugarcane Cultivars in Florida. New sugarcane cultivars in Florida are continuously needed for sustained or improved yields, resistance to intense disease pressures, and for improved adaptability to freezes and high water tables. Also, higher yields are needed on sand soils which comprise about 20% of Florida’s sugarcane; muck soils comprise the remaining 80%. Through the cooperative efforts of the ARS Sugarcane Field Station, Canal Point, FL; the University of Florida Institute of Food and Agricultural Sciences Everglades Research and Education Center at Belle Glade, FL; and the Florida Sugar Cane League, Inc. at Clewiston, FL, two new sugarcane cultivars (CP 03-1912 and CPCL 00-4111) were recommended for release in Florida. The new cultivars will add genetic variability for disease resistance while yielding well in Florida, the state in the U.S. with the highest sugar production; 19% of all sugar produced in the U.S. CP 03-1912 is expected to yield well on sand soils and CPCL 00-4111 is expected to yield well on muck soils in Florida.
Glaz, B.S., Morris, D.R. 2009. Sugarcane Responses to Water-Table Depth and Periodic Flood. Agronomy Journal. 102:372-380.
Zhao, D., Glaz, B.S., Edme, S.J., Del Blanco, I.A. Precision of sugarcane biomass estimates in pot studies using fresh and dry weights. American Society of Sugar Cane Technologists. 30:37-49. 2010.
Ray, J.D., Sinclair, T.R., Glaz, B.S. 2010. Sugarcane Response to High Water Tables and Intermittent Flooding. Journal of Crop Improvement. 24:12-27.
Glynn, N.C., Dixon, L.J., Castlebury, L.A., Szabo, L.J., Comstock, J.C. 2010. PCR assays for the sugarcane rust pathogens Puccinia kuehnii and P. melanocephala and detection of a SNP associated with geographic distribution in P. kuehnii. Plant Pathology. 59:703-711.
Del Blanco, I.A., Glaz, B.S., Edme, S.J. Improving efficiency of sugarcane genotype selection in Florida. Crop Sci., doi: 10.2135/cropsci2009.09.0539 50:1744-1753. 2010.