2011 Annual Report
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.
True seeds, developed from crosses at Canal Point, Florida, were sent to the ARS cultivar development program in Louisiana, and Texas A&M University program, Texas. It is estimated that there were 77,609 seeds from 278 crosses sent to Louisiana; 53,602 seeds from 95 crosses sent to Texas; and 716,257 seeds from 998 crosses remained in Florida.
Cultivars developed by ARS occupy more than 97% of the sugarcane acreage in Florida. This breeding and selection program develops sugarcane cultivars for sand and organic (muck) soils in Florida. Improvements are needed in for cultivar selection for sand soils. In 2011, all stages of the selection program were planted on sand soils, beginning with the seedling stage (but bypassing Stage 1 and going directly to Stage 2). In addition, all stages of the selection program were conducted on muck soils. Three recently released varieties CP 03-1912, CP 00-1101, and CP 01-1372 are being expanded rapidly by growers with sand soils. In addition, in 2011, there were six new varieties released. Three of these six were specifically for sand soils, two were for muck and sand soils, and one was for muck soils. Indications are positive that changes made in selecting for resistance to the brown and orange rust diseases are resulting in the ability of this program to release varieties with resistance to these diseases as four of the six newly released cultivars were resistant to both rusts and two cultivars were moderately susceptible to orange rust.
In research to conserve muck soils on which sugarcane in Florida is grown, to help growers meet Best Management Practices for reduction of phosphorus export, a lysimeter and two pot experiments were conducted to learn how shallow water tables and periodic flooding affect the roots and growth of recently planted sugarcane.
A DNA sequence polymorphism that separates pathogenic isolates originating from the Western and Eastern Hemispheres was discovered in the orange rust pathogen Puccinia kuehnii a future breeding challenge of the Canal Point program is to develop sugarcane cultivars resistant to both strains.
Developing varieties that tolerate freeze conditions is an important aspect of our breeding research. To understanding how sugarcane responds to freeze, the timecourse deterioration in the sucrose profile of elite sugarcane genotypes was studied under field conditions and the physiological underpinning of freeze tolerance was investigated by screening several sugarcane germplasm under controlled conditions.
Water deficit during the early growing season is a key abiotic stress which limits sugarcane yields on sand soils in Florida. Pot studies indicated that nondestructive measurements of chlorophyll fluorescence and leaf photosynthesis could be useful for early detection of sugarcane water-deficit stress. Field studies are underway to test if these physiological traits can be used to screen and evaluate sugarcane genotypes.
Zhao, D., Glaz, B.S., Comstock, J.C. 2010. Sugarcane Response to Water-Deficit Stress during Early Growth on Organic and Sand Soils. Amer. J. of Agr. and Biological Science. 5(3):403-414.
Davidson, R., Milligan, S.B., Glaz, B.S., Comstock, J.C., Hu, C., Glynn, N.C., Edme, S.J., Holder, D.G., Gilbert, R.A., Sood, S.G., Del Blanco, I.A., Zhao, D.Registration of ‘CPCL 99-4455’ Sugarcane. Journal of Plant Registrations. 5:54-61. 2011.
Glaz, B.S., Shine, J.M., Irey, M.S., Perdomo, R., Powell, G., Comstock, J.C. 2011. Fiber Content of Three Sugarcane Cultivars in Three Crop Cycles on Sand and Muck Soils. Agronomy J. 103:211-220.
Zhao, D., Wright, D., Marois, D., Mackowiak, C., Brennan, M. 2010. Improved growth and nutrient status of an oat cover crop in sod-based versus conventional peanut-cotton rotations. Agronomy for Sustainable Development. 30:497-504.
Zhao, D., Glynn, N.C., Glaz, B.S., Comstock, J.C., Sood, S.G. 2011. Orange Rust Effects on Leaf Photosynthesis and Related Characters of Sugarcane. Plant Dis. 96:640-647.
Reed, S.T., Joseph, R., Ayala Silva, T., Glaz, B.S. 2011. The effects of natural and induced short-term floods on four sugarcane accessions. International Sugar Journal. 113:64-70.
Zhao, D., Reddy, R., Kakani, G.V., Read, J.J. 2010. Remote sensing algorithms for estimating nitrogen uptake and nitrogen use efficiency in cotton. Acta Agriculturae Scandinavica, Section B-Plant Soil Science. 60:500-509.