Sucrose Accumulation Maturity Curves for CP 78-1628 ¹

Robert A. Gilbert, James M. Shine, Jr., Jimmy D. Miller, Ronald W. Rice, and Curtis R. Rainbolt²

Introduction

Sugarcane (Saccharum spp.) is harvested during a 5-month period (October to March) in south Florida. “Early maturing” cultivars milled in October or November may not have reached their peak sucrose content, but may have higher sugar per ton (SPT, lbs sucrose/ton of sugarcane biomass) than other cultivars at the onset of milling operations (Miller and James, 1977). Under current industry milling capacities, harvesting the 450,000 acres of Florida sugarcane takes roughly 5 months. Unavoidably, sugarcane plants harvested during the early harvest period have not yet achieved maximum sugar content. Consequently, sugar content for any given cultivar will change over the course of the harvest season, which can impact the profitability of the harvest. Maturity curves of SPT vs. time have been developed for sugarcane cultivars in South Africa (Bond, 1982), Louisiana (Legendre and Fanguy, 1975; Legendre, 1985; Richard et al., 1981) and Mauritius (Mamet and Galwey, 1999). Although it is known that sucrose accumulation rates vary between varieties, maturity curves for recently released “CP” sugarcane cultivars (those developed at the USDA-ARS Sugarcane Field Station in Canal Point, FL) have not been reported since 1977 (Rice, 1974; Miller and James, 1977). CP cultivars occupy > 70% of Florida sugarcane acreage, and are also economically important (Tew, 2003) in many countries including Argentina (25% of total acreage), Belize (16%), El Salvador (50%), Guatemala (65%), Honduras (47%), Mexico (15%), Morocco (54%), Nicaragua (75%), Senegal (9%) and Venezuela (9%). Since most sugarcane growers in Florida plant a diverse selection of cultivars, these maturity curves are needed as tools to help growers make informed choices regarding harvest scheduling decisions.

This fact sheet presents the sucrose accumulation maturity curves for different crop ages (plant cane, 1^st ratoon, and 2^nd ratoon) of CP 78-1628. CP 78-1628 harvest samples were collected at 2-week intervals at 5 locations over 4 harvest seasons in the Everglades Agricultural Area. Biomass and sugar yields were determined on all samples in order to generate SPT trends over time. A full comparison of CP 78-1628 SPT trends with 12 other CP cultivars may be found in EDIS publication SS-AGR-221 Maturity Curves and Harvest Schedule Recommendations for CP Sugarcane Varieties http://edis.ifas.ufl.edu/sc069.

Cultivar Description

CP 78-1628 is grown on 11.5 % of the EAA sugarcane acreage (Glaz and Gilbert, 2003). This clone is the most widely grown cultivar on mineral (sandy) soils in south Florida. Descriptive information and photographs of CP 78-1628 can be found at http://edis.ifas.ufl.edu/ag132.

Maturity Curves

Figure 1 presents the sugar per ton (SPT, lbs sugar/ton sugarcane biomass) for CP 78-1628 from mid-October to mid-March. Separate curves are presented for plant cane, 1^st ratoon, 2^nd ratoon, and the entire data set.

Research has shown that older ratoon crops generally have higher SPT values but lower tonnage (Glaz et al., 1989; MacColl, 1976). Thus, growers should generally expect the SPT of their sugarcane crop to increase with crop age (see Figure 1). The mean SPT of CP 78-1628 increased from 267 lbs/ton in plant cane to 270 lbs/ton in1^st ratoon and 274 lbs/ton in 2^nd ratoon. The overall mean across crop ages ranked 2nd out of 13 CP cultivars.

Grower recommendations are based on the entire data set across all crop ages. Early-season predicted SPT for CP 78-1628 at the onset of harvest on Oct. 14 was 207 lbs/ton (ranked 5th out of 13 cultivars), and maximum predicted SPT was 288 lbs/ton on Jan. 28 (ranked 3rdout of 13 cultivars). In comparison to other CP cultivars, CP 78-1628 should be harvested during the middle 50 days of the harvest season http://edis.ifas.ufl.edu/sc069. CP 78-1628 has been known to dry back severely after flowering. This increases the importance of harvesting this cultivar during mid-season.

References

Bond, R.S. 1982. Maturity differences between varieties in the selection programme. Proc. Ann. Cong. S. African Sugar Technol. Assoc. 56:136-139.

Gilbert, R.A., J.M. Shine, Jr., J.D. Miller and R.W. Rice. 2004. Sucrose accumulation and harvest schedule recommendations for CP sugarcane varieties. University of Florida Cooperative Extension Service Fact Sheet SS-AGR-221. University of Florida, UF/IFAS Extension Digital Information Source (EDIS) Database. http://edis.ifas.ufl.edu/sc069.

Glaz, B. and R.A. Gilbert. 2003. Sugarcane Variety Census: Florida 2001. University of Florida Cooperative Extension Service Fact Sheet SS-AGR-198. University of Florida, UF/IFAS Extension Digital Information Source (EDIS) Database, http://edis.ifas.ufl.edu/sc060.

Glaz, B., M.F. Ulloa and R. Parrado. 1989. Cultivation, cultivar and crop age effects on sugarcane. Agron. J. 81:163-167.

Legendre, B.L. 1985. Changes in juice quality of nine commercial sugarcane varieties grown in Louisiana. J. Am. Soc. Sugarcane Technol. 4:54-57.

Legendre, B.L and H. Fanguy. 1975. Relative maturity of six commercial sugarcane varieties grown in Louisiana during 1973. Sugar Bull. 53(2):6-8.

MacColl, D. 1976. Growth and sugar accumulation of sugarcane: II. Percentage of sugar in relation to pattern of growth. Expl. Agric. 12:369-377.

Mamet, L.D. and N.W. Galwey. 1999. A relationship between stalk elongation and earliness of ripening in sugarcane. Expl. Agric. 35:283-291.

Miller, J.D. and N.I. James. 1977. Maturity of six sugarcane varieties in Florida. Proc. Am. Soc. Sugar Cane Tech. 7:107-111.

Richard, C.A., F.A. Martin, and G. M. Dill. 1981. Maturity patterns of several Louisiana sugarcane varieties. J. Am. Soc. Sugarcane Technol. 8:62-65.

Rice, E. 1974. Maturity studies of sugarcane varieties in Florida. Proc. Am. Soc. Sugarcane Technol. 4:33-35.

Schueneman, T.J., J.D. Miller, R.A. Gilbert and N.L. Harrison. 2001. Sugarcane cultivar CP 78-1628 descriptive fact sheet. University of Florida Cooperative Extension Service Fact Sheet SS-AGR-117. University of Florida, UF/IFAS Extension Digital Information Source (EDIS) Database, http://edis.ifas.ufl.edu/ag132.

Tew, T.L. 2003. World sugarcane variety census – year 2000. Sugar Cane International March/April 2003:12-18.

Figure 1.

Sucrose Accumulation Maturity Curves for CP 78-1628.

[Click thumbnail to enlarge.]

Footnotes

This document is SS-AGR-214, one of a series of the Agronomy Department, Florida Cooperative Extension Service, Institute of Food and Agricultural Sciences, University of Florida. Published April, 2004. Reviewed September 2011. This publication is also a part of the Florida Sugarcane Handbook, an electronic publication of the Agronomy Department. For more information, contact the editor of the Sugarcane Handbook, Ronald W. Rice (rwr@ufl.edu). Please visit the EDIS website at http://edis.ifas.ufl.edu.

R. A. Gilbert, associate professor, Agronomy Department, Everglades REC-Belle Glade, FL; J. M. Shine, Jr., Sugar Cane Grower's Cooperative of Florida, 1500 W. Sugar House Rd, Belle Glade, FL 33430; J. D. Miller, courtesy professor, Agronomy Department (Retired), USDA-ARS, Sugarcane Field Station, 12990 US Hwy 441, Canal Point, FL 33438; R. W. Rice, Sugar Cane Grower's Cooperative of Florida, 1500 W. Sugar House Rd, Belle Glade, FL 33430; and C. R. Rainbolt, Palm Beach County Extension, 2976 SR-15, Belle Glade, FL 33430; Florida Cooperative Extension Service, Institute of Food and Agricultural Sciences, University of Florida, Gainesville, FL 32611.

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