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a USDA-ARS Sugarcane Field Station, 12990 US Hwy. 441 N, Canal Point, FL 33438
b Florida Sugar Cane League, Inc., P.O. Box 1208, Clewiston, FL 33440
c Univ. of Florida, Everglades Research and Education Center, 3200 East Palm Beach Rd., Belle Glade, FL 33430. Mention of trade names or commercial products is solely for the purpose of providing specific information and does not imply recommendation or endorsement by the USDA, the University of Florida, or the Florida sugarcane League, Inc
* Corresponding author (Barry.Glaz{at}ars.usda.gov).
ABSTRACT
‘CP 01-1372’ (Reg. No. CV-136, PI 655942) sugarcane (a complex hybrid of Saccharum spp.) was developed through cooperative research conducted by the USDA–ARS, the University of Florida, and the Florida Sugar Cane League, Inc., and was released to growers in Florida in December 2008. CP 01-1372 was selected from a cross of genotype CP 94-1200 x ‘CP 89-2143’ made at Canal Point, FL, in December 1998. The female parent, CP 94-1200, was advanced to the final selection stage (Stage 4) of the Canal Point sugarcane cultivar breeding and selection program. The male parent, CP 89-2143, is a major sugarcane cultivar in Florida. CP 01-1372 was released because of its high cane yield and commercial recoverable sucrose on both organic and sand soils, and its acceptable levels of resistance to brown rust (caused by Puccinia melanocephala Syd. & P. Syd.), orange rust [caused by P. kuehnii (Kruger) E. Butler], leaf scald [caused by Xanthomonas albilineans (Ashby) Dowson], Sugarcane mosaic virus strain E (mosaic), and ratoon stunt (caused by Clavibacter xyli subsp. xyli Davis et al.) in Florida.
Abbreviations: CP, Canal Point • CP program • CRS, commercial recoverable sucrose
‘CP 01-1372’ (Reg. No. CV-136, PI 655942) is a sugarcane (a complex hybrid of Saccharum spp.) derivative of a long-term recurrent selection program conducted through cooperative research of the USDA–ARS, the University of Florida, and the Florida Sugar Cane League, Inc. It was released in Florida in December 2008. Modern sugarcane cultivars, such as CP 01-1372, are allopolyploid (with aneuploidy) hybrids, and in the mainland United States, they can be traced back to 17 founder clones (Deren, 1995). These founders were used in S. officinarum x S. spontaneum crosses, and the F1 hybrids were backcrossed to the S. officinarum background to recover high sucrose content (Roach, 1972; Sreenivasan et al., 1987). Modern sugarcane cultivars represent advanced generations of long-term breeding that began with these backcrosses.
CP 01-1372 was released because of its high yields of cane and commercial recoverable sucrose (CRS) on organic and sand soils and its resistance to brown rust (caused by Puccinia melanocephala Syd. & P. Syd.), orange rust [caused by Puccinia kuehnii (Kruger) E. Butler], leaf scald [caused by Xanthomonas albilineans (Ashby) Dowson], and ratoon stunt (caused by Clavibacter xyli subsp. xyli Davis et al.) in Florida. The name CP 01-1372 was assigned according to routine Canal Point (CP) naming protocol, being the 372nd selection assigned in the year 2001 in the first clonal selection stage. Selection numbers in the range from 1000 to 2999 are reserved for genotypes selected from the CP sugarcane cultivar breeding and selection program and bred for the Florida industry.
CP 01-1372 was selected from the cross CP 94-1200 x CP 89-2143 made at Canal Point, FL, in December 1998. The female parent, CP 94-1200, was not released due to mediocre yields in Stage 4 of the CP breeding and selection program. CP 89-2143 was released in fall 1999 (Glaz et al., 2000) and was the most widely planted sugarcane cultivar with 26.8 and 29.8% of Florida's sugarcane acreage in 2006 and 2007, respectively (Glaz 2008). One reason for the rapid adoption of CP 89-2143 was its consistently high sucrose concentrations across locations in Florida (Gilbert et al., 2006). The male parent of CP 94-1200 was cultivar CP 80-1743 (Deren et al., 1991). CP 80-1743 was the most widely planted sugarcane cultivar in Florida from 1999 to 2005 (Glaz, 2008). The female parent of CP 89-2143 was cultivar CP 81-1254 (Tai et al., 1991b), and the male parent was cultivar CP 72-2086 (Miller et al., 1984). CP 81-1254 had high yields, but because it was difficult to harvest, its adoption peaked at 1.6% of Florida's sugarcane acreage in 1997 (Glaz, 1997). CP 72-2086 was planted on 3.5% of Florida's sugarcane acreage in 2007 (Glaz, 2008); its peak usage was in 1996 when it comprised 18% of Florida's sugarcane acreage (Glaz, 1997). A major concern with CP 72-2086 is its susceptibility to Sugarcane mosaic virus. There are five genotypes in the pedigree of CP 01-1372 that were the most widely planted cultivars for at least 1 yr in Florida or Louisiana (CP 89-2143, parent; CP 72-2086, grandparent; CP 80-1743, grandparent; CP 63-588 (Rice et al., 1969), great grandparent; and CP 65-357 (Breaux et al., 1974), great-great grandparent). Beginning with one great-great grandparent, the pedigree of CP 01-1372 also includes CL genotypes developed by the private breeding program of the United States Sugar Corporation that was located in Clewiston, FL.
Methods
Early Selection Stages
CP 01-1372 was selected through standard selection procedures of the CP program (Table 1
). The cross (X98-1044) between CP 94-1200 x CP 89-2143 was made at Canal Point in December 1998. The F1 seed was planted in flats in a greenhouse early in 2000 and was transplanted to the field in May 2000 at Canal Point with approximately 100,000 other genotypes in the Seedling stage. From this stage on, the CP program propagates genotypes clonally. One stalk from the stool that was to become CP 01-1372 was selected from the Seedlings stage and advanced to Stage 1 in January 2001 with about 15,000 other unreplicated selections. Stage-1 plots were one row 0.5 m long and were separated by 0.5-m alleys. As in all other selection stages, row spacing was 1.5 m. Selection in Seedlings and Stage 1 was visual. Emphasis was placed on vigor and resistance to natural infection of brown rust, smut (caused by Ustilago scitaminea Syd. & P. Syd.), and leaf scald.
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Stalks were counted in Stage 2 in July and August 2002. In October 2002, 10-stalk samples were collected from each plot and weighed. Cane yield was calculated as the product of stalk weight by stalk number:
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All stalks were then milled to extract juice and determine theoretical recoverable sucrose, which was calculated as described by Legendre (1992). Fiber in this formula was estimated as 10% for all genotypes in Stages 2 and 3 and estimated as described later in Stage 4. All values of theoretical recoverable sucrose were multiplied by 0.86 to approximate CRS. Similarly, Legendre (1992) reported the calculation of a liquidation factor (ranging from 0.83 to 0.90) that was used by commercial mills in Louisiana to convert theoretical recoverable sucrose to CRS. Theoretical economic index (profitability) was calculated based on a procedure that integrated sucrose content with costs of harvesting, hauling, and milling the cane in Florida (Deren et al., 1995).
The major selection criteria in Stage 2 (and later in Stages 3 and 4) were profitability, production of sucrose, and resistance to diseases (primarily brown rust, mosaic, and leaf scald). Sucrose yield (Mg ha–1) was calculated as
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Yield Trials in Commercial Fields
From Stage 2, 135 genotypes were advanced to Stage 3 in November to December 2002. Stage-3 genotypes and three reference cultivars (CP 72-2086, CP 78-1628 [Tai et al., 1991a], and CP 89-2143) were planted in yield trials in commercial fields at four grower farms representative of the Florida sugarcane industry. Farms A. Duda & Sons', Inc., Okeelanta Corporation, and Sugar Farms Cooperative North–Osceola Region had organic (muck) soils, and Hilliard Brothers' of Florida Ltd. had a sand soil. All four trials had two replications of each genotype planted in randomized complete-block designs in plots with two rows 4.5 m long. Plots were arranged in sections such that the first plot was separated from the second by a 1.5-m alley. The second plot in each section was separated from the first plot of the next section by a 6.0-m alley. Data were collected in the plant-cane (October 2003 and January 2004) and first-ratoon (October 2004) crops. Estimates of cane and sucrose yields and profitability were determined as described for Stage 2. On the basis of its cane and sucrose yields, profitability, and its resistance to brown rust by natural infection, and to leaf scald and mosaic by artificial inoculation and natural infection, CP 01-1372 was among 13 genotypes selected for advancement from Stage 3 to Stage 4 in November 2004.
The 13 Stage-4 genotypes, including CP 01-1372, were planted in yield trials within commercial fields at eight grower farms in November to December 2004 and two additional farms in August and November 2005. These included five trials at the same four farms used for Stage 3 (two trials planted at Okeelanta Corporation) plus four more locations with organic soils (Eastgate Farms, Inc., Knight Management, Inc., Sugar Farms Cooperative North–SFI Region, and Wedgworth Farms, Inc.) and one more location with a sand soil (Lykes Brothers', Inc.). The primary reference cultivars in trials planted on organic soils were CP 72-2086 and CP 89-2143, and the primary reference cultivar in the trials planted on sand soils was CP 78-1628. All trials had six replications with genotypes planted in randomized complete-block designs in plots three rows wide and 10.5 m long. Alleys of 1.5 m separated plots. Experiments were generally two plots wide and 48 plots long. For the eight experiments planted in 2004, cane tonnage was estimated by first counting stalks in the two interior rows of each plot from July through September in 2005 (plant cane), 2006 (first ratoon), and 2007 (second ratoon). Stalk weight and CRS were estimated as described for Stage 2 from a 10-stalk sample collected from the middle row of each plot from October through March of 2005–2006 (plant cane), 2006–2007 (first ratoon), and 2007–2008 (second ratoon). For the two experiments planted in 2005, these same procedures were followed 1 yr later.
Thirteen samples of CP 01-1372 were processed for analysis of fiber content. Each sample consisted of five stalks and was collected from a border row (so as not to affect rows used for yield estimation). Leaves were stripped from these stalks, which were then cut into three approximately even sections (bottom, middle, and top stalk sections). Two randomly selected bottom, middle, and top sections were processed through a Jeffco cutter-grinder (Jeffries Brothers, Ltd., Brisbane Queensland, Australia). About 75 g of material (fresh bagasse) were collected and weighed. These fresh bagasse samples were then placed in cloth bags, and washed twice in the gentle cycle of a washing machine to remove soluble solids. The entire wash cycle was approximately 30 min. Samples were then dried at 63°C to a constant weight. The fiber percentage of a genotype was calculated as
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Samples of a reference cultivar were processed on all dates that fiber samples of CP 01-1372 were processed. All fiber percentages calculated on a given day were corrected to the historic fiber percentage of the reference cultivar. For example, the reported fiber percentage of CP 89-2143 was 9.85%. On days when CP 89-2143 was the reference cultivar, if its estimated fiber was 10.00%, then all estimated fiber samples of other genotypes were multiplied by 0.985.
Agronomic, Botanical, and Molecular Descriptions
Data for the agronomic and botanical descriptions of CP 01-1372 were recorded on 10 mature stalks sampled on 23 and 25 July 2008 from a field with Torry muck soil at Eastgate Farms, Inc., near Pahokee, FL, and from a Margate/Oldsmar sand soil at the United States Sugar Corporation's Townsite Farm near Clewiston, FL. Stalks were sampled from the inner rows, and the agronomic and botanical descriptions were based on Artschwager and Brandes (1958). Colors were characterized according to Munsell Color Charts for Plant Tissues. Stalks of CP 01-1372 were compared with those of CP 72-2086 and CP 89-2143; all cultivars were planted the same day on the same fields.
Characterization by Microsatellite Genotyping
Six pairs of microsatellite primers (Table 2
) developed through the International Consortium for Sugarcane Biotechnology (Cordeiro et al., 2003) were used to generate a genetic fingerprint for CP 01-1372. This was compared with those of cultivars CP 72-2086, CP 78-1628, CP 80-1743, CP 88-1762 (Tai et al., 1997), and CP 89-2143. These five major commercial cultivars occupied 86% of the sugarcane acreage in Florida in 2007 (Glaz, 2008).
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Characteristics
Field Performance
CP 01-1372 was tested in 26 harvests at 10 trial locations in Florida during 2005–2006 (eight plant-cane harvests), 2006–2007 (two plant-cane and seven first-ratoon harvests), and 2007–2008 (two first and seven second-ratoon harvests). Fiber content of CP 01-1372 was 10.15%. Stalks of CP 01-1372 were generally lighter in weight than those of the reference cultivars on both soil types (Table 3
).
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Cane yield of CP 01-1372 on sand soils did not differ significantly from that of CP 78-1628, the reference cultivar for sand soils, in all three crop cycles; however, the CRS of CP 01-1372 was significantly higher than that of CP 78-1628 in each crop cycle (Table 4 ). Sucrose yields and economic indices of CP 01-1372 were significantly higher than those of CP 78-1628 in all three crop cycles except in the second-ratoon crop where the values were similar.
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Agronomic, Botanical, and Molecular Descriptions
On the muck soil, the portions of CP 01-1372 stalks that were covered by leaf sheaths had a black wax layer, whereas on the sand soil these portions had a yellow wax layer (2.5Y 5/2). Beneath the wax layer, covered stalk portions of CP 01-1372 had similar shades of green-yellow (2.5 GY 8/8), similar shades of green-yellow on exposed wax layers (2.5 GY 7/2), and similar shades of green-yellow on exposed stalk portions (2.5 GY 6/6 and 2.5 GY 6/4) on muck and sand soils. The color of the covered wax layer on CP 72-2086 stalks was yellow-red (7.5 YR 4/2), and beneath the wax, the covered stalk was yellow (5Y 8/4 on the muck soil and 5 Y 8/6 on the sand soil). The color of the exposed wax layer of CP 72-2086 was yellow (5 Y 8/4) and green-yellow (2.5 GY 8/2) on the muck and sand soil, respectively; and the exposed stalk portions were green-yellow (5 GY 5/6 on the muck soil and 2.5 GY 7/4 on the sand soil). The covered portions of CP 89-2143 stalks exhibited a black wax coating on both soils; underneath the wax, the colors of these covered stalks were yellow (5 Y 8/4) and green-yellow (2.5 GY 8/6) on muck and sand soils, respectively. Exposed stalk portions of CP 89-2143 exhibited black and green-yellow (2.5 GY 7/2) wax coatings on stalks on the sand soil. The color of the exposed stalk portions of CP 89-2143 was green-yellow (2.5 GY 8/8 on the muck soil and 2.5 GY 6/4 on the sand soil).
Growth measurements and descriptions of CP 01-1372, CP 72-2086, and CP 89-2143 were compared for both the muck (Table 5 ) and sand soils (Table 6 ). Stalk height of CP 01-1372 (254 cm), measured from the ground to the top visible dewlap, was similar to that of CP 89-2143 (252 cm) but shorter than that of CP 72-2086 (302 cm) on the muck soil. On the sand soil, CP 01-1372 was taller (200 cm) than CP 72-2086 (175 cm) and CP 89-2143 (169 cm). Internodes of CP 01-1372 were longer than those of CP 72-2086 and CP 89-2143 on both soils. Therefore, several measurements and descriptions from the middle stalk area were taken at the 5th internode on CP 01-1372 stalks but at the 10th internode of CP 72-2086 and CP 89-2143 stalks. Growth cracks were few and shallow when present on CP 01-1372 on both soils. No growth cracks were identified on CP 72-2086 on both soil types or on CP 89-2143 on the muck soil. On the sand soil, growth cracks on CP 89-2143 stalks were sparse, but with moderate depth when present.
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It was difficult to distinguish the shape of buds on the stalks of CP 01-1372. Using the illustrations and terminology given by Artschwager and Brandes (1958), these buds were either ovate with emarginated basal wing region or squarish pentagonal with wing inserted high. The bud shape for CP 72-2086 and CP 89-2143 was round with central germ pore. The color of the buds on CP 01-1372 stalks was green-yellow (2.5 GY 8/6 and 2.5 GY 8/4) but yellow (5 Y 8/4) on CP 72-2086 and CP 89-2143. Bud length and width of CP 01-1372 were larger on the muck soil (9.0 and 8.4 mm, respectively) than those of CP 72-2086 (7.3 and 6.1 mm, respectively) or of CP 89-2143 (7.7 and 7.1 mm, respectively). On the sand soil, bud lengths of all three cultivars were similar (5.9–6.2 mm), but with a more narrow shape for CP 01-1372 (5.3 mm) than for CP 72-2086 (6.4 mm) and CP 89-2143 (7.2 mm).
The canopy was open for CP 01-1372 and compact for CP 89-2143 on each soil type, but open for CP 72-2086 on the muck soil and compact on the sand soil. Leaf shape was erect with drooping tip and ascending for all three cultivars. Mean leaf blade length and width at the top visible dewlap were smaller for CP 01-1372 (134.3/4.5 cm on muck, 151.7/3.4 cm on sand) compared with CP 72-2086 (152.8/5.2 cm on muck, 152.6/4.6 cm on sand) and CP 89-2143 (155/4.7 cm on muck, 156.2/4.0 cm on sand). Leaf sheaths of CP 01-1372 adhered loosely to the stalk on the muck soil and adhered moderately to the stalk on the sand soil. CP 01-1372 leaf sheaths had light to moderate pubescence with short hairs concentrated in the center of the leaf sheath. Pubescence on the leaf sheaths of CP 72-2086 and CP 89-2143 was light. The color of the leaf sheath of CP 01-1372 was green-yellow (5 GY 4/6 on the muck soil and 5 GY 6/4 on the sand soil). The leaf-sheath color of CP 72-2086 was green-yellow (5 GY 7/4) on both soils and a different shade of green-yellow for CP 89-2143 on the muck (5 GY 7/6) and on the sand soils (5 GY 5/4). Midrib width of CP 01-1372 (5.8 mm) was larger than that of CP 72-2086 (5.0 mm) and smaller than that of CP 89-2143 (6.9 mm) on the muck soil; however, CP 01-1372 had the smallest midrib width (4.8 mm) on the sand soil among CP 72-2086, (6.1 mm) and CP 89-2143 (6.7 mm). Midrib color on the adaxial leaf side was white for all three cultivars. The midrib color on the abaxial leaf side of CP 01-1372 was green-yellow (5 GY 5/6 on muck and 5 GY 5/4 on sand). The abaxial midrib color of CP 72-2086 was green-yellow (5 GY 6/6 and 5 GY 5/4, on muck soil and sand soil, respectively), and the midrib color of CP 89-2143 was also green-yellow (5 GY 5/6) on both soil types.
The auricles of CP 01-1372 were short lanceolate on one side and long lanceolate on the opposite side. The auricles of CP 72-2086 and CP 89-2143 were deltoid on one side and long lanceolate, if present, on the opposite side. The short and long auricles were longer on CP 01-1372 (12.4 and 61.0 mm) compared with those of CP 72-2086 (6.8 and 16.1 mm) and CP 89-2143 (7.7 and 35.0 mm) on the muck soil. On the sand soil, the short auricles were similar in length on the three cultivars, and only CP 01-1372 had long auricles. The fourth dewlaps below the top visible dewlap were deltoid to squarish deltoid with a moderate wax cover on the stalks of CP 01-1372, narrow squarish to deltoid on the stalks of CP 72-2086, and double crescent deltoid with a light wax coating on the stalks of CP 89-2143. Dewlaps of CP 01-1372 were red (10R 4/2 on muck soil and 10R 5/2 on sand soil). Dewlaps of CP 72-2086 were yellow and green-yellow (5 Y 5/4 and 2.5 GY 6/4) on the muck and sand soil, respectively.
The shape of the ligule of stalks of CP 01-1372 was crescent with lozenge on both soil types. Ligules of CP 72-2086 were linear crescent on the muck soil and crescent with lozenge on the sand soil. Ligules of CP 89-2143 were broad crescent on both soils. Ligule color was green-yellow for CP 01-1372 (2.5 GY 8/8 on the muck soil and 2.5 GY 5/4 on the sand soil). The ligule colors of CP 72-2086 on both soils were yellow at the top portion of the ligule (7.5 YR 5/8), and yellow or green-yellow at the bottom of the ligule (5 Y 7/4 to 2.5 GY 6/8). CP 89-2143 ligules were yellow (5 Y 8/2) on the muck soil and green-yellow (2.5 GY 8/4) on the sand soil.
The six microsatellite primer pairs amplified 31 fragments, ranging from 105 to 248 bp, in CP 01-1372 (Table 2). The number of fragments amplified by each primer pair ranged from 4 to 6. Of the 31 fragments amplified, 20 were polymorphic and 11 monomorphic. CP 01-1372 shared 18 fragments with CP 78-1628, 22 with CP 72-2086, 17 with CP 89-2143, 22 with CP 80-1743, and 23 with CP 88-1762. Fragments unique to CP 01-1372 were identified in the fingerprints obtained using primer pairs SMC334BS, SMC17CG, SMC1493CL, and mSSCIR53.
Disease Reactions
Screening of CP 01-1372 was conducted by inoculation testing and/or monitoring for natural infection to smut, leaf scald, brown rust, mosaic, Sugarcane yellow leaf virus, and ratoon stunt (Table 7
).
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When CP 01-1372 was in Stage 2, it showed no symptoms of eye spot [caused by Bipolaris sacchari (E.J. Butler) Shoemaker] based on field inoculations. Field inoculations with smut were also conducted on CP 01-1372 during Stages 3 and 4. Susceptibility to smut in inoculated tests was determined by comparing number of sori produced by CP 01-1372 and cultivars CP 73-1547 (Miller et al., 1982) and CP 78-1628. Smut susceptibilities of CP 73-1547 and CP 78-1628 are at the upper limits of acceptability for commercial production in Florida. CP 01-1372 had no sori in its first year of testing and 14 sori in its second year. CP 73-1547 had no sori in both years, and CP 78-1628 had 11 and 6 sori in the first and second year, respectively. Six sori were found in Stage 4 on CP 01-1372 due to natural infection compared with 11 sori on CP 78-1628. Based on these artificial inoculation and natural infection data, CP 01-1372 was considered moderately susceptible to smut. As with CP 73-1547 and CP 78-1628, this level of susceptibility was considered acceptable for commercial production in Florida.
Greenhouse inoculations were conducted with leaf scald and mosaic from 2004 to 2006. CP 01-1372 was compared with CP 80-1743 for the number of infected plants with leaf scald and compared with CP 72-2086 for the number of infected plants with mosaic. CP 80-1743 and CP 72-2086 are at the upper limits of infection for leaf scald and mosaic, respectively, for acceptability for commercial production in Florida. In all 3 yr of leaf scald inoculations, CP 01-1372 had substantially less infection than CP 80-1743 (21.5, 1.1, and 2.4% plants infected for CP 01-1372 in 2004, 2005, and 2006, respectively, compared with 50.6, 19.9, and 14.3% plants infected for CP 80-1743 in 2004, 2005, and 2006, respectively). Similarly, infection of CP 01-1372 with mosaic by artificial inoculation was substantially less than that of CP 72-2086 (0.0, 5.4, and 11.8% CP 01-1372 plants infected in 2004, 2005, and 2006, respectively, compared with 19.0, 18.1, and 70.3% CP 72-2086 plants infected in 2004, 2005, and 2006, respectively). Throughout Stages 3 and 4, no plants of CP 01-1372 were identified that were naturally infected with leaf scald or mosaic. Based on these inoculated tests and natural infection, CP 01-1372 was considered to have sufficient resistance to leaf scald (moderately resistant) and mosaic (resistant) for commercial production in Florida (Table 7).
Inoculation tests to compare ratoon stunt susceptibility of CP 01-1372 and cultivar CP 72-1210 (Miller et al., 1981) were conducted from 2003 through 2005. Also, in 2003, colonized vascular bundles of CP 01-1372 and cultivar CP 80-1827 (Glaz et al., 1990) were compared. The 3-yr mean number of colonized vascular bundles of CP 01-1372 (2.5) and CP 72-1210 (2.3) were similar. However, in 2003, CP 01-1372 (3.8) had fewer colonized vascular bundles than did CP 80-1827 (9.4). Based on these results, CP 01-1372 was considered moderately resistant to ratoon stunt (Table 7). Ratoon stunt can be controlled by the use of noninfected planting material, but when not controlled, Dean and Davis (1990) reported that it caused sucrose yield losses of 5% in Florida. More recently, Comstock (2008) reported that ratoon stunt infections in the plant-cane and first-ratoon crops reduced stalk number, cane yield, and sucrose yield. Reductions were not always significant when compared with healthy plants, but trends were consistent.
Cold Tolerance
To assess cold tolerance, Stage-4 genotypes were subjected to freezing temperatures in two field experiments established at the Hague Farm of the Florida Institute of Food and Agricultural Sciences University of Florida, Hague, near Gainesville, FL. CP 01-1372, along with 12 other Stage-4 genotypes and three reference cultivars (CP 72–2086, CP 78–1628, and CP 89–2143) were planted on 22 Feb. 2005 in two randomized complete-block experiments with four replications in single-row plots 1.5 m long and 2.4 m apart with 2.4-m breaks between replications. Five stalk samples were cut for analyses of sucrose content on 13 and 27 Jan. and 15 March 2006. Cold-tolerance rankings were based on temporal deterioration of percentage sucrose in the juice extracted from mature stalks after exposure to freezing temperatures. Rankings from 1st to 16th signified best to worst cold tolerance. CP 01-1372 ranked third among these 16 genotypes in cold tolerance. CP 72-2086, CP 78-1628, and CP 89-2143 ranked 12th, 1st, and 4th in cold tolerance, respectively.
Availability
In its initial year of release, seed cane of CP 01-1372 will be available from the Florida Sugar Cane League, Inc., for commercial planting in Florida. It is not anticipated that patent protection for CP 01-1372 will be sought. Small quantities of seed cane for research purposes may be obtained at the USDA–ARS Sugarcane Field Station, Canal Point, FL, where CP 01-1372 will be maintained for at least five years from the date of this publication.
Footnotes
All rights reserved. No part of this periodical may be reproduced or transmitted in any form or by any means, electronic or mechanical, including photocopying, recording, or any information storage and retrieval system, without permission in writing from the publisher. Permission for printing and for reprinting the material contained herein has been obtained by the publisher.
Received for publication January 27, 2009.
References
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