Results and Discussion
Table 1 lists the parentage, percentage
of fiber, and reactions to smut, rust, leaf scald, and mosaic
diseases for each clone included in these experiments and cold
tolerance for the clones in the CP 92 and CP 93 series. Tables
2-5 contain the results of the CP 93 series plant-cane experiments,
and tables 6 and 7 contain the results of the CP 92 series plant-cane
experiments. Tables 8-10 contain the results of the CP 92 series
first-ratoon experiments, and tables 11 and 12 contain the results
of the CP 91 series first-ratoon experiments. Tables 13-15 contain
the results of the CP 91 series second-ratoon experiments, and
tables 16 and 17 contain the results of the CP 90 series second-ratoon
experiments. Table 18 lists the dates
that stalks were counted in each experiment.
This year for the first time since this annual report has been
published, no experiments were conducted on a Terra Ceia muck.
Terra Ceia muck is the deepest of the four organic soil types
composed mostly of decomposed sawgrass. Its nonpresence is a sign
of the soil subsidence that occurs when organic soils are drained.
For the 5,000 years before humans began draining it, the Everglades
agricultural area was flooded for 9 to 11 months during years
of normal rainfall. Under these conditions, the organic soils
accreted at the mean rate of 0.08 cm per year (McDowell
et al. 1969). Since drainage, soils in this region subsided
at the rate of about 2.5 cm per year until 1978 (Shih
et al. 1978). From 1978 to 1997, the rate of subsidence decreased
to 1.4 cm per year due to growers' efforts to maintain higher
water tables (Shih et al. 1997).
Although there are other factors, the major cause of this soil
subsidence is the oxidation of organic matter; many of these soils
contain more than 85 percent organic matter.
Plant-Cane Crop, CP 93 Series
CP 70-1133 and four new clones--CP 93-1596, CP 93-1309, CP
93-1634, and CP 93-1382--make up the group with the highest TS/H
yields (table 5). The TS/H yields of CP
93-1596, CP 93-1309, and CP 93-1634 were more stable than those
of CP 70-1133 and CP 93-1382. CP 93-1596 TC/H yields were significantly
higher than those of any other clone except CP 93-1634 and CP
70-1133. Otherwise, CP 70-1133, CP 93-1309, CP 93-1634, and CP
93-1382 all had similar TC/H yields (table
2). The commercial desirability of CP 93-1596 was reduced
by its low preharvest and harvest KS/T yields, both significantly
less than those of CP 70-1133 (table 3
and table 4). Also detracting from CP
93-1596's commercial desirability were its undetermined susceptibility
ratings for leaf scald and mosaic (table 1).
CP 93-1596 developed leaf scald and mosaic in inoculated tests,
but it is not yet known if it can be grown safely for commercial
production.
CP 93-1309 had outstanding preharvest and harvest KS/T yields
(table 3 and table
4). Its preharvest KS/T yield was significantly greater than
that of eight other new clones, and its harvest KS/T yield was
significantly greater and much more stable than that of any other
clone. CP 93-1309 also had a good rating for cold tolerance and
was found resistant to all major diseases except rust and mosaic.
Increases of seed cane of CP 93-1309 were begun for potential
release (table 1).
The TC/H yield of CP 93-1634 was significantly greater than
those of five other CP 93 clones but similar to that of CP 70-1133
(table 2). The preharvest and harvest
KS/T yields of CP 93-1634 were also similar to those of CP 70-1133
(table 3 and table
4). CP 93-1382 and CP 93-1634 had similar TC/H yields, but
the TC/H yield of CP 93-1382 was significantly greater than the
TC/H yields of only three rather than five other new CP 93 clones
(table 2). CP 93-1382 had a very low mean
preharvest KS/T yield, significantly lower than that of CP 70-1133
(table 3). Conversely, CP 93-1382 had
moderately high KS/T yields at normal harvest dates (table
4). The preharvest and harvest KS/T yields of CP 93-1382 across
locations were unstable (table 4). Both
CP 93-1634 and CP 93-1382 had good cold tolerance, and between
the two clones the only disease concern was the undetermined leaf
scald rating of CP 93-1634. Seed-cane supplies of CP 93-1634 and
CP 93-1382 are being increased for potential commercial release
(table 1). CP 93-1596, CP 93-1309, and
CP 93-1634 had low fiber percentages, each between 9 and 10 percent,
and CP 93-1382 had a moderately low fiber percentage.
Plant-Cane Crop, CP 92 Series
Last year's report contained the results from six locations
of the CP 92 series from the plant-cane crop (Glaz
et al. 1998). This year, results are available from three
additional locations (table 6 and table 7). When averaged across the three
locations, CP 92-1666, CP 92-1167, CP 92-1435, CP 92-1641, and
CP 70-1133 were in the highest group of clones for TS/H yields
(table 7). The same four new clones had
high yields in the plant-cane tests last year. All except CP 92-1435
had similar yield characteristics this year and last year. CP
92-1666 and CP 92-1167 had high TC/H yields (table
7) and KS/T yields similar to the KS/T yield of CP 70-1133
(table 6). Conversely, CP 92-1641 had
moderate TC/H yields (table 7) and very
high KS/T yields, significantly higher than that of any other
clone (table 6). CP 92-1435 had significantly
greater TS/H, TC/H, and KS/T yields than CP 70-1133 last year
as plant cane. This year the same three yield characteristics
for CP 92-1435 and CP 70-1133 were similar in the plant-cane crop
(table 6 and table
7).
First-Ratoon Crop, CP 92 Series
When yields for the CP 92 clones were averaged across all seven
first-ratoon locations, no new clone yielded significantly greater
TS/H than CP 70-1133 (table 10). However,
CP 92-1666, CP 92-1167, and CP 92-1435, along with CP 70-1133,
made up the top group of clones for TS/H. These three new clones
also had significantly greater yields of TC/H than CP 70-1133
this year in the first-ratoon crop (table
8) and last year in the plant-cane crop (Glaz
et al. 1998). CP 92-1641 yielded significantly more KS/T than
CP 70-1133 (table 9). Last year CP 92-1641
had similarly high yields of KS/T, but its TC/H yield was not
significantly less than that of CP 70-1133 as it was this year
in the first-ratoon crop (table 8 and
Glaz et al. 1998). CP 92-1666 had
far more stable TC/H and TS/H yields than any of the other clones
in this test (table 8 and table
10).
Table 1 contains cold tolerance ratings,
disease ratings, and fiber percentages for these clones. CP 92-1666,
CP 92-1167, CP 92-1435, and CP 92-1641 all had only fair or poor
cold tolerance. CP 92-1666, CP 92-1167, and CP 92-1641 had fiber
percentages in the normal commercial range for Florida, but the
fiber of CP 92-1435 was above normal for sugarcane grown in Florida.
The major disease concern for CP 92-1435 and CP 92-1641 was mosaic,
for CP 92-1666 it was smut, and for CP 92-1167, smut and rust.
Seed-cane supplies of CP 92-1435, CP 92-1641, CP 92-1666, and
CP 92-1213 are being increased for potential release. CP 92-1213
had moderate yields this year, is susceptible to smut, and has
an undetermined leaf-scald rating. The Florida Sugar Cane League
began increasing seed-cane supplies of CP 92-1167 and CP 92-1684
last year, but the Florida Sugarcane Variety Committee later decided
to discontinue increasing these two varieties.
First-Ratoon Crop, CP 91 Series
Last year's report contained the results from seven locations
of the CP 91 series from the first-ratoon crop (Glaz
et al. 1998). This year, results are available in the first-ratoon
crop from three additional locations for these clones (table
11 and table 12).
All eleven CP 91 clones yielded less TS/H than CP 70-1133;
TS/H yields for five of these clones were significantly less than
that of CP 70-1133. Three clones of note in these tests were CP
91-1924, CP 91-1883, and CP 91-1238. CP 91-1924 yielded significantly
more TS/H than any other clone in the successively planted experiment
at Okeelanta (table 12), where it yielded
moderately high KS/T and TC/H (table 11
and table 12). CP 91-1924 has had a history
of unstable yields, particularly at Okeelanta. Two years ago in
the plant-cane crop at Okeelanta it had high yields (Glaz
et al. 1997), and last year it had low yields at Okeelanta
in the first-ratoon crop and moderately high yields in the plant-
cane crop of the successively planted experiment (Glaz
et al. 1998). CP 91-1924 had a normal fiber percentage but
an undetermined susceptibility to leaf scald (table
1).
CP 91-1883 yielded significantly more TS/H than any other clone
on the Torry muck soil at Eastgate except CP 91-1238 (table
12). CP 91-1883 also had high KS/T and TC/H yields at Eastgate
(table 11 and table
12). CP 91-1883 was well adapted to the Torry muck soil since
its KS/T yields were relatively low on the sand soil at Hilliard
and on the Pahokee muck soil at Okeelanta, the two other soils
on which these clones were tested. CP 91-1238 had TC/H and TS/H
yields similar to those of CP 91-1883 at Eastgate, but its KS/T
yield was significantly lower than that of CP 91-1883. CP 91-1883
and CP 91-1238 had high yields at Eastgate last year in the plant-cane
crop, but, relative to the other clones, not as high as this year
in the first-ratoon crop. CP 91-1238 had a low fiber percentage
and CP 91-1883 a normal one (table 1).
CP 91-1238 was susceptible to rust, and CP 91-1883 had no major
disease susceptibility.
CP 91-1062 and CP 91-1150 are being increased for potential
release (table 1) on sand soils. Both
clones' KS/T yield was similar to CP 70-1133's, but the TC/H and
TS/H yields of these two new clones were significantly less than
those of CP 70-1133 on the sand soil at Hilliard (table
11 and table 12).
Second-Ratoon Crop, CP 91 Series
When averaged across all seven locations, CP 91-1914, CP 91-1560,
and CP 91-1924, along with CP 70-1133, had similarly high yields
of TS/H (table 15). Along with CP 91-1865,
these three CP 91 clones and CP 70-1133 also had similarly high
TC/H yields (table 13). CP 91-1914 had
significantly greater KS/T yields than all other clones; and CP
91-1924, CP 91-1560, and CP 70-1133 had similar KS/T yields (table 14).
When considering the three-crop cycle of plant-cane, first
ratoon, and second ratoon, CP 91-1914 is the clone in this group
that had the most consistently high KS/T, TC/H, and TS/H yields
(Glaz et al. 1997 and 1998
and table 13, table
14, and table 15). However, this year
the second-ratoon TC/H and TS/H yields of CP 91-1914 were not
stable, partially because of low yields on the sand soil at Lykes
(table 13 and table
15). CP 91-1914 did not have low TS/H yields relative to CP
70-1133 at Lykes in the plant-cane and first-ratoon crops (Glaz
et al. 1997 and 1998).
As mentioned in the previous section, CP 91-1062 and CP 91-1150
are being increased for potential release (table
1) on sand soils. Both new clones had TC/H, KS/T, and TS/H
yields similar to those of CP 70-1133 this year in the second-ratoon
crop on the sand soil at Lykes (table 13,
table 14, and table
15). CP 91-1062 and CP 91-1150 had acceptable fiber levels
for commercial production in Florida (table
1). CP 91-1062 had no major disease problems, but CP 91-1150
had undetermined susceptibility to smut, leaf scald, and mosaic.
CP 91-1883, which had high yields at Eastgate in the first-ratoon
crop, had very low TC/H, KS/T, and TS/H yields when averaged across
the seven locations in the second-ratoon crop (table
13, table 14, and table
15). These three characteristics for CP 91-1883 also had high
stability-safety indices relative to its mean yields, indicating
that it had consistently low yields for all three characteristics
across the seven locations.
Second-Ratoon Crop, CP 90 Series
No clone in this group yielded significantly more TS/H than
CP 70-1133 (table 17). However, CP 90-1549,
CP 90-1222, and CP 90-1464 had nearly equal TS/H yields, each
almost significantly higher than the TS/H yield of CP 70-1133.
CP 90-1549 and CP 90-1222 had significantly greater TC/H yields
than CP 70-1133 but mediocre yields of KS/T (table
16 and table 17). CP 90-1549 had similar
although not relatively as high TC/H and TS/H yields last year
at seven locations in the second-ratoon crop, as well as in the
first-ratoon crop at the same three locations as this year (Glaz et al. 1998). The relative yields
of CP 90-1222 this year in the second-ratoon crop were similar
to its yields in all test results reported since the plant-cane
crop (Glaz et al. 1995, 1997,
and 1998). Both CP 90-1549 and CP
90-1222 have never been considered as potential commercial cultivars
because of their low KS/T yields, both on sand and organic soils.
In addition, CP 90-1222 had undetermined susceptibility to rust
and leaf scald (table 1).
CP 90-1464 yielded well on the Torry muck soil at Eastgate.
Its TS/H yield at Eastgate was significantly greater than the
TS/H yields of all other clones except CP 90-1549 and CP 90-1222
(table 17). In addition, its TC/H and
KS/T yields were both significantly greater than those of CP 70-1133
at Eastgate (table 16 and table
17). CP 90-1464 had similarly high yields on the Torry muck
at Eastgate last year in the first-ratoon crop, but two years
ago in the plant-cane crop its TS/H yield was similar to that
of CP 70-1133 (Glaz et al. 1997
and 1998). CP 90-1464 has shown
some susceptibility to rust and leaf scald (table
1).
United States
Department of Agriculture
Agricultural
Research Service
The material on this page is in the public
domain.
Original posting: April 19, 1999.
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