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STUDIES WITH POPCORN VARIETIES IN THE EVERGLADESN
AREA
1952 1958

by

Victor E. Green, Jr. and Emmett D. Harris, Jr.


This report contains results of research with popcorn
grown on organic soils in south Florida and super-
cedes Mimeo 58-4. The work was conducted in coopera-
tion with the Ames Seed Farms of Ames, Iowa and the
Central Popcorn Company of Schaller, Iowa, who fur-
nished seed and determined expansion ratios.


EVERGLADES STATION M2MEO REPORT 5$-10

Belle Glade, Florida


January 23, 1959


S~Y Y U Y Y V YYY Y YVY YYYII YYY YYYYYYVYY~YY~L~Y~L~L\L~OLZL~L~L~~LY~C]t


1f^o






STUDIES WITH POPCORN VARIETIES IN THE EVERGLADES AREA
1952-1958

by

Victor E. Green, Jr., and Emmett D. Harris, Jr. i


Agronomic Evaluation


To date, the agronomic research on popcorn in the Everglades area ha. corn.i-
ted chiefly of screening released and experimental hybrids. Testc were brt'ens i
1952 and are continuing. Poor yiel'iing and disease susceptible varieties are oic-
carded each year and are replaced by other varieties.

The tests have had the following characteristics in the various years:


1952


No. of Varieties
Date of Planting
Dates of Harvest


Width between rows, ft.
Drill Spacing-Plants/Hill
Population, Plants/Acre
Row Length, Ft.
Rows per Plot
Harvested Area, Rows
Replications, Number
Design, Randomized Com-
plete Block
Insect Control
Leaf Bliaht Control


6
3/6/52
6/16/52
to
7/3/52

2-15"
19,333
50
3
1
4


1953


4
1/28/53
5/28/53


1954 1955


12 15
2/1/54 1/28/55
5/21/54 6/6/55
to to
6/9/54 6/20/55


Three-foot rows
1-12" 1-12"
14,520 14,520
50 50
6 3
6 3
4 3


R.C.B. Latin
Square
3 sprayings/crop
None in any year


R.C.B.


1956


19C

6/7/56


used each year


1-12"
14,520
40
3
1
4


1-12"
11, -20
89
1
1
4


R.C.B. R.C.Bi


21
2/7/ I 7

and
6/12/57


1-12"
14,520
25
1
1
4


1-32"

'C
1


of 1 quart 25% DDT emusion per acre


Each year wireworms were controlled by applying 3 to 5 pounds of technical aldrm
per acre into the soil by spraying and immediately disking. Annually, tbh crop
was planted and thinned by hand, and skips in the stand were replanted ason to in-
sure a perfect stand. Cultivations numbered three per crop at about two-week ~n-
tervals after germination. Soil was thrown to the rows to help reduce root lodg.ng.

Stalk and ear heights were measured following anthesis. About two weeks after
anthesis, reaction to northern leaf blight caused by Helminthosporium turcicum
Pass. was determined. No blight readings were made in 1952. In 1953, they were
made by W. N. Stoner, then Assistant Plant Pathologist, Everglades Station: in
1954 by the Senior Author, and in 1955 to 1958 by Miss Alice Robert of the Crops
Research Division, U.S.D.A.

As the varieties ripened, they were picked, husked and weighed. Samples
were taken for moisture determination, weight-per-bushel test, and for popping.
The latter two tests were performed by the Central Popcorn Company for the 1952-
1957 crops and by the Ames Seed Farms in 1958. Yields were calculated at 15.5
percent moisture on an acre basis. Shelling percentages were calculated in 1955
and 1956.

I/ Victor E. Green, Jr., Associate Agronomist and Emmett D. Harris, Jr,, Assis-
tant Entomologist, Everglades Experiment Station, Belle Glade, Florida.


--~- ---~-- -L--~r-


re.




-2-


The test in 1952 was merely observational and was carried out to check
whether arn of the varieties from Iowa were adaptable to the south Florida environ-
ment. The March 6 planting yielded marketable popcorn, but the April 1 planting
was a complete failure. All corn usually fails when planted late in this area.
Table 1 shows the 1952 yields and harvest dates.

Table 1. The Characteristics and Performance of Six Popcorn
Varieties at Belle Glade, Florida, 1952.


Central Hybrid
Number


Yield, Ibs./A
at I'.' Moisture


Date of Harvest I/


1 1930 7-2-52
2 1745 7-2-52
3 2065 7-3-52
4 1860 7-3-52
5 585 6-16-52
6 325 7-3-52

/ Planted March 6, 1952

In 1953, four improved varieties were received from the Central Popcorn
Company. They were numbered according to days required to approximate maturity
near Schaller, Iowa. The data collected during 1953 are shown in Table 2.
Table 2. The Characteristics and Performance of Four Popcorn
Varieties at Belle Glade, Florida, 1953


Variety Yields, Ibs/A
at 15.S5
Moisture


Disease
Index /


Stalk
Ht,, Ft*


Popping
Expansion,
Volumes


Normal
Expansions,
Volumes


Moisture -
at Harvest,2/
$


C-105 1985 0.5 6 27 32 21.97
C-110 2600 2.0 8 29 33 18.82
C-112 2780 4.0 8 33 35 24.61
C-115 3330 3.0 8 35 35 26.06


L.SD. for yields: .e05 506 Ibs.j .01 = 766 lbs.
SReadings on April 23. Higher numbers indicate more injury.
Planted January 28, 1953. Harvested May 28, 1953.


Scale 0-5


The variety C-115, the latest maturing variety, yielded better than the
earlier varieties, even though resistance to Helminthosporium leaf blight was great-
er in two of the other three, On lots of seed that were dried, shelled and equal-
ised for prime moisture content, the popping volumes of Florida grown material were
two to four volumes lower than Iowa grown corn. This was the first indication that
the later varieties might give the highest yields and the best popping quality in
south Florida. The shortness of the stalks suggested the possibility of combining
the grain.

Hybrid 110 had considerable weevil infestation, but the other hybrids
were free from insect damage. The ears of 115 were normal in size, while those
of the earlier varieties were much shorter than normal.








During the crop year 1954, the five best 1952 varieties, the 1953 varieties,
Purdue 31 and 32, and Japanese Hulless (Improved Baby Rice) were grown. 1954
was a bad blight year and some of the varieties had dry leaves when the grain was
in the milk stage. Stalk heights did not exceed seven feet and ears were no more
than three and one half feet from the soil surface. With such low ear formation,
weed control assumes major importance. Expansion of the kernels was reduced by
2.5 to 8 volumes by leaf blight. The variety Central Hybrid 1 was the highest
yielding variety, 2990 pounds per acre. Central 4 rated second. Both these va-
rieties had the highest popping volumes. See Tible 3.

In 1955, Central Hybrids 1, 2 and 4 were planted again along with ten new
released from Iowa, the variety South American and the inbred YS(RS)Fll from the
Cuba Agricultural Experiment Station. The year was very good from the standpoint
of corn production. Blight readings were not taken until three weeks before har-
vest. Good yields were received from all varieties except South American. Stalk
heights of the corn belt popcorns varied from 5.4 feet to 6.8 feet and all varie-
ties seemed well suited to combine harvesting if care is taken not to break the
hull of the grains. The Cuban variety averaged 8.8 feet in height and possessed
the most resistance to leaf blight. It yielded 3670 pounds per acre. However, it
had the lowest shelling percentage and popping volumes of Flcrida grown corn were
higher than the normal exp~asiob figures for all varieties. Shelling percen-
tages of the Central varieties were between 76.7 and 82.5, and the Cuban variety,
due to a large cob, yielded about 72 percent grain. Central Hybrid 4 was the
earliest maturing variety as reflected by the moisture content at harvest.

In 1956, 19 varieties of popcorn were grown. These included the best varie-
ties from former years along with additional crosses from the Central Popcorn
Company. Central Hybrid No. 1 gave the highest yield of grain again for the third
year. The characteristics and performance of the varieties are shown in Table 5.

In 1957, northern leaf blight assumed epiphytotic proportions. This factor
along with an extremely high rainfall during the early growth of the plants caus-
ed severe stunting and reduced yields. The three highest yielding entries were
experimental varieties 7-303, 7-336 and 7-310 from the Central Popcorn Company.
However, the varieties scoring less than 3.0 for blight were Purdue 202 and Cen-
tral Hybrid No. 1. The tallest stalks did not produce the highest yields. Nor
were high yields related to the length of the growing season. The agronomic and
industrial characteristics of the popcorns grown in 1957 are shown in Table 6.

In 1958, seven varieties were repeated along with eleven popcorns that had
not been tested before in this area. Yields generally were low in 1958, and are
attributable to poor growth of the plants during their early life brought about
by low air and soil temperatures and abnormal plant nutrition. The highest yield-
ing varieties were, along with the best three in 1957--C7-303(ASF54-3435), C7-310
(ASF54-3437) and C7-336(ASF92-3454), the newly tried varieties-Iowa 4258, ASF A-81,
ASF 38-2874, and ASF 2894-3856.

Yields were not related to incidence of Northern Leaf Blight. Good resis-
tance to blight was displayed by Purdue 202, Iowa 4258, Nebraska 104 and ASF 2894-
A34, all of which had readings below 2.0.

An ear corn quality index was used this year to define the overall appear-
ance of the ears. Grades range from 10.0 for perfect ears down to 1.0 for very
poor ears. The above data plus weight per bushel determinations, popping quality,
and average yields of the older varieties are shown in Table 7. The official vol-










Table 3.-The Characteristics and Performance of 12 Popcorn Varieties at Belle Glade, Florida, 1954


Variety /


C-1
c-;
L-32
C-2
C-3
0-3
0-115

P-31
C4$
C-110
Jap. H.
C-112


Yields, Ibs./A
at 15.5% Moisture


2990
2270
2200
2080
2020
1980
1670
1600
l480
1380
980
950


Date
of
Harvest


6- 8-54
5-25-54
6- 9-54
6- 8-54
6- 8-54
6 9-554
5-21-1
6- 8-54


6- 2-54


Disease
Index Y


2.0
2.5
2.0
3.0
2.5
2.5
3.0
2.0
3.0
4.0
2.5
4.0


Height, Ft.
Stalk Ear


6.0
5.5
7.0
6.5
6.5
7.0
6.0
7.0
6.0
7.0
6.0
6.5


3.0
2.5
3.5
3.5
3.5
3.5
2.5
3.0
2.5
3.0
2.5
3.0


Weight/
bushel,
lbs.


65.5
63.0
65.0
65.5
62.0
64.0
61.0
63.5
61.5
61.0
59.5
63.0


Popping
Expansion,
Volumes


Normal
Expansion,
Volumes


32.5
33.5
31.5
31.0
26.0
29.0
26.0
30.0
30.0
30.0
21.5
30.5


L.S.D. for yields: .05 = 750 Ibs; .01 = 1000 lbs.
' C Central Popcorn hybrid; P = Purdue Hybrid

21 Readings on April 26. Higher numbers indicate more injury









Table 4. The Characteristics and Performance of 15 Popcorn Varieties at Belle Glade, Florida. 1955.


Variety /


Yields, Ibs./A.
at 15.5% Moisture


Disease
Index 2/


Height, Ft.
Stalk -EFar


Weight/
Bushel
Ibs.


Popping
Expansion,
Volumes


Normal
Expansion,
Volumes


Moisture
at
Harvest, %


Shelling
Percentage


C-I Hy.
C-5-319
C-5423
Y S(RS) Fll
C-5-428
c-5-3U3
c-U fy.
c-5-Uolt
C-5-U09
C-2 HY
c-5-436
C-5-331
0-5-330
C-5-332
South American


L.S.D. for Yields: 0.5 =


1280 Ibs.; .01 = 1710 Ibs.


/C Central Popcorn
Readings on May 16.


Company; YS(RS) FI1 is an open-pollinated variety from the Cuba Agri.
Higher numbers indicate more injury,


Planted Jan. 28, 1955. Harvested June 6, 1955. High moisture indicates lateness. YS(RS)
June 20.


Expt. Station.

FIl harvested


4610
4260
3670
3670
3430
3110
2990
2990
2920
2750
2650
2640
2370
2330
1060


3.U
.0o
.o0
3.0
3.6
U.5
4.5
4.1
3.8
3.6
4.5
4.8
5.0
4.9
4.9


6.8
6.3
6.0
8.8
5.8
6.0
5.4
6.0
6.0
7.0
5.9
5.9
6.0
5.8
6.3


3.6
3.3
3.0
5.1
2.9
3.0
2.8
2.8
2.9
3.6
3.0
3.0
2.8
3.0
3.3


65.5
66.5
63.5
6U.0
65.0
65.5
66.5
65.0
65.5
63.0
65.5
66.0
63.5
63.5
62.0


37.5
40.0
38.0
23.0
38.0
39.0
39.0
40.0
39.0
36.0
37.5

37.5
40.0
31.5


31.1:
28.59
23.57
3L.4U
24.17
28.59
21.20
25.77
29.61
32.77
23.72
23.57
24.33
28.59
23.72


82.5
77.6
79.9
71.9
78.4
78.2
76.7
78.3
79.8
80.6
81.3
80.U
79.6
81.3
78.7


_







Table 5. The Characteristics and Performance of 19 Popcorn Varieties at Belle Glade, Florida. 1956


Height, Ft. Wt/Bu.
Stalk Ear Lbs.


Popping
Expansion,
Volumes


Normal
Expansion,
Volumes


Shelling
Percent-
age


Years
Grown
Yrs.


Yield, Av.
lbs./A @
15.5 %


4 3155

2 2080


2360
2270


2560
1470


C-1-HY
C-6-329
P-31
C-5-o01
P-32
C-2-HY
c-55
C-6-343
C-115
C-$-HY
P-202
C-6-_17
C-4-HY
0-6-303C
YS(RS)FU1
C-6-412
C-6-337
C-6-312
c-105


No Significant


Difference between Yields


J/ C Central Popcorn Company. YS(RS)F1l is an open-pollinated variety from the Cuba Agr. Exp. Sta. P = Purdue Hybrid

2/ Readings by Miss Alice L. Robert, FCRB, ARS, USDA on May 15, 1956. Scale 0.5. O = No injury.


Planted January 30, 1956 Harvested June 7, 1956


Variety


Yields
Ibs./A @
15.5 %


Disease
Index
2/


3085
2750
2560
2550
2515
2500
21435
2370
2370
2345
2335
2325
2255
2140
2125
2065
1720
150
1365


1.9
2.1
2.1
2.6
2.3
2.5
2.3
2.7
2.1
3.1
1.4
2.5
3.0
2.1
1.9
2.8
2.3
1.6
3.3


6.0
6.3
6.5
5.9
6.5
6.5
5.6
6.8
6.5
6.0
5.1
5.9
5.3
6.0
6.4
5.6
6.1
6.1
5.5


3.3
3.1
3.0
2.9
2.6
3.3
2.8
3.6
3.5
2.4
2.9
3.1
2.8
2.8
3.5
2.6
3.0
2.9
2.4


65.7
67.0
66.0
67.0
66.0
66.7
65.0
66.0
66.3
65.3
66.0
66.0
65.3
66.0
64.5
65.0
66.3
65.6
62.7


36.0
35.0
34.0
37.0
34.0
32.0
34.0
36.5
33.0
40.0
38.0
38.0
35.0
33.0
37.5
37.5
33.0
3U.$


81.1
81.8
82.4
80.6
82.8
80,3
81.5
82.3
83.3
82.3
78.5
80.9
79.2
82.1
76.7
85.1
83.6
77.9
76.8


4 2345

2 2900


3 1675


__


_III_ UI ____ _ I _






Table 6. The Characteristics and Performance of 21 Popcorn Varieties at Belle Glade, Florida. 1957


Height, Ft. Wt./Bu.
Stalk Ear Lbs.


Popping
Expansion,
Volumes


normal
Expansion,
Volumes


C-7-303
C-7-336
c-7-310
C-7-389
C-1-HY
P-31
C.-7-419
C-4-HY
P-32
C-7-374
C-7-369
YS(RS)F11
C-6-408
C-7-313
Gattoni
C-7-300
.-115
C-7-432
C-7-1424
F-202
0-7-306


3120
2735
2555
2080
1950
1950
1730
1615
1540
1465
1405
1395
1385
1380
1280
1250
1200
1075
1040
985
850


3.5
3.0
3.8
3.8
2.9
3.3.
3.9
4.0
3.1
3.0-
3.8
3.3
4.4
3.3
3.0
4.3
3.3
3.6
3.0
2.5
3.3


5.5
6.5
5.5
6.0
5.0
5.5
5,0
4.5
5.5
6.5
5.5
5.0
5.0
6.0
8.0
4.5
5.0
5.5
5.0
4.0
5.5


3.0
3.5
2.5
3.0
3.0
2.5
2.5
2.0
2.5
3.0
3.0
2.0
2.0
3.0
4.5
2.0
2,5
3.0
2.5
2.0
3.0


30.0
35.0
29.0
31.5
34.0
24.0
32.0
31.5
24.0
28.5
30.5
33.0
30.5
35.0
10.0
31.0
29.0
30.5
29.0
27.0
33.0


84.1
82.4

82.8


76.7



83.3

78,5


18.98
26.00
17.34
20.00
18.37
19.34
19.34
17.84
20.00
22.67
16.33
17.58
17.94
22.67
16.84
16.62
29.00
22.67
18.64
15.55
18.64


2915
2035

2200
2085


3 2395



4 2220

2 1660


ILD .05 =


/ C = Central
Cuba.


665 Ibs;


LSD .01 =


885 Ibs.


Popcorn Company; P Purdue Hybrid. Gattoni is an open-pollinated variety from Panama and YS(RS)F11 is from


2/ Yields joined by the same vertical line are not significantly different from each other, whereas those not joined are.

/ Readings by Miss Alice L. Robert, CRD-ARS-USDA. Scale 0-5. 0 = No injury. May 8, 1957.
Planted February 7, 1957 Harvested June 5, 1957. Gattori Harvested June 18, 1957.


Variety
1/


Yields,
LbsA,/
15 .5Y


Disease
Index
Y/


Shelling
Percent-
age, %o


Moisture
at
Harvest
%


Years
Grown,
Yrs.


Av.Yield,
Lbs./A 2
15.5%


__







Table 7. The Characteristics and Performance of 18 Popcorn Varieties at Belle Glade, Florida, 1958.


Variety I/


Yields,
Lbs/A @
15.5%


Disease
Index
2/


Ear Corn
Quality
I/


Wt/Bu.
Lbs.


Official
Volume
Test 4/


Weight
Volume
Test 5/


Times
Grown,
Years


Avg. Yields,
Lbs/A @
15.5%


Purdue 31
Purdue 32
Purdue 202
Purdue 303
Iowa 3574
Iowa 4258
Nebraska 104
Ames Seed Farms
Ames Seed Farms
Ames Seed Farms
Ames Seed Farms
Ames Seed Farms
Ames Seed Farms
Ames Seed Farms
Ames Seed Farms
Ames Seed Farms
Ames Seed Farms
Central 4 Hybrid


A-81
28-2894
96-3856
3856-A92
2894-A34
2894-3138
2894-3856
54-3435 (07-303)
54-3437(07-310)
92-3454(07-336)


lf vA Veries 15, 16, and 17 shown as Ames Seed Farm Varieties are identical with the Central Popcorn Co. numbers


shown in parentheses, and were the best varieties grown in 1957.


L.S.D. .05 = 405 Lbs./A.
L.S.D. .05 : 537 Lbs/A.


2/ Readings by Miss Alice L. Robert, Plant Pathologist, Corn and Sorghum Section, CCRB-CRD-ARS-USDA. May 26, 1958.

3/ A score of 10.0 indicates a perfect popcorn ear and a score of 1.0 a very poor ear in appearance.

4/ Popping expansion volume ratio Raw:Popped.

5/ Cubic inches of popped corn per pound of raw popcorn.


570
435
550
780
360
1415
905
1120
1190
495
575
795
930
1215
1690
1420
1350
520


1670
1670
1290


4.1
2.9
1.4
2.9
2.0
1.9
1.9
2.4
2.8
2.5
2.3
1.9
3.4
2.1
2.6
2.8
2.3
2.8


6.0
7.0
8.0
8.0
8.0
8.5
8.5
8.5
8.5
6.5
6.5
7.0
6.5
8.5
7.5
9.0
7.5
7.0


62.0
62.8
65.0
65.8
64.9
67.7
65.7
67.0
65.7
66.1
66.5
67.6
66.3
66.5
67.8
67.0
65.9
65.0


28.0
31.8
35.8
34.4
36.2
37.0
33.4
37.0
36.1
34.7
33.3
32.2
33.1
37.5
34.0
31.8
27.0
37.0


850
950
1040
975
1045
1035
960
1040
1040
995
950
900
940
1055
945
900
775
1070


2405
1990
2045
1920









ume test data are compared with the new weight volume test method. The new me-
thod gives an index figure for calculating expansions by measuring the Cubic
inches of popped corn from 150 grams of raw popcorn and calculating cubic inches
per pound of raw popcorn.

On 18 samples, there was a very close correlation between the two test me-
thods. The correlation coefficient was + 0.971, which was highly significant.
At the one percent level, a value of only 0.575 was required for significance.

Entomological Evaluation

On June 21 and 22, 1956 a 25-ear sample was taken from each replicate of
each variety and examined for tip and side injury by the corn earworm, Heliothis
zea (Boddie) and also for weevil injury. Injury to the side of the ears by the
corn earworm and injury by weevils was too light to make comparisons and the data
are not given in this paper.

For tip injury by earworms, each ear was given a score (O to 5) based on
the depth from the tip that feeding occurred. The number of ears of each sam-
ple having a certain score were multiplied by that score and the resulting pro-
ducts were added and the sum divided by 25 and multiplied by 100. The average
score for four replicates of each variety is reported along with the percentage
of worm-free ears (Table 8). The method of scoring was as follows:

Score Amount of Injury

0 None
1 Up to 1/8 the length of the ear
2 Up to 1/4 the length of the ear
3 Up to 1/3 the length of the ear
4 Up to 1/2 the length of the ear
5 More than 1/2 the length of the ear.

Of the 25 ears in the sample, five ears of representative size were mea-
sured to obtain an average for each replicate of each variety. The number of
ears per plot had been counted when the popcorn was harvested.

The data were analyzed statistically in such a way that the effect of ear
length, number of ears per plot, and yield upon the earworm score could be de-
termined. The length of ear did not have a significant effect upon the earworm
score (r = 0.2220). As the weight (r: -0.4203**) and the number (r= 0.2784*)
of ears per plot increased the amount of injury as measured by earworm score de-
creased.

Variety C-6-329 had significantly less earworm injury than all other varie-
ties except P-32, C-1-4Y, C-6-312, C-55, and C-6-417 in 1956.

In 1957, because of low yields, it was necessary to omit some of the varie-
ties from the entomological investigation and to examine only 10 ears per plot.
For damage by both corn earworm, Heliothis zea Boddie, and scored-grain insects
(predominantly the rice weevil, Sitophilus oryza (L.)) each ear was scored from
0 to 5 to indicate the degree of-injury. The scores were averaged and multi-
plied by 100 for each plot. These examinations were made July 31, 1957, or 56
days after harvest. Between the time of harvest and examination the ears were
stored in open bags with no protection against stored grain insects. The method








Table 8. Earworm Damage, Number, and Length of Popcorn
Ears, Belle Glade, Florida. 1956


Variety

7 C-6-329
1 P-32
3 C-1-HY
6 C-6-312
4 c-55
L1 C-6-417
L4 P-31
18 C-2-HY
L2 C-5-401
L3 YS(RS)F11
LO C-6-412
2 P-202
8 c-6-337
L9 C-4-HY
5 C-6-303C
L6 C-115
9 C-6-343
20 C-5-HY
L5 C-105


Length of
Ear, Mm

18.4
16.1
14.7
16.2
17.3
16.0
17.1
16.6
16.5
18.0
16.4
16.3
16.0
15.8
15.3
17.0
17.1
16.6
11.2


Av. Number of
Ears/Plot


105
121
139
83
110
111
116
115
117
102
102
97
85
124
109
104
125
125
102


Scores joined by the
other.
Scores not joined by
other.


same line are not significantly different


from each


the same line are significantly different from each


Table 9. Earworm and Stored Grain Insect Damage to Popcorn Ears.
Belle Glade, Florida. 1957.


Variety


Earworm
Damaaea


Stored Grain
Insect Damage a


14 c-7-336 163 203j
12 C-7-310 155 223
8 c-6-4o8 190 22 i
10 C-7-303 193 265
2 C-4-HY 195 277
15 C-7-369 183 290
17 C-7-389 160 298
18 C-7-419 200 305
5 P-32 195 313

a Damage scores joined by the same line are not significantly different;
Damage scores not joined by the same line are significantly different.


% Worm-
Free Ears


Earworm
Score a


110
119
126
128
130
134
143
143
145
145
146
147
147
148
150
157
161
178
282








of scoring was as follows:

No. Corn Earworm Stored Grain Insects

0 no damage no damage
1 damage to tip of ear only 1-10 kernels
2 damage to kernels to one-half 10-20 kernels
inch below tip of ear
3 damage to kernels to one and one- 20-30 kernels
fourth inches below tip
4 damage to kernels to two and one- 30-40 kernels
half inches below tip
5 damage to kernels to more than two and 50 plus kernels
one-half inches below tip.

Differences among varieties in the degree of earworm damage were non-
significant (Table 9). Among the varieties examined, C-7-336 was significantly
more resistant than all varieties other than C-7-310 and C-6-408 to stored-
grain insects. In 1957, the number of ears yielded per plot did not have a sig-
nificant effect on the degree of earworm or stored-grain insect damage.

In 1958, it was again necessary to omit some of the varieties and to examine
only 10 ears per plot because of low yields. Damage by the corn earworm was eval-
uated by assigning a score (0 to 5) to indicate the degree of damage. The scores
for each plot were averaged and multiplied by 100.

The method of scoring individual ears for corn earworm damage was as follows:

Score Amount of Injury

0 None
1 Up to 1/8 the length of the ear
2 Up to 1/ the length of the ear
3 Up to 3/8 the length of the ear
4 Up to 1/2 the length of the ear
5 Greater than 1/2 the length of the ear.

To evaluate stored grain insect damage 100 kernels were taken from each plot
after shelling and observed for the number of damaged kernels. Examinations for
both corn earworm and stored grain insect damage were made on December 17 and 18,
1958.

Covariance analysis indicated a significant negative correlation (r: -0.3712)
between stored grain insect damage and ear length but non-significant correla-
tion between ear length and earworm damage (r: -0.0127) and between earworm da-
mage and stored grain insect damage (0.2322).

The F value for comparing varieties for earworm damage was significant
(F : 2.33* d.f. : 10,30). The multiple range test indicated that Ames Seed Farms
38-2894 had significantly less earworm damage than Ames Seed Farms 2894-3138 or
Nebraska 104. (Table 10). Ames Seed Farms 92-3454(07-336) had significantly less
earworm damage than Nebraska 104.

The F value for comparing varieties for stored grain insect damage was not
Significant
** Highly significant






Table 10.

Variety


Earworm damage to Popcorn Ears.
Belle Glade, Florida, 1958.
Earworm
Score a


Ames Seed Farms 38-2894
92-3454(07-336)
A-81
Iowa 4258
Purdue 303
Ames Seed Farms 2894-A34
S 2894-3856
54-3437(C7-310)
54-3435(C7-303)
2894-3138
Nebraska 104


105
118
130
135
14o
148
153
160
178
193
210


a) Scores joined by the same line are not sijg
nificantly different; those not joined are
significantly different.


Table 11.


Ear length and stored grain insect damage to
popcorn ears. Belle Glade, Florida, 1958.


Variety


ies Seed Farms A-81
S " 54-3435(C7-303)
S 92-3454(C7-336)
f" "t 2894-A34
2894-3138
38-2894
54-3437(07-310)
2894-3856


Nebraska 104
Purdue 303
Iowa 4258


Average Ear
Length
Inches*

5.4
6.5
6.5
6.2
5.8
6.1
6.4
5.9
6.1
5.0
5.7


Not correc-
ted for re-
gression on
Length

66
65
66
68
72
75
76
82
70
75
92a


a Significantly different from all varieties other than Ames Seed
rieties 2894-3856, 54-3437 (C7-310), 38-2894, and Purdue 303.


b Significantly different from all varieties other
rieties 2894-3856, 54-3437(07-310), and 38-2894.


than Ames Seed Farms va-


* F test for differences in ear length was significant.


Correc-
ted


70
69
70
70
70
76
79
82
71
68
90b


Farms va-


Am









significant (F: 1.97, d.f. : 10,30) and was changed little when the regression
of damage on ear length was considered (F : 1.92, d.f. : 10,29). The multiple
range test showed that Iowa 4258 suffered significantly more stored grain in-
sect damage than all varieties other than Ames Seed Farms varieties 2894-3856,
54-3437 (C7-310), and 38-2894, when regression on ear length was considered in
the analysis (Table 11). When the regression was not considered, the damage suf-
fered by Purdue 303 was also not significantly different than that to Iowa 4258.




SUMMARY AND CONCLUSIONS

Tests were begun in 1952 to determine if popcorn could be profitably pro-
duced in the Everglades region of Florida. The area is characterized by high
rainfall, large corn insect populations and the possibility of an epiphytotic of
northern leaf blight annually.

Data collected during the seven-year period showed that profitable yields
of high quality grain could be produced by planting early in February, by good in-
sect and weed control measures, and by promptly harvesting the grain as soon as
the moisture therein had dropped to about 25 percent. Spraying for leaf blight
may be necessary.

Late maturing varieties (requiring in excess of 115 days) gave higher yields
of popcorn with greater expansion ratios. Premature drying caused by northern
leaf blight was detrimental to expansion of the popped product. Central Hybrid
No. 4 gave a six year average yield of 1920 pounds per acre, and Purdue 31 and
Purdue 32 gave four years average yields of 1670 pounds per acre.

Tests showed that Florida grown grain when dried properly to prime moisture
content would, upon popping, give expansion ratios up to 40:1. Normal expansion
figures vary from 33:1 to 39:1.

Shelling percentages of the varieties varied from 76 to 84 percent grain,
which is quite satisfactory. Test weight of the shelled corn was normal.

Florida-grown popcorn was shown to be excellent for taste, tenderness and
flakiness by numerous testimonials, many of which were voluntary and spontan-
eous.









EES 59-10
200 copies