Everglades Station Mimeo Report 60-5


POPCORN TESTS EVERGLADES AREA
1952 1959

by

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


This report contains results of research with popcorn
grown on organic soils in south Florida and supercedes
Mimeo 59-10, 58-4 and 57-4, which can be discarded.
The work was conducted in cooperation with the Ames
Seed Farms of Ames, Iowa and the Central Popcorn
Company of Schaller, Iowa, who furnished seed and
determined expansion ratios and quality.

Agronomic Evaluation

To date, the agronomic research on popcorn in the Everglades area has
consisted chiefly of screening released and experimental hybrids. Tests
were begun in 1952 and are continuing. Poor yielding and disease susceptible
varieties are discarded each year and are replaced by other varieties.

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


1952 1953


1954 1955 1956 1957 1958


No. of Varieties
Date of Planting
Dates of Harvest


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


Three-foot rows used each year
2-15" 1-12" each year thereafter
19.3 14.5 each year thereafter
50 50 50 40 89 25 50 50
3 6 3 3 1 1 1 1
1 6 3 1 1 1 1 1
4 4 3 4 each year thereafter
R.C.B. Latin R.C.B. each year thereafter
square
3 sprayings/crop .of 1 quart 25% DDT emulsion per acre
None in any year


Each year wireworms were controlled by applying 3 to 5 pounds of technical aldrin
or heptachlor per acre into the soil by spraying and immediately disking. An-
nually, the crop was planted and thinned by hand, and skips in the stand were
replanted soon to insure a perfect stand. Cultivations numbered three per crop
at about two-week intervals after germination. Soil was thrown to the rows to
help reduce root lodging. '?

V/ Victor E. Green, Jr., Associate Agronomist and Emmett D. Harris, Jr.,-,:
Assistant Entomologist, Everglades Experiment Station, Belle Gladei,' < 5 -2
Fl orida.
\'3 f. \95


4
1/28
5/28


6
3/6
6/16
to
7/3


12
2/1
5/21
to
6/9


1959


19
1/30
6/7


15
1/28
6/6
to
6/20


21
2/7
6/5
and
6/18


18
2/26
6/16/


23
2/17
6/10


16 September 1959







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 and 1959 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 and 1959. Yields were calculated
at 15.5 percent moisture on an acre basis. Shelling percentages were calculated
in 1955 and 1956.

In 1952 the test was merely observational and was carried out to check
whether any of the varieties from Iowa were adaptable to the south Florida
environment. 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 15.59 Moisture


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

1_ 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, lbs/A Disease Stalk Off. Normal Moisture
at 15.5% Index L/ Ht.,Ft. Volume Expansion, at Harvest, 2/
Moisture Test Volumes
C-105 1985 0.5 6 27 32 21.97
C-110 2600 2.0 8 29 33 18.82
0-112 2780 4.0 8 33 35 24.46
C-115 3330 3.0 8 35 35 26.06


Scale 0-5


L.S.D. for yields: .05 : 505 lbs.; .01 = 765 lbs.
I/ Readings on April 23. Higher numbers indicate more injury.
2/ Planted January 28, 1953. Harvested May 28, 1953.


nRtp h4 namtpat L/








The variety C-115, the latest maturing variety, yielded better than the
earlier varieties, even though resistance to Helminthosporium leaf blight was
greater in two of the other three. On lots of seed that were dried, shelled
and equalized 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.

In 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 varieties
had the highest popping volumes. See Table 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)F11 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 Florida grown corn
were higher than the normal expansion figures for all varieties. Shelling per-
centages 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
varieties 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 porportions. This factor
along with an extremely high rainfall during the early growth of the plants
caused 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 Central 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.





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


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
Ibs.


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


Off.
Volume
Test


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 Ibs.


C : Central Popcorn hybrid; P : Purdue Hybrid
2/ Readings on April 26. Higher numbers indicate more injury.
Planted February 1, 1954.

Table 4.--The Characteristics and Performance of 15 Popcorn Varieties at


Belle Glade, Florida.


1955.


Variety I/


Yields
lbs/A
15.5%


Disease
Index 2/


Height,Ft.
Stalk Ear


Weight/
Bushel
lbs.


Off.
Volume
Test


Normal
Expansion
Volumes


1 c-i Hy. 4610
8 0-5-319 4260
5 0-5423 3670
15 YS(RS)F11 3670
6 C-5-428 3430
12 C-5-343 3110
2 C-4 Hy. 2990
3 C-5-404 2990
4 0-5-409 2920
13 C-2 HY 2750
7 C-5-436 2650
10 C-5-331 2640
9 0-5-330 2370
11 C-5-332 2330
14 South 1060
American


3.4
4.0
4.0
3.0
3.6
4.5
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
64.0
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.o
38.0
23.0
38.0
39.0
39.0
40.0
39.0
36.0
37.5
40o.o
37.5
40.0
31.5


31.14
28.59
23.57
34.40
24.17
28.59
21.20
25.77
29.61
32.77
23.72
23.57
24.33
28.59
23.72


S.D. for Yields: .05 e 1280 Ibs.; .01 = 1710 Ibs.
C Central Popcorn Company; YS(RS) F11 is an open-pollinated variety from the
Cuba Agri. Expt. Station.
Readings on May 16. Higher numbers indicate more injury.
Planted Jan. 28, 1955. Harvested June 6, 1955. High moisture indicates
lateness. YS(RS)F11 he.rvested June 20.


Variety V


C-1
c-4
P-32
C-2
C-3
c-115
0-105
P-31
C-5
C-110
Jap. H.
C-112


Yields
Ibs/A
15.5%


2990
2270
2200
2080
2020
1980
1670
16co
148o
1380
980
950


Date
of
Harvest


6- 8-54
5-25-54
6- 9-54
6- 8-54
6- 8-54
6- 9-54
5-21-54
6- 8-54
5-25-54
5-25-54
5-21-54
6- 2-54


Disease
Index 2/


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


Moisture
at
Harvest
4


L.


V


__







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


Variety i/


Yields
Ibs./A @
15.5%


Disease
Index 2/


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


Off.
Volume
Test


Normal
Expansion,
Volumes


* Pulling
Percent-
age


Times
Grown,
yrs.


Yield, Av.
Ibs./A @
15.5%


C-1-HY
C-6-329
P-31
C-5-401
P-32
C-2-HY
C-55
C-6-343
C-115
C-5-HY
P-202
c-6-417
C-4-lHY
C-6-3o3c
YS(RS)FU1
C-6-412
c-6-337
c-6-312
C-105


No Significant


Difference between Yields


1/C Central Popcorn Company. YS(RS)F1 is an open-pollinated variety from the Cuba Agr. Exp. STa.

2/ Readings by Miss Alice Robert, FCRB,ARS,USDA on May 15, 1956. Scale 0-5. 0 no injury.


P Purdue Hybrid


Planted January 30, 1956. Harvested June 7, 1956.


3085
2750
2560
2550
2515
2500
2435
2370
2370
2345
2335
2325
2255
2140
2125
2065
1720
1450
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.o
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
38.0
35.0
33.0
37.5
37.5
33.0
34.5


84.1
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


3155

2080

2360
2270


2560
1470


2345

2900



1675


._ __







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


Variety I/


Yields,
Ibs./A @
15.5% V/


Disease
Index 3/


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


Off.
Volume
Test


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)FlU
c-6-408
C-7-313
Gattoni
C-7-300
C-115
C-7-432
C-7-424
P-202
C-7-306


3120
2735
2555
2080
1950
1950
1730
1615
1540
1465
1405
1395
1385
1380
1280
1250
1200
1075
lo4o
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


LSD .05 : 665 Ibs.; LSD .01 = 885 Ibs.

/ C Central Popcorn Company; P Purdue Hybrid. Gattoni is an open-pollinated variety from Panama and YS(RS)FUI
is from Cuba.
/ Yields joined by the same line are not significantly different; others 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. Gattoni Harvested June 18, 1957.


Shelling
Percent-
age
S


Moisture
at
Harve st


Times
Grown
Yrs.


Av.Yield
lbs./A @
15.5%










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
yielding varieties were, along with the best three in 1957--C7-303(ASF5'-.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 in 1958 to define the overall appearance
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
volume test data are compared with the new weight volume test method. The new
method 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
methods. The correlation coefficient was 4 0.971, which was highly significant.
At the one percent level, a value of only 0.575 was required for significance.

In 1959, a test of 23 varieties was grown. Eight varieties were repeated
from the 1958.test, six of which were high yielding and two of which had given
fair yields over a four-year period. Seed of Iowa 4258 and ASF 92-3454 (C-7-336)
were not obtained for the 1959 test. Fifteen varieties were tested for the first
time. They represented new, improved crosses for yielding ability, resistance
to leaf blights and for quality. Sulfur was added to the soil and thoroughly
mixed therein to reduce the soil pH value to 6.0 or below. The nutrient status
of the soil was improved considerably over that in the past. The agronomic
characteristics and performance of the 1959 varieties are shown in Table 8.
The average yields over a number of years are also shown. Two varieties gave
a three-year average yield of about a ton of grain per acre. These were ASF
54-3435 and ASF 54-3437. These varieties are identical to Central 7-303 and
Central 7-310. The highest yielding 1959 variety was ASF 3881. This popcorn,
along with a number of other multiple-eared varieties gave excellent yields.
Four varieties yielded over 3000 pounds per acre.

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 (0 to 5) based on
the depth from the tip that feeding occurred. The number of ears of each sam-
ple having a certain score was multiplied by that score and the resulting
products 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 9). The method of scoring was as follows:









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


Yields,
lbs/a @
Variety i/ 15.5%


Disease
Index 2/


Ear Corn
Quality
3/


Wt/Bu.
lbs.


Off.
Volume
Test 4/


Weight
Volume
Test 5/


Times
Grown,
Years


Avg. Yields,
lbs/A
15.5%


Ames Seed Farms 54-3435 (
Ames Seed Farms 54-3437 (
Iowa 4258
Ames Seed Farms 92-3454 (
Ames Seed Farms 2894-385(
Ames Seed Farms 28-2894
Ames Seed Farms A-81
Ames Seed Farms 2894-3138
Nebraska 104
Ames Seed Farms 2694-A34
Purdue 303
Ames Seed Farms 3856-A92
Purdue 31
Purdue 202
Central 4 Hybrid
Ames Seed Farms 96-3856
Purdue 32
Iowa 3574


07-303)
:C7-310)

C07-336)
63

B


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


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


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


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


34.0
31.8
37.0
27,0
37.5
36.1
37.0
33.1
33.4
32.2
34.4
33.3
28.0
35.8
37.0
34.7
31.8
36.2


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


2405
1990

2045







1670
1290
1920

1670


Varieties 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. LSD .05 405 lbs./A.
LSD .05 535 lbs./A.
Readings by Miss Alice L. Robert, Plant Pathologist, Corn and Sorghum Section, CCRB-CRD-ARS-USDA. May 26, 195
A score of 10.0 indicates a perfect popcorn ear and a score of 1.0 a very poor ear in appearance.
Popping expansion volume ratio Raw: Popped.
Cubic inches of popped corn per pound of raw popcorn.
Planted February 26, 1958. Harvested June 16, 1958.


y/


8.








Table 8. The Characteristics and Performance of 23 Popcorn Varieties at Belle Glade, Florida. 1959.


Varieties Vl


Yields,
Ibs/A C
15.5%


Disease
Index 2/


Ear Corn
Quality
I/


Wt./Bu.
Ibs.


Off.
Volume
Test /


Weight
Volume
Test 2/


Height,Ft.
Stalk Ear


Ears/50'
Row,No.


Erect Stalks
at harvest
S


Times
Grown,
Years


Avg.Yields,
Ibs./A @
15.5%


ASFUA381 3455
"3843 28K 3210
lopop 8 3110
ASFB8 5696 3050
Purdue 213 2880
ASFP8 4496 2775
" KA 3538 2750
Iopop 6 2650
ASF96 3843 2605
" 968 3138 2565
" 38 2894 2385
" 81 5696 2080
" 54 34371/ 2050
" A84356 2035
Purdue 32 2015
Nebraska 104 1930
AsF81 4496 1880
"2894-3856 1760
" 84 5696 1680
" 45A 5696 1630
Purdue 202/ 1540
ASF54 34353J 1460
" A-81 1375


3.5
2.0
2.0
2.5
3.5
2.5
3.0
3.5
2.5
3.0
3.5
3.0
3.5
2.0
3.5
3.5
3.5
3.0
3.5
3.0
1.5
3.5
3.0


9.0
8.0
8.5
9.0
8.5
9.0
8.5
8.5
7.5
8.5
8.5
8.5
8.0
7.5
7.5
8.5
6.0
7.5
8.0
8.5
7.5
8.0
8.0


66.5
65.0
65.0
66.5
66.0
65.5
66.o
65.0
66.0
66.5
66.5
64.5
65.0
66.5
65.0
65.0
65.5
65.o
63.5
65.5
64.5
65.5
63.5


38.3
33.6
36.8
40.1
35.1
38.6
36.2
33.9
33.2
34.4
36.9
37.6
36.2
37.8
35.7
35.2
37.4
33.1
37.0
34.5
33.5
35.9
35.1


logo
975
1070
1140
1000
1100
1040
985
950
98Q
1025
1100
1050
1075
1040
1020
o1060o
960
1090
985
985
1075
1025


7.5
7.0
7.0
7.0
7.0
7.0
7.0
7.0
6.5
7.5
7.5
7.0
7.0
6.0
7.0
7.5
7.0
7.0
7.0
7.0
5.5
7.5
7.0


3.5
3.5
4.0
4.0
4.0
3.5
3.5
4.5
3.0
4.0
4.0
3.5
3.5
3.0
4.0
4.0
3.0
3.5
3.5
3.5
3.0
3.5
3.5


114
121
83
104
91
94
96
84
83
96
81
69
49
63
56
51
69
64
62
45
46
43
43


3 2005


1740
14#00


2 1450


1350
2090
1250


L.S.D. for Yields .05 440 Ibs./A; .01 585 Ibs./A.,
Variety 22, ASF54-3435 is identical to Central 7-303; Variety 23, ASF54 3437 to C7-310.
0.5 resistant to 5.0 susceptible to Northern Corn Leaf Blight. Readings on May 12, 1959.
3 A score of 10.0 indicates a perfect popcorn ear and a score of 1.0 a very poor ear in appearance.
Popping expansion volume ratio Popped: Erw.
SCubic inches of popped corn per pound of raw popcorn.


___






-5-
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 meas-
ured 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
determined. The length of ear did not have a significant effect upon the ear-
worm score (r 0.2220). As the weight (r s -0.4203**) and the number (r n 0.2784*)
of ears per plot increased the amount of injury as measured by earworm score
decreased.

Variety C-6-329 had significantly less earworm injury than all other
varieties except P-32, C-l-$l, 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
varieties from the entomological investigation and to examine only 10 ears
per plot. For damage by both corn earworm, Heliothis zea Boddie, and stored-
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 multiplied 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 of scoring was as follows:

No. Corn Earworm Stored Grain Insects

0 no damage no damage
1 damage to tip 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 10). 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
significant 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 ear-
worm was evaluated by assigning a score (0 to 5) to indicate the degree of
damage. The scores for each plot were averaged and multiplied by 100.




-6-


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 1/4 the length of the ear
3Up to 3/8 the length of the ear
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. Examina-
tions 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 correlation
between ear length and earvorm damage (r -0.0127) and between earworm damage
and stored grain insect damage (0.2322).

The F value for comparing varieties for earworm damage was significant
(F s 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. (Tablb 11). Ames Seed Farms 92-3454 (C7-336) had
significantly less earworm damage than Nebraska 104.

The F value for comparing varieties for stored grain insect damage was not
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
insect 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 consi-
dered in the analysis (Table 12). When the regression was not considered, the
damage suffered by Purdue 303 was also not significantly different than that to
Iowa 4258.

On July 1 to 3, 1959, ears were rated for earworm damage exactly as in 1958
with the exception that a sample size of 25 ears per plot were examined. Corn
was examined for stored grain insect damage using the same method as that in
1958. For each plot the length of five ears was taken to the nearest half-inch.

Stored grain insect damage was practically non-existent so no variety com-
parisons could be made.

Covariance analysis indicated a non-significant negative correlation
(r s -0.0364) between ear length and the earworm damage score.

The F value for comparing varieties for earworm damage was highly signi-
ficant (F s 3.27** d.f. a 22,66) as was that for comparing ear lengths (F a 12.13**'
Average ear length and earworm score are shown for each variety in Table 13.
The number of significant differences shown by the Student-Newman-Keuls test
(Federer, Walter T. 1955. Experimental Design. 544 pp. The MacMillan Company,
New York, N.Y.) was relatively small.

Significant
** Highly significant









Table 9. Earworm Damage, Number, and Length of
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
L8 C-2-HY
L2 C-5-401
L3 YS(RS)FU
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
)0 C-5-HY
.5 0-105


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


Popcorn Ears,


% Worm-
Free Ears


a Scores joined by the same line are not significantly different; others are.


Table 10.


Variety

0-7-336
C-7-310
0-6-408
0-7-303
C-4-HY
0-7-369
0-7-389
C-7-419
P-32


Earworm and Stored Grain Insect
Belle Glade, Florida. 1957.


Earworm
Damages


163
155
190
193
195
183
160
200
195


Damage to Popcorn Ears.


Stored Grain
Insect Damages


203
223
228
265
277
290
298
305
313


Earworm
Scores


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


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








Table 11.


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


Variety


Ames Seed Farms 38-2894
92-3454(C7-336)
A-81
Iowa 4258
Purdue 303


aes Seed Farms 2894-A34
" 2894-3856
" 54-3437(07-310)
" 54-3435(07-303)
" 2894-3138


Nebraska 104


a) Scores Joined by the same line are not signifi-
cantly different; others are.


Table 12.


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


Average Ear
Length
Variety Inches*


Not Corrected
for regression
on Length


Corrected


Am


ies Seed Farms A-81
" 54-3435(07-303)
" " 92-3454(c7-336)
S 2894-A34
it I It 2894-3138
" 38-2894
" 54-3437(07-310)
S t 2894-3856


Nebraska 104
Purdue 303
Iowa 4258


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


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


Ames Seed Farms varieties


than Ames Seed Farms varieties


* F Test for differences in ear length was significant.


Earworm
Score a


An


105
118
130
135
140
148
153
160
178
193
210


5.4
6.5
6.5
6.2
5.8
6.1
6.4
5.9
6.1
5.0
5.7


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


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


- ---






Table 13. Ear Length and Corn Earworm Damage to Popcorn Ears.
Belle Glade, Florida, 1959.

Ear
Variety Length, Earworm
Inches Scorea
ASF KA 3881 6.5 174

ASP 3843 28K 6.2 182

ASF 96 3843 6.6 189

ASF KA 3538 6.3 192

ASF 88 5696 7.2 194

ASF 81 5696 6.8 199
AS? 88 4496 6.9 199

Purdue 213 5.9 206

ASF A 81 6.7 216

ASF 84 5696 6.9 217

ASF 54 3437 (07-310) 7.8 217

Iopop 8 5.6 219

ASF 2894 3856 6.4 221

Nebraska 104 6.9 223

ASF 45A 5696 7.0 223

ASF 38 2894 6.2 224

ASF 968 3138 6.2 225

ASF 54 3435 (07-303) 6.9 228

Iopop 6 6.0 231

Purdue 202 7.0 236

Purdue 32 7.0 242
ASF A84356 6.8 246

ASF 81 4h96 6.5 261
a Means joined by the same line are not significantly different; others are.

EES 60-5
250 copies







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 eight-year period showed that profitable yields
of high quality grain could be produced by planting early in February, by good
insect 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, Purdue 32
gave a five year average of 1740 pounds, ASF 54-3435 and ASF 54-3437 gave three
year average yields of 2090 and 2005 pounds per acre, resp.

Tests showed that Florida grown grain when dried properly to prime mois-
ture content could, 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 spontaneous.























EES 60-5
150 copies