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Group Title: Commercial corn variety testing results from south-central Florida.
Title: Commercial corn variety testing results from south-central Florida. 1978
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Permanent Link: http://ufdc.ufl.edu/UF00075790/00003
 Material Information
Title: Commercial corn variety testing results from south-central Florida. 1978
Series Title: Commercial corn variety testing results from south-central Florida.
Translated Title: Research Report - University of Florida Agricultural Research Center ; 1978-12 ( English )
Physical Description: Serial
Language: English
Creator: Mislevy, P.
Kalmbacher, R. S.
Everett, P. H.
Horner, R. S.
Publisher: University of Florida, Agricultural Research Center
Publication Date: 1978
 Record Information
Bibliographic ID: UF00075790
Volume ID: VID00003
Source Institution: University of Florida
Rights Management: All rights reserved by the source institution and holding location.
Resource Identifier: oclc - 143646330

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HISTORIC NOTE


The publications in this collection do
not reflect current scientific knowledge
or recommendations. These texts
represent the historic publishing
record of the Institute for Food and
Agricultural Sciences and should be
used only to trace the historic work of
the Institute and its staff. Current IFAS
research may be found on the
Electronic Data Information Source
(EDIS)

site maintained by the Florida
Cooperative Extension Service.






Copyright 2005, Board of Trustees, University
of Florida








0i


Agricultural Research Center
Research Report RC-1978-12


October 1978


COMMERCIAL CORN VARIETY TESTING RESULTS HUMS LIBAAR (

FROM SOUTH-CENTRAL FLORIDA, 1978 \OV 2 8 1978
1/
P. Mislevy, R. S. Kalmbacher, P. H. Everett and E. S. Horne .
I.F.A.S.-Univ. of Fioida


Corn can be extremely valuable in a livestock feeding program. With
its rapid growth and high yielding ability, corn harvested and stored as
silage, can supplement perennial grasses at times when their production
is low. This crop may follow winter vegetables or be used in a pasture
renovation program. High quality corn silage can provide cattle with
a substantial carbohydrate input, possibly reducing high grain costs and
also providing growing calves with quality feed.


Well managed corn harvested for silage at the proper stage of
can produce 7-10 tons/acre dry matter in a 3.5 to 4 month period.
would allow the land to be free for the growth of other crops over
remaining eight months.


maturity
This
the


Corn silage harvested at the hard dent stage usually contains 30-35%
dry matter and is high in energy, carotene, vitamin D, but low in minerals
with a protein content of about 8%. To produce high yields of quality
corn forage, adapted hybrids, proper seeding date, high fertility, water
control, correct plant populations, and weed and insect control are
necessary.

The purpose of these studies was to evaluate commercial corn
hybrids for silage and/or grain production at Ona and Immokalee.

Experimental Procedure

The experiments were conducted at the Agricultural Research Centers,
(ARC) at Ona and Immokalee. The experimental design at Ona and Immokalee
was a randomized complete block with 4 replications. Twenty seven commer-
cial corn varieties were seeded at Ona and 18 varieties at Immokalee. The
experiment at Ona was seeded on Ona fine sand February 28, 1978, however
due to saturated soils and a seeding failure, the experiment was reseeded
on March 20, 1978. The Immokalee experiment was seeded on February 2, 1978.


1/
Associate and Assistant Professors, Agricultural Research Center, Ona;
Professor, Agricultural Research Center, Immokalee; Professor,
Agronomy Department, Gainesville, Florida.


0 t









Fertility

Fertilization practices carried out at Ona were 76 a36-272 Ib/A
N-P205-K20 plus 27 Ib/A fritted micronutrients FTE 503- at seeding.
Additionally, 74 and 100 Ib/A N was applied when the corn was 8 to 10
and 24 to 28 inches tall, respectively.

At Immokalee 50-100-200 Ib/A of N-P205-K20 plus 20 lbs/A FTE 503 was
disked into the seedbed. When plants were 8 to 12 and 24 to 28 inches
tall an additional 100 Ibs/A of N was applied as ammonium nitrate. The
side-dressed nitrogen was applied in a band near the corn row and covered
with soil by a rolling coulter. The effect of this treatment was to keep
the fertilizer within capillary contact of the soil in this seepage-
irrigated experiment.

Plant populations and pest control.

Corn at Ona was seeded in 30 inch rows to a final population of
24,000 plants per acre. In Immokalee the corn was seeded in 30 inch rows
to a final population of 26,000 ilnts per acre. The herbicideR practices
used at Ona were 2.5 Ib/A AAtrex (active) and 2.0 Ib/A Duel (active)
pre-emerge in 30 gallons of water per acre. No cultivation practi
were employed after the corn was seeded. The insecticide Counter" 15G
was applied at seeding, at a rate of 2. lb/A active to control soil
born insects. The insecticide Mesurol was applied on the seed at the
rate of 1 lb/100 Ib seed to act as a bird repellent.

At Immokalee AAtrex(R) was applied at 2.0 Ib/A active ingredient with
2 Ib/A of active Lasso(R). At seeding the insecticide Furidan )lOG was
applied at 2.0 lb/A active ingredient. Mes rol was applied at 1 lb/100
lb. of seed. Corn was sprayed with Lannate R at the rate of 1 lb/100 gal.
of water to control bud worms.

Irrigation

The inigial irrigation at Ona was applied immediately following
seeding. A total of 4.2 inches of irrigation water was applied in 6
applications at the Ona ARC. The Immokalee experiment was irrigated by a
seepage system with laterals on 40 foot certers.

Maturity at Harvest

Corn was harvested for silage when the kernels were at the hard
dent stage, with plants containing approximately 37% and 43% dry matter
at Ona and Immokalee, respectively. This was coincidental with black-layer
formation in kernel. The experiments were also harvested for grain.
The ear moisture over all varieties at Ona and Immokalee averaged 41 and
41.7%, respectively. These values were then converted and expressed in

2/FTE 503(R)contains the following elemental content: iron 18.0%;
zinc 7.0%; manganese 7.5%; copper 3.0%; boron 3.0% and molybdenum 0.2%.












bushels of shelled corn at 15.5% moisture. No lodging was observed among
varieties at Ona or Immokalee.


Results and Discussion

Ona ARC

Dry matter forage yields of commercial corn hybrids ranged from a
high of 12.0 T/A for the full season hybrid 'Greenwood 747' to a low of
7.0 T/A for the early maturing hybrid 'Dekalb XL 75A' (Table 1). Due to
variation of some corn hybrids between replications, the 5 T/A difference
between the low and high yielding varieties was not significant. Average
dry matter yield of all 27 varieties was 9.0 T/A. The two highest
yielding varieties, Greenwood 747 and 'Dekalb XL 395A' were among the full
season hybrids. Both varieties also dried down quite rapidly after
maturity as evidenced by the 42.0 and 44.8% dry matter. This varietal
characteristic is quite important, since fast dry down indicates the
variety would be ready for whole plant harvesting sooner, allowing the
commercial grower to remove the crop before summer rains start.

When selecting a corn hybrid to be grown in south central Florida,
grain production should also be an important criterion. Significant
differences in grain yields among the 27 hybrids was observed (Table 1).
Two corn hybrids 'McCurdy 75-200' and 'Coker 18' produced the highest
grain yields averaging 173 bu/A shelled corn @ 15.5% moisture. The ear
moisture content of these two varieties at harvest was quite high
averaging 38.8 and 41.1% for McCurdy 75-200 and Coker 18,respectively. Ear
moisture for all varieties grown in this experiment was quite high,averaging
41%. The main reason for high moisture content was early removal of all
hybrids (106 days after seeding).

An important factor to consider when selecting corn hybrids for silage
is the grain-stover ratio. This is the amount of grain intake by the animal
while consuming corn forage or silage. Producing a corn crop with a high
forage dry matter yield and low grain yield (McNair S-338) results in a
low grain-stover ratio (33-67%) (Table 1). Whereas Coker 18 produced a
low forage dry matter yield and high grain yield resulting in a 63-37% ratio.
Good commercial varieties should produce high forage and grain yields with
approximately a 50-50% ratio or higher.

Southern corn rust (Puccinia polysora) did not appear to be a serious
problem on any commercial corn hybrids grown at Ona in 1978.

Immokalee ARC

There were significant differences in dry matter yields of corn hybrids
tested at Immokalee (Table 2) Greenwood 747 was the highest yielding entry
(9.3 T/A) followed closely by 'Dekalb 1295' (9.1 T/A), 'Funks G5945' (9.0
T/A), 'Funks G4864' (9.0 T/A), 'McCurdy 67-14' (9.0 T/A), Dekalb XL 395A
(8.9 T/A), and 'McNair 508' (8.7 T/A). The lowest yielding entry was
'Asgrow RX 114' (6.1 T/A). The average yield of all entries was 8.2 T/A.


L











Dry matter percentages are indicative of maturity groups. Early
hybrids like Asgrow RX 114 or 'Dekalb XL 80' averaged 47.4 and 45.5%,
respectively while later hybrids such as Dekalb XL 395A or Coker 77,
averaged 40.5 and 36.6%, respectively. Average dry matter for all
corn hybrids grown at Immolalee was 43%

There were no significant differences in the yields of grain (Table 1).
Generally, the entries which were higher in forage yield were also higher
in grain yield: for example Greenwood 747 or Dekalb 1295. Average grain
yield based on 15.5% moisture was 144 bu/A, with a range of 163 to 125
bu/A. Moisture content of the ears averaged 41.7% at harvest.

Grain-stover ratios averaged 50-50 (Table 2). As a rule the
earlier hybrids, such as McNair S-338, Coker 18, Dekalb XL 80 or Asgrow
RX 114 had higher grain-stover ratios. Later maturing hybrids are often
good grain producers, but the greater stover production results in lower
ratios.

Several agronomic characteristics of the 18 hybrids tested at Immokalee
are listed on table 3. Southern leaf blight (Helminthosporium spp.) was
a greater problem than southern corn rust (Puccinia polysora). Average
ratings on a scale of 1 to 10 were 3.9 for leaf blight and 2.2 for rust.
There were apparent differences in varietal susceptability to leaf blight.
For example, McCurdy 67-14 averaged 5.5 and was heavily infested with
leaf blight, while Dekalb 1295 averaged 2.2. Most of the varieties were
consistent in their ratings for rust with a range of 3.8 to 1.8.

Conclusions

Ona ARC

Commercial growers should study the performance of corn varieties
carefully prior to purchasing seed of a variety to be grown. It is
generally best to select a high yielding, early maturing variety with
a high (50-50 or above) grain-stover ratio.

Immokalee ARC

There were significant differences in dry matter yield among 18
varieties tested. Higher yielding varieties ranged in yield from 9.3
to 8.7 T/A. All varieties averaged 8.2 T/A.

There were no significant differences in grain yield. Grain yield
at 15.5% moisture ranged from 163 to 125 bu/A and averaged 144 bu/A.
Grain-stovers ratios averaged 50-50.















Table 1. Forage and grain yields of commercial corn varieties grown at the Ona ARC 1978.

Grain Ear
Forage yield DMO at Yield 15.5% moisture Grain- stover
Brand Variety (dry matter) harvest moisture atharvest ratio
T/A- -%-- bu/A- -%- % -

Greenwood 747 12.0 42.0 154 abct 41.4 36-64
Dekalb XL 395A 11.7 44.8 149 abc 45.2 36-64
McNair S-338 10.7 44.8 127 bc 42.8 33-67
Asgrow RX 140A 10.2 41.9 150 abc 40.1 41-59
McCurdy 67-14 9.9 40.2 153 abc 42.9 43-57
PAG 751 9.9 34.1 136 abc 40.0 38-62
Asgrow RX 114 9.8 45.4 143 abc 38.2 41-59
Funks G4864 9.6 34.6 146 abc 43.0 43-57
Funks G5945 9.5 34.4 127 bc 41.9 37-63
Funks G4810 9.5 32.8 148 abc 45.8 44-56
Dekalb XL 394 9.0 33.9 150 abc 40.9 47-53
Dekalb XL 1295 8.9 33.2 140 abc 42.9 44-56
McCurdy 75-200 8.9 35.7 173 a 38.8 54-46
Funks G4507 8.9 47.0 158 ab 34.9 50-50
Pioneer 3030 8.8 30.4 123 bc 43.2 39-61
Dekalb XL 80 8.7 40.0 133 abc 41.3 43-57
Coker 77 8.5 26.4 153 abc 45.4 50-50
Funks G4776 8.5 32.7 153 abc 41.2 50-50
Golden Harvest H2750 8.4 37.5 141 abc 39.5 47-53
McNair 508 8.0 28.8 117 c 43.1 41-59
Asgrow RX 112 7.9 40.2 157 abc 35.5 56-44
Coker 22 7.8 34.9 133 abc 40.6 48-52
Coker 18 7.7 32.4 173 a 41.1 63-37
Golden Harvest H2775 7.7 33.7 145 abc 40.0 53-47
Funks G4709 7.3 34.0 151 abc 41.0 58-42
Dekalb XL 54 7.3 42.4 127 be 35.4 49-51
Dekalb XL 75A 7.0 38.0 119 be 37.8 48-52
Average 9.0 37.0 144 41.0 46-54

+ No significant difference was observed among variety means in this column.


Means within this column followed by different letters are
(Duncan's LSD, K=100.)
Grain at 15.5% moisture.
I DM=dry matter.


significantly different.


I _










Table 2. Forage and grain yields of commercial corn varieties grown at the
Immokalee ARC 1978.

Grain Ear
Forage yield DMtat Yield 15.5% moisture Grain-stover
Brand Variety (dry matter) harvest moisture at harvest ratio
T/A- % -bu/A- -%- -- % -

Greenwood 747 9.3 a 41.5 163 a 45.6 49-51
Dekalb 1295 9.1 ab 40.0 163 a 42.9 50-50
Funks G5945 9.0 ab 41.8 143 a 42.6 44-56
Funks G4864 9.0 ab 46.5 147 a 39.9 46-54
McCurdy 67-14 9.0 ab 49.5 155 a 39.3 48-52
Dekalb XL 395A 8.9 ab 40.5 160 a 46.1 50-50
Coker 77 8.9 ab 36.6 153 a 49.0 48-52
McNair 508 8.7 abc 39.4 134 a 44.5 43-57
McNair 75-200 8.2 bcd 42.9 155 a 41.1 53-47
McNair S-338 8.1 bcd 42.7 162 a 38.2 56-44
Asgrow RX 140A 7.8 de 46.4 132 a 41.4 47-53
Funks G4810 7.7 de 42.3 137 a 40.9 50-50
Pioneer 3030 7.7 de 40.3 133 a 44.6 48-52
Coker 18 7.5 de 45.4 139 a 40.7 52-48
Dekalb XL 80 7.4 e 45.5 139 a 37.5 53-47
PAG 751 7.3 e 43.8 125 a 38.6 48-52
Golden Harvest H2750 7.3 e 43.1 133 a 44.0 51-49
Asgrow RX 114 6.1 f 47.4 127 a 34.5 58-42
Average 8.2 43.0 144 41.7 50-50
*? .r./- t t /- <- _


Means within columns followed by the
(Duncan's LSD, K=100.)

SGrain at 15.5% moisture.

+ DM=dry matter.


same letter are not significantly dif t.


-~. ._....._. ..., .,..,,,.,,,,..,.,.. ...,,. .-.....~..,.....: ....,.~.,., .,,,.,..~......~. .;..... ... ~ ~.... .;;~. .. .... ..~ ~ ~. ~ ~ ......... .. ...I ., ....- ..- -
















Table 3. Agronomic characteristics of corn varieties grown at the
Immokalee ARC 1978.

Disease
Southern leaf Southern corn
Brand Variety Height blight rust
ft.

Greenwood 747 8.3 3.8 3.0
Dekalb 1295 8.1 2.2 2.0
Funks G5945 8.0 3.2 2.2
Funks G4864 7.8 4.2 2.5
McCurdy 67-14 7.4 5.5 3.8
Dekalb XL 395A 7.9 2.5 3.2
Coker 77 8.1 2.5 1.8
McNair 508 8.1 2.5 2.2
McNair 75-200 7.8 4.8 2.5
McNair S-338 7.0 4.0 2.2
Asgrow RX 140A 6.2 3.5 3.2
Funks G4810 7.6 5.8 2.2
Pioneer 3030 7.9 5.0 2.5
Coker 18 7.6 2.8 2.5
Dekalb XL 80 7.5 4.0 3.0
PAG 751 8.2 5.2 2.2
Golden Harvest H2750 7.8 4.2 2.0
Asgrow RX 114 7.5 3.8 3.8
Average 7.8 3.9 2.6


Disease rated on a scale 1 to 10; 1= none


and 10= complete loss.




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