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Copyright 2005, Board of Trustees, University
Agricultural Research and Education Center, Ona
Research Report RC-1984-8 September 1984
COMMERCIAL CORN VARIETY TEST RESULTS
FROM SOUTH-CENTRAL FLORIDA, 1984
P. Mislevy and E. S. Horner-
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. Corn
may follow winter vegetables or be used in a pasture renovation program.
High quality corn silage can provide dairy and beef cattle with a substantial
carbohydrate input, possibly reducing high grain costs and providing growing
calves with quality feed.
Well managed corn harvested for silage at the proper stage of maturity
can produce 7 to 12 t/A of dry matter in 3.0 to 4.0 months. This would allow
the land to be free for the growth of other crops during the remaining eight
to nine months.
Corn silage harvested at the hard dent stage salcontains 30 to 4
dry matter, 8% crude protein and is high in ener, carotege, vitamSn D, bu
low in minerals. To produce high yields of quality cornJ ra adaptedd
hybrids, proper seeding date, high fertility, water control, correct plant
populations, and weed, insect and disease control Of F orlda
The purpose of this study was to evaluate commercial corn hybrids for
silage and/or grain production at Ona.
The experiment was conducted at the Agricultural Research and Education
Center (AREC) Ona. The experimental design was a randomized complete block
with 4 replications. Thirty commercial corn varieties were seeded on an Ona
fine sand on March 21, 1984.
Fertilization practices were 950 Ib/A of 0-10-20 (N-P205-K20) prior to
seeding. Nitrogen was applied at a rate of 100 lb/A pre-emergence, and 56
and 100 lb/A when corn plants were 6 and 24 inches tall, respectively.
Calcium and magnesium content was adequate with a pH of 5.8.
1/ Professor, Agricultural Research and Education Center, Ona; Professor,
Agronomy Department, Gainesville, Florida.
Plant populations and pest control
Corn was seeded in 30 inch rows and thinned to a final population of
26,000 plants per acre. Herbicide practices used were 2.0 lb/A atrazine
(active) and 2.0 lb/A Lasso (active) pre-emerge in 35 gallons of water per
acre. No cultivati practices were employed after the corn was seeded. The
insecticide Furadan 15 G (2.7 lb active/A) was applied in a 7 inch band at
seeding, to control soil insects. This systemic material controls mole
crickets and bud worms when corn is small. No addi tinal insecticide was
used for bud worm control. The insecticide Mesurol was applied on the
seed at the rate of 1 Ib commercial product/100 lb seed to repel birds.
A total of 6.3 inches of water was applied using over-head irrigation
Corn maturity at harvest
Corn plants were harvested for dry matter yield when the kernels of most
varieties were at the hard dent stage as recommended for silage production.
This was coincidental with black layer formation at the base of kernels in
most varieties. Other variables recorded for the experiment were, grain
yield, forage dry matter (percent and yields), kernel moisture, shelling
percentage and grain-to-stover ratio. Grain yield values were converted and
expressed in bushels of shelled corn at 15.5% moisture.
Results and Discussion
Significant (P<0.05) differences among the 30 commercial corn varieties
were obtained for forage dry matter yield and percent, grain yield, kernel
moisture, shelling percentage and grain-to-stover ratio (Table 1).
Forage dry matter yields of commercial corn hybrids grown at Ona during
the 1984 growing season were very good, averaging 8.8 t/A (Table 1). These
yields ranged from a high of 10.6 t/A for 'Paymaster 9902' to a low of 6.9
t/A for Ring Around 'RA 1502' and Stauffers 'S-5602'. The 1984 corn
experiment was delayed in seeding by about 21 days due to excessive soil
moisture. Consequently, the corn was not seeded until March 21 and harvested
July 5, 1984. As a result, corn matured earlier (average 33.0% forage dry
matter) and ready for harvest in only 106 days due to the high temperature of
April, May and June. Corn matured about 15 days earlier than plants seeded
at the normal February 20 to March 1 date. Dry matter ranged from a high of
41.9% for 'McCurdy 8150' to a low of 25.3% for 'Coker 77 B'. The ability of
top yielding hybrids to dry rapidly is a very desirable characteristic. Fast
dry down indicates that. a variety would be ready for ensiling (30 to 40% dry
matter) sooner, allowing the producer to remove the crop before the start of
summer rains. Varieties like 'Paymaster 9902' and Asgrow 'RX 114' have this
Growers should also consider using early maturing hybrids like 'Asgrow
777', which mature 7 to 10 days earlier than full season hybrids, allowing
growers to harvest sooner. This allows the grower additional time for
seeding the second crop before summer rains. Early maturing hybrids
generally produce low dry matter yields (Table 1), but plants dry fast, have
low kernel moisture, and have good grain yields and grain-to-stalk ratios.
Grain yield is another characteristic to consider when selecting corn
hybrids. Grain yields in 1984 averaged 144.7 bu/A shelled corn adjusted to
15.5% moisture. The highest grain yielding variety in 1984 was 'Dekalb 747'
producing 196.0 bu/A shelled corn. This variety had an average dry down (not
fast or slow) averaging 39.5% kernel moisture and 31.6% plant dry matter at
harvest. On a commercial basis this variety would have to remain in the
field for 5-7 additional days before harvest.
When selecting corn hybrids for silage an important factor to consider
is the grain-to-stover ratio. The grain-to-stover ratio is expressed as a
percentage by weight of grain available in the silage. Corn varieties with a
relatively high forage dry matter yield and low grain yield ('Pioneer YOM
06', 'Coker 77 B' and 'Asgrow 909') resulted in a low grain-to-stover ratio
(31-69%) (Table 1). There are other varieties 'Asgrow 777' that produce high
grain yields and low forage yields (short stalks) resulting in a 66-34%
grain-to-stalk ratio. When selecting a corn hybrid, choose a variety with a
high dry matter yield, high grain yield and high grain-to-stover ratio.
Varieties like 'Dekalb 747' and Ring Around 'RA 1604' are two varieties that
fit these criteria.
Southern corn rust (Puccinia polysora) was not a serious problem during
the 1984 growing season with some rust appearing at the milk stage, but have
no effect on yield. However, due to the later than normal seeding (March 21)
army worm (Spodoptera frugiperda Smith), commonly called bud worm, damage was
greater than normal, especially when plants were greater than 3 ft tall.
Normally when commercial dent corn varieties are seeded in late February(go
early March along with the use of a systemic insecticide such as Furadan
or an equal product, bud.worm problems are usually limited, requiring the use
of no insecticides.
When considering commercial corn hybrids for forage and/or grain
production in the Ona area it is desirable to select varieties that have
performed consistently well over a three to six year period. Based on these
data Northrup King NK 508, Coker 77 and Ring Around RA 1604 consistently
produced 10+ t/A dry matter (Table 2). However, if grain production was the
objective, Ring Around RA 1604, Golden Harvest 2680 and Jacques JX 247
yielded 176, 175, and 173 bu/A, respectively.
When selecting a commercial corn hybrid to be grown and stored as silage
in south-central Florida, it is best to select a variety that produces high
forage and grain yields, resulting in a high (50-50 or above) grain-to-stover
ratio. Varieties selected should also have a high forage dry matter
percentage and low kernel moisture. If corn hybrids are grown for grain,
then high grain yields at low kernel moisture should be selected. Kernel
moisture is extremely important since it is an indication of how fast a
hybrid dries, allowing for an earlier harvest. In 1984 Dekalb 747, Ring
Around RA 1604 and Asgrow 777 were three varieties that met these criteria at
Ona. Other varieties may also be suitable for central Florida, by allowing
plants one additional week of growing before harvest.
Forage and grain yields
Forage dry matter
XL 395 A
Forage and grain yields
Means within a column
the same letters
5Calculated on oven dry
18 lb/A commercial
over corn row at
lb/A N-P20 -K O, respectively; a
N when corn plants were 6 and 24
100 lb/A N
Pre-emergence application of
of water via overhead
Table 2. Average grain and forage dry matter yields of selected dent corn
varieties grown at Ona for three or more years during 1979-84.
Grain @ Forage
Brand Variety 15.5% moisture dry matter
Ring Around RA 1604 176 10.0
Golden Harvest 2680 175 8.5
Jacques JX 247 173* 9.4
Big D 6986 171T 8.5
Northrup King NK 508 171 10.9
Coker C 21 165 8.9
Funks G 4740 164 8.1
McCurdy 8150 163 8.7
Funks G 4864 159t 9.4
Asgrow RX 114 150 8.7
Asgrow RX 909 149 8.4
Dekalb XL 395 A 147 9.5
Funks G 4507 146 8.4
Coker 77 143 10.2
Average 162 9.1
Based on 3
on 4 years data.
Based on 5 years data.
"Based on 6 years data.