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Agronomy Research Report AY-84-16

Growth and Yield Variables of Temperate
and Tropical No-Tillage Planted Corn
Cultivars in Florida

By

John A. Baldwin and Raymond N. Gallaher
Graduate student and Professor of Agronomy
respectively, Dept. of Agronomy, IFAS,
University of Florida, Gainesville, Fla.
32611

ABSTRACT
Interest has occurred recently in the production of tropical corn (Zea
Mays L.) as a grain and forage crop in Florida. Growth and yield variables
were evaluated utilizing two temperate, one open pollinated, and six tropical
corn cultivars. Cultivars were planted in early March 1983 and managed for high
yields including irrigation. Temperate hybrids Asgrow RXII4 and DeKalb DK747
exhibited the highest grain yields with 9,977 and 9,828 kg/ha, respectively.
Whole plant yields were highest for RX114 (30,432 kg/ha) followed by pioneer
brand X304C a tropical hybrid (27,823 kg/ha) and DeKalb DK747 (26,535 kg/ha).
Whole plant yields ranged from 18,171 kg/ha for tropical hybrid DeKalb EXA 815
to 30,432 kg/ha for Asgrow RX114. There were also differences among the nine
cultivars for N content in grain, stalks, total plant, and for the ratio of N
in grain/stalks and in shelling percent, and the grain/stalk ratio.

INTRODUCTION

Interest has occurred recently in the possible utilization of tropical corn
hybrids for grain and forage production. A few attempts have been made to
plant tropical hybrids succeeding early planted corn and other crops
(Chambliss, Champagne, and Horer 1979; Chambliss and Champagne 1980, Gallaher
1982). Mid to late summer- plantings 'of temperate hybrids developed for
different planting dates and environments experience numerous pest problems
(All and Gallaher 1976-77).
Yield of corn is controlled by genetics, the environment, and the
interaction of the two. Thus, it is important to evaluate aybri s under many
varying conditions to help determine which mangeenrr 1prfaes are best suited
for a particular hybrid or how the hy .yill'react.1t "a give environment.
The objective of this experiment was to vialaate" growth .and yie d variables of
temperate and tropical corn cultivars w en planted: dhg the normal spring
planting period utilizing irrigation and ma aged 0 high yields.

-MATE RIALS" N?

The experiment was planted on March 16th, 1983. The soil was a Zuber
Variant loamy fine sand (member of the fine, mixed, hyperthermic, family or
ultic Hapludalfs). A randomized complete block design was utilized with 4
replications. The nine corn cultivars studied were temperate hybrids Asgrow
RX114 and DeKalb DK747, one open pollinated experimental cultivar, and tropical

hybrids Pioneer brand YOM03, Pioneer brand YOM06, Pioneer brand X304C, DeKalb
XL560, DeKalb EXA815, and DeKalb EXA816.
The plots were 4 rows, 76 cm wide, and 12.2 m in length. On March 5th,
1983 224 kg K2 SO4:MgSO4/ha (K-Mag) and 224 kg Ammonium Nitrate/ha was applied
broadcast to all plots. The cultivars were hand planted at 101,000 plants/ha
over rows made with an in-row subsoil no-tillage planter into the previous
years corn residue. In the planting operation 112 kg N/ha (as Anhydrous
Ammonia) was injected 25 cm under the row through metal tubes attached to the
back of the subsoil units. Also at planting, 2.24 kg active ingredient (a.i.)
Carbofuran (2,3-Dihydro-2,2-dimethyl-7-benzofuranyl methylcarbamate) (Furadan)
was applied in a band in front of the press wheel. At planting .41 kg/ha a.i.
Paraquat (1,1'-Dimethyl-4,4'-bipyridinium ion) plus 470 ml X-77 surfactant/378
L. of water was broadcast sprayed. When the corn was 12 cm in height, 2.24
kg/ha a.i. Atrazine (2-chloro-4 ethylamino-6-isopropylamino-l,3,5 triazine)
(Aatrex) plus 1050 ml crop oil/ha was sprayed broadcast over the corn. When
the corn was approximately 50 cm in height, .13 kg/ha a.i. Paraquat plus 112
kg/ha N as 22% liquid Ammonium Nitrate N was applied as a directed spray.
Supplemental moisture was provided throughout the growing season utilizing a
travelling gun irrigation system.
Yield was estimated by hand harvesting 2.25 m2 of area per plot on July
9th, 1983. Data collected included population at harvest, plant height, ear
number, whole plant dry matter, grain dry matter, shelling percent, and grain
yield. Plant samples were dryed at 70 C for 48 hours and plant dry matter was
determined. Samples were then chopped and mixed then ground through a 1 mm
screen in a Wiley mill. Nitrogen analysis was determined utilizing
micro-Kjeldahl and auto-analyzer. Statistical analysis of variance for a
randomized complete block design was performed according to Steel and Torrey
(1960). Differences among means were tested the same as for analysis of
variance utilizing Duncan's new multiple range test.

RESULTS AND DISCUSSION

Temperate hybrids Asgrow RX114 and DeKalb DK747 exhibited the highest
grain yields with 9,977 and 9,828 kg/ha respectively. Whole plant yields were
highest for RX114 followed by Pioneer brand X304C tropical hybrid and DeKalb
DK747 (Table 1). Whole plant yields ranged from 18,171 kg/ha for tropical
hybrid DeKalb EXA815 to 30,432 kg/ha for Asgrow RX114 (Table 1). Shelling
percent was highest for DK747 and RX,114 at 87 % and 86 %, respectively (Table
2). It can be noted that hybrids differed significantly in the grain
composition of the plant (Table 2). The grain/residue ratio may reflect on the
efficiency among hybrids to partition photosynthate into the grain rather than
other plant parts. Grain to stalk ratio was highest for tropical hybrid Pioneer
YOM06 at .84. RX114 temperate hybrid contained the highest amount of N in
grain (144 kg/ha), stalks (199 kg/ha), and whole plant (344 kg/ha) (Table 3).
The ratio of N in grain/stalks ranged from .49 for tropical hybrid DeKalb
EXA816 to 1.67 for tropical hybrid Pioneer YOM06 (Table 4). Severe lodging
occurred in all replications of tropical hybrid DeKalb EXA816 (Table 5).

REFERENCES

All, J.N and R.N. Gallaher. 1976. Insect infestation in .no-tillage corn
cropping systems. Georgia Agr. Res. 17 (4):17-19

All, J.N. and R.N. Gallaher. 1977. Detrimental impact of no-tillage corn
cropping systems involving insectisides hybrids, and irrigation on lessor

cornstalk borer (Elsmopalpus Lignosellus) infestations. J.Econ. Entomol.
70(3):361-365.

Chambliss, C.G.,
commercial field cc
Report GC-1979-20.

R.J. Champagne, and
rn varieties in Dade

E.S. Horner. 1979. Evaluation of
County Fla. AREC-Bradenton Research

Chambliss, C.G. and R.J. Champagne. 1980. Grain yields of 27 tropical and
temperate corn hybrids grown in Dade County Florida during 1980. Agron.
Research Report AY81-8. Florida Field and Forage Crop Variety Report 1980.

Gallaher, R.N.
no-tillage corn.

and E.S. Horner. 1983. Evaluation of late summer planted
Agron. Research Report AY83-11.

AC KNO WLEDGEMENTS

The authors acknowledge the following individuals for their resources and
technical support of this research project. Raymond and Andy Robinson, Sonny
Tompkins, Betty Hurst, and Evelyn Bluckhorn.

Use of trade names in this publication is solely for the purpose of
providing specific information. It is not a guarantee or warranty of products
named and does not signify approval to the exclusion of others of suitable
composition. Users of pesticides should follow all labeled direction and use
pesticides safely.

Table 1. Forage and grain dry matter yields of temperate and
tropical no-tillage early planted corn cultivars 1983

Brand

Asgrow
Dekalb

Variety
Temperate
RX114
DK747

Exper. Open Pollinated

Tropical

Pioneer
Pioneer
Pioneer
Dekalb
Dekalb
Dekalb

YOMO6

YOMO3
X304C
XL560
EXA815
EXA816

Grain Yield
Kg/ha
9977 a
9828 a

7051 b

8750
8200
7046
7177
5025
3792

Forage Yield Whole Plant
Mg/ha Mg/ha

20.4 a
16.4 ab

16.8 a

10.4
12.1
20.2
10.2
13.1
16.4

30.4 a
26.5 ab

23.8 a-c

21.4
20.3
27.3
17.4
18.2
20.2

20.2

Values in columns within a variable not followed
are significantly different at-the 0.05 level of
Duncan's new multiple range test.

by the swrie letter
probability according to

6/6/8). .lih

Table 2. Agronomic variables of nine corn cultivars no-til-
lage early planted during 1983

Variety
Temperate

RX114

DK747

Open Pollinated

Tropical

YOM06

YOM03

X304C

XL560

EXA815

EXA816

Shelling
Percentage
Z

86 a

87 a

77 bc

Grain/Stalk
Ratio
Z

.49 cd
.63 bc

.44 d

ab

ab

c

a-c

a-c

bc

- Values in columns within a variable not followed by the same letter are
significantly different at the 0.05 level of probabiltiy according to
Duncan's new multiple range test-

6/16/ ; bijh

Brand

Asgrow

Dekalb

Exper.

Pioneer

Pioneer

Pioneer

Dekalb

Dekalb

Dekalb

Table 3. Nitrogen content of grain
no-tillage corn in 1983

and stalks

in early planted

Brand

Asgrow
Dekalb

Exper.

Pioneer

Pioneer
Pioneer
Dekalb
Dekalb
Dekalb

Variety
Temperate
RX114
DK747

Open Pollinated

Tropical
YOM06
YOMO3
X304C
XL560
EXA815
EXA816

Total N
Grain
Kg/ha
144 a
128 ab

121 ab

130
124
112
107
71
61

Total N
Stalks
Kg/ha
199 a
137 a-c

139 a-c

78 c
102 c
191 ab
100 c
127 bc
128 bc

Values in columns within a variable not followed by the same letter are
significantly different at the- 0.05 level of probability according to
Duncan's new multiple range test.

6/6/84 bjh

--

Table 4. Nitrogen content of plants and grain/stalk ratio of
no-tillage early planted corn cultivars in 1983

Variety
Temperate
RX114
DK747

Open Pollinated

Tropical
YOM06

YOMO3
X304C
XL560
EXA815
EXA816

Total N
Plants
Kg/ha
344 a
237 bc

259 bc

208 c
226 c
304 ab

207 c

197 c
189 c

Ratio N
Grain/Stalk
.74 b-d

1.09 bc

1.07 bc

1.67 a
1.22 ab
.63 cd
1.14 a-c
.58 cd
.49 d

Values in columns within a variable not followed by the same letter are
significantly different at the 0.05 level of probability according to
Duncan's new multiple range test-

6/6/8b bjh

Brand
Asgrow

Dekalb

Exper.

Pioneer

Pioneer
Pioneer
Dekalb
Dekalb
Dekalb

: Table 5.

AGRONOMIC VARIABLES OF 9 VARIETIES
OF EARLY PLANTED NO-TILLAGE CORN

Temperate Corn
Exp # Hybrid

Asgrow RX11
Dekalb DKTh7

Plants 1
#/ha

95060
95800

Open Pollinated

3 Experimental
Tropical Corn
Pioneer Ycro 6
5 Pioneer Yomo 3
6 Pioneer X30LC
7 Dekalb XL560
8 Dekalb EXA815
9 Dekalb EXA816

71110

85925
81975
77530
60250
90370
79500

Ears 1
#/ha

91360
91360

66670

81730
77530
73000
56050
58025
47900

Day
50% Silk

Ear Ht. 2
Cm

127
132

171
160
168
155
168
173

Ht. to Flag 2
Cm

254
264

295

284
279
282
257
287
282

Ht. Full Silk 2
Cm

Lodged Plants
%

305
320

338
322
333
310
333
338

* 1 Multiply by .405 to obtain plants
2 Divide by 2.5L to obtain inches
3 All plots planted at 101,235 Seed

and ears/acre

per hectare