American Journal of Plant Sciences, 2013, 4, 1713-1720
http://dx.doi.org/10.4236/ajps.2013.49209 Published Online September 2013 (http://www.scirp.org/journal/ajps)
Evaluation of Weed Control Options for Herbicide
Resistant Transgenic Stacked (TC 1507 X NK603) and
Conventional Maize Hybrids for Higher Productivity
Sivagamy Kannan*, Chinnusamy Chinnagounder
Department of Agronomy, Tamil Nadu Agricultural University, Coimbatore, India.
Received June 4th, 2013; revised July 1st, 2013; accepted July 25th, 2013
Copyright © 2013 Sivagamy Kannan, Chinnusamy Chinnagounder. This is an open access article distributed under the Creative
Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original
work is properly cited.
ABSTRACT
Weeds are posing a serious problem in maize. The congenial climatic conditions encourage more weed growth in the
widely spaced crop like maize and cause yield reduction to the tune of 29 to 70 percent. A field experiment was con-
ducted for two years at Tamil Nadu Agricultural University, Coimbatore during kharif seasons of 2010 and 2011 to
evaluate the weed management options for transgenic stacked (TC 1507 & NK 603) and conventional maize hybrids.
The experiments were conducted with the following objective to evaluate the weed control efficiency and crop produc-
tivity with K salt of glyphosate formulations under field conditions. Treatments consisted of two transgenic stacked
hybrids named 30V92 and 30B11 applied with glyphosate as early post emergence at 900 and 1800 g a.e ha–1 during
kharif, 2010 and conventional maize hybrids named 30V92 and 30B11 applied with glyphosate by controlled droplet
application method at 900, 1350 and 1800 g a.e ha–1 during kharif, 2011 compared with non transgenic counterpart maize
hybrids applied with pre emergence atrazine at 0.5 kg ha–1 followed by one hand weeding on 40 DAS with and without
insect management. Based on the two years field experimentation, it was found that early post emergence application of
glyphosate at 1800 g a.e ha–1 gave significantly lower weed density, weed dry weight and higher weed control effi-
ciency at all the intervals. Higher grain yield was registered with post emergence application of glyphosate at 1800 g a.e
ha–1 in transgenic and conventional maize hybrid of 30V92 (12.21 t ha–1 and 11.23 t ha–1 ) during both seasons of the
study. Unweeded control accounted for grain yield which in turn reflected through higher weed index of 58.39 and
57.26 per cent, respectively during both the years, due to heavy competition of weeds for nutrients, space and light.
Keywords: Herbicide Tolerant Maize; Weed Density; Weed Dry Weight; Yield Attributes; Grain Yield
1. Introduction
The development of crop cultivar with resistance to se-
lected herbicides has a positive impact on agricultural
production. Selection of proper herbicides is essential for
successful weed management in all crop production sys-
tems [1]. Maize was an ideal crop due to availability of
the plant to acclimate to many soil and climate conditions.
It is an important cereal crops cultivated worldwide. It is
not only an important human nutrient source, but also a
basic element of animal feed and raw material for manu-
facture of many industrial products. The major yield re-
ducing factors for maize cultivation in India are weeds
and insects. Weeds cause considerable yield loss due to
competition of resources with maize crop [2].
Herbicidal weed control seems to be a competitive and
promising way to control weeds at initial stages of crop
growth. Post emergence herbicides have been achieving
adequate weed control programmes, due to its broad
spectrum of activity, excellent crop safety, convenience
and flexibility [3]. This necessitates the development and
testing of selective early post emergence herbicides for
weed control in maize. Glyphosate is a foliar applied,
broad spectrum, post emergence herbicide capable of
controlling annual, perennial grasses and dicotyledonous
weeds. The introduction of glyphosate resistant crops has
created new opportunities for the use of effective, non
selective herbicides like glyphosate as selective weed
control in crop production. Prior to the introduction of
*Corresponding author.

Evaluation of Weed Control Options for Herbicide Resistant Transgenic Stacked (TC 1507 X NK603)
and Conventional Maize Hybrids for Higher Productivity
1714
glyphosates resistant crops, glyphosate is being applied
to control existing vegetation prior to sowing the crops.
Now, it can be used as post emergence herbicide in
glyphosate resistant crops [4]. Herbicide resistant corn
plants confer tolerance to glyphosate by production of
glyphosate resistant CP4 5-enolpyruvyl shikimate-3 phos-
phate synthase (CP4 EPSPS) proteins. Transgenic stacked
hybrid maize (TC1507 X NK 603) was developed for
preventing yield losses for maize crop due to pests and
weeds and to improve productivity. Post emergence ap-
plication of glyphosate at 1800 g a.e ha–1 gave signifi-
cantly lower weed index, weed dry weight and high weed
control efficiency at all the intervals. Post emergence
application of glyphosate at 1800 g a.e ha–1 in transgenic
maize and post emergence control droplet application
method of glyphosate at 1800 g a.e ha–1 in conventional
maize hybrid (30V92) recorded high productivity and
profitability. In view of the above facts, an experiment on
“Evaluation of weed management options for transgenic
stacked and non transgenic maize hybrids’ was formu-
lated with the following objectives:
1) To evaluate the weed management efficiency of
glyphosate K salt formulation under field conditions and
carry-over on succeeding crops;
2) To study the effect of different weed management
practices on maize growth and development.
2. Materials and Methods
2.1. Experimental Site and Initial Soil
Characteristics
Field experiments were laid out during kharif seasons of
2010 & 2011 in Eastern block farm of Tamil Nadu Ag-
ricultural University, located at Coimbatore, India. The
geographical location of the experimental site is situated
in western agro climatic zone of Tamil Nadu at 11˚N
longitude and 77˚E latitude with an altitude of 426.7 m
above MSL and the farm receives the total annual rainfall
of 674 mm in 45.8 rainy days. The soil of the experi-
mental site was sandy clay loam in texture (32.48% clay,
18.50% silt and 28.96% coarse sand) with low available
nitrogen,medium in available phosphorous and high in
available potassium. The soil analysed 260, 11.90 and
490 Kg ha–1 of KMnO4-N, Olsen-P and NH4OAc-K, re-
spectively with EC of 0.16 dSm–1, Ph of 8.11 and or-
ganic carbon of 0.31%.
2.2. Experimental Design, Selection of Cultivar
and Sowing
The experiment was laid out in randomized complete
block design (RBD) with sixteen treatments and repli-
cated thrice. The gross plot size adopted was (5 m × 3.6
m) 18 Sq meter. The adopted spacing between the rows
and plants were 60 cm and 25 cm respectively. Herbicide
tolerant transgenic maize test hybrids namely 30V92,
30B11 and conventional hybrids of 30V92, 30B11, BIO
9681 and COHM5 during kharif, 2010. Conventional
maize hybrids 30V92, 30B11, BIO 9681 and COHM5
were raised during kharif, 2011. After sowing the seed,
immediate light irrigation was given to the crop for uni-
form germination.
2.3. Treatment Details
The experiment I and II comprises of sixteen treatments.
The experiment I during kharif, 2010 comprises two
transgenic stacked hybrids 30V92 and 30B11 with post
emergence of glyphosate at 900 and 1800 g a.e ha–1 and
conventional maize hybrids of 30V92 with pre emer-
gence atrazine at 0.5 kg ha–1 on 3 DAS fb HW 40 DAS
and insect control, 30V92 no weeding and insect control,
30V92 no weeding and no insect control, conventional
maize hybrid of 30B11 with pre emergence atrazine at
0.5 kg ha–1 on 3 DAS fb HW 40 DAS and insect control,
30B11 no weeding and insect control, 30B11 no weeding
and no insect control, conventional maize hybrids of BIO
9681 with pre emergence atrazine at 0.5 kg ha–1 on 3
DAS fb HW 40 DAS and insect control, BIO 9681 no
weeding and no insect control, COHM5 with pre emer-
gence atrazine at 0.5 kg ha–1 on 3 DAS fb HW 40 DAS
and insect control, COHM5 no weeding and no insect
control.
The experiment II during kharif, 2011 comprises of
conventional maize hybrid of 30V92 with post emer-
gence controlled droplet application of glyphosate at 900,
1350 and 1800 g a.e ha–1, 30B11 hybrid with post emer-
gence glyphosate at 900,1350 and 1800 g a.e ha–1, 30V92
with pre emergence atrazine at 0.5 kg ha–1 on 3 DAS fb
HW 40 DAS and insect control, 30V92 no weeding and
insect control, 30V92 no weeding and no insect control,
30B11 with pre emergence atrazine at 0.5 kg ha–1 on 3
DAS fb HW 40 DAS and insect control, 30B11 no weed-
ing and insect control,30B11 no weeding and no insect
control, BIO 9681 with pre emergence atrazine at 0.5 kg
ha–1 on 3 DAS fb HW 40 DAS and insect control, BIO
9681 no weeding and no insect control and COHM5 with
pre emergence atrazine at 0.5 kg ha–1 on 3 DAS fb HW
40 DAS and insect control, COHM5 no weeding and no
insect control.
The herbicides as per the treatments schedule were ap-
plied as pre emergence at third day after sowing, gly-
phosate application at 2 - 4 leaf stage of weeds (20 - 25
DAS of maize). Hand operated knapsack sprayer fitted
with a flat fan type nozzle (WFN 40) was used for spray-
ing the herbicides adopting a spray volume of 250 litres

Evaluation of Weed Control Options for Herbicide Resistant Transgenic Stacked (TC 1507 X NK603)
and Conventional Maize Hybrids for Higher Productivity
1715
ha–1. The recommended dose of 150:75:75 Kg of NPK
ha–1 in the form of urea, single super phosphate and mu-
riate of potash. During the course of experiment, the data
were revealed our predominant weed flora, weed density
and dry weight with grain yield.
2.4. Observation on Weeds
2.4.1. Weed D e nsity
The weed count was recorded species wise using 0.5 m ×
0.5 m quadrated four randomly fixed places in each plot
and the weeds falling within the frames of the quadrat
were counted, recorded and the mean values were ex-
pressed in number m–2. The density of grasses, sedges
and broadleaved weeds and the total weeds were re-
corded at 20, 40, 60 and 80 days after sowing and ex-
pressed in number m–2.
2.4.2. Weed Dry Weight
The weeds falling within the frames of the quadrant were
collected, categorized into grasses, sedge and broad-
leaved weeds, shade dried and later dried in hot air oven
at 80ºC for 72 hrs. the dry weight of grasses, sedge and
broadleaved weeds were recorded separately at 20, 40
and 60 days after sowing and expressed in kg ha–1.
2.4.3. Weed Control Efficiency
Weed control efficiency was calculated as per the proce-
dure [5]
t
c
WDc WD
WCE% 100
WD


where,
WCE—Weed control efficiency (per cent);
WDc—Weed biomass (g m–2) in control plot;
WDt—Weed biomass (g m–2) in treated plot.
2.4.4. Weed I ndex
Weed index was calculated as per the method [6]
XY
WI 100
X


where, X = Yield (Kg ha–1) from minimum weed compe-
tition plot, Y = yield (Kg ha–1) from the treatment plot
for which WI is to be worked out.
2.5. Statistical Analysis
The data were statistically analysed following the proce-
dure given by Gomez and Gomez (2010) for randomised
block design.The data pertaining to weeds and germina-
tion were transformed to square root scale of

X 2
and analysed as suggested by [7]. Whenever significant
difference existed, critical difference was constructed at
five per cent probability level.
3. Results and Discussion
3.1. Effect on Weeds
Weed flora of the experimental field in maize was pre-
dominantly consisted of twelve species of broad leaved
weeds, five species of grasses and a sedge weed. The
dominant broadleaved weeds were Trianthema portula-
castrum, Datura stramonium, Cleome gynandra, Digera
arvensis, Physalis minima and Corchorus olitorius. The
dominant grass weeds were Setaria verticillata and Cy-
nodon dactylon. Cyperus rotundus was the only sedge
present in the experimental field.
3.2. Weed Density
During kharif, 2010 season, lower weed density was
achieved under non transgenic maize hybrid BIO 9681
and 30B11 with pre emergence application of atrazine at
0.5 Kg ha–1 followed by hand weeding at 20 DAS. Rela-
tively, a higher density was observed under unweeded
checks and transgenic maize before imposing post emer-
gence application of glyphosate. At 40 DAS and 60 DAS,
lower weed density observed under transgenic maize
hybrid 30V92 with post emergence application of gly-
phosate at 1800 g a.e ha–1 resulted in effective control of
broad leaved weeds, grasses and sedges due to its broad
spectrum action [8]. This may due to more impressive
control of broadleaved weeds like Trainthema portula-
castrum, Datura stramonium, Cleome gy nandra and Ph y-
sallis minima. Foliar application of glyphosate was read-
ily and rapidly translocated throughout the actively grow-
ing aerial and under ground portions at active growing
stage of broadleaved weeds might have blocked the 5-
Enolpyruvyl shikimate-3-phosphate synthase enzyme and
arrest the amino acid synthesis which led to complete
control [9] (Table 1). During kharif, 2011 season, post
emergence controlled droplet application of glyphosate at
conventional maize hybrid of 30V92 at 1800 g a.e ha–1
(1.84 Nos m–2) observed lesser total weed density at 40
DAS. Thus glyphosate effectively controlled a broad
spectrum of annual and perennial grasses, sedges and
broadleaved weeds could be due to increased transloca-
tion of glyphosate inside the plant tissues [10] (Table 2).
3.3. Weed Dry Weight
Weed dry weight is the most important parameter to as-
sess the weed competitiveness for the crop growth and
productivity. Considerable reduction in weed dry weight
as recorded with the application of glyphosate at 1800 w

Evaluation of Weed Control Options for Herbicide Resistant Transgenic Stacked (TC 1507 X NK603)
and Conventional Maize Hybrids for Higher Productivity
1716
Table 1. Effect of glyphosate application on total weed density and total weed dry weight in herbicide tolerant transgenic
maize.
Kharif, 2010
Total weed density (No m–2) Total weed dry weight (g m–2) WCE (%)
Treatments
20 DAS 40 DAS 60 DAS 20 DAS 40 DAS 60 DAS 20 DAS40 DAS
T1—30V92 POE Glyphosate
@ 900 g a.e ha–1 15.43 (236.22) 2.78 (5.75) 3.4 (9.63) 7.61 (55.94)1.88 (1.52) 2.35 (3.54) 0.00 98.56
T2—30V92 POE Glyphosate
@ 1800 g a.e ha–1 15.33 (233.08) 2.04 (2.15) 2.35 (3.52) 7.37 (52.37)1.58 (0.49) 1.87 (1.50) 0.00 99.53
T3—30V92 POE Glyphosate
(Weedy check) 15.74 (245.60) 14.3 (202.93)13.81 (188.75)7.66 (56.62)10.39 (106.03)10.22 (102.43) 0.00 0.00
T4—30B11 POE Glyphosate
@ 900 g a.e ha–1 15.78 (246.89) 3.31 (8.98) 3.84 (12.74) 7.40 (52.79)2.16 (2.68) 2.60 (4.75) 0.00 97.72
T5—30B11 POE Glyphosate
@1800 g a.e ha–1 16.06 (256.07) 2.55 (4.50) 3.06 (7.35) 7.71 (57.41)1.79 (1.20) 2.21 (2.87) 0.00 98.97
T6—30B11 POE Glyphosate
(Weedy check) 15.81 (248.10) 14.5 (209.43)14.42 (205.99)8.18 (64.92)10.94 (117.59)10.22 (102.51) 0.00 0.00
T7—30V92 PE atrazine 0.5
kg ha–1 + HW+ Insect Control 7.99 (61.85) 7.81 (59.00) 5.79 (31.48) 3.68 (11.57)5.78 (31.43)4.52 (18.39) 80.28 72.57
T8—30V92 No Weed control
and only Insect Control 15.45 (236.55) 13.64 (183.99)12.7 (160.36)7.08 (48.17)9.99 (97.79)9.42 (86.77) 0.00 14.66
T9—30V92 No Weed control
and no Insect Control 16.05 (255.75) 14.37 (204.37)14.38 (204.69)7.79 (58.70)10.80 (114.59)10.58 (109.99) 0.00 0.00
T10—30B11 PE atrazine 0.5
kg ha–1 + HW+ insect control 7.55 (55.00) 8.14 (64.34) 5.87 (32.43) 3.88 (13.04)6.12 (35.48)4.72 (20.32) 79.66 70.33
T11—30B11No Weed control
and only Insect Control 15.51 (238.44) 13.5 (182.38)13.12 (170.11)7.41 (52.92)10.3 (105.35)9.97 (97.47) 0.00 11.92
T12—30B11 No Weed control
and no Insect Control 16.25 (262.00) 15.05 (224.47)15.0 (224.57)8.13 (64.14)11.03 (119.61)10.98 (118.66) 0.00 0.00
T13—BIO9681 PE atrazine 0.5
kg ha–1 + HW+ Insect Control 7.15 (49.14) 7.52 (54.58) 5.96 (33.49) 3.74 (11.98)6.23 (36.77)5.12 (24.24) 77.27 68.73
T14—BIO9681No Weed
control and no Insect Control 14.69 (213.70) 13.8 (189.93)14.52 (208.94)7.40 (52.71)10.94 (117.62)10.90 (116.82) 0.00 0.00
T15—CoHM5 PE atrazine 0.5
kg ha–1 + HW+ Insect Control 7.83 (59.37) 8.32 (67.3) 6.20 (36.44) 4.08 (14.61)6.75 (43.55)5.69 (30.32) 79.28 68.56
T16—CoHM5 No Weed control
and no Insect Control 16.38 (266.19) 15.24 (230.37)15.79 (247.44)8.52 (70.54)11.8 (138.52)12.16 (145.78) 0.00 0.00
SEd 1.34 1.11 1.06 0.65 0.83 0.80 - -
CD (P = 0.05) 2.74 2.27 2.17 1.34 1.70 1.63 - -
Figures in parenthesis are original values must need for differentiating the original and transformed values, DAS—Days After sowing, POE—Post-emergence,
PE—Pre emergence, WCE—Weed control efficiency, HW—Hand Weeding.

Evaluation of Weed Control Options for Herbicide Resistant Transgenic Stacked (TC 1507 X NK603)
and Conventional Maize Hybrids for Higher Productivity
1717
Table 2. Effect of glyphosate application on total weed density and total weed dry weight in conventional maize hybrids.
Kharif, 2011
Total weed density (No m–2) Total weed dry weight (g m–2) WCE (%)
Treatments
20 DAS 40 DAS 60 DAS 20 DAS40 DAS 60 DAS 20
DAS 40 DAS
T1—30V92 POE Glyphosate
@ 900 g a.e ha–1 15.43 (236.22) 2.78 (5.75)3.4 (9.63) 7.61 (55.94)1.88 (1.52)2.35 (3.54) 5.14 96.15
T2—30V92 POE Glyphosate
@ 1350 g a.e ha–1 15.33 (233.08) 2.04 (2.15)2.35 (3.52)7.37 (52.37)1.58 (0.49)1.87 (1.50) 14.29 97.66
T3—30V92 POE Glyphosate
@ 1800 g a.e ha–1 15.74 (245.60) 14.3 (202.93)13.81 (188.75)7.66 (56.62)10.39 (106.03)10.22 (102.43) 8.73 99.14
T4—30B11 POE Glyphosate
@ 900 g a.e ha–1 15.78 (246.89) 3.31 (8.98)3.84 (12.74)7.40 (52.79)2.16 (2.68)2.60 (4.75) 21.41 95.86
T5—30B11 POE Glyphosate
@1350 g a.e ha–1 16.06 (256.07) 2.55 (4.50)3.06 (7.35)7.71 (57.41)1.79 (1.20)2.21 (2.87) 14.16 97.17
T6—30B11 POE Glyphosate
@ 1800 g a.e ha–1) 15.81 (248.10) 14.5 (209.43)14.42 (205.99)8.18 (64.92)10.94 (117.59)10.22 (102.51) 11.15 98.87
T7—30V92 PE atrazine 0.5
kg ha–1 + HW+ Insect Control 7.99 (61.85) 7.81 (59.00)5.79 (31.48)3.68 (11.57)5.78 (31.43)4.52 (18.39) 82.26 68.96
T8—30V92 No Weed control
and only Insect Control 15.45 (236.55) 13.64 (183.99)12.7 (160.36)7.08 (48.17)9.99 (97.79)9.42 (86.77) 13.97 10.25
T9—30V92 No Weed control
and no Insect Control 16.05 (255.75) 14.37 (204.37)14.38 (204.69)7.79 (58.70)10.80 (114.59)10.58 (109.99) 0.00 0.00
T10—30B11 PE atrazine 0.5
kg ha–1 + HW+ insect control 7.55 (55.00) 8.14 (64.34)5.87 (32.43)3.88 (13.04)6.12 (35.48)4.72 (20.32) 80.03 65.71
T11—30B11No Weed control
and only Insect Control 15.51 (238.44) 13.5 (182.38)13.12 (170.11)7.41 (52.92)10.3 (105.35)9.97 (97.47) 13.57 8.31
T12—30B11 No Weed control
and no Insect Control 16.25 (262.00) 15.05 (224.47)15.0 (224.57)8.13 (64.14)11.03 (119.61)10.98 (118.66) 0.00 0.00
T13—BIO9681 PE atrazine 0.5
kg ha–1 + HW+ Insect Control 7.15 (49.14) 7.52 (54.58)5.96 (33.49)3.74 (11.98)6.23 (36.77)5.12 (24.24) 78.97 63.82
T14—BIO9681No Weed control
and no Insect Control 14.69 (213.70) 13.8 (189.93)14.52 (208.94)7.40 (52.71)10.94 (117.62)10.90 (116.82) 0.00 0.00
T15—CoHM5 PE atrazine 0.5
kg ha–1 + HW+ Insect Control 7.83 (59.37) 8.32 (67.3)6.20 (36.44)4.08 (14.61)6.75 (43.55)5.69 (30.32) 73.19 61.68
T16—CoHM5 No Weed control
and no Insect Control 16.38 (266.19) 15.24 (230.37)15.79 (247.44)8.52 (70.54)11.8 (138.52)12.16 (145.78) 0.00 0.00
SEd 1.34 1.11 1.06 0.65 0.83 0.80 - -
CD (P = 0.05) 2.74 2.27 2.17 1.34 1.70 1.63 - -
Figures in parenthesis are original values must need for differentiating the original and transformed values, DAS—Days After sowing, POE—Post-emergence,
PE—Pre emergence, WCE—Weed control efficiency, HW—Hand Weeding.

Evaluation of Weed Control Options for Herbicide Resistant Transgenic Stacked (TC 1507 X NK603)
and Conventional Maize Hybrids for Higher Productivity
1718
g a.e ha–1 in transgenic 30V92 and post emergence con-
trolled application of glyphosate at 1800 g a.e ha–1 in
conventional maize hybrid of 30V92 (1.58 and 1.82 g
m–2) at 40 DAS during kharif, 2010 and kharif, 2011
(Tables 1 and 2).This might be weed control as achieved
by glyphosate [11] this findings were in accordance with
earlier reports that post emergence application followed
by pre emergence herbicide reduced total weed dry
weight by at least 97 per cent when compared to without
glyphosate applied plots [12].
3.4. Weed Control Efficiency
Weed control efficiency which indicates the comparative
magnitude of reduction in weed dry matter was highly
influenced by different weed control treatments. Pre
emergence application of atrazine at 0.5 Kg ha–1 fol-
lowed by hand weeding recorded higher weed control ef-
ficiency of 80.28 percent in non transgenic maize hybrid
30V92 at 20 DAS. Whereas at 40 DAS after spraying of
herbicide, higher weed control efficiency of 99.53 per-
cent was recorded in glyphosate at 1800 g a.e ha–1 fol-
lowed by 30B11was observed 98.97 percent during
kharif, 2010 (Table 1). Whereas during kharif, 2011
higher weed control efficiency was observed with gly-
phosate at 1800 g a.e ha–1 in conventional maize hybrid
of 30V92 registered maximum weed control efficiency of
99.14 percent owing to the fact that registered lesser
weed density and weed dry weight (Table 2).
3.5. Effect on Crop
During both the years of study, among the weed control
treatments, post emergence application of glyphosate at
1800 g a.e ha–1 in transgenic corn hybrid recorded higher
grain yield of 12.21 t ha–1 this was 36.64 percent higher
than the unweeded check plot of transgenic 30V92 dur-
ing kharif, 2010, whereas, during kharif, 2011post emer-
gence controlled droplet application of glyphosate at
1800 g a.e ha–1 in conventional maize hybrid of 30V92
resulted in higher grain yield of 11.23 t ha–1 (T able 3 and 4).
This was 44.79 percent higher than the unweeded check
Table 3. Effect of weed control methods on yield attributes and grain yield in herbicide tolerant transgenic maize.
Kharif, 2010
Treatments Cob length
(cm) Cob girth (cm) Number of kernels/row Number of rows/cob Test weight (g) Yield (t ha–1) Weed index (%)
T1—30V92 POE Glyphosate
@ 900 g a.e ha–1 21.03 16.76 38.80 15 40.11 11.10 9.09
T2—30V92 POE Glyphosate
@ 1800 g a.e ha–1 21.70 16.84 41.27 16 42.67 12.21 0.00
T3—30V92 POE Glyphosate
(Weedy check) 20.06 15.83 37.18 13 33.28 8.84 27.60
T4—30B11 POE Glyphosate
@ 900 g a.e ha–1 19.70 16.19 37.90 15 39.10 10.97 10.15
T5—30B11 POE Glyphosate
@ 1800 g a.e ha–1 20.20 16.44 38.50 16 42.05 11.98 1.88
T6—30B11 POE Glyphosate
(Weedy check) 19.36 15.32 35.93 13 32.11 9.12 25.30
T7—30V92 PE atrazine 0.5
kg ha–1 + HW+ Insect Control 19.73 15.92 38.23 15 37.72 10.23 16.21
T8—30V92 No Weed control
nd only Insect Control 19.30 15.68 36.55 12 34.78 8.33 31.77
T9—30V92 No Weed control
and no Insect Control 18.66 15.17 36.23 12 33.12 7.52 38.41
T10—30B11 PE atrazine 0.5
kg ha–1 + HW+ insect control 18.33 15.80 38.00 15 37.00 9.76 20.06
T11—30B11No Weed control
and only Insect Control 17.81 15.50 36.03 12 33.35 8.20 32.84
T12—30B11 No Weed control
and no Insect Control 17.73 15.13 35.90 12 31.23 7.35 39.80
T13—BIO9681 PE atrazine 0.5
kg ha–1 + HW+ Insect Control 17.92 15.87 37.60 14 37.22 8.00 34.47
T14—BIO9681No Weed control
and no Insect Control 15.31 14.93 35.23 12 30.45 6.12 49.87
T15—CoHM5 PE atrazine 0.5
kg ha–1 + HW+ Insect Control 16.20 15.60 36.80 14 31.88 7.33 39.96
T16—CoHM5 No Weed control
and no Insect Control 15.01 13.37 33.93 12 28.54 5.08 58.39
SEd 0.23 0.72 0.47 0.62 1.63 0.41 -
CD (P = 0.05) 0.48 1.47 0.96 1.28 3.33 0.84 -

Evaluation of Weed Control Options for Herbicide Resistant Transgenic Stacked (TC 1507 X NK603)
and Conventional Maize Hybrids for Higher Productivity
1719
Table 4. Effect of weed control methods on yield attributes and grain yield in conventional maize hybrids.
Kharif, 2011
Treatments Cob length
(cm) Cob girth (cm) Number of kernels/row Number of rows/cob Test weight (g) Yield (t ha–1) Weed index (%)
T1—30V92 POE Glyphosate
@ 900 g a.e ha–1 18.88 15.67 38 15 36.70 9.12 18.79
T2—30V92 POE Glyphosate
@ 1350 g a.e ha–1 19.90 16.10 38 16 38.70 10.36 7.75
T3—30V92 POE Glyphosate
@ 1800 g a.e ha–1 21.43 16.73 41 16 42.87 11.23 0.00
T4—30B11 POE Glyphosate
@ 900 g a.e ha–1 18.56 15.23 36 14 35.52 8.25 26.54
T2—30V92 POE Glyphosate
@ 1350 g a.e ha–1 19.62 15.89 37 15 38.10 9.52 15.23
T3—30V92 POE Glyphosate
@ 1800 g a.e ha–1 20.12 16.33 39 15 40.45 10.39 7.48
T7—30V92 PE atrazine 0.5
kg ha–1 + HW+ Insect Control 18.43 15.46 39 14 36.55 8.72 22.35
T8—30V92 No Weed control
and only Insect Control 16.76 14.10 33 12 34.62 7.40 34.11
T9—30V92 No Weed control
and no Insect Control 15.79 13.96 34 12 34.00 6.20 44.79
T10—30B11 PE atrazine 0.5
kg ha–1 + HW+ insect control 18.08 15.12 36 14 36.12 8.01 28.67
T11—30B11No Weed control
and only Insect Control 16.12 14.65 33 13 34.78 6.80 39.45
T12—30B11 No Weed control
and no Insect Control 16.01 14.23 32 12 33.24 6.22 44.61
T13—BIO9681 PE atrazine 0.5
kg ha–1 + HW+ Insect Control 17.00 15.00 36 14 35.41 7.10 36.78
T14—BIO9681No Weed control
and no Insect Control 15.50 13.76 32 12 31.13 5.60 50.13
T15—CoHM5 PE atrazine 0.5
kg ha–1 + HW+ Insect Control 16.10 14.17 34 13 34.52 6.10 45.68
T16—CoHM5 No Weed control
and no Insect Control 14.92 13.09 29 12 29.23 4.80 57.26
SEd 1.12 0.67 2.49 1.35 1.65 0.80 -
CD (P = 0.05) 2.29 1.48 5.10 2.76 3.38 1.64 -
plot of conventional maize hybrid. This could be achi-
eved control of weeds with non selective, translocated
herbicide, provided the favourable crop growth environ-
ment at the establishment stage of the crop itself by mini-
mizing the perennial and annual weeds and increased the
seed and stalk yields [13]. This might be due to the fact
that the perennial weeds like Cyperus rotundus, Cynodon
dactylon, troublesome broadleaved weeds like Trian-
thema portulacastrum weeds were effectively controlled
and might increase the maize yield may be due to better
light utilization of narrow row zone and faster canopy
closure [14].
Higher yield attributes of increased cob length, cob
girth and number of grains per cob and test weight were
recorded with post emergence application of glyphosate
at 1800 g a.e ha–1 in both the transgenic and conventional
maize hybrids of 30V92 and 30B11 respectively. This
might due to better control of weeds at critical stages and
shifted the balance in favour of crop in the utilization of
nutrients, moisture, light and space and creates the fa-
vourable environment for recording higher growth of
maize leading to enhanced yield attributes [15]. Among
the weed control treatments methods, lower weed index
was recorded with 9.09 and 10.15 per cent in transgenic
30V92 (T1) and 30B11 (T5) whereas at conventional
maize hybrids observed glyphosate at 1350 g a.e ha–1
recorded lower weed index of 7.75 and 15.23 per cent in
non transgenic maize hybrids of 30V92 (T2) and 30B11
(T5). Unweeded check plots resulted in higher weed in-
dex and performed poorly during both the years of study.
4. Conclusion
From the results of the field experiments, it could be
concluded that post emergence spraying of potassium salt
of glyphosate at 1800 g a.e ha−1 in transgenic and con-
ventional maize hybrid of 30V92 enhanced complete
control of broad spectrum weeds, could keep the weed
density, dry weight reasonable at lower level and en-
hance higher productvity and profitability with higher
grain yield during both the kharif seasons.

Evaluation of Weed Control Options for Herbicide Resistant Transgenic Stacked (TC 1507 X NK603)
and Conventional Maize Hybrids for Higher Productivity
1720
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