Effects of Varieties and Intra Row Spacing on Yield
of Maize (Zea mays L.) under Supplementary Irrigation at Guliso, Western Ethiopia
Tasisa Temesgen* and Teshome Kebena
School of Natural Resource Management and Environmental Sciences, Haramaya University, Ethiopia
Submission: March 20, 2019; Published: June 04, 2019
*Corresponding author: Tasisa Temesgen, School of Natural Resource Management and Environmental Sciences, Haramaya University, Ethiopia
How to cite this article: Tasisa Temesgen, Teshome Kebena. Effects of Varieties and Intra Row Spacing on Yield of Maize (Zea mays L.) under Supplementary
Irrigation at Guliso, Western Ethiopia. Int J Environ Sci Nat Res. 2019; 19(5): 556024. DOI:10.19080/IJESNR.2019.19.556024
Determination of optimum plant population and the use of improved varieties in combination with appropriate agronomic practices are important components of maize production package for maximizing productivity. The study was conducted 2017-2018 under supplementary irrigation at Gulliso district, Western Ethiopia, to determining the effects of variety and intra-row spacing on yield of maize (Zea mays L.). The experiment was conducted in factorial arrangement of four intra-row spacing (20, 25, 30 and 35cm) with three maize varieties (BH546, Shone and BHQPY-545) in RCBD. The interaction of variety and intra-row spacing was highly significant (P<0.01) on yield components and yield of maize. The highest (1.75) average number of ears per plant was recorded from varieties BH546 and BHQPY-545 at 35cm intra-row spacing. The highest (35cm) ear length was recorded from BH546 at 35 cm intra-row spacing. Generally, leaf area, stand count, ears per plant, ear length, and ear diameter showed a decreasing trend with decreasing intra-row spacing. Based on these results, it can be tentatively concluded that the variety BH546 could be used at plant density of 53,333 plants ha-1 and (25cm) intra-row spacing is best to get the highest green cob yield of maize under supplemental irrigation during the off-season in the study area.
Maize (Zea mays L.) is the most widely grown cereal crop. It ranks third after wheat and rice in hectare and total production. It is predicted that by 2020, it will surpass both wheat and rice to become the number one cereal in the world Maize demand is projected to increase by 50% worldwide and by 93% in sub-Saharan Africa between 1995 and 2020 (FAO, 2015).
Among cultural practices, which affect the yield, intra-row spacing is a one factor since it is ultimately related with plant density, root development, plant growth and fruiting . In most cases the optimum spacing is one, which enables the plants to make the best use of conditions at their disposal . Too close spacing interferes with normal plants development and increase competition resulting in yield reduction, while too wide spacing may result in excessive vegetative growth of plant and abundant weed population due to more feeding area available. Therefore, use of optimum plant population per unit area without exceeding the economic threshold can increase the competitive ability of the plants in weed-infested field . In addition to improving crop yields, reduced row spacing can also provide the crop with a competitive advantage over weeds.
Andrade et al.  reported that spacing of 75cm x 35cm resulted in increased grain yield of maize, while 75 cm x 15 cm gave maximum cob. In the both the hybrid and the local maize, plant spacing of 25cm x 75cm had the highest grain yield with 66,667 plants ha-1, followed by plant spacing of 30cm x 65cm that had 50,949 plants ha-1, while plant spacing of 100cm x 10cm had the least grain yield .
In Ethiopia, the national spacing recommendation for maize is 75cm x 30cm (44,444 plants/ha). This spacing has been used, without considering the numerous factors such as the existences of soil and climatic differences. In the study area, the production of maize under irrigation takes on a special significance; because there is high demand for green fresh consumption during off season if water is available for irrigation and production during the off season. For this reason, farmers produce maize under irrigation with varied plant spacing and as a result, plant population per hectare varies among farmers due to miss using proper spacing. Some of the farmers say that the national recommended spacing is too wide that it does not give higher yield. Moreover, they think as use of higher plant population may result in more yields that was visually observed.
Thus, effects of different spacing on maize must be
investigated for practical purposes, as planting spacing is a major
management variable used in matching crop requirements to
the environmental offer of resources. This study was addressed
this problem with the objective: assess the effects of variety and
intra- row spacing on growth, yield components and green cob
yield of maize.
The study was conducted at Guliso District, Western
Ethiopia located about at 512km North West of Addis Ababa
(Figure 1). The experimental site is situated at 9o 10’ 00’’ N’
latitude and 35o22’ 00′′ E longitude at 1538 meters above sea
level. The experiment was conducted under supplementary
irrigation during 2017/2018 cropping season. The rainy season
starts in May and extends up to October. Meteorological data
taken from Aira station, which is at about 12km away from
experimental site, showed annual (May-beginning of November)
rain fall of 1460.9mm, and the mean maximum and minimum air
temperature of 27oC and 14.94oC respectively.
Three hybrid maize varieties, (BH546 and BHQPY-545 which
were used for the study were released by Bako Agricultural
Research Center and variety Shone (30G19) that was released by
Pioneer hybrid) were used as experimental material. The yield
potentials of BH546 and BHQPY 545 on research center were
8.5-11.5ton ha-1 and 8-9ton ha-1 respectively, while on farmers
field their yield potential were 6.5-7.5ton ha-1 and 5-6ton ha-1
respectively . The variety Shone yield potential was 7-11ton
ha-1 and 6.5-8.5ton ha-1 on research center and farmer field
respectively  (Table 1).
The treatment consists of factorial combination of 4 intrarow
spacing (20, 25, 30 and 35cm) and three varieties of maize
(BH546, Shone (30G90) and BHQPY-545. The recommended
inter row spacing of 75cm for maize was used uniformly. The
experiments were laid out in randomized complete block design
(RCBD) in 4 x 3 factorial arrangements with three replications.
The space between plot and block was 0.5m and 1m respectively.
The gross plot consists of 4 rows, each 3m long. The net plots
were the middle 2 rows; the 2 outer rows of each plot were
used as border rows. Thus, the size of the gross and net plot was
9m2 (3m x 3m) and 4.5m2 (3 x1.5m).Thus, the plant population
corresponding to the 20cm x 75cm, 25cm x 75cm, 30cm x 75cm
and 35cm x 75cm intra-inter row spacing were 66,666, 53333,
44444 and 38095 plants per hectare.
For the1st month field was shallow irrigated at 7 interval
days, while after a month till to tasseling and silking irrigation
10 to 12 days interval applied deeply by furrow system. And at
critical time at tasseling and silking stage field was irrigated by
4 days interval to initiate flowering and silking. Most of the time
irrigation has been done after noon to avoid loses of water from
the field by evaporation.
Phenological and growth parameters of maize: Days to
50% anthesis, Days to 50% silking, Leaf area, Leaf area index
(LAI), Plant height (cm) and Plant height (cm) were measured.
Yield and yield component: Number of ears per plant, Ear
height (cm), Number of kernels per ear, hundred kernels weight
(g), Grain yield (kg∙ha−1) and Harvest index were collected at the
time of data collection.
Days to 50% anthesis: The main effect of variety showed
highly significant (P< 0.01) effect while intra- row spacing, and
the interactions did not affect significantly days of 50% anthesis
(Table 1). The longest days to 50% anthesis (82.00 days) was
recorded from variety Shone; while the shortest (79.50) was
recorded under variety BHQPY-545 (Table 2). It might be due to
the genetic variation between the varieties on maturity period.
This finding is in line with Kahiu et al.  who stated that there
was difference in days to anthesis and days to silking among
Days to 50% silking: The period of silking is a critical time
for kernels formation after pollination. Any factor that affects
silking and duration of silking can affect grain production
directly. The main effect of variety showed highly significant
(P<0.01) effect on 50% days to silking, while intra- row spacing,
and the interactions did not significantly affect days to 50%
silking (Table 1).
Varity Shone took the longest (86.58) days to reach 50%
silking stage, while variety BHQPY-545 took shortest (83.08)
days. There was significant difference among all varieties (Table
2). The significant difference among the varieties might be due
to the variation in the genetic characteristics of the varieties.
This finding is in line with Kahiu et al.  Who stated that there
were difference in days to anthesis and days to silking among
maize genotypes, while this finding disagree with Tokatlis &
Koutroubas  who reported that plant density affects the
required interval for pollen shedding and silk emergence were
takes long days as planting density of maize increased.
LSD (5%) =Least significance difference at 0.05% level CV=Coefficient
of variation; NS=non-significant, PP= plants ha-1. Means in the same
column within a parameter followed by the same letter(s) are not
significantly different at 5% level of significance.
Leaf area: The analysis of variance showed highly significant
(p<0.01) difference in leaf area due to main effect of intra-row
spacing. There was no significance difference due to variety
and interaction (table 1). The highest leaf area (6291cm2) was
recorded from 35cm intra-row spacing (38,093 plants ha-1)
which was statistically at par with at 30cm intra-row spacing,
while the lowest (5867cm2) was recorded from 20cm intra-row
spacing (66,667 plants ha-1) (Table 3). This might be due to that
reduction of leaf area as a result of increasing plant density that
led to the accelerated leaf senescence, increased shading of
leaves, and reduced net assimilation of individual plants.
LA=leaf area, LAI= leaf area index, PH=plant height. LSD (5%) =Least
significance difference at 5% level, CV (%) =Coefficient of variation in
percent; NS=non-significant. PP= the number in parentheses indicate
plant ha-1, Means column with in a parameter followed by the same
letter(s) are not significantly different at 5% level of significance.
This agrees with Sangakura et al. (2004) who reported that
the leaf area per plant tended to decline with increasing plant
density in maize. Similarly, Imran et al.  reported that lower
plant population got more nutrients and water compared to
higher population, thus contributed increased leaf area unlike
high plant population density that reduced that reduced low leaf
area of maize decreased.
Leaf area index: Leaf area index (LAI) showed highly
significant (P<0.01) effect as affected by the main effect of intrarow
spacing; but there was significant effect of variety and
interaction (Table 1). The highest LAI (4) was recorded under
20cm intra-row spacing with plant density of 66,667 plants ha-1
and the lowest (3) was observed under 35cm intra-row spacing
with 38,093 plants ha-1. Leaf area index significantly decreased
as plant density increased from 38,093 plants ha-1 (35cm intrarow)
to 66,667 plants ha-1 (20cm intra-row) (Table 3).
In the current study, increase of LAI at narrowest row spacing
(66,667 plants ha-1) and decrease with increasing intra-row
indicates that LAI decrease as plant density increase. This study
agrees with that of Valdabad and Farahani (2010) who reported
that LAI is influenced by genotype, plant population, climatic
condition and soil fertility. Saberali (2007) also indicated that
in high maize density LAI increase more than at lower density
throughout crop growing season.
However; this study agrees with that of Abuzar et al. 
who reported that LAI of maize was significantly affected and
increased in linear fashion with increase plant population. Other
workers found results which disagree this finding. Imran et
al.  reported maximum LAI from the lowest plant density
and minimum LAI from the highest plant density. In this case,
increase in number of plants per unit area beyond optimum
level could probably reduce the amount of light availability to
the individual plant, especially, to lower leaves due to shading.
Generally, consistent increments in LAI were observed with
increased plant population density. This dramatic increase in
LAI with reduced intra row spacing or with increase in the plant
population density might be due to occupation of more unit area
by green canopy of the plants.
Plant heights: The analysis of variance showed statistically
significant (P<0.05) different in plant height due to main effects
of the variety; but there is no significance difference due to intrarow
spacing and interaction effects (Table 1). This finding agrees
with report of Raouf et al.  that had been significant plant
height difference among maize cultivar.
Variety Shone was the tallest (263.3cm), while variety
BHQPY-545 was the shortest (235.5cm) (Table 3). This variation
showed the existence of genetic difference among the varieties.
In conformity with this result, Kunoskan  and Gozubenli et
al. (2001) reported considerable varietal variation among plant
height of maize cultivars. Narrow plant spacing is longer plant
height 85.22 from 20cm intera-row spacing; while the shortest
(84.11cm) plant height from wide 35cm intera-row spacing this
is may be due to nutrients competition
Stand count (%): The maize percent stand count was highly
significantly (P< 0.01) affected by the main effect of variety and
intra-row spacing but the interaction effect was non-significant
(Table 2). The highest (96.60%) stand count was recorded from
variety BH546 and the lowest (91.56%) from variety BHQPY-545
(Table 4). This can be attributed to genetic difference of the
varieties. Regarding the intra-row spacing the highest (97.92%)
stand count was recorded from 35cm intra-row spacing, while
the lowest (89.63%) was recorded from 20cm intra-row spacing
LSD (5%) = Least significance difference at 5% level CV (%)
=Coefficient of variation; NS=non-significant at 5% level and SC=
stand count in%, pp= the number in parentheses indicate plant ha-1,
Means in the same column with in a parameter followed by the same
letter(s) are not significantly different at 5% level of significance.
Stand count percent increase at wider intra-row spacing and
decrease at narrow intra-row spacing. In general, plant stand
percent decreased as plant population increased and this might
be due to crowding effect. The other reason is that at lower
population comparatively availability of more space might have
resulted in less competition for resources (nutrients, moisture
and light) whereas at high density competition resulted in
weaker plants and mortalities by the time the crop approached
maturity. This result agrees with; Eskandarnejada et al.  who
reported higher plant stand count percent due to wider spacing
combination of 75cm x 30cm than narrow spacing of 55cm x
20cm. Similarly, Sangoi et al.  report that who wider inter
and intra-row spacing of 75cm x 26.6cm had greater plant stand
count percent of maize compared to the initial count than that of
narrow inter and intra-spacing of 5cm x 17.7cm.
Ear diameter:The main effect of intra-row spacing showed
highly significant (P<0.01) effect on maize diameter while that of variety was significant (P<0.05) effect on ear diameter. However,
the interaction effect was not significant (Table 3). The highest
ear diameter (4.19cm) was record from variety BH546, while
the lowest (3.99) was produced by variety BHQPY-545. The ear
diameter of variety BHQPY-545 and shone were not significantly
different (Table 4). This might be due to genetic variation among
the varieties. The highest (4.29cm) and the lowest (3.82cm) ear
diameter were recorded at intra-row spacing of 35cm and 20cm
respectively (Table 4).
There was statistically significant difference among 20, 25,
and 35cm and no significance difference between 30 and 25cm
intra-row spacing. Ear diameter increase as intra-row increased.
This might be because of comparatively less computation for
resources like moisture, nutrient, and light in low in this plant
Number of ears per plant: The analysis of variance showed
highly significant (P<0.01) effect of intra-row spacing, variety
and the interaction on number of ears per plant (Table 2). The
highest (1.75) number of ear plant-1 was scoured from the
interaction of the variety BH546 and BHQPY-545 with 35cm
intra- row spacing produced.
This showed that variety BH546 and BHQPY-545 performed
better at 35cm intra-row spacing in bearing ears per plant than
at other spacing and variety Shone. The lowest (1.00) ear per
plant was recorded from the variety Shone and BH 546 with
20cm intra- row spacing. In general number of ears per plant
increased in all varieties as intra-row increased (Table 5).
LSD = least significant difference, NS=non significance CV=coefficient
of variation in percent. Means column within a parameter followed
by the same letter(s) are not significantly different at 5% level of
This study agrees with Zamir et al.  who report that as
plant density in unit area increased the numbers of ears per
plants become decrease due to competition among the plants.
Also, in line with this result, Hashemi-Dezifouli and Herbert
(1992) reported significantly higher number of cobs plant-1 at
lower plant density compared to higher plant density. Variety
(Shone) the lowest ears per plant than the other two varieties at
all intra row spacing, except at 20cm produced. In this currently
study generally number of ears per plant increase in all varieties
as intera-row spacing increased.
The analysis of variance showed that ear length
was highly significantly (P< 0.01) affected by the main effect of
intra-row spacing, variety and their interaction (Table 3).
The significantly longest ear (35.00cm) was recorded from
BH546 treated under 35cm intra-rows spacing at plant density
38,095 plants ha-1. The shortest ear length (23cm) was obtained
from Shone grown at intra-row spacing 20cm (66,667 plants
ha-1). In general ear length decreased with decreased intra-row
spacing (increased plant density) (Table 6). The longer ear at
lower plant population (increased intra-row spacing) might be
because at lower population level there are available space and
less competition for resources in low plant population density.
LSD =least significant difference, CV (%) =coefficient of variation in
present, pp= the number in the parentheses indicate plant ha-1, Means
column within a parameter followed by the same letter(s) are not
significantly different at 5% level of significance.
Regarding the longest ear (35cm) of maize was observed
from variety BH546 treated fewer than 35cm intra-rows spacing;
while the variety BHQPY-545 produced shortest ear length
(31.67cm) at the same intra-row spacing might be due to genetic
variation among these varieties. This result is in line with the
finding of Abuzar et al. , who reported significant differences
among the varieties of maize for ear length. Similarly, Lakew et
al.  where they reported significant differences among the
varieties of maize in ear length and ear diameter.
Adeniyan  also observed decreased maize ear length
under increased population densities and attributed that the
plant population above and below critical density has a negative
effect on yield per plant because of inter plant competition
for light, water, nutrient and other potential yield-limiting
environmental factors. Reduction of ear length and diameter with
narrower row spacing is attributed to limitation of assimilates as
a result of low photosynthetic processes of leaves at narrow row
spacing due to less availability of growth influencing factors and
genetic variation among the varieties, which resulted in high or
low ear length and diameter.
Number of ears per hectare: The main effect of intra-row
spacing showed highly significant (P<0.01) effect on ear per
hectare and variety showed significant (p<0.05) effect. But the
interaction effect was nonsignificant effect (Table 3).
The highest (57,962) number of ears per hectare was
obtained from variety BH546, while the lowest (52,037ha-1) was
from variety Shone. Variety BHQPY 545 was at par with BH546
and Shone varieties. Variety BH546 gave more ear ha-1 than the
other two varieties, indicating that this variety is preferable than
other in terms of cob number (Table 7). The highest number of
ear (62,222ha-1) was recorded from 25cm intra-row spacing at
plant population (53,333ha-1) which was statistically at par with
(57,530ha-1) from 20cm intra-row spacing (66,667 plants ha-1).
There was no significant difference between 20cm and 25cm
intra row spacing, indicating that one of the two could be used
for green cob production; while 25cm intra-row spacing is the
best one. The lowest (47,654) number of ears per hectare was
recorded from 35cm intra-row spacing.
LSD = least significant difference, CV (%) = coefficient of variation
in percent, PP= the number in the parentheses indicate plants ha-1,
Means column with in a parameter followed by the same letter(s) are
not significantly different at 5% level of significance.
This finding agrees with  who reported that grain yield
increased with increasing plant density linearly until production
factors are not limiting. Also, it is in line with Sabo et al. 
who report that intra-row spacing 25cm resulted in the highest
(23.11) cob per plot 30cm followed (21.56); while 20 cm
resulted the least (17.78) cob per plot. In this current study
the reason 25cm intra-row spacing record high cob yield ha-1
was the plant population is greater than that of 30 and 35cm
intra-row spacing; while 20cm intra-row spacing may affected
by limitation factor than the other [21-26].
Among agronomic practices, variety and plant spacing
require special attention. Therefore, the present experiment
was conducted in 2017/18 irrigation cropping season at
the study area, with the objectives of assessing the effects of
maize variety and intra-row spacing on growth, yield and yield
components, and on green cob yield of maize. The treatment
consisted of factorial combination of 4 intra-row spacing (20,
25, 30 and 35cm) and three varieties of maize (BH546, Shone,
and BHQPY-545). The recommended inter row spacing of 75cm
for maize was used uniformly. The experiments were laid out
in randomized complete block design (RCBD) in 4 x 3 factorial
arrangements with three replications.
The main effect of variety was highly significant (P<0.01)
on days to 50% anthesis, days of 50% silking, plant height,
ear diameter, and ears per hector; whereas intra-spacing
and interaction were not significant. The variety Shone took
maximum (82) days to reach 50% anthesis; while the variety
BHQPY-545 took minimum (79.50) days to reach 50% anthesis.
Variety shone took the longest (86.56) days to reach 50% of
silking; while variety BHQPY-545 was the earliest (83.08) to
reach days to 50% silking stage.
Intra-row spacing had highly significant (P<0.01) effect
on plant leaf area and leaf area index. The highest leaf area
(6291cm2) was recorded from 35cm intra-raw spacing, which
was statistically at par with 30cm intra-row spacing (6285cm2).
Leaf area index showed an increasing trend with decreasing
intra-row spacing. The highest (3.975) leaf area index recorded
was from 20cm intra-row spacing, while the minimum (2.476)
leaf area index recorded was from 35cm intra-row spacing.
Variety Shone (30G19) had the tallest plant height (263.3cm),
while the variety BHQPY-545 was shortest (235.5cm).
BH546 gave the highest ear diameter (4.19cm), while
variety BHQPY-545 gave the narrowest ear diameter (3.99cm).
Regarding the main effect of intra-row spacing, the largest
diameter (4.29m) was obtained from 35 cm intra-row with
plant population density of 38,095 plants ha-1, while the
smallest (3.82cm) ear diameter was recorded from 20cm intrarow
spacing. The highest number of ears per hectare (57,962)
was obtained from variety BH546, while the lowest number of
ears (52,037) ha-1 was recorded from variety Shone. Intra-row
spacing also has significant different ear ha-1; the highest ears
ha-1 recorded from 20cm and 25cm at par with (57,530) and
(62,222); while the lowest ears ha-1 was recorded at 3 cm intrarow
Variety with intra-row spacing had highly significant effect
on the number of ears per plant and ear length. The highest
(1.75) number of ear plant-1 was obtained from BH546 at 35
cm intra- row spacing, whereas, the lowest (1.00) number of
ears per plants was form Shone at 20 cm intra-row spacing. This
result showed that the varieties BH546 and BHQPY-545 at 35cm
intra-row spacing were better in bearing ears per plant, having
an average of 1.75 ears per plant.
The highest ear length (35cm) was recorded from BH546
with intra-row spacing of 35cm, while the shortest ear lengths
(23cm) was obtained from Shone (30G19) at intra-row spacing
20cm. Generally, long ears were observed at lower plant
populations, which might be due to less competition, thus more available space and resources for individual plants to produce
long ears at low plant density.
Finally, the result of present study showed that variety and
intra-row spacing had significant influences on most of the
phonological parameters, yield and yield components of maize.
The result also indicated that variety BH546 was the most
suitable of the three maize varieties tested, and 25cm intra-row
spacing was better to achieve optimum yield. However, this is
a one season experiment at one location, thus the experiment
must be repeated over locations and seasons to reach at a better