GENETIC
EVALUATION OF YIELD-RELATED AGRONOMIC
TRAITS FROM HALF-SIB FAMILIES OF MAIZE (ZEA
MAYS L.)
Nasr Ullah Khan1*,
Muhammad Ishfaq Khan2, Rida Nisar3, Muhammad Muddasir1, Muhammad Umer
Mustafa1, Abdul Majid4, Muhammad Saad Ahmed5, Muhammad
Arshad6, Rehan Naeem7, Mohsin Khurshid8, Muhammad
Khuram Razzaq9
1Department of
Plant Breeding & Genetics, Faculty of Agriculture, Gomal University, Dera
Ismail Khan, Khyber Pakhtunkhwa, Pakistan.
2Department
of Botany, University of Science and Technology Bannu, Khyber Pakhtunkhwa,
Pakistan.
3Department
of Horticulture, Faculty of Agriculture, Gomal University, Dera Ismail Khan,
Khyber Pakhtunkhwa, Pakistan.
4Department
of Agricultural Chemistry & Biochemistry, The University of Agriculture
Peshawar, Khyber Pakhtunkhwa, Pakistan.
5Department
of Biological Sciences, National University of Medical Sciences, Rawalpindi,
Pakistan.
6Department
of Biosciences, International Islamic University Islamabad, Islamabad, Pakistan.
7Department
of Biotechnology and Genetic Engineering, Kohat University of Science &
Technology, Kohat, Pakistan.
8Department
of Microbiology, Government, College University Faisalabad, Pakistan.
9Soybean
Research Institute, National Center for Soybean Improvement, Nanjing
Agricultural University, Nanjing, China.
*Corresponding
Author: Nasr Ullah Khan Email:
nasrkhanpbg@gu.edu.pk
Received: 11-05-2025 Accepted:
20-05-2025 Published
online: 24-05-2025
DOI: https://doi.org/10.33687/ricosbiol.03.05.62
Abstract
This
study was conducted to evaluate half-sib families (HSF) for yield and agronomic
traits in maize (Zea mays L.).
One hundred and ninety-six half-sib families were used in this study derived
from the maize variety Azam. The experiment was laid out in 14×14 partial
lattice square designs with two replications. Results indicated that the phenotypic
coefficient of variance was higher than the
genotypic coefficient of variance for all
traits except for fresh ear weight, which reflects
the environmental influence on the expression of
the trait. High to moderate heritability was observed for days to tasseling,
days to mid silking, days to anthesis, anthesis silking-interval, kernel rows
per cob, cob length, and grain yield. Highly significant and positive
correlations were observed between grain
yield and cob length (0.99), kernel rows per cob (0.88), grain moisture (1.00),
days to tasseling (0.94), silking (0.99), and anthesis (0.96). The negative and
non-significant correlation was observed between grain yield and fresh ear
weight (-0.06). Maximum grain yields of 10710 kg ha-1 were recorded
for HSF-180, while a minimum 2046 kg ha-1 was obtained by HSF-31.
These results suggest that these half-sib families could be used as a source of
maize germplasm for developing maize genotypes with superior attributes.
Keywords:
Half-sib Families, Replication, Yield Attributes, Zea mays L.
Introduction
Global production of all cereal crops is not adequate
to nourish the whole population, although the crops yield is increasing day-by-day
(STAT, 2012). According to the
FAO data, in 2010 the coarse crop-producing
countries that contribute greater than
20% of total production are the United States of America and China (STAT, 2012). Maize (Zea
mays L.) is the world’s
primary coarse grain that plays a vital role as the source of bioenergy, animal
feed, and human food (Zhou et al., 2012). It is
the world’s foremost cereal crop a production of 695 million tons and a per-unit
area yield of 4815 kg, ha-1
and a vast quantity of production is concentrated
in the United States of America. The top five maize producing countries are the
USA, China, Brazil, Mexico and Argentina have drastically increased the maize
production since 1961 (STAT, 2012). It is the prime
crop of Sub-Saharan Africa, accounting 51% of consumed calories although the
yield level is low and vehemently variable across years at less than 2 t/ha. On
the other hand, in Asia, the yield level
is much higher. China and Indonesia accounting an average yield of 5.2 and 4.2
t/ha (STAT, 2012).
Fig. 1 Area (000 ha),
Production (000 tons), and average yield (ton/ha) of spring maize in Pakistan
Pakistan contributes
a production of 3.3 million tons per year with an estimated planted area of 1.016
million hectares and an average yield of 2864
kgha-1 (Tariq and Iqbal, 2010). In Pakistan, production
per year increases with a decrease in the cultivated areas (STAT, 2012). The production
of maize has increased drastically over the decades from 0.38 to 3.037 million
tons during 1947-2007 (Tariq and Iqbal, 2010). The area,
production, and average yield of spring maize from 2001 to 2007 increased drastically (Figure 1). 99 % of the total
production of maize comes from the Khyber Pakhtunkhwa and Punjab provinces of
Pakistan. Khyber Pakhtunkhwa accounts for 31 % of the total maize production
and 51 % of the total area (Tariq and Iqbal, 2010). In Khyber Pakhtunkhwa, maize is normally grown
to produce grain and also as fodder, due
to which its demand increased drastically. In combination with the Green Revolution, improved agronomic
practices enhanced yields up to 40% (Evenson and Gollin, 2003). Maize
improvement mainly includes evaluation, selection, and recombination of
genetically distinct inbred lines or families (Pixley et al., 2006).
A number of
recurrent selection methods have been used by the breeders, like mass
selection, recurrent selection, half-sib selection, and full-sib family
selection, for developing high-yielding maize varieties and increasing yield
per unit area (Keeratinijakal and Lamkey, 1993). Recurrent
selection methods comprising half-sib family selection and S1
progeny selection are particularly of prime interest as these not only improve
the breeding population for the required attributes but also sustain the
genetic variability in the population (Hallauer, 2012). Coors (1988) observed a 1.5%
reduction in grain moisture and a gain of 3.5% in grain yield per cycle in
response to four cycles of combined half-sib and S1 family selection
in maize. Tanner and Smith (1987) recommended that
half-sib family selection was highly efficient in reducing inbreeding
depression in maize populations. Marquez-Sanchez (2003) evaluated different
selection methods for maize and based on their results recommended that HS-selection
is the best method.
The present
research was designed with the objectives to evaluate half-sib families
developed from maize variety Azam and to identify superior half-sib families for
yield and agronomic traits that can be used in future maize breeding programs for
developing maize genotypes with desirable attributes.
Materials and methods
Experimental
material of the study comprised 196 half-sib family lines-having one parent in common-derived from maize variety
Azam, which were provided by the Cereal Crops Research Institute (CCRI),
Pirsabak, Nowshera, Pakistan. A partial lattice square design, having two
replications, was used. Plant-to-plant and row-to-row distance was 25 cm and 75
cm, respectively. The land was prepared
by giving three plowings followed by planking. Standard cultural practices,
including irrigation, fertilizer application, and
hoeing, were carried out over the growing season. Agronomic practices were
carried out at the proper time. Data on
yield and morphological parameters were recorded at the proper time for each character.
Silking data were recorded on a plant
basis as the number of days from silking till 50% of plants in the plot showed
silks, while days to anthesis were worked out by visual observation when 50% of
the plants in the plot started pollen shedding. From the date of sowing, days were counted. Anthesis silking
interval (ASI) was computed on a plot basis as the difference between silking
and anthesis. Plant height using a graduated meter rod in cm was computed from
the ground level to the topmost node of
the plant, and an average of five randomly selected plants per row was taken,
whereas ear height was also computed in cm as an average of five randomly
selected plants per row from ground level to the node bearing the uppermost
ear. Ear length was computed as an average of three per row from the tip to the
base of the ear with the scale in cm, whereas kernel rows per ear were counted
on the three randomly selected ears after harvesting. The moisture content of the grains was
taken using a grain moisture tester after shelling the middle rows from three
randomly selected ears per row at harvesting time. A hundred kernels were counted randomly from the grain lot of each
row and weighed with the help of an electronic balance. Total grain yield per
hectare was calculated from the data of fresh ear weight using formula:
Grain Yield (kg ha-1) = (F.wt
(kg) × 100-M.C) × 0.8 × 10,000
(100-15) × harvesting area
Whereas
MC = moisture content (%) in grains at harvest, 0.8 = Shelling co-efficient,
15% = moisture content required in grain at storage
The data of agronomic traits were analyzed
using PROC MIXED procedure to determine the relationship among the traits;
phenotypic correlation coefficients were computed among all the traits.
Variance components were estimated to know the environmental and genetic
effects on different characters. Phenotypic (δ 2P),
genotypic (δ 2G) and error (δ 2E)
variances were computed from mean squares of analysis of variance by using the
formula suggested by Hallauer et al. (2010). The standard
errors of estimates of genotypic and error variance components were computed
using the methods of Hallauer et al. (2010). The genetic
advance (GA) was calculated as devised by Johnson (1955). The following
formulas were used are;
Error Variance, δ 2E= MSE,
where MSE = mean square of error
Genotypic
variance, δ 2G= (MSG-
MSE)/r, where MSG = mean square of genotype, MSE =
mean square of error, and r = number of replications
Phenotypic
variance, δ 2P= δ 2E+ δ 2G, where
δ 2E= error
variance and δ 2G= genotypic variance
Genotypic
coefficient of variation, GCV= (
Phenotypic
coefficient of variation, PCV = (
Heritability
h2 = δ 2G/ δ 2P, where δ 2G=
genotypic variance and δ 2P= phenotypic variance
Genetic
Advance GA = k √ δ 2P. h2,
where √ δ 2P= Square root of
Phenotypic Variance, h2= Heritability, and K= Constant, 2.063 at 5%
selection intensity
Results and discussion
This
research was conducted at (34° 0' 29" N / 71°
34' 22" E), Peshawar, Pakistan which, under Koppen's climate classification, features a semi-arid climate with very hot summers
and mild winters.
Days to 50% tasseling
The
analysis of variance was taken for days
to 50% tasselling and observed highly significant differences
at P<0.01 for half-sib families. For days to tasselling a minimum mean value
of 54 was observed for HSF-13, HSF-63, HSF-163, and
HSF-189, while the maximum mean value of
60 was observed for HSF-114. The grand mean of 56.14 was observed for all 196
entries (Tab. 1). These results are in agreement with those observed by Hidayat et al. (2006), who also reported a highly
significant difference for days to 50% tasselling when evaluating the
performance of local and exotic inbred lines of maize under agro-ecological
conditions of Peshawar. The genotypic coefficient
of variance was at the very low side as
it was 0.03 % (Tab. 2).
Days to 50% Silking
Analysis of variance for days to 50% showed a significant difference among the half-sib
families at P<0.05. For days to 50% silking minimum mean value of 57 was
observed for HSF-13, HSF-116, HSF-66, and
HSF-183, while the maximum mean value of
64.5 was observed in HSF-92, with a grand mean of 60.10 computed for all 196
entries (Tab. 1). The results of Hidayat et al. (2006) are also in comparison to our results. Because he
also reported a highly significant
difference for days to 50% silking when evaluating the performance of local and
exotic inbred lines of maize under agro-ecological conditions of Peshawar.
Similar results were also observed while working on “recurrent selection for grain yield
in two Spanish maize synthetic populations”. The genotypic coefficient of variance computed was 0.03 (Tab.
2).
Days to 50% Anthesis
Analysis
of variance regarding days to 50% anthesis showed no significant difference
among the half-sib families. The minimum
value for days to 50% anthesis was observed as 54.5 days for HSF-13, while the maximum of 61.5 days was observed for HSF-114,
having a grand mean of 57.52 days among 196 half-sib families (Tab. 1, Tab. 6).
The coefficient of variance was very low,
as it was recorded as 0.02 % (Tab. 2).
Anthesis Silking Interval (ASI)
ANOVA regarding anthesis silking interval showed a significant difference (P<0.05) with the
genotypic coefficient of variance as 0.52 % (Tab. 2). ASI calculated ranged
from 0.5 days for HSF-102, HSF-191, HSF-194, and HSF-16 (protogynous), while a maximum of 6.5
days was calculated for HSF-24 (protandrous), having a grand mean of 2.59 days among
half-sib families (Tab. 1, Tab. 6). Rahman et al. (2010) observed similar
results for anthesis-silking interval in test cross-evaluation
of maize synthetic “BSSS” lines.
Plant Height
Plant height requires special attention from plant
breeders as it plays an important role in plant lodging. Plants having an
optimum height and central or near-to- central placement of cobs are more
resistant to lodging and therefore play a vital role in improving grain yield.
Highly significant differences (P<0.01) were recorded for plant height among
the half-sib families. The genotypic coefficient of variance 0.09 was recorded,
which was very low (Tab. 2). The average
plant height ranged from 130 cm for HSF-120 and HSF-159 to 186 cm for HSF-56,
with a grand mean of 154.1 cm (Tab. 1). Stromberg and Compton (1989) reported
significant differences regarding plant height after 10 cycles of the full-sib recurrent section in Nebraska Krung open-pollinated maize.
Ear Height
ANOVA
for ear height revealed highly significant differences (P<0.01) among 196
half-sib families. The genotypic coefficient
of variance was 0.13 % (Tab. 2). Minimum mean ear height of 54cm was observed
for HSF-156, while the maximum ear height 91 was recorded for HSF-56, with a
grand mean of 71.98 for all 196 half-sib families (Tab. 1). Stromberg and Compton (1989) reported
significant differences regarding ear height after 10 cycles of full-sib
recurrent selection in an open-pollinated
maize population.
Table
1: General Statistics for the yield related agronomic
traits.
|
DT |
DS |
DA |
ASI |
PH (cm) |
EH (cm) |
CR |
FEW |
GMC |
KR |
CL |
100-KW (g) |
GY (kg ha-1) |
|
|
Grand mean |
56.14 |
60.10 |
57.52 |
2.59 |
154.11 |
71.98 |
8.67 |
0.98 |
23.44 |
13.35 |
14.81 |
32.27 |
4367.54 |
|
Maximum |
60.00 |
64.50 |
61.50 |
6.50 |
186.0 |
91.00 |
14.50 |
2.15 |
30.75 |
16.84 |
19.17 |
41.00 |
10710.50 |
|
Minimum |
54.00 |
57.00 |
54.50 |
0.50 |
130.0 |
54.00 |
3.00 |
0.30 |
14.95 |
11.00 |
9.34 |
20.00 |
2046.50 |
|
Standard Deviation |
1.16 |
1.61 |
1.27 |
1.22 |
11.76 |
7.85 |
2.04 |
0.35 |
2.87 |
0.98 |
1.74 |
3.39 |
1180.95 |
|
Standard Error |
0.08 |
0.12 |
0.09 |
0.09 |
0.84 |
0.56 |
0.15 |
0.02 |
0.21 |
0.07 |
0.12 |
0.24 |
84.35 |
Days
To Tasseling (DT), Days to Silking (DS), Days to Anthesis (DA), Anthesis
Silking Interval (ASI), Plant Height (PH), Ear Height (EH), Cobs Per Row (CR),
Fresh Ear Weight (FEW), Grain Moisture Content (GMC), Kernal Rows Per Cob (KR),
Cob Length (CL), 100-Kernal Weight (100-KW), Grain Yield (GY)
Table 2: Components of variance for the agronomic traits in Half-Sib Families of
maize.
|
Parameters |
(δ 2G) |
(δ 2P) |
(δ 2E) |
GCV% |
PCV% |
|
Days
to Tasseling |
2.36 |
2.71 |
0.35 |
0.03 |
0.03 |
|
Days
to Silking |
3.43 |
5.20 |
1.77 |
0.03 |
0.09 |
|
Days
to Anthesis |
1.84 |
3.22 |
1.38 |
0.02 |
0.06 |
|
Anthesis
Silking Interval (ASI) |
1.84 |
2.96 |
1.13 |
0.52 |
1.14 |
|
No of
Plants/Row |
6.79 |
11.07 |
4.28 |
0.24 |
1.01 |
|
Plant
Height |
183.87 |
276.73 |
92.86 |
0.09 |
1.80 |
|
Ear
Height |
81.35 |
123.14 |
41.79 |
0.13 |
1.71 |
|
No of
Cobs/Row |
7.45 |
8.34 |
0.89 |
0.31 |
0.96 |
|
Fresh
Ear Weight/Row |
0.23 |
0.25 |
0.02 |
0.49 |
0.25 |
|
Grain
Moisture/Row |
9.17 |
16.50 |
7.33 |
0.13 |
0.70 |
|
Kernel
Rows/Cobs |
1.30 |
1.94 |
0.63 |
0.09 |
0.10 |
|
Cob
Length |
5.72 |
6.06 |
0.34 |
0.16 |
0.41 |
|
100
Kernel Weight Grain
Yield |
21.13 25.12 |
22.99 25.98 |
1.86 1.45 |
0.14 1.21 |
0.71 0.99 |
δ2G = Genotypic Variance,
δ 2P = Phenotypic
Variance, δ 2E = Error Variance, GCV % = Genotypic Co-efficient of Variance, PCV % =
Phenotypic Co-efficient of Variance.
Tab. 3 Mean squares
values for agronomic characteristics, of half-sib families from maize variety
Azam.
|
Parameter |
Reps |
Treatments |
Blocks |
|
Tasseling |
5.635 |
2.709** |
0.635 |
|
Silking |
41.145 |
5.198** |
9.470 |
|
Anthesis |
120.125 |
3.222N.S |
4.795 |
|
ASI |
20.207 |
2.964** |
3.948 |
|
Plant height(cm) |
10175.734 |
276.727** |
649.210 |
|
Ear height(cm) |
913.873 |
123.140** |
296.890 |
|
Kernel rows |
0.130 |
1.935** |
1.735 |
|
Cob length (cm) |
15.844 |
6.059** |
0.607 |
|
100-kernal wt. |
0.125 |
22.992** |
3.257 |
|
Grain yield (Kgha-1) |
4671532.778 |
2789345.672** |
2945605.393 |
N.S = non-significant
**
= Significant at 1% level of significance
Kernels rows per cob
Analysis
of variance for kernel rows cob revealed highly significant differences among
half-sib families, with the genotypic coefficient of variance noted as 0.09 %
(Tab. 2). Minimum average kernel rows per cob were observed as 11 for HSF-157,
while maximum average values were 16.84 for HSF-83, with a grand mean of 13.35
among 196 half-sib families (Tab. 1). These results are similar to those
reported by Gnanasekaran et al. (2008), who observed
highly significant differences among the genotypes for kernel rows per cob.
Cob Length
Data
recorded for cob length also showed highly significant differences among the
half-sib families. The genotypic coefficient
of variance was 0.16 % (Tab. 2). The cob length of half-sib families ranged
from 9.34 cm to 19.17 cm for HSF-15 and HSF-41, respectively, having a grand
mean of 14.81 (Tab. 1). The results are in contrast to those observed by Carlon
and Russel (1989), who observed significant differences (P<0.05) for cob
length in the testcross evaluation of
maize synthetic ‘BSSS’ lines.
Weight of 100 Kernels
Analysis
of variance revealed highly significant differences (P<0.01) among the
half-sib families with a 5.98% coefficient of variation (Tab. 3). Mean values
for the weight of 100 kernels ranged from 20 for HSF-140 to 41 for HSF-153. The
grand mean was recorded as 32.27 (Tab. 1). These results are similar to those
of Rahman et al. (2007), who also
reported significant differences (P<0.05) for this trait while comparing
original and selected maize populations for grain yield.
Tab. 4 Genetic Parameters for the agronomic traits in
Half-Sib Families of maize.
|
Parameters |
h2BS |
GA |
GG |
|
Days
To Tasseling |
† 0.87 |
2.95 |
5.26 |
|
Days
To Silking |
† 0.66 |
3.10 |
5.15 |
|
Days
To Anthesis |
‡ 0.57 |
2.11 |
3.67 |
|
Anthesis
Silking Interval (ASI) |
† 0.62 |
2.20 |
84.63 |
|
No of
Plants/Row |
† 0.61 |
4.21 |
38.25 |
|
Plant
Height |
† 0.66 |
22.77 |
14.77 |
|
Ear
Height |
† 0.66 |
15.10 |
20.98 |
|
No of
Cobs/Row |
† 0.89 |
5.32 |
61.32 |
|
Fresh
Ear Weight/Row |
† 0.94 |
0.96 |
97.19 |
|
Grain
Moisture/Row |
‡ 0.56 |
4.65 |
19.85 |
|
Kernal
Rows/ Cob |
† 0.67 |
1.93 |
14.44 |
|
Cob
Length |
† 0.94 |
4.79 |
32.33 |
|
100
Kernal Weight Grain
Yield |
† 0.92 † 0.85 |
16.08 20.23 |
28.14 26.25 |
†= High
Heritability
‡=
Moderate Heritability
h2BS
= Heritability (broad scence), GA= Genetic Advance, GG= Genetic Gain
Variance Analysis
The variance analysis
results for the investigated traits are shown
in Table 2. The grain quantity characteristics and the grain yield of 196 half-sib families of maize were studied. To
find the extent of yield variation components that
are responsible for the yield differences, it must be kept in mind that
total variability is contingent upon
non-heritable and heritable components. The coefficient of variation measures the extent of variation present in the
population, genetic advances and
heritability, as these are prime important steps of the breeding program because
this gives information required in the
efficient breeding program. The genotypic variance (δ2G),
phenotypic variance (δ2P), error variance (δ2E),
genotypic coefficient of variance (GCV
%), and phenotypic coefficient of
variance (PCV %) expressed as a percentage
for 14 parameters are presented in Table 2. The phenotypic coefficient of variance (PCV%) was higher than the genotypic coefficient of
variance (GCV%) for all traits except for fresh ear weight, where the genotypic co-efficient of variance was greater,
which reflect the environmental influence on the trait’s expression (Tab. 2).
Heritability
Heritability
(h2) of a trait is vital to
find out its response to selection. The genetic improvement for quantitative
characters of plants requires reliable estimates of heritability for the plan
of efficient breeding. A high
heritability of 0.87 was observed for days to tasseling,
and for days to mid-silking high heritability of 0.66 was observed, which
specifies the low effect of the environment
with a relative improvement of the trait
(Tab. 4). A moderate heritability estimate
of 0.57 was recognized for days to
anthesis, which reflects considerable environmental effects on anthesis. For
anthesis silking interval (ASI), high heritability estimates of 0.62 were observed. For a number of plants and plant height, high
heritability estimates of 0.61 and 0.66 were
observed. Mahmood and Hubbard (2004) recognized a high heritability estimate of 0.99 for plant
height that shows our results are the same
as his results. A high heritability estimate
of 0.67 was observed for kernel rows per cob. Mahmood and Hubbard (2004) also observed a high
heritability estimate of 0.87 for this parameter. For cob length and 100-kernel
weight, a high heritability of 0.94 and 0.92 was observed (Tab. 4), which are
in agreement for 100-kernel weight, scrutinized by Sujiprihati et al. (2007). High
heritability estimates of 0.85 were
observed for the grain yield parameter, and such high heritability estimates were also observed (Mohamed and Mohamed, 2017).
Tab. 5 Correlations among yield related agronomic traits.
|
DT |
DS |
DA |
ASI |
PR |
PH |
EH |
CR |
FEW |
GM |
KR |
KW |
GY |
|
|
DT |
0.98** |
1.00** |
1.00** |
0.96** |
0.93** |
0.93** |
0.97** |
0.28** |
0.95** |
0.99** |
0.98** |
0.94** |
|
|
DS |
0.99** |
0.99** |
0.99** |
0.98** |
0.98** |
1.00** |
0.09 N.S |
0.99** |
0.94** |
1.00** |
0.99** |
||
|
DA |
1.00** |
0.97** |
0.95** |
0.95** |
0.98** |
0.22** |
0.97** |
0.98** |
0.99** |
0.96** |
|||
|
ASI |
0.97** |
0.94** |
0.94** |
0.97** |
0.24** |
0.96** |
0.98** |
0.98** |
0.95** |
||||
|
PR |
1.00** |
1.00** |
1.00** |
-0.01 N.S |
1.00** |
0.90** |
1.00** |
1.00** |
|||||
|
PH |
1.00** |
0.99** |
-0.09 N.S |
1.00** |
0.86** |
0.99** |
0.90** |
||||||
|
EH |
0.99** |
-0.09 N.S |
1.00** |
0.86** |
0.99** |
0.94** |
|||||||
|
CR |
0.02 N.S |
1.00** |
0.91** |
1.00** |
1.00** |
||||||||
|
FEW |
-0.04 N.S |
0.42** |
0.07 N.S |
-0.06N.S |
|||||||||
|
GM |
0.89** |
0.99** |
1.00** |
||||||||||
|
KR |
0.93** |
0.88** |
|||||||||||
|
CL |
0.99** |
DT-Days To Tasseling,
DS-Days To Silking, DA-Days To Anthesis, ASI-Anthesis Silking Interval (ASI),
PR-No of Plants/Row, PH-Average Plant Height of Five Plants, EH-Average Ear
Height of Five Plants, CR-No of Cobs/Row, FEW-Fresh Ear Weight/Row, GM-Grain
Moisture/Row, KR-Kernal Rows/ Cob (Average of 3 Cobs), CL-Cob Length (Average
Cob Length In 3 Cobs), KW-100 Kernal Weight, GY-Grain Yield
N.S = non-significant,
** = Significant at 1% level of significance
Correlation Analysis
The
degree of correlation is important to factor in yield, which is a complex character among different characters. Steel and Torrie (1960) scrutinized that
correlation is the intensity of the measures between the traits. The assortment of
one trait affects the progress of all
characters that are positively
correlated. The correlation coefficients among the different traits were
studied (Tab. 5), which shows a highly
significant and positive correlation between grain yield with all parameters,
especially with the number of plants per
row and the number of cobs per row. This shows that our results are quite good
and true because when the number of plants per row increases, the grain yield
will be increasing; this will automatically increase the number of cobs per row,
which results in the increment of grain yield. A
highly significant and positive correlation was also observed between grain yield and cob length, kernel rows
per cob, grain moisture, days to tasseling,
silking, and anthesis. However, a non-significant and negative correlation
factor was observed between grain yields and fresh ear weight. A non-significant
and positive correlation factor was observed between 100-kernel weights with
fresh ear weight, and a highly significant and positive correlation was
observed with no plant per row (Tab. 5).
Tab. 6 (Part-A) List of half-sib families (HSF)
showing grain yield (GY kg ha-1) of two replications.
|
HSF |
GY |
HSF |
GY |
HSF |
GY |
HSF |
GY |
HSF |
GY |
HSF |
GY |
HSF |
GY |
|
HSF-1 |
3697 |
HSF-15 |
2293.5 |
HSF-29 |
3661.5 |
HSF-43 |
3670 |
HSF-57 |
4107.5 |
HSF-71 |
3026 |
HSF-85 |
3462 |
|
HSF-2 |
2870.5 |
HSF-16 |
3404 |
HSF-30 |
3065 |
HSF-44 |
2803 |
HSF-58 |
3042.5 |
HSF-72 |
3895.5 |
HSF-86 |
3055 |
|
HSF-3 |
3131 |
HSF-17 |
3676.5 |
HSF-31 |
2046.5 |
HSF-45 |
4043 |
HSF-59 |
3970 |
HSF-73 |
3662 |
HSF-87 |
4785.5 |
|
HSF-4 |
4023 |
HSF-18 |
3527.5 |
HSF-32 |
3066 |
HSF-46 |
3839 |
HSF-60 |
3785 |
HSF-74 |
4949 |
HSF-88 |
3996.5 |
|
HSF-5 |
4767 |
HSF-19 |
4061 |
HSF-33 |
3734.5 |
HSF-47 |
3725 |
HSF-61 |
4578 |
HSF-75 |
4719.5 |
HSF-89 |
4527 |
|
HSF-6 |
4174 |
HSF-20 |
3316 |
HSF-34 |
3428 |
HSF-48 |
6905.5 |
HSF-62 |
5180 |
HSF-76 |
3845 |
HSF-90 |
5198 |
|
HSF-7 |
5333 |
HSF-21 |
4843.5 |
HSF-35 |
4169.5 |
HSF-49 |
4148 |
HSF-63 |
5755.5 |
HSF-77 |
5215 |
HSF-91 |
4475.5 |
|
HSF-8 |
4942 |
HSF-22 |
4695 |
HSF-36 |
5996 |
HSF-50 |
4313.5 |
HSF-64 |
6660 |
HSF-78 |
5299.5 |
HSF-92 |
4299.5 |
|
HSF-9 |
7225.5 |
HSF-23 |
3484 |
HSF-37 |
3178.5 |
HSF-51 |
4460.5 |
HSF-65 |
5099.5 |
HSF-79 |
5115.5 |
HSF-93 |
3335 |
|
HSF-10 |
3980.5 |
HSF-24 |
4033 |
HSF-38 |
4409.5 |
HSF-52 |
5300.5 |
HSF-66 |
4989.5 |
HSF-80 |
4017 |
HSF-94 |
5557 |
|
HSF-11 |
4053 |
HSF-25 |
5387.5 |
HSF-39 |
4117.5 |
HSF-53 |
6613 |
HSF-67 |
5494 |
HSF-81 |
4345.5 |
HSF-95 |
4105.5 |
|
HSF-12 |
4436.5 |
HSF-26 |
4752 |
HSF-40 |
4474 |
HSF-54 |
4347 |
HSF-68 |
4354 |
HSF-82 |
3350.5 |
HSF-96 |
3430 |
|
HSF-13 |
3816 |
HSF-27 |
6555 |
HSF-41 |
5373.5 |
HSF-55 |
5936.5 |
HSF-69 |
4367 |
HSF-83 |
6940 |
HSF-97 |
5593 |
|
HSF-14 |
4645.5 |
HSF-28 |
4601 |
HSF-42 |
5112.5 |
HSF-56 |
4711 |
HSF-70 |
5068 |
HSF-84 |
8378 |
HSF-98 |
2437.5 |
Tab. 6 (Part-B) List of half-sib families (HSF)
showing grain yield (GY kg ha-1) of two replications.
|
HSF |
GY |
HSF |
GY |
HSF |
GY |
HSF |
GY |
HSF |
GY |
HSF |
GY |
HSF |
GY |
|
HSF-99 |
3060.5 |
HSF-113 |
2446.5 |
HSF-127 |
6048.5 |
HSF-141 |
3447 |
HSF-155 |
3817 |
HSF-169 |
3658 |
HSF-183 |
4193.5 |
|
HSF-100 |
3153 |
HSF-114 |
3449.5 |
HSF-128 |
3662.5 |
HSF-142 |
3208 |
HSF-156 |
3589 |
HSF-170 |
3288 |
HSF-184 |
3490.5 |
|
HSF-101 |
3745 |
HSF-115 |
5169.5 |
HSF-129 |
3519 |
HSF-143 |
3846 |
HSF-157 |
4438.5 |
HSF-171 |
3915.5 |
HSF-185 |
3367.5 |
|
HSF-102 |
4407.5 |
HSF-116 |
3791.5 |
HSF-130 |
3894 |
HSF-144 |
3271.5 |
HSF-158 |
4043.5 |
HSF-172 |
4131 |
HSF-186 |
3551 |
|
HSF-103 |
4907.5 |
HSF-117 |
3175 |
HSF-131 |
3074 |
HSF-145 |
4525.5 |
HSF-159 |
3867 |
HSF-173 |
3843 |
HSF-187 |
4746.5 |
|
HSF-104 |
4224.5 |
HSF-118 |
4808 |
HSF-132 |
4758.5 |
HSF-146 |
4360.5 |
HSF-160 |
4442 |
HSF-174 |
4850.5 |
HSF-188 |
4552 |
|
HSF-105 |
4420 |
HSF-119 |
5298 |
HSF-133 |
3550.5 |
HSF-147 |
3623.5 |
HSF-161 |
5200 |
HSF-175 |
4365 |
HSF-189 |
4151 |
|
HSF-106 |
5409.5 |
HSF-120 |
2385 |
HSF-134 |
4551.5 |
HSF-148 |
3217 |
HSF-162 |
3631.5 |
HSF-176 |
5285.5 |
HSF-190 |
5560 |
|
HSF-107 |
4460 |
HSF-121 |
3013.5 |
HSF-135 |
4561 |
HSF-149 |
4634.5 |
HSF-163 |
5735.5 |
HSF-177 |
5424.5 |
HSF-191 |
4197.5 |
|
HSF-108 |
2427 |
HSF-122 |
3296 |
HSF-136 |
3677 |
HSF-150 |
5099.5 |
HSF-164 |
5931 |
HSF-178 |
3455 |
HSF-192 |
4141 |
|
HSF-109 |
5024.5 |
HSF-123 |
3657.5 |
HSF-137 |
3137 |
HSF-151 |
3850.5 |
HSF-165 |
5268 |
HSF-179 |
7376.5 |
HSF-193 |
4157.5 |
|
HSF-110 |
3684 |
HSF-124 |
3330 |
HSF-138 |
3226 |
HSF-152 |
4686.5 |
HSF-166 |
8257.5 |
HSF-180 |
10710 |
HSF-194 |
8283.5 |
|
HSF-111 |
3687 |
HSF-125 |
4326 |
HSF-139 |
5262.5 |
HSF-153 |
3661.5 |
HSF-167 |
4841.5 |
HSF-181 |
4268.5 |
HSF-195 |
5782.5 |
|
HSF-112 |
5700.5 |
HSF-126 |
3919 |
HSF-140 |
4804 |
HSF-154 |
3239.5 |
HSF-168 |
6138.5 |
HSF-182 |
4752 |
HSF-196 |
2729.5 |
Grain yield (kg ha-1)
Grain yield improvement is one of the
major aims of every plant breeding program. Several methods of selection have
been used by maize breeders to improve yield per unit area and develop high-
yielding genotypes. Among them, the four
major types are mass selection, selection based on half-sib progeny
performance, full-sib performance, and selfed progeny selection (Okoye et al., 2018). Statistical
analysis of the data regarding grain yield revealed highly significant genetic variation (P<0.01) among
the half-sib families. The genetic coefficient
of variance (CV) for grain yield was 15.62 % (Tab. 3). Grain yield of half-sib
families ranged from 2046.50 kg ha-1 for HSF-31 to 10710.50 kg ha-1
for HSF-180. The grand mean calculated was 4367.54 kg ha-1 (Tab. 1).
Our results are consistent with those of Tanner and Smith (1987), who conducted
eight cycles of half-sib family (BSK(S)) recurrent selection in the
Krug yellow dent maize population, in
which they obtained significant variances among test
crosses for grain yield.
Conclusion
The phenotypic
coefficient of variance was higher than
the genotypic coefficient of variance for
all traits except for fresh ear weight which reflects
the environmental influence on the expression of
the trait. High to moderate heritability was observed for days to
tasseling, days to mid silking, days to anthesis, anthesis- silking interval,
kernel rows per cob, cob length, and grain yield. Highly significant and
positive correlations were observed
between grain yield and cob length (0.99), kernel rows per cob (0.88), grain
moisture (1.00), days to tasseling (0.94), silking (0.99), and anthesis (0.96).
The negative and non-significant correlations were observed between grain yield
and fresh ear weight (-0.06). Maximum grain yields of 10710 kg ha-1
was recorded for HSF-180 while the minimum 2046 kg ha-1 was obtained
by HSF-31
Acknoledgement:
The authors are also thankful to the
Cereal Crop Research Institute (CCRI) Pakistan for providing germplasm and
technical support.
Authors contributions:
Nasr Ullah Khan and Muhammad
Saad Ahmed conceived the idea and designed the project. Muhammad
Ishfaq Khan, Rida Nisar, Muhammad
Muddasir, and Muhammad Umer Mustafa conducted the experiment and collected the
data. Muhammad Arshad, Rehan Naeem, Mohsin Khurshid, and Muhammad
Khuram Razzaq analyzed the data. Nasr Ullah Khan, Muhammad Saad Ahmed, Muhammad
Ishfaq Khan, and Abdul Majid drafted the manuscript. All authors read the
manuscript before submission.
Conflict of interests:
None
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