Introduction
In
Pakistan, maize is mostly grown in the provinces of Punjab and Khyber Pakhtunkhwa, and very little
(2-3%) maize grains are produced by two other provinces. In Punjab and Khyber
Pakhtunkhwa, during spring season the progressive
farmers are getting good yield by planting maize hybrids for grains with
improved production technology (Ali 2015; Ali et al. 2019; Hassan et al. 2019). However,
hybrid seed supplied by the seed companies is very costly as they mainly rely
on the imported seed and a very small amount of locally produced hybrid seed is
available in the market. In Pakistan, hybrid seed production offers the most
effective strategy for improving maize yield. Thus, there is enormous scope for establishing the local
maize hybrids, and to study them at different ecological zones to get a good
yield.
Maize (Zea mays L.) is ranked as the third
essential cereal crop after wheat and rice globally and in Pakistan, and grown
in irrigated and in rain-fed regions (Kumar et
al. 2019; Ullah et al. 2019). Usually, maize is cultivated up to 3300 meters above
sea level, 500 N to 400 S latitude in the majority of the
areas of the world (Sajjad 2018; Cherchali
et al. 2019). Maize is adapted
to a variety of soils; however,
the soils with a pH range of 6.5 to 7.5 are most favorable. In
Pakistan, maize used as green and dry fodder, and maize grains are used as the
main staple food by the farming community (Sajjad et al. 2016; Khan et al. 2018). However, its usage as human food is decreasing,
whereas its industrial use is rising rapidly. In current
maize production, about 60% is being utilized in poultry feed, 28% in wet
milling, and 6% in food. Food utilization is reducing but poultry feed and
silage demand are increasing. During 2018-19,
maize was grown on an area of 1.318 million hectares and total production was
6.309 million tones with average grain yield of 4787 kg ha-1 in
Pakistan (PBS 2018-19).
In the early 20th century, heterosis was
first established in maize, however, at that time the hybrids could not be
economically made available on a large scale for commercial use (Li et al.
2018; Ali et al. 2019).
Later on, the breeders produced inbred lines with sufficient vigor for
practical production of double-cross and single-cross maize hybrids.
Development of F1 hybrids not only revolutionized maize breeding
schemes but also constituted the foundation of the maize seed industry (Kiani et al. 2015; Ullah et al. 2017; Khan et al. 2018).
In maize hybrids, the persistence of heterosis is
necessary for their commercial exploitation, and the hybrids with significant heterosis could be recommended for commercial cultivation
(Ali et al. 2018; Kumar et al. 2014, 2019). Usually, heterosis has been gauged in genetically diverse
populations which combine the associations. Neither heterozygosity
nor genetic diversity is a suitable indicator for predicting the desirable heterosis (Govindaraju, 2019; Liu et al. 2019).
Estimation of heterosis is beneficial in the
valuation of parent's performance for hybrid combinations, and past studies
revealed substantial standard heterosis in F1 populations for leaf area,
anthesis silking interval, and grain yield in maize (Venkatesha et al. 2013; Sharma et al. 2019).
In maize hybrids, the standard heterosis was reported
for earliness, grains per ear, ear length, ear diameter, and grain yield and
some desirable crosses were recommended for the development of commercial
hybrids (Barata et al. 2019; Yi et al.
2019). Therefore, keeping in view these considerations, the present study was
planned with the objectives to a) study the performance of 5 × 5 F1
complete diallel hybrids along with parental
genotypes for earliness, morphological and yield traits across four
environments, b) quantify the mid, better, economic and commercial parent heterosis, and c) identify the promising F1 hybrid
based on their genetic potential for commercial cultivation in Khyber Pakhtunkhwa, Pakistan.
Materials and Methods
Plant material,
environments, and procedure
Five
white kernel maize inbred lines i.e., FRHW-22(F2)-5 (FRHW-1), FRHW-22(F2)-4-7
(FRHW-2), FRHW-20-4 (FRHW-3), PSEV3-120-2-2-2 (PSEV3) and SWAJK-6-6-3-6
(SWAJK-1) with distinct genetic makeup were crossed in a complete diallel fashion during spring season 2011 at Cereal Crops Research Institute (CCRI), Pirsabak, Nowshera,
Pakistan (Table 1). The resulting 20 F1 hybrids, five parental
inbred lines and two check genotypes (OPV 'Jalal' and 'Pioneer hybrid 30K08')
were evaluated during subsequent summer crop season 2011 through field
experiments at four different locations in the province of Khyber
Pakhtunkhwa, Pakistan. The study four sites were a) Cereal Crops
Research Institute (CCRI), Pirsabak Nowshera (situated between 34° N latitude and 72° E
longitude with an altitude of 288 m), b) University of Haripur
(UOH), Haripur (lies between 34° North latitude and
72° East longitude with an altitude of 520 m), c) Agricultural Research Station
(ARS), Baffa Mansehra
(located between 33° North latitude and 71° East longitude with an altitude of
1067 m), and d) Agricultural Research Institute (ARI) Mingora Swat (lies
between 34.79° North latitude and 72.29° East longitude with an altitude of 984
m). The maximum and minimum temperatures, and rainfall data of maize summer
crop season during 2011 for the above four locations are provided in
Fig. 1 and 2, respectively.
The experiments at
all the four locations were laid out in a randomized complete block
design (RCBD) with three replications. Experimental sub-plots for all the maize
genotypes comprising four rows with 10 m length. Rows and plants spacing was
kept 75 and 25 cm, respectively. Recommended cultural practices and inputs were
uniformly applied to all the genotypes at all the locations to minimize the
field variations.
Characters
investigation and data collection
Data
for all the parameters were recorded on 10 randomly selected
plants in each genotype/replication/location. Data regarding days to 50%
tasseling, days to 50% pollen shedding and days to 50% silking
were recorded by regular visits to the field and days were counted from sowing
to the day when 50% of the plants produced tassels, silks and when pollen
shedding was started after dehiscence of anthers on central branch of the
tassel in a genotype in each subplot. Data regarding days to physiological
maturity was recorded when a black layer was observed in the grains on
the mid-portion of ear and numbers of days were then counted from the date of
sowing to physiological maturity. Grain yield (kg ha-1) of each
genotype was calculated in kg after harvesting and adjusting the
fresh ear weight to 150 g kg-1 grain moisture by using the relationship of Carangal
et al. (1971).
Statistical
analyses
All the
data were subjected to G × E interaction analysis to partition the variances
due to genotypes, environments, and genotype by environment interactions (Gomez
and Gomez 1984). Genotypes, environments, and genotype × environment
interactions with significant means differences for various traits were further
compared and separated by using the least significant difference (LSD0.05).
After G × E interaction analysis, heterotic effects
over mid-parent (MP), better-parent (BP), economic (EH) and commercial heterosis (CH) were calculated by comparing the F1 hybrid
means with existing parental genotypes, commercial open-pollinated variety (OPV
'Jalal') and commercial hybrid (Pioneer hybrid 30K08), respectively for various
traits (Fonseca 1965; Fehr 1987). In F1 hybrids, the heterotic effects were subjected to 't-test'
to determine whether F1 hybrid means were statistically different
from their mid and better-parents, and OPV and hybrid or not (Wynne et al.
1970; Falconer and Mackay 1996).
Table
1: Parental inbred lines and their 5 × 5 F1 diallel hybrids of maize used in the studies
|
S. No. |
Inbred line |
Code |
Pedigree |
|
|
1 |
FRHW-22(F2)-5 |
FRHW-1 |
Male parental single cross of
maize hybrid 'Babar' |
|
|
2 |
FRHW-22(F2)-4-7 |
FRHW-2 |
Male parental single cross of
maize hybrid 'Babar' |
|
|
3 |
FRHW-20-4 |
FRHW-3 |
Female parental single cross of
maize hybrid 'Babar' |
|
|
4 |
PSEV3-120-2-2-2 |
PSEV3 |
Derived from white maize
population 'PSEV3' |
|
|
5 |
SWAJK-6-6-3-6 |
SWAJK-1 |
Derived from open pollinated
long duration maize variety 'Sarhad White' |
|
|
Check genotypes |
||||
|
6 |
OPV 'Jalal' |
|
||
|
7 |
Pioneer hybrid 30K08 |
|
||
Fig. 1:
Maximum and minimum temperatures during maize summer crop season 2011
at four locations
Fig. 2:
Rainfall during maize summer crop season 2011 at four locations
Table 2:
Mean squares and proportional contribution of G, E, and G × E interaction for
earliness traits and grain yield in 5 × 5 maize F1 diallel hybrids at four locations
|
Variables |
S.O.V. |
M.S. |
C.V.
(%) |
|
Days to 50% tasseling |
G |
18.205** |
1.32 |
|
E (locations) |
693.765** |
||
|
G × E |
7.289** |
||
|
Replications |
1.475** |
||
|
Error |
0.469 |
||
|
Days to 50% pollen shedding |
G |
18.102** |
1.26 |
|
E (locations) |
619.312** |
||
|
G × E |
6.724** |
||
|
Replications |
2.966** |
||
|
Error |
0.479 |
||
|
Days to 50% silking |
G |
17.983** |
1.19 |
|
E (locations) |
621.789** |
||
|
G × E |
7.806** |
||
|
Replications |
2.917** |
||
|
Error |
0.458 |
||
|
Days to physiological Maturity |
G |
237.18** |
0.71 |
|
E (locations) |
7988.90** |
||
|
G × E |
3.63** |
||
|
Replications |
0.13N.S. |
||
|
Error |
0.44 |
||
|
Grain yield |
G |
5.750E+07** |
4.68 |
|
E (locations) |
2.303E+08** |
||
|
G × E |
3591133** |
||
|
Replications |
329509N.S. |
||
|
Error |
179730 |
Results
Significant
(P ≤ 0.01)
differences were observed among the genotypes, environments (locations) and
genotype by environment interactions (GEI) for earliness traits and grain yield
(Table 2). Results revealed greater genetic variability among the genotypes
which might be due to their diverse genetic makeup as well as environments. In
proportional contribution to total sum of squares, environments and genotypes
played a major role in managing the earliness traits and grain yield. However,
shares of G × E interaction and experimental error
(replications) were negligible. Larger effects of environment and genotypes to
total variation (G + E + GEI) persuade the earliness traits and grain yield.
For earliness traits, the negative heterotic effects
are considered desirable for identification of F1 hybrids with
lesser days to tasseling, pollen shedding, silking
and physiological maturity. The trait-wise results are presented as follows.
Days
to 50% tasseling
For days
to 50% tasseling, in F1 hybrids the negative mid-, better parent,
economic and commercial heterotic effects ranged from
-1.35 to -10.32%, -1.99 to -8.55%, 0.69 to -3.47%, and -0.71 to -1.42%,
respectively at CCRI, Pirsabak - Nowshera
(Table 3). Overall, 18, 12, 6, and 3 hybrids showed significant heterotic effects for above four types of heterosis. However, maximum negative mid- and better-parent
heterosis were recorded in F1 hybrids
FRHW-2 × FRHW-3, FRHW-3 × FRHW-1, FRHW-1 × SWAJK-1, and its reciprocal,
respectively for days to 50% tasseling. By comparing the F1 hybrids
with OPV - Jalal and commercial hybrid (Pioneer hybrid 30K08), three F1 hybrids
FRHW-2 × PSEV3, FRHW-2 × FRHW-3, and FRHW-2 × PSEV3 showed maximum negative
economic and commercial heterosis for days to 50%
tasseling.
At the University of Haripur, 10, 6, 8 and 2
F1 hybrids out of 20 showed negative mid-, better-parent, economic
and commercial heterosis ranged from -0.33 to -4.58%,
-1.30 to -3.95%, -0.66 to -3.31%, and zero to -1.35%, respectively for days to 50%
tasseling (Table 3). Overall, 6, 4, 4, and zero hybrids showed significant heterotic effects for above four types of heterosis. F1 hybrids FRHW-1 × PSEV3 and its reciprocal, and SWAJK-1 × FRHW-3 showed highest negative
mid- and better parent heterosis. For economic and commercial
heterosis, the F1 hybrids FRHW-1 × PSEV3
and SWAJK-1 × FRHW-2 performed well for having maximum negative effects for
days to 50% tasseling.
At Agriculture Research Station (ARS), Baffa
Mansehra, 15, 11, 15, 20 F1 hybrids
enunciated negative mid-, better-parent, economic and commercial heterosis in which 14, 10, 13, and 20 out of 20 hybrids
showed significant heterosis (Table 3). For above
four categories of negatives heterosis, the ranges
were -0.91 to -8.88%, -0.62 to -4.97%, -0.54 to -7.17%, and -1.79 to -11.61%,
respectively. Highest negative mid-, better-parent, economic and commercial heterosis were recorded in F1 hybrids FRHW-3 ×
PSEV3, FRHW-1 × FRHW-3, and it's reciprocal, FRHW-2 × FRHW-3 and its reciprocal
and PSEV3 × FRHW-1.
At Agricultural Research Institute (ARI), Mingora Swat, out of 20 the
14, 11, 17 and 18 F1 hybrids revealed negative mid-, better-parent,
economic and commercial heterosis ranged from -0.30
to -10.85% and -0.62 to -8.98%, -0.66 to -9.04% and -1.72 to -10.01%,
respectively for days to 50% tasseling (Table 3). However, 13, 10, 16 and 17 F1
hybrids exhibited significant negative mid-, better-parent, economic, and
commercial heterosis. By comparing with mid-,
better-parent, commercial OPV and hybrid cultivar, the F1 hybrids
FRHW-2 × FRHW-3, and PSEV3 × FRHW-3 showed maximum negative heterotic
effects.
Days
to 50% pollen shedding
At
CCRI, Pirsabak, 19, 12, 17, and 7 F1 hybrids
exhibited negative mid-, better-parent, economic and commercial heterosis in which 16, 12, 8, and 4 hybrids showed
significant heterosis, respectively days to 50%
pollen shedding (Table 4). However, in F1 hybrids the above four
types of negatives heterotic effects ranged from
-0.32 to -10.51%, -2.50 to -8.02%, -0.64 to -4.49%, and -0.65 to -2.61%,
respectively. The maximum negative mid- and better-parent heterotic
values were observed in F1 hybrids FRHW-2 × FRHW-3, FRHW-1 ×
SWAJK-1. For economic and commercial heterosis, the F1
hybrids FRHW-1 × SWAJK-1, FRHW-2 × FRHW-3, and FRHW-2 × PSEV3 performed
better over standard OPV - Jalal and hybrid cultivar for taking fewer days to
50% pollen shedding.
At the University of Haripur, 10, 6, 10, and
one out of 20 F1 hybrids exhibited negative mid-, better-parent,
economic and commercial heterosis ranged from -0.61
to -5.23%, -1.23 to -4.94%, -0.62 to -4.94%, and zero to -2.53%, respectively
for days to 50% pollen shedding (Table 4). However, 7, 5, 5, and one F1 hybrid
attained significant negative level for mid-, better-parent, economic, and
commercial heterosis. The promising F1 hybrids
FRHW-1 × PSEV3, FRHW-1 × SWAJK-1, and FRHW-1 × FRHW-3 recorded with the highest
values for all the four types heterosis
for days to 50% pollen shedding.
For days to 50% pollen shedding at ARS, Baffa,
13, 11, 16, and 19 F1 hybrids revealed negative mid-, better-parent
economic and commercial heterosis ranged from -1.14
to -7.43%, -0.56 to -7.95%, -1.69 to -8.47%, and - Table 3: Mid-
and better-parents, economic and commercial heterosis
in 5 × 5 maize F1
diallel hybrids for days to 50% tasseling across four locations
|
F1
hybrids |
Days
to 50% tasseling |
|||||||||||||||
|
CCRI,
Pirsabak - Nowshera |
University
of Haripur, Haripur |
ARS, Baffa - Mansehra |
ARI, Mingora - Swat |
|||||||||||||
|
MP heterosis (%) |
BP heterosis (%) |
Economic heterosis (%) |
Commercial Heterosis (%) |
MP heterosis (%) |
BP heterosis (%) |
Economic heterosis (%) |
Commercial heterosis (%) |
MP heterosis (%) |
BP heterosis (%) |
Economic heterosis (%) |
Commercial heterosis (%) |
MP heterosis (%) |
BP heterosis (%) |
Economic heterosis (%) |
Commercial heterosis (%) |
|
|
FRHW-1 × FRHW-2 |
-5.92** |
-5.98** |
-0.69 |
1.42* |
3.05** |
7.80** |
0.66 |
2.70** |
-0.91 |
0.62 |
-1.75* |
-5.83** |
-3.95** |
-2.47** |
-5.45** |
-6.45** |
|
FRHW-1 × FRHW-3 |
-6.45** |
-4.61** |
0.69 |
2.84** |
-2.88** |
-1.30 |
0.66 |
2.70** |
-7.56** |
-4.79** |
-4.16** |
-8.15** |
-4.17** |
-0.62 |
-3.65** |
-4.68** |
|
FRHW-1 × PSEV3 |
-4.14** |
0.72 |
-3.47** |
-1.42* |
-4.58** |
-3.95** |
-3.31** |
-1.35 |
-3.66** |
-1.86* |
-4.76** |
-8.72** |
1.56* |
2.52** |
-2.45** |
-3.49** |
|
FRHW-1 × SWAJK-1 |
-7.59** |
-7.28** |
-2.78** |
-0.71 |
-2.93** |
-2.61** |
-1.32 |
0.68 |
1.49* |
1.80* |
2.47** |
-1.79* |
1.20 |
3.70** |
0.54 |
-0.53 |
|
FRHW-2 × FRHW-1 |
-3.95** |
-4.01** |
1.39 |
3.55** |
4.41** |
9.22** |
1.99* |
4.05** |
0.91 |
2.47** |
0.06 |
-4.10** |
-3.95** |
-2.47** |
-5.45** |
-6.45** |
|
FRHW-2 × FRHW-3 |
-10.32** |
-8.55** |
-3.47** |
-1.42* |
0.00 |
6.38** |
-0.66 |
1.35 |
-6.78** |
-2.47** |
-4.76** |
-8.72** |
-10.85** |
-8.98** |
-9.04** |
-10.01** |
|
FRHW-2 × PSEV3 |
-4.14** |
0.72 |
-3.47** |
-1.42* |
1.71* |
5.67** |
-1.32 |
0.68 |
0.31 |
0.62 |
-2.35** |
-6.41** |
0.61 |
3.14** |
-1.86* |
-2.90** |
|
FRHW-2 × SWAJK-1 |
-5.61** |
-5.30** |
-0.69 |
1.42* |
2.72** |
7.09** |
0.00 |
2.03* |
-1.82* |
0.00 |
-2.35** |
-6.41** |
0.30 |
1.20 |
1.14 |
0.06 |
|
FRHW-3 × FRHW-1 |
-8.39** |
-6.58** |
-1.39 |
0.71 |
-2.88** |
-1.30 |
0.66 |
2.70** |
-5.81** |
-2.99** |
-2.35* |
-6.41** |
-7.74** |
-4.32** |
-7.24** |
-8.23** |
|
FRHW-3 × FRHW-2 |
-6.45** |
-4.61** |
0.69 |
2.84** |
6.00** |
12.77** |
5.30** |
7.43** |
-6.78** |
-2.47** |
-4.76** |
-8.72** |
-7.33** |
-5.39** |
-5.45** |
-6.45** |
|
FRHW-3 × PSEV3 |
-1.35 |
5.80** |
1.39 |
3.55** |
-0.96 |
1.32 |
1.99* |
4.05** |
-8.88** |
-4.35** |
-7.17** |
-11.03** |
-3.90** |
0.63 |
-4.25** |
-5.27** |
|
FRHW-3 × SWAJK-1 |
-4.21** |
-1.99* |
2.78** |
4.96** |
-1.28 |
0.65 |
1.99* |
4.05** |
-4.35** |
-1.79* |
-0.54 |
-4.68** |
-4.65** |
-3.53** |
-1.86* |
-2.90** |
|
PSEV3 × FRHW-1 |
-2.07* |
2.90** |
-1.39 |
0.71 |
-3.27** |
-2.63** |
-1.99* |
0.00 |
-6.71** |
-4.97** |
-7.78** |
-11.61** |
2.18** |
3.14** |
-1.86* |
-2.90** |
|
PSEV3 × FRHW-2 |
-2.07* |
2.90** |
-1.39 |
0.71 |
2.39** |
6.38** |
-0.66 |
1.35 |
-0.93 |
-0.62 |
-3.56** |
-7.57** |
-2.45** |
0.00 |
-4.85** |
-5.86** |
|
PSEV3 × FRHW-3 |
10.14** |
18.12** |
13.19** |
15.60** |
6.75** |
9.21** |
9.93** |
12.16** |
-2.96** |
1.86* |
-1.15 |
-5.26** |
-8.71** |
-4.40** |
-9.04** |
-10.01** |
|
PSEV3 × SWAJK-1 |
0.35 |
5.07** |
0.69 |
2.84** |
2.30** |
2.63** |
3.31** |
5.41** |
0.91 |
3.11** |
0.06 |
-4.10** |
-0.30 |
3.14** |
-1.86* |
-2.90** |
|
SWAJK-1 × FRHW-1 |
-7.59** |
-7.28** |
-2.78** |
-0.71 |
-0.33 |
0.00 |
1.32 |
3.38** |
-2.69** |
-2.40** |
-1.75* |
-5.83** |
-4.82** |
-2.47** |
-5.45** |
-6.45** |
|
SWAJK-1 × FRHW-2 |
-5.61** |
-5.30** |
-0.69 |
1.42* |
-0.68 |
3.55** |
-3.31** |
-1.35 |
-3.64** |
-1.85* |
-4.16** |
-8.15** |
-5.04** |
-4.19** |
-4.25** |
-5.27** |
|
SWAJK-1 × FRHW-3 |
-4.21** |
-1.99* |
2.78** |
4.96** |
-3.85** |
-1.96* |
-0.66 |
1.35 |
-2.61** |
0.00 |
1.27 |
-2.95** |
-3.49** |
-2.35** |
-0.66 |
-1.72** |
|
SWAJK-1 × PSEV3 |
-1.73* |
2.90** |
-1.39* |
0.71 |
4.26** |
4.61** |
5.30** |
7.43** |
0.91 |
3.11** |
0.06 |
-4.10** |
3.34** |
6.92** |
1.74* |
0.65 |
**, * = Significant at 1% and 5%
level of probability, MP = Mid-parent, BP = Better-parent
Table 4: Mid-
and better-parents, economic and commercial heterosis
in 5 × 5 maize F1
diallel hybrids for days to 50% pollen shedding across four locations
|
F1
hybrids |
Days
to 50% pollen shedding |
|||||||||||||||
|
CCRI,
Pirsabak - Nowshera |
University
of Haripur, Haripur |
ARS, Baffa - Mansehra |
ARI, Mingora - Swat |
|||||||||||||
|
MP heterosis (%) |
BP heterosis (%) |
Economic heterosis (%) |
Commercial Heterosis (%) |
MP heterosis (%) |
BP heterosis (%) |
Economic heterosis (%) |
Commercial heterosis (%) |
MP heterosis (%) |
BP heterosis (%) |
Economic heterosis (%) |
Commercial heterosis (%) |
MP heterosis (%) |
BP heterosis (%) |
Economic heterosis (%) |
Commercial heterosis (%) |
|
|
FRHW-1 × FRHW-2 |
-5.88** |
-5.65** |
-2.56** |
-0.65 |
3.16** |
6.54** |
0.62 |
3.16** |
-3.45** |
-2.33** |
-5.08** |
-6.20** |
-1.44* |
0.00 |
-0.52 |
-4.52** |
|
FRHW-1 × FRHW-3 |
-6.63** |
-3.73** |
-0.64 |
1.31 |
-3.01** |
-1.23 |
-0.62 |
1.90* |
-3.66** |
-0.58 |
-3.39** |
-4.52** |
-6.96** |
-5.11** |
-2.85** |
-6.76** |
|
FRHW-1 × PSEV3 |
-3.90** |
0.68 |
-5.13** |
-3.27** |
-5.23** |
-4.94** |
-4.94** |
-2.53** |
1.47* |
2.37** |
-2.26** |
-3.41** |
-2.62** |
0.00 |
-2.85** |
-6.76** |
|
FRHW-1 × SWAJK-1 |
-7.17** |
-6.88** |
-4.49** |
-2.61* |
-3.66** |
-3.07** |
-2.47** |
0.00 |
1.42* |
3.49** |
0.56 |
-0.61 |
0.57 |
0.51 |
2.97** |
-1.17 |
|
FRHW-2 × FRHW-1 |
-3.41** |
-3.17** |
0.00 |
1.96* |
4.43** |
7.84** |
1.85* |
4.43** |
-3.45** |
-2.33** |
-5.08** |
-6.20** |
-0.86 |
0.58 |
0.06 |
-3.96** |
|
FRHW-2 × FRHW-3 |
-10.51** |
-8.02** |
-4.49** |
-2.61* |
-1.24 |
3.92** |
-1.85 |
0.63 |
-9.75** |
-7.95** |
-8.47** |
-9.55** |
-5.65** |
-2.34** |
-2.85** |
-6.76** |
|
FRHW-2 × PSEV3 |
-3.56** |
1.36 |
-4.49** |
-2.61* |
0.95 |
3.92** |
-1.85* |
0.63 |
0.87 |
2.96** |
-1.69* |
-2.85** |
1.18 |
2.40** |
-0.52 |
-4.52** |
|
FRHW-2 × SWAJK-1 |
-4.97** |
-4.38** |
-1.92* |
0.00 |
1.26 |
5.23** |
-0.62 |
1.90* |
0.85 |
1.70** |
1.13 |
-0.06 |
-1.44* |
0.00 |
-0.52 |
-4.52** |
|
FRHW-3 × FRHW-1 |
-7.23** |
-4.35** |
-1.28 |
0.65 |
-1.81* |
0.00 |
0.62 |
3.16** |
-7.04** |
-4.07** |
-6.78** |
-7.87** |
-6.41** |
-4.55** |
-2.27* |
-6.20** |
|
FRHW-3 × FRHW-2 |
-7.51** |
-4.94** |
-1.28 |
0.65 |
3.11** |
8.50** |
2.47** |
5.06** |
-6.41** |
-4.55** |
-5.08** |
-6.20** |
-6.21** |
-2.92** |
-3.43** |
-7.31** |
|
FRHW-3 × PSEV3 |
-3.14** |
4.76** |
-1.28 |
0.65 |
-0.91 |
1.23 |
1.23 |
3.80** |
-3.41** |
0.59 |
-3.95** |
-5.08** |
-7.43** |
-2.99** |
-5.76** |
-9.55** |
|
FRHW-3 × SWAJK-1 |
-6.34** |
-3.13** |
-0.64 |
1.31 |
-2.99** |
-1.82* |
0.00 |
2.53** |
-3.87** |
-2.79** |
-1.69* |
-2.85** |
-3.62** |
-1.70* |
0.64 |
-3.41** |
|
PSEV3 × FRHW-1 |
-1.95* |
2.72** |
-3.21** |
-1.31 |
-2.15** |
-1.85* |
-1.85* |
0.63 |
2.05** |
2.96** |
-1.69** |
-2.85** |
-5.54** |
-2.99** |
-5.76** |
-9.55** |
|
PSEV3 × FRHW-2 |
-0.32 |
4.76** |
-1.28 |
0.65 |
2.22** |
5.23** |
-0.62 |
1.90* |
-2.03** |
0.00 |
-4.52** |
-5.64** |
0.00 |
1.20 |
-1.69 |
-5.64** |
|
PSEV3 × FRHW-3 |
8.18** |
17.01** |
10.26** |
12.42** |
7.55** |
9.88** |
9.88** |
12.66** |
-7.95** |
-4.14** |
-8.47** |
-9.55** |
-1.14 |
3.59** |
0.64 |
-3.41** |
|
PSEV3 × SWAJK-1 |
-0.33 |
4.08** |
-1.92 |
0.00 |
2.14** |
3.09** |
3.09** |
5.70** |
0.00 |
2.96** |
-1.69** |
-2.85** |
0.87 |
3.59** |
0.64 |
-3.41** |
|
SWAJK-1 × FRHW-1 |
-4.05** |
-3.75** |
-1.28 |
0.65 |
-0.61 |
0.00 |
0.62 |
3.16** |
-4.27** |
-2.33** |
-5.08** |
-6.20** |
-2.27** |
-2.33** |
0.06 |
-3.96** |
|
SWAJK-1 × FRHW-2 |
-4.97** |
-4.38** |
-1.92 |
0.00 |
-0.63 |
3.27** |
-2.47** |
0.00 |
-4.23** |
-3.41** |
-3.95** |
-5.08** |
-3.17** |
-1.75* |
-2.27* |
-6.20** |
|
SWAJK-1 × FRHW-3 |
-5.74** |
-2.50** |
0.00 |
1.96* |
-3.59** |
-2.42** |
-0.62 |
1.90* |
-1.66* |
-0.56 |
0.56 |
-0.61 |
-1.95** |
0.00 |
2.39** |
-1.73* |
|
SWAJK-1 × PSEV3 |
-0.98 |
3.40** |
-2.56** |
-0.65 |
3.36** |
4.32** |
4.32** |
6.96** |
3.45** |
6.51** |
1.69* |
0.50 |
2.04** |
4.79** |
1.80** |
-2.29** |
**, * = Significant at 1% and 5%
level of probability, MP = Mid-parent, BP = Better-parent
Table 5: Mid-
and better-parents, economic and commercial heterosis
in 5 × 5 maize F1
diallel hybrids for days to 50% silking across four
locations
|
F1
hybrids |
Days
to 50% silking |
|||||||||||||||
|
CCRI,
Pirsabak - Nowshera |
University
of Haripur, Haripur |
ARS, Baffa - Mansehra |
ARI, Mingora - Swat |
|||||||||||||
|
MP heterosis (%) |
BP heterosis (%) |
Economic heterosis (%) |
Commercial Heterosis (%) |
MP heterosis (%) |
BP heterosis (%) |
Economic heterosis (%) |
Commercial heterosis (%) |
MP heterosis (%) |
BP heterosis (%) |
Economic heterosis (%) |
Commercial heterosis (%) |
MP heterosis (%) |
BP heterosis (%) |
Economic heterosis (%) |
Commercial heterosis (%) |
|
|
FRHW-1 × FRHW-2 |
-4.82** |
-4.24** |
-1.87* |
-0.01 |
3.05** |
6.29**** |
0.00 |
2.42** |
-2.52** |
-2.25** |
-4.92** |
-6.00** |
-1.10 |
1.13 |
0.57 |
-3.25** |
|
FRHW-1 × FRHW-3 |
-6.40** |
-3.59** |
-0.01 |
1.89* |
-4.65** |
-2.96** |
-2.96** |
-0.61 |
-3.54** |
-0.56 |
-3.28** |
-4.38** |
-7.49** |
-6.49** |
-2.80** |
-6.49** |
|
FRHW-1 × PSEV3 |
-4.05** |
0.00 |
-4.35** |
-2.54** |
-5.04** |
-4.76** |
-5.33** |
-3.03** |
3.12** |
4.00** |
-0.55 |
-1.67* |
-3.35** |
0.00 |
-2.80** |
-6.49** |
|
FRHW-1 × SWAJK-1 |
-5.11** |
-4.82** |
-1.87* |
-0.01 |
-4.73** |
-4.73** |
-4.73** |
-2.42** |
1.10 |
3.37** |
0.55 |
-0.59 |
-0.27 |
0.55 |
2.81** |
-1.09 |
|
FRHW-2 × FRHW-1 |
-2.41** |
-1.82* |
0.61 |
2.53** |
4.27** |
7.55** |
1.18 |
3.64** |
-2.52** |
-2.25** |
-4.92** |
-6.00** |
-0.55 |
1.69* |
1.13 |
-2.71** |
|
FRHW-2 × FRHW-3 |
-9.36** |
-6.06** |
-3.73** |
-1.90* |
-1.20 |
3.77** |
-2.37** |
0.00 |
-9.78** |
-7.26** |
-9.29** |
-10.32** |
-5.46** |
-2.26** |
-2.80** |
-6.49** |
|
FRHW-2 × PSEV3 |
-2.82** |
0.65 |
-3.73** |
-1.90* |
-0.92 |
1.89* |
-4.14** |
-1.82* |
1.69* |
2.86** |
-1.64* |
-2.76** |
0.00 |
1.16 |
-1.68* |
-5.41** |
|
FRHW-2 × SWAJK-1 |
-5.14** |
-4.85** |
-2.49** |
-0.64 |
1.83* |
5.03** |
-1.18 |
1.21 |
-0.27 |
1.68* |
-0.55 |
-1.67* |
-1.39* |
0.00 |
-0.56 |
-4.33** |
|
FRHW-3 × FRHW-1 |
-6.98** |
-4.19** |
-0.63 |
1.26 |
-1.74* |
0.00 |
0.00 |
2.42** |
-6.81** |
-3.93** |
-6.56** |
-7.62** |
-5.35** |
-4.32** |
-0.56 |
-4.33** |
|
FRHW-3 × FRHW-2 |
-8.19** |
-4.85** |
-2.49** |
-0.64 |
2.99** |
8.18** |
1.78* |
4.24** |
-7.07** |
-4.47** |
-6.56** |
-7.62** |
-6.01** |
-2.82** |
-3.37** |
-7.03** |
|
FRHW-3 × PSEV3 |
-3.32** |
3.90** |
-0.63 |
1.26 |
0.87 |
2.98** |
2.37** |
4.85** |
-3.30** |
0.57 |
-3.83** |
-4.92** |
-7.18** |
-2.89** |
-5.61** |
-9.19** |
|
FRHW-3 × SWAJK-1 |
-4.37** |
-1.20 |
1.86* |
3.79** |
-2.33** |
-0.59 |
-0.59 |
1.82* |
-2.40** |
-1.61* |
0.00 |
-1.13 |
-4.58** |
-2.75** |
-0.56 |
-4.33** |
|
PSEV3 × FRHW-1 |
-4.05** |
0.00 |
-4.35** |
-2.54** |
-2.08** |
-1.79* |
-2.37** |
0.00 |
1.98** |
2.86** |
-1.64* |
-2.76** |
-6.15** |
-2.89** |
-5.61** |
-9.19** |
|
PSEV3 × FRHW-2 |
0.31 |
3.90** |
-0.63 |
1.26 |
2.14** |
5.03** |
-1.18 |
1.21 |
-1.13 |
0.00 |
-4.37** |
-5.46** |
0.00 |
1.16 |
-1.68* |
-5.41** |
|
PSEV3 × FRHW-3 |
7.55** |
15.58** |
10.55** |
12.65** |
7.29** |
9.52** |
8.88** |
11.52** |
-9.34** |
-5.71** |
-9.84** |
-10.86** |
-2.76** |
1.73* |
-1.12 |
-4.87** |
|
PSEV3 × SWAJK-1 |
1.25 |
5.19** |
0.61 |
2.53** |
0.89 |
1.19 |
0.59 |
3.03** |
-1.39* |
1.71** |
-2.73** |
-3.84** |
2.54** |
5.20** |
2.25** |
-1.63* |
|
SWAJK-1 × FRHW-1 |
-3.90** |
-3.61** |
-0.63 |
1.26 |
0.00 |
0.01 |
0.00 |
2.42** |
-3.30** |
-1.12 |
-3.83** |
-4.92** |
-3.00** |
-2.20** |
0.01 |
-3.79** |
|
SWAJK-1 × FRHW-2 |
-3.93** |
-3.64** |
-1.25 |
0.63 |
0.00 |
3.14** |
-2.96** |
-0.61 |
-3.56** |
-1.68 |
-3.83** |
-4.92** |
-3.06** |
-1.69* |
-2.24** |
-5.95** |
|
SWAJK-1 × FRHW-3 |
-5.54** |
-2.41** |
0.61 |
2.53** |
-2.91** |
-1.18 |
-1.18 |
1.21 |
-1.87** |
-1.08 |
0.55 |
-0.59 |
-1.89** |
0.00 |
2.25** |
-1.63* |
|
SWAJK-1 × PSEV3 |
-1.25 |
2.60** |
-1.87* |
-0.01 |
3.86** |
4.17** |
3.55** |
6.06** |
3.05** |
6.29** |
1.64* |
0.49 |
0.28 |
2.89** |
0.01 |
-3.79** |
**, * = Significant at 1% and 5%
level of probability, MP = Mid-parent, BP = Better-parent
Table 6: Mid-
and better-parents, economic and commercial heterosis
in 5 × 5 maize F1
diallel hybrids for days to physiological maturity across four locations
|
F1
hybrids |
Days
to physiological maturity |
|||||||||||||||
|
CCRI,
Pirsabak - Nowshera |
University
of Haripur, Haripur |
ARS, Baffa - Mansehra |
ARI, Mingora - Swat |
|||||||||||||
|
MP heterosis (%) |
BP heterosis (%) |
Economic heterosis (%) |
Commercial heterosis (%) |
MP heterosis (%) |
BP heterosis (%) |
Economic heterosis (%) |
Commercial heterosis (%) |
MP heterosis (%) |
BP heterosis (%) |
Economic heterosis (%) |
Commercial heterosis (%) |
MP heterosis (%) |
BP heterosis (%) |
Economic heterosis (%) |
Commercial heterosis (%) |
|
|
FRHW-1 × FRHW-2 |
0.00 |
2.95** |
-8.92** |
-13.75** |
3.31** |
7.76** |
-8.12** |
-13.46** |
0.65 |
3.69** |
-6.93** |
-9.91** |
-2.50** |
0.00 |
-10.28** |
-14.81** |
|
FRHW-1 × FRHW-3 |
-0.38 |
5.58** |
-1.08* |
-6.33** |
0.00 |
6.75** |
-1.14** |
-6.89** |
0.76* |
4.75** |
-0.30 |
-3.50** |
0.35 |
6.39** |
0.35 |
-4.71** |
|
FRHW-1 × PSEV3 |
-0.79 |
-0.40 |
-6.68** |
-11.63** |
2.91** |
5.16** |
-2.61** |
-8.27** |
1.25** |
2.22** |
-2.71** |
-5.83** |
-0.93* |
-0.38 |
-6.03** |
-10.77** |
|
FRHW-1 × SWAJK-1 |
-2.06** |
3.98** |
-2.58** |
-7.74** |
1.29** |
8.73** |
0.70 |
-5.16** |
0.30 |
4.11** |
-0.90* |
-4.08** |
-0.71 |
4.89** |
-1.06* |
-6.06** |
|
FRHW-2 × FRHW-1 |
-1.23* |
1.69** |
-10.04** |
-14.81** |
2.48** |
6.90** |
-8.86** |
-14.16** |
0.65 |
3.69** |
-6.93** |
-9.91** |
-1.35** |
1.19* |
-9.22** |
-13.80** |
|
FRHW-2 × FRHW-3 |
-1.93** |
7.17** |
-5.19** |
-10.22** |
-1.93** |
9.48** |
-6.65** |
-12.08** |
-0.78* |
6.38** |
-4.52** |
-7.58** |
-3.45** |
5.14** |
-5.67** |
-10.44** |
|
FRHW-2 × PSEV3 |
-0.82 |
2.53** |
-9.29** |
-14.10** |
0.61 |
7.33** |
-8.49** |
-13.81** |
-0.97* |
3.02** |
-7.53** |
-10.50** |
-1.92** |
1.19* |
-9.22** |
-13.80** |
|
FRHW-2 × SWAJK-1 |
-2.50** |
6.75** |
-5.56** |
-10.57** |
-1.34** |
10.78** |
-5.55** |
-11.04** |
-0.31 |
6.71** |
-4.22** |
-7.29** |
-4.92** |
3.16** |
-7.45** |
-12.12** |
|
FRHW-3 × FRHW-1 |
0.75 |
6.77** |
0.04 |
-5.27** |
-0.37 |
6.35** |
-1.51** |
-7.23** |
1.07** |
5.06** |
0.00 |
-3.21** |
-1.42** |
4.51** |
-1.42** |
-6.40** |
|
FRHW-3 × FRHW-2 |
-0.77* |
8.44** |
-4.07** |
-9.16** |
-0.77 |
10.78** |
-5.55** |
-11.04** |
1.10** |
8.39** |
-2.71** |
-5.83** |
-1.63** |
7.11** |
-3.90** |
-8.75** |
|
FRHW-3 × PSEV3 |
1.12* |
6.72** |
0.78 |
-4.56** |
-1.28** |
3.04** |
-0.40 |
-6.20** |
-1.06** |
1.86** |
-1.20** |
-4.37** |
-2.65** |
2.60** |
-2.13** |
-7.07** |
|
FRHW-3 × SWAJK-1 |
0.53 |
0.71 |
5.64** |
0.04 |
-0.52 |
0.00 |
5.11** |
-1.00* |
1.03** |
1.18** |
3.61** |
0.29 |
-1.35** |
-1.01* |
3.90** |
-1.35** |
|
PSEV3 × FRHW-1 |
-1.98** |
-1.59** |
-7.80** |
-12.69** |
2.91** |
5.16** |
-2.61** |
-8.27** |
1.88** |
2.85** |
-2.11** |
-5.25** |
-1.68** |
-1.13* |
-6.74** |
-11.45** |
|
PSEV3 × FRHW-2 |
1.22* |
4.64** |
-7.43** |
-12.34** |
2.63** |
9.48** |
-6.65** |
-12.08** |
-0.32 |
3.69** |
-6.93** |
-9.91** |
-3.07** |
0.00 |
-10.28** |
-14.81** |
|
PSEV3 × FRHW-3 |
-3.00** |
2.37** |
-3.32** |
-8.45** |
-2.00** |
2.28** |
-1.14** |
-6.89** |
-1.36 |
1.55** |
-1.51** |
-4.66** |
-3.35** |
1.86** |
-2.84** |
-7.74** |
|
PSEV3 × SWAJK-1 |
-2.80** |
2.77** |
-2.95** |
-8.09** |
-0.72 |
4.18** |
0.70 |
-5.16** |
0.30 |
3.11** |
0.00 |
-3.21** |
-1.24** |
3.72** |
-1.06* |
-6.06** |
|
SWAJK-1 × FRHW-1 |
-1.31** |
4.78** |
-1.83** |
-7.03** |
0.18 |
7.54** |
-0.40 |
-6.20** |
1.22** |
5.06** |
0.00 |
-3.21** |
0.00 |
5.64** |
-0.35 |
-5.39** |
|
SWAJK-1 × FRHW-2 |
-1.73** |
7.59** |
-4.82** |
-9.86** |
0.58 |
12.93** |
-3.71** |
-9.31** |
0.31 |
7.38** |
-3.61** |
-6.71** |
-3.46** |
4.74** |
-6.03** |
-10.77** |
|
SWAJK-1 × FRHW-3 |
0.18 |
0.36 |
5.26** |
-0.32 |
0.52 |
1.05** |
6.21** |
0.03 |
-0.44 |
-0.29 |
2.11** |
-1.17** |
0.00 |
0.34 |
5.32** |
0.00 |
|
SWAJK-1 × PSEV3 |
-2.06** |
3.56** |
-2.20** |
-7.39** |
-0.72 |
4.18** |
0.70 |
-5.16** |
0.91** |
3.73** |
0.60 |
-2.62** |
-0.53 |
4.46** |
-0.35 |
-5.39** |
**, * = Significant at 1% and 5%
level of probability, MP = Mid-parent, BP = Better-parent
0.06 to -9.55%, respectively (Table 4). As
compared to concerned parents, commercial OPV and hybrid cultivar, 13, 9, 16,
and 16 F1 hybrids showed significant negative effects for the said
trait. Promising F1 hybrids FRHW-2 × FRHW-3 and its reciprocal, and
PSEV3 × FRHW-3, FRHW-3 × FRHW-1, FRHW-2 × FRHW-1 performed better than both parents, OPV-Jalal and commercial hybrid to took fewer
days to 50% pollen shedding.
At ARI, Mingora, for mid-, better-parent, economic and commercial heterosis, 15, 9, 12, and 20 F1 hybrids
exhibited negative effects for days to 50% pollen shedding ranged from -0.86 to
-7.43%, -1.70 to -5.11%, -0.52 to -5.76%, and -1.17 to -9.55%, respectively (Table
4). However, 13, 9, 8, and 19 F1 hybrids showed significant negative
heterotic effects for above four types of heterosis. The F1 hybrids FRHW-3 × PSEV3, FRHW-1
× FRHW-3 and its reciprocal, and FRHW-3 × FRHW-2 performed better than both the
parents. While the highest and at par negative economic and commercial heterotic effects were observed in F1 hybrids
FRHW-3 × PSEV3 and PSEV3 × FRHW-1, respectively days to 50% pollen shedding.
Days
to 50% silking
At
CCRI, Pirsabak for days to 50% silking,
the negative mid-, better-parent, economic and commercial heterotic
were recorded in 17, 12, 15, and 8 F1 hybrids ranged from -1.25 to
-9.36%, -1.20 to -6.06%, -0.01 to 4.35%, and -0.01 to 2.54%, respectively
(Table 5). However, 16, 11, 11, and 4 F1 hybrids attained the
significance level for the said trait. Maximum negative mid- and better-parent heterosis was recorded in F1 hybrids FRHW-2 ×
FRHW-3 and its reciprocal, FRHW-3 × FRHW-1. The highest negative economic and
commercial heterosis were recorded in F1 hybrids
FRHW-1 × PSEV3 and its reciprocal, FRHW-2 × FRHW-3, and FRHW-2 × PSEV3 for days
to 50% silking.
At the University of Haripur, 9, 6, 11, and 5
F1 hybrids exhibited negative mid-, better-parent, economic and
commercial heterosis, in which 7, 4, 7, and 3 hybrids
revealed significant heterotic values for days to 50%
silking (Table 5). However, the ranges for various heterosis were -0.92 to -5.04%, -1.18 to -4.76%, -0.59 to
-5.33%, and -0.61 to -3.03%, respectively. The F1 hybrids
FRHW-1 × PSEV3, and FRHW-1 × SWAJK-1 showed maximum negative heterotic effects over mid-, better-parent, economic and
commercial heterosis for days to 50% silking.
For days to 50% silking at ARS, Baffa, Mansehra, 15, 11, 16, and
19 F1 hybrids revealed negative heterosis
after comparing with both mid- and better-parents, commercial OPV and
hybrid, ranged from -0.27 to -9.78%, -0.56 to -7.26%, -0.55 to -9.84%, and
-0.59 to -10.86%, respectively (Table 5). However, 13, 7, 14, and 16 F1
hybrids authenticated their significance for the said trait. The F1 hybrids
FRHW-2 × FRHW-3, and its reciprocal, and PSEV3 × FRHW-3 showed the highest heterosis after comparing with mid-, better-parent,
commercial OPV-Jalal and hybrid for days to 50% silking.
Table 7: Mid-
and better-parents, economic and commercial heterosis
in 5 × 5 maize F1
diallel hybrids for grain yield across
four locations
|
F1
hybrids |
Grain yield |
|||||||||||||||
|
CCRI,
Pirsabak - Nowshera |
University
of Haripur, Haripur |
ARS, Baffa - Mansehra |
ARI, Mingora - Swat |
|||||||||||||
|
MP heterosis (%) |
BP heterosis (%) |
Economic heterosis (%) |
Commercial heterosis (%) |
MP heterosis (%) |
BP heterosis (%) |
Economic heterosis (%) |
Commercial heterosis (%) |
MP heterosis (%) |
BP heterosis (%) |
Economic heterosis (%) |
Commercial heterosis (%) |
MP heterosis (%) |
BP heterosis (%) |
Economic heterosis (%) |
Commercial heterosis (%) |
|
|
FRHW-1 × FRHW-2 |
56.85** |
36.25** |
-14.34** |
-41.81** |
147.51** |
127.93** |
-34.47** |
-43.18** |
55.93** |
41.55** |
-23.58** |
-21.90** |
84.59** |
71.90** |
-13.01** |
-20.95** |
|
FRHW-1 × FRHW-3 |
100.35** |
90.89** |
-2.27 |
-33.61** |
109.67** |
69.79** |
-21.22** |
-31.69** |
116.08** |
113.58** |
-3.72 |
-1.61 |
123.56** |
94.82** |
-1.41 |
-10.40** |
|
FRHW-1 × PSEV3 |
66.13** |
51.21** |
-14.56** |
-41.96** |
88.30** |
43.01** |
-20.77** |
-31.31** |
121.72** |
91.83** |
-15.53** |
-13.68** |
54.10** |
39.88** |
-13.19** |
-21.11** |
|
FRHW-1 × SWAJK-1 |
64.20** |
38.69** |
-6.73 |
-36.64** |
106.60** |
54.90** |
-10.84** |
-22.70** |
175.02** |
150.79** |
34.05** |
36.99** |
114.03** |
89.61** |
24.33** |
12.98** |
|
FRHW-2 × FRHW-1 |
57.48** |
36.80** |
-13.99** |
-41.57** |
197.40** |
173.87** |
-21.26** |
-31.73** |
86.56** |
69.36** |
-8.56** |
-6.56* |
98.57** |
84.92** |
-6.41* |
-14.96** |
|
FRHW-2 × FRHW-3 |
88.94** |
71.40** |
7.76 |
-26.79** |
162.19** |
99.47** |
-7.45* |
-19.75** |
103.19** |
86.42** |
0.65 |
2.85 |
151.25** |
133.82** |
2.06 |
-7.25** |
|
FRHW-2 × PSEV3 |
103.32** |
93.03** |
21.36** |
-17.56** |
147.41** |
77.74** |
-1.53 |
-14.62** |
125.38** |
79.81** |
-2.92 |
-0.79 |
97.10** |
67.86** |
4.18 |
-5.33* |
|
FRHW-2 × SWAJK-1 |
71.68** |
66.08** |
11.70** |
-24.12** |
123.74** |
58.90** |
-8.53** |
-20.70** |
79.99** |
79.09** |
-3.31 |
-1.19 |
78.91** |
49.01** |
-2.29 |
-11.21** |
|
FRHW-3 × FRHW-1 |
91.64** |
82.58** |
-6.52 |
-36.50** |
131.52** |
87.49** |
-13.01** |
-24.57** |
101.44** |
99.10** |
-10.25** |
-8.28** |
103.66** |
77.48** |
-10.18** |
-18.38** |
|
FRHW-3 × FRHW-2 |
88.13** |
70.66** |
7.30 |
-27.11** |
137.60** |
80.76** |
-16.13** |
-27.28** |
68.71** |
54.79** |
-16.43** |
-14.60** |
112.14** |
97.42** |
-13.82** |
-21.69** |
|
FRHW-3 × PSEV3 |
118.60** |
108.32** |
17.72** |
-20.03** |
78.45** |
63.95** |
-9.17** |
-21.25** |
141.28** |
106.70** |
-6.82* |
-4.78 |
116.27** |
73.64** |
7.77** |
-2.07 |
|
FRHW-3 × SWAJK-1 |
90.24** |
67.53** |
12.67** |
-23.46** |
91.32** |
72.77** |
-0.55 |
-13.78** |
105.95** |
89.82** |
1.46 |
3.68 |
72.06** |
35.36** |
-11.25** |
-19.35** |
|
PSEV3 × FRHW-1 |
144.25** |
122.32** |
25.63** |
-14.66** |
159.46** |
97.05** |
9.17** |
-5.34* |
175.56** |
138.40** |
4.98* |
7.28* |
80.74** |
64.06** |
1.82 |
-7.47** |
|
PSEV3 × FRHW-2 |
77.16** |
68.19** |
5.74 |
-28.17** |
103.86** |
46.46** |
-18.86** |
-29.65** |
89.78** |
51.41** |
-18.25** |
-16.46** |
83.78** |
56.52** |
-2.86 |
-11.73** |
|
PSEV3 × FRHW-3 |
131.78** |
120.89** |
24.82** |
-15.21** |
84.65** |
69.65** |
-6.01* |
-18.51** |
140.55** |
106.08** |
-7.10* |
-5.07 |
83.47** |
47.31** |
-8.58** |
-16.93** |
|
PSEV3 × SWAJK-1 |
37.95** |
26.93** |
-14.64** |
-42.01** |
66.07** |
62.96** |
-6.20* |
-18.67** |
197.66** |
138.38** |
27.42** |
30.21** |
81.93** |
77.06** |
16.10** |
5.50* |
|
SWAJK-1 × FRHW-1 |
68.05** |
41.94** |
-4.54 |
-35.15** |
160.08** |
94.99** |
12.24** |
-2.69 |
132.68** |
112.18** |
13.41** |
15.90** |
88.32** |
66.84** |
9.40** |
-0.59 |
|
SWAJK-1 × FRHW-2 |
84.35** |
78.34** |
19.94** |
-18.52** |
138.78** |
69.59** |
-2.38 |
-15.36** |
84.37** |
83.45** |
-0.96 |
1.21 |
70.17** |
41.73** |
-7.07** |
-15.55** |
|
SWAJK-1 × FRHW-3 |
86.54** |
64.27** |
10.48** |
-24.95** |
42.29** |
28.49** |
-26.04** |
-35.87** |
139.67** |
120.90** |
18.07** |
20.66** |
98.12** |
55.86** |
2.20 |
-7.13** |
|
SWAJK-1 × PSEV3 |
77.66** |
63.47** |
9.94* |
-25.32** |
69.23** |
66.06** |
-4.41 |
-17.12** |
145.82** |
96.86** |
5.23* |
7.53* |
56.08** |
51.91** |
-0.39 |
-9.49** |
**, * = Significant at 1% and 5%
level of probability, MP = Mid-parent, BP = Better-parent
Regarding days to 50% silking at ARI, Mingora
- Swat, 16, 9, 13, and 20 F1 hybrids manifested negative mid-,
better-parent, economic and commercial heterosis
ranged from -0.55 to -7.49%, -1.69 to -6.49%, -0.56 to -5.61%, and -1.69 to
-9.19%, respectively (Table 5). However, 13, 9, 9, and 19 F1 hybrids
confirmed their significance for above four types of heterosis,
respectively. Overall, the F1 hybrids FRHW-1 × FRHW-3, FRHW-3 ×
PSEV3, PSEV3 × FRHW1, and FRHW-3 × FRHW-2 performed better and revealed maximum
negative effects for mid-, better-parent economic and commercial heterosis for days to 50% silking.
Days
to physiological maturity
At
CCRI, Pirsabak for days to physiological maturity,
14, 2, 16, and 19 F1 hybrids revealed negative mid-, better-parent,
economic and commercial heterosis, ranged from -0.38
to -3.00%, -0.40% to -1.59%, -1.08 to -10.04%, and -0.32 to -14.81%,
respectively (Table 6). However, for the said trait the
significance level achieved by 11, 1, 16, and 18 hybrids. As compared to
mid-parent values, F1 hybrids PSEV3 × FRHW-3, PSEV3 × SWAJK-1 and
its reciprocal, and for better parent the hybrid FRHW-1 × PSEV3 enunciated
maximum negative heterotic effects. However, by
comparing with commercial OPV - Jalal and hybrid, the promising F1 hybrids
FRHW-2 × FRHW-1, and its reciprocal, and FRHW-2 ×
PSEV3 showed maximum negative heterotic effects.
For days to physiological maturity at the University of Haripur, 9, zero, 13, and 19 F1 hybrids
exhibited negative mid-, better-parent, economic and commercial heterosis, ranged from -0.37 to -2.00%, 0 to 0, -0.40 to
-8.86%, and -1.00 to -14.16%, respectively (Table 6). However, 4, zero, 13, and
19 hybrids attained the level of significance for the said trait. Highest
mid-parent negative heterosis was recorded in F1
hybrids PSEV3 × FRHW-3 and FRHW-2 × FRHW-3. while
three F1 hybrids FRHW-2 × FRHW-1 and its reciprocal, and FRHW-2 ×
PSEV3 were considered as promising for economic and commercial heterosis for days to physiological maturity.
At ARS, Baffa - Mansehra
for days to physiological maturity, 7, one, 14, and 19 F1 hybrids
exhibited negative mid-, better-parent, economic and commercial heterosis, in which 3, zero, 11, and 19 attained the level
of significance, respectively (Table 6). However, the ranges for above four
types of heterosis were -0.31 to -1.36%, 0 to -0.29%,
-0.30 to -7.53%, and -1.17 to -10.50%, respectively. Maximum heterosis over mid-parents was observed in F1 hybrids
PSEV3 × FRHW-3 and its reciprocal, and FRHW-3 ×
SWAJK-1. Promising F1 hybrids FRHW-2 × PSEV3 and FRHW-2 × FRHW-1 and
their reciprocals showed maximum negative economic and commercial heterotic effects for days to physiological maturity.
For days to physiological maturity at ARI, Mingora - Swat, 17, 3, 17,
and 19 F1 hybrids showed negative heterosis
by comparing with mid, better-parent, and commercial OPV - Jalal and hybrid,
ranged from -0.53 to -4.92%, -0.38 to -1.13%, -0.35 to -10.28%, and -1.35 to
-14.81%, respectively (Table 6). The above four types of significant heterosis was seen in 15, 2, 15, and 19 hybrids,
respectively. Promising F1 hybrids FRHW-2 × SWAJK-1 and
its reciprocal, FRHW-2 × FRHW-3 and PSEV3 × FRHW-3 showed the highest negative
mid-parent heterosis. Two F1 hybrids PSEV3
× FRHW-1 and FRHW-1 × SWAJK-1 showed highest negative better-parent heterosis. The promising F1 hybrids FRHW-1 ×
FRHW-2 and PSEV3 × FRHW-2 and their reciprocals exhibited the highest negative
economic and commercial heterosis for days to
physiological maturity.
Grain yield
All
the F1 hybrids manifested significant positive mid- and
better-parent heterosis ranged from 37.95 to 144.25%
and 26.93 to 122.32%, respectively for grain yield at CCRI, Pirsabak
(Table 7). Promising F1 hybrids PSEV3 × FRHW-1, PSEV3 × FRHW-3 and
their reciprocals, and FRHW-2 × PSEV3 showed highest positive heterosis by comparing with mid- and better-parents. For
economic heterosis, 12 F1 hybrids revealed
positive effects ranged from 5.74 to 25.63%, in which 11 hybrids achieved significance
for grain yield. By comparing with commercial OPV-Jalal, maximum economic heterotic effects were recorded in F1 hybrids
PSEV3 × FRHW-1, PSEV3 × FRHW-3, FRHW-2 × PSEV3, and SWAJK-1 × FRHW-2 for grain
yield. For commercial heterosis, none of the F1 hybrids
out-yielded the commercial hybrid for grain yield.
For grain yield at the University of Haripur,
all the F1 hybrids revealed significant positive heterosis
over mid- and better-parents ranged from 42.29 to 197.40% and 28.49 to 173.87%,
respectively (Table 7). However, the highest mid- and better parent positive heterotic effects were observed in F1 hybrids
FRHW-2 × FRHW-1 and its reciprocal, FRHW-2 × FRHW-3, SWAJK-1 × FRHW-1, PSEV3 ×
FRHW-1, and FRHW-2 × PSEV3 for grain yield. Two F1 hybrids SWAJK-1 ×
FRHW-1 and PSEV3 × FRHW-1 exhibited significant positive economic heterosis and proved to be the high yielding hybrids than
check OPV-Jalal for grain yield. For commercial heterosis,
none of the F1 hybrids excelled the commercial hybrid to exhibit positive
heterotic effects.
At ARS, Baffa - Mansehra
for grain yield, all the F1 hybrids revealed significant positive
mid- and better-parent heterotic effects ranged from
55.93 to 197.66% and 41.55 to 150.79%, respectively (Table 7). Maximum mid- and
better-parents heterotic effects were recorded in F1
hybrids PSEV3 × SWAJK-1, FRHW-1 × FRHW-2, and FRHW-1 × SWAJK-1 for grain
yield. For economic and commercial heterosis, 8 and 9
F1 hybrids revealed positive heterotic
values ranged from 0.65 to 34.05%, and 1.21 to 36.99%, respectively in which
six each hybrids attained the significance. By comparing the F1 hybrids
with commercial OPV and hybrid, the F1 hybrids FRHW-1 × SWAJK-1,
PSEV3 × SWAJK-1, and SWAJK-1 × FRHW-3 revealed highest economic and commercial heterosis for grain yield.
For grain yield at ARI, Mingora - Swat, all the F1 hybrids
exhibited significant positive mid- and better-parents heterosis
ranged from 54.10 to 151.25% and 35.36 to 133.82%, respectively (Table 7).
Maximum mid- and better-parent heterotic effects were
observed in F1 hybrids FRHW-2 × FRHW-3, FRHW-1 × FRHW-3, FRHW-3 ×
PSEV3, and FRHW-1 × SWAJK-1. For economic heterosis,
eight F1 hybrids showed positive values ranged from 1.82 to 24.33%,
in which five hybrids attained the level of significance for grain yield.
Maximum economic heterosis was recorded in F1 hybrids
FRHW-1 × SWAJK-1 and its reciprocal, and PSEV3 × SWAJK-1.
Significant positive commercial heterosis was
recorded in two F1 hybrids FRHW-1 × SWAJK-1 and PSEV3 × SWAJK-1 for
grain yield.
For earliness trait i.e., days to tasseling, pollen shedding and silking, the negative heterotic
effects are desirable and favored because of their positive association with
early maturity. The environmental data including temperature, rainfall, and
humidity also confirmed that the hilly areas i.e., ARS, Baffa
- Mansehra followed by ARI, Mingora - Swat were found
cooler than plain areas i.e., CCRI, Pirsabak Nowshera, and University of Haripur,
Khyber Pakhtunkhwa, Pakistan (Fig. 1, 2). Results
further enunciated that due to interaction of genotypes with existing
environmental factors, the F1 hybrids revealed significantly varying
heterotic effects for earliness traits and grain
yield at different locations. Overall, F1 hybrids matured earlier
than parental inbred lines and commercial 'OPV - Jalal' and 'Pioneer hybrid
30K08' in plain areas as compared to hilly areas. On average, the highest negative
heterotic effects were observed in F1 hybrids
at CCRI, Pirsabak - Nowshera
and took fewer days to tasseling, pollen shedding, silking,
and physiological maturity because of high temperature, less rainfall and a
warmer climate, followed by University of Haripur,
and ARI, Mingora, Swat. At ARS, Baffa - Mansehra, the F1 hybrids showed less negative heterotic effects for earliness traits and took more days
to tasseling, pollen shedding, silking, and
physiological maturity due to low temperature, more rainfall and humidity, and
high altitude which make the environment cooler and delayed the flower
initiation and maturity. Overall for earliness traits, majority of the F1
hybrids performed better by showing highly significant negative heterotic effects and taking less days to tasseling, pollen
shedding, silking and physiological maturity as
compared to parental inbred lines and commercial OPV and hybrid at all the
locations. For grain yield, the F1 hybrids surpassed parental inbred
lines by showing significant (P ≤
0.01) positive mid- and better-parent heterosis but
not able to perform better than commercial OPV and hybrid at all the locations.
Discussion
Heterosis refers to the superior
performance of F1 hybrids than their parental inbred lines, standard
cultivars, and commercial hybrids concerning growth and yield traits (Ali et
al. 2019). Although little known about the genetic and molecular basis of heterosis, however, it has been reported that heterosis managed by both dominant and epistatic
gene actions (Khan et al. 2018; Govindaraju
2019). The main target of hybrid crop breeding is to identify parental
genotypes with high genetic diversity that have a high proportion of strong heterosis in F1 hybrids (Kumar et al.
2014, 2019; Liu et al. 2019).
Genotypes, environments (locations) and genotype by environment
interactions revealed significant (P ≤
0.01) differences for earliness traits and grain yield. Significance of these
three major components authenticated that differences might be due to varied
genetic makeup of the maize genotypes and their interaction with varying
environmental factors at different locations. Present study also enunciated
that in proportional contribution to the total sum of squares, larger effects
of environment and genotypes to total variation (G + E + GEI) persuade the
studied traits. Significant differences in genotypes and environments preceded
to various types of desirable negative and positive heterotic
effects under four environments. Significant differences among inbred lines and
F1 populations manifested the choice for exploitation of heterosis for earliness traits and grain
yield in maize across environments (El-Hosary et
al. 2014; Panda et al. 2017; Sajjad et al. 2020). Past
findings revealed significant variations among the maize populations and
environments, and their greater role in proportional contribution total sum of
square studied for earliness and grain yield in distinct environments (Kiani et al.
2015; Ullah et al. 2019). Significant
diversity was observed among maize F1 hybrids for earliness and
grain yield which might be due to their varied genetic background and their
interaction with environment (Nzuve et al.
2014; Kumar et al. 2019).
For earliness traits, the negative heterosis
is desirable because it could be used for the development and production of
early maturing maize hybrids. Overall, the F1 hybrids
performed better by showing significant (P
≤ 0.01) negative heterotic effects by
taking less days to tasseling, pollen shedding, silking
and physiological maturity as compared to parental inbred lines and commercial
OPV and hybrid at almost all the locations. However, at the University of Haripur, minimum number of F1 hybrids showed
negative economic and commercial heterotic effects,
and that varied performance of the maize genotype might be due to diverse
environmental conditions. Greater genetic variability and desirable negative
and positive mid- and better parents heterotic
effects were reported in F1 populations for earliness and yield
traits, respectively in maize under different environments (Ali et al.
2019; Yi et al. 2019). By comparing with mid- and better-parents, and
standard cultivar, F1 maize hybrids exhibited negative heterotic effects of varying magnitudes for earliness
traits and grain yield in varied environmental conditions (Kumar et al.
2014; Rajesh et al. 2014). Negative
economic and commercial heterotic effects were
determined in F1 maize hybrids by comparing with check genotypes
(commercial cultivar and hybrid) under diverse climatic conditions for days to
tasseling, pollen shedding, silking and physiological
maturity (Singh 2015; Khan et al. 2018). Therefore, in genotype by
environment interaction studies, the role of the environment cannot be ignored
during the recommendation of maize genotypes for specific and different
localities. Present results about different types of heterosis
were in line with past findings as reported significant negative heterotic effects in F1 maize populations for
days to tasseling, pollen shedding, silking and
physiological maturity (Ali et al. 2013a, b; Ding et al. 2014; Li et al. 2018). Significant negative standard heterosis was reported in the majority of the maize test
crosses for tasseling, pollen shedding, silking and
other earliness traits (Izhar and Chakraborty
2013; Abrha 2014: Kumar et al. 2019).
Overall, a large number of F1 hybrids revealed significant
negative mid- and better parent, economic and commercial heterosis
for earliness traits at most of the locations except the University of Haripur, Haripur where a small
number of F1 hybrids revealed negative heterosis.
Present also results revealed that parental inbred lines and F1 hybrids
showed a similar tendency in response to environmental factors and both are
donating to the observed genotype by environment interactions for heterosis (Li et al. 2018). Varying magnitudes of
negative mid- and better parents, and standard heterosis
were reported in F1 populations for various earliness traits (Singh
2015; Kumar et al. 2014). Some other past findings also summarized that
varying degrees of negative mid- and better parents heterotic effects were recorded in maize F1 hybrids
for earliness traits (Nethra et al. 2013).
The identified promising F1 hybrids with significant
earliness in flowering and maturity traits (FRHW-2 × FRHW-3, FRHW-1 × SWAJK-1,
and FRHW-3 × FRHW-2), and grain yield (PSEV3 × FRHW-1, PSEV3 × FRHW-3, FRHW-1 ×
SWAJK-1, FRHW-2 × FRHW-3, and FRHW-3 × PSEV3) have greater potential for
developing early maturing and high yielding hybrids for multiple cropping
systems. Past studies revealed varying degrees of heterosis
and heterobeltiosis among in F1 maize
populations for days to male and female flowering and physiological maturity
under different environmental conditions (Ali et al. 2019; Cherchali
et al. 2019). Significant negative
better parent, economic and commercial heterosis were observed in F1 maize hybrids for earliness
traits and physiological maturity in diverse environments (Nethra
et al. 2013; Rajesh et al. 2014). Previous findings revealed that
experimental hybrids were developed with a determined extent of heterosis in respect of maturity and grain yield in maize
(Sharma et al. 2019; Ullah et al. 2017;
2019).
For grain yield, all the F1 hybrids surpassed parental inbred
lines by showing significant (P ≤
0.01) positive mid- and better-parent heterosis,
however, majority of the hybrids were not able to perform better than
commercial OPV and hybrid for economic and commercial heterosis
at all the locations. For commercial heterosis, nine
and two F1 hybrids showed positive heterotic
effects at ARS, Baffa - Mansehra,
and ARI, Mingora - Swat, respectively by comparing with the commercial hybrid.
However, at CCRI, Pirsabak and the University of Haripur, the F1 hybrids cannot compete with
commercial hybrid and showed negative heterotic
effects for grain yield. Results further authenticated that environment has
greater contribution in phenotypic performance of the same genotypes at
different locations result in due to interaction of maize genotypes with
existing environmental factors. Significant mid- and better-parent heterotic effects have been reported in F1 hybrids
by comparing with their inbred lines for yield related traits in maize in
different environments (Khan et al. 2018). In F1 maize
populations, varied values of economic and commercial heterosis
have been reported for grain yield and its attributes in different environments
(Ali 2015, Ali et al. 2018; Shrestha et al.
2018). However, in some other studies, significant mid- and
better parents heterotic effects were reported in F1
maize hybrids for yield related traits (Ali et al. 2013a, b; Singh
2015; Ige et al. 2018). Standard positive heterosis was reported in various studies of F1 maize
cross combinations for grain yield and its components in diverse environments (Izhar and Chakraborty 2013; Nethra et al. 2013). Similarly,
various levels of mid- and better parents and standard heterosis
was reported in F1 maize hybrids for grain yield under different
growing seasons (Kumar et al. 2014, 2019).
Heterosis is considerably influenced by
the genetic background of the genotypes and environmental conditions. Results
further revealed that due to varying levels of soil, temperature, rainfall,
humidity and altitude at four locations, the inbred lines and their F1 hybrids
revealed significant differences in performance through heterotic
effects for earliness and grain yield. Because of high temperature, less
rainfall and warmer climate at CCRI, Pirsabak - Nowshera, the F1 hybrids showed the highest
negative heterotic effects and took fewer days to
tasseling, pollen shedding, silking, and
physiological maturity followed by University of Haripur,
and ARI, Mingora, Swat. However, due to low temperature, more rainfall and
humidity, and high altitude at ARS, Baffa located in
a hilly area, make the environment cooler and the same maize genotypes took
more time to flower and maturity, resulting in less magnitude of negative heterotic effects.
Present results also authenticated that extent of heterosis
is not an inherent trait of a specific hybrid, but its appearance depends on
the trait measured and the environment where the study was carried out.
Promising F1 hybrids FRHW-2 × FRHW-3, FRHW-1 × SWAJK-1,
and FRHW-3 × FRHW-2 showed significant negative heterotic
effects for earliness traits. For grain yield across the four environments, F1
hybrids PSEV3 × FRHW-1, PSEV3 × FRHW-3, FRHW-1 × SWAJK-1, FRHW-2 ×
FRHW-3, and FRHW-3 × PSEV3 showed best performance with significant positive heterotic effects. On average, F1 hybrids took
less days to flowering and maturity than their parental genotypes in plains as
compared to hilly areas which might be due to high temperature (Fig. 1 and 2).
Maturity duration of maize increased in hilly area than that in plains, and
substantially increased the grain yield which might be due low temperature and
cooler climate (Singode et al. 2014). Early maturing and high yielding genotypes could help
in adapting maize to diverse climatic conditions, and to escape the crop from
drought stress due to warmer climate that occurs during the grain-filling stage
in late season maize crop (Ali et al. 2019; Fromme
et al. 2019; Yi et al. 2019). These promising F1 populations
could be used in future breeding programs for the development of early maturing
and high yielding maize hybrids/cultivars.
Conclusion
Overall,
maize F1 hybrids excelled the parental inbred lines and check
genotypes ('OPV - Jalal' and 'Pioneer hybrid 30K08') by showing significant
negative heterotic effects for earliness traits while
positive values for grain yield across environments. Promising F1 hybrids
FRHW-2 × FRHW-3, FRHW-1 × SWAJK-1, and FRHW-3 × FRHW-2 showed significant
negative heterotic effects by comparing with parental
inbred lines and check genotypes across locations. However, F1 hybrids
PSEV3 × FRHW-1, PSEV3 × FRHW-3, FRHW-1 × SWAJK-1, FRHW-2 × FRHW-3, and FRHW-3 ×
PSEV3 showed significant positive heterotic effects
and best mean performance for grain yield across environments. Therefore, these
promising F1 hybrids could be used in the development of early
maturing and high yielding maize hybrids/cultivars. Based on present finding,
the hybrid crop production is recommended for hilly as well as plain areas in
Pakistan.
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