ABSTRACT
Twenty hybrid maize genotypes were evaluated in Umuahia Abia state, to study their yield, yield components and proximate composition. The genotypes were separated into two (yellow and white genotypes) and each group laid out as a separate experiment for two years from June- November 2014 and 2015. In each experiment, the genotypes were laid out in a randomized complete block design replicated three times. Genotypes did not show significant differences (p> 0.05) among themselves for all Agronomic attributes in both experiments; however, genotypes exhibited significant variability (p< 0.001) for most yield traits and for insects, disease and rodents score parameters. There was significant genotype x environment interactions for most traits. Broadsense heritability and genetic advance for number of plants harvested/plot, shelled grain weight, ear height, ear aspect, rust, ear rot, blight and stalk lodging were high for white maize genotypes evaluated in 2015, but only streak was high in 2014; likewise, for the yellow maize, only cob length was high in 2014, while others, including those in 2015 were low. Correlation for days to tasselling, ear aspect traits, plant aspect, stem borer, insect damage, blight, rodents damage and ear rot were high and significant in the white and the yellow maize genotypes. For proximate composition, crude fat, moisture content and dry matter had high heritability for white maize in 2015, low in all traits of both 2014 white maize genotypes and those of yellow maize genotypes in 2014 and 2015. There was no correlation of any of the proximate components with seed yield. Results also showed that the range of proximate composition obtained for both white and yellow genotypes were: crude protein 9.54-11.18 for yellow, 10.70-1.78 for white, crude fat 2.15-5 for yellow, 4.76-5.05 for white, moisture content 12.3014.33 for yellow, 10.64-16.45 for white, Ash 0.97-1.46 for yellow, 1.16-2.29 for white, crude fibre 1.36-1.75 for yellow, 1.75-1.97 for white, carbohydrate 68.35- 70.89 for yellow, 67.92-70.77 for white and dry matter 85.68-87.70 for yellow, 86.69-89.42 for white. Generally, yield was higher in 2014 than 2015, the yields obtained from both experiments showed that the hybrids far exceeded those of their local checks, that is oba 98 and Oba supper2. From the result, some outstanding genotypes were selected for performance in yield. For the white maize genotypes, we had, DKC 21-47 with field weight 2.8t/ha, shelled grain weight 2.5t/ha and seed weight of 2t/ha. For the yellow maize genotypes, we had DKC91-44 with field weight 5t/ha, shelled grain weight 4,t/ha and seed weight of 2.3t/ha. Yields from the yellow maize far exceeded those obtained from white maize. The Yellow maize genotypes were more tolerant to insect pest, disease and animal damage than the white. Result suggested that the test population may have been bred from identical parents. It was concluded that further improvement of the white genotypes be made by incorporating factors that will increase tolerance/ control to traits like ear rot, streak, blight and rodents damage to make it suitable for the Umudike/ S/E ecological zone.
TABLE OF CONTENTS
Title i
Certification ii
Declaration iii
Dedication iv
Acknowledgements v
Table of contents vi
Lists of tables ix
Lists of plates xiii
List of appendices xiv
Abstract xiv
CHAPTER
1
Introduction 1
CHAPTER 2
2.0 Literature
Review
2.1 Origin,
Domestication and Distribution of Maize 5
2.2
Morphology and Physiology of the Maize Plant 6
2.3 Agronomy of the Maize Plant 7
2.4 Economic Importance of Maize 9
2.5 Production Constraints 10
2.6 Poor Agronomic Practices 17
2.7 Trends in Maize Breeding
in Nigeria 18
2.8 Analysis of Yield
Components of Hybrid Maize 20
2.9 Analysis of Proximate
Composition of Hybrid Maize 23
2.10 Cytogenetics of
Maize 25
2.11 Genetic Variability and
Heritability in Maize 27
CHAPTER
3
3.0 Materials and Methods 30
3.1 Experimental Site 30
3.2 Genotypes 33
3.3 Land Preparation 35
3.4
Soil Sample for Analysis 35
3.5 Experimental Design and Layout 35
3.6 Analysis of Yield and Yield Components 37
3.7 Statistical Analysis 41
CHAPTER 4
4.0 Results and Discussion 41
Experiment 1. Evaluation of White Maize Genotypes Studied
in
2014 and 2015 Cropping Seasons 41
4.1 Agronomic Characteristics of White Maize
Genotypes Grown in 2014
and
2015 Cropping Seasons 41
4.2 Proximate
Composition of White Maize Genotypes in Umuahia
69
4.3
Inter-Relationships between Yield Attributes
and Seed Yield in White Maize
Genotypes in 2014 and 2015 Cropping
Seasons 76
4.4 Inter-Relationships between Agronomic Attributes
and Seed Yield
of White Maize Genotypes in 2014 and 2015
Cropping Season 80
4.5 Inter-Relationships between insects, Diseases
and Rodents Score with
Seed Yield 82
4.6 Inter-Relationships between Proximate Composition
and Seed Yield in White Maize Genotypes 85
Experiment 2. Evaluation of Yellow Maize
Genotypes Studied in
2014 and 2015 Cropping Seasons 87
4.7 Agronomic Characteristics of Yellow Maize
Genotypes Grown in 2014
and 2015 Cropping Seasons 87
4.8 Proximate Composition of Yellow Maize
Genotypes in Umuahia 115
4.9 Inter-Relationships between Yield Attributes
and Seed
Yield
in Yellow Maize Genotypes in 2014 and 2015 Cropping Seasons 121
4.10 Inter-Relationships between Agronomic Attributes
and Seed Yield
of Yellow Maize Genotypes in 2014 and 2015
Cropping Season 124
4.11 Inter-Relationships between Insects, Diseases
and Rodents
Score Attributes and Seed Yield 127
4.12 Inter-Relationships between Attributes of
Proximate Composition
and Seed Yield 130
CHAPTER 5
5.0 Discussion, Conclusion and
Recommendation 146
REFERENCES 148
APPENDIX 157
LISTS OF TABLES
2.1 Proximate composition of some selected maize varieties in Ibada
3.1 Characteristics of the location of the field, World Bank Housing
Estate, Umuahia North LGA, Abia state
3.2 Agrometeorological data of the experimental
location in 2014 and 2015
3.3
Names, grain colour and sources of the 20 maize genotypes.
3.4 Physico-chemical properties of soil of
the experimental location in 2014 and 2015 cropping
seasons
4.1 Means (¯x) for various Agronomic attributes of white maize
studied in 2014 and 2015 cropping
seasons
4.2 Values of sums of squares (SS), mean squares (MS) and variance
ratios (VR) for Agronomic attributes of white maize genotypes in 2014
and 2015 cropping seasons
4.3
Genotypic and phenotypic correlation coefficients forAgronomic attributes of white maize genotypes in 2014 and 2015 cropping seasons.
4.4 Means (¯x) for various yields attributes of
white maize genotypes studied in 2014 and
2015 cropping seasons
4.5 Values of sums of squares (SS), mean squares (MS) and
variance ratios (VR) for plant yield attributes of white maize genotypes in 2014 and 2015
cropping seasons
4.6 Genotypic and phenotypic correlation coefficients for yield of white
maize Attributes in 2014 and 2015 cropping seasons
Table
4.7 Means (¯x) for insects, disease and rodents
damage scores for white maize in 2014 and
2015 cropping seasons
4.8 Values of sums of squares (SS), mean squares (MS) and
variance ratios (VR) for plant
attributes of white maize genotypes for
insect, disease and rodents scores in 2014
and 2015 cropping seasons
4.9 Genotypic
and phenotypic correlation coefficients of insects, disease and
rodents damage scores
in white maize
studied in 2014 and 2015 cropping seasons
4.10 Means
(¯x) for proximate analysis of various attributes of white maize studied in 2014 and 2015 cropping seasons.
4.11 Values of sums of squares (SS), mean squares (MS) and
variance ratios (VR) for proximate
composition of white maize genotypes in 2014 and 2015 cropping seasons
4.12 Genotypic and phenotypic
correlation coefficients of proximate
composition of white
maize genotypes in 2014 and
2015 cropping seasons
4.13 Correlation
coefficients for the relationship between seed yield and yield components in white maize genotypes in 2014 and 2015 cropping seasons
4.14 Correlation
coefficients for the relationship between seed yield and Agronomic attributes in white maize genotypes in 2014 and 2015 cropping seasons
4.15 Correlation
coefficients for the relationship between seed yield and insects, diseases
and rodents scores in
white maize genotypes 2014 and 2015 cropping seasons
4.16 Correlation
coefficients between yield and proximate
composition attributes in white maize genotypes in 2014 and
2015 cropping seasons.
4.17
Means (¯x) for various Agronomic attributes of yellow
maize studied in 2014 and 2015
cropping seasons.
4.18 Values of sums
of squares (SS), mean squares (MS) and variance ratios (VR) for Agronomic plant attributes of yellow maize genotypes in 2014 and 2015 cropping seasons.
4.19 Genotypic and phenotypic correlation coefficients of Agronomic attributes of yellow maize genotypes in 2014 and 2015 cropping seasons.
4.20 Means (¯x) for various yield attributes of yellow maize
studied in 2014 and 2015 cropping
seasons.
4.21
Values of sums of squares (SS), mean squares (MS) and
variance ratios (VR) for plant
yield attributes of yellow maize
genotypes in 2014 and 2015 cropping seasons.
4.22
Genotypic and phenotypic correlation coefficients of yellow maize
yield attributes in 2014 and 2015 cropping seasons.
4.23 Means (¯x) of scores for insects, disease and rodents
damage of yellow maize studied in 2014
and 2015 cropping seasons.
4.24 Values of sums of
squares (SS), mean squares (MS) and variances ratios (VR) for insects, disease and rodents damage for
plant attributes of yellow maize genotypes in 2014 and 2015 cropping seasons.
4.25 Genotypic and phenotypic correlation coefficient of
insects, disease and rodents damage score in yellow maize 2014 and 2015 cropping seasons.
4.26 Means (¯x) for proximate composition of yellow maize
studied in 2014 and 2015 cropping
seasons.
4.27
Values of sums of squares (SS), mean squares (MS) and
variance ratios (VR) for proximate
composition of yellow maize genotypes in 2014 and 2015 cropping seasons.
4.28 Genotypic and phenotypic correlation coefficients
of proximate composition of yellow
maize genotypes in 2014 and 2015 cropping seasons.
4.29 Correlation coefficients between seed
yield and agronomic characteristics in yellow maize genotypes in 2014 and 2015 cropping seasons.
4.30
Correlation coefficients between
seed yield and yield components in yellow maize genotypes 2014 and 2015 cropping
seasons.
4.31
Correlation coefficients between seed yield and insects, disease and rodents damage scores of yellow maize genotypes in 2014 and
2015 cropping seasons.
4.32 Correlation coefficients between seed
yield and proximate composition in yellow maize genotypes 2014 and
2015 cropping seasons.
LISTS OF PLATES
1 Cross section of white maize genotypes; (a)
OBA 98 (b)DKC 21-47 (c)DKC 80-53 (d)
DKC 80-31
2 Cross section of white maize genotypes; (a)
DKC 80-33(b) DKC 90-53 (C) DKC90- 89 (d) DKC 80-73.
3
Cross section of white/Yellow
maize genotypes; (a) DKC 234(b) DKC 777 (C) DKC91-45 (d) DKC 81-44.
4
Cross section of Yellow maize genotypes; (a) DK 008 (b) DKC 70-74 (C)900MGOLD (d) DOUBLE
5
Cross section of Yellow maize
genotypes; (a) DKC 91-44(b) PRABAL (C)OBA SUPPER (d) ALLROUNDER
6
Cross section of diseases and
insects effect in the field (a) Streak (b) Rust (C) Blight (d) Stem borer
7
Cross section of maize
experimental fields and disease effect (a) experimental field for white maize genotypes (b)
experimental field for yellow maize genotypes (C) Downy mildew (d) Curvulera
CHAPTER
1
INTRODUCTION
Maize (Zea mays Linn) in the family Poaceae is one of the most important
cereals in sub-Saharan Africa (Iken and Amusa, 2004). Maize is a multi-purpose
crop and provides food and fuel for man and feed for animals. The grains have
high nutritional values and are used as raw material for manufacturing and for
industrial purposes (Afzal et al., 2009). Information on maize nutritional
value will guide in nutritional planning. The best way of obtaining its
nutritional value is through the study of its proximate composition.
Various studies have been carried out on proximate composition of
open pollinated and hybrid maize varieties. It is reported that maize contains
protein, starch, ash, fat, sugar, pentose, vitamins and amino acids. Some of
them have protein content as high as 13.5% and lysine 3.67%, tryptophan 0.87% and
vitamin A-carotenoids (Oloyin maize),
(Iken and Amusa, 2004; Olakojo, 2014).
The important features that
distinguish maize are its wide adaptability, which is the reason behind the
rapid spread in its cultivation worldwide.
Maize grows well in the different agro-ecological zones in Nigeria. Philips et al., (2000) have reported maize
adaptation rates of 18-52% in some states in the northern guinea savanna, where
maize was hardly grown in the 1970s. However, most farmers grow one crop of
maize per year, a practice which reduces effective potential land utilization.
Obi, (1991), Iken and Amusa,(
2004) reported that maize has high versatility, which is why, it is gradually
replacing traditionally grown cereals such as sorghum and millet, particularly
in the northern savanna agro-ecological zones. This character is established in
its high yield/per unit area, husks protection against birds and rain, fairly
easy to weed as well as possession of a good competitive ability with weeds,
because of its rapid vertical growth (Onwueme and Singha, 1991; Otung, 2014).
Maize also has high diversity which
is why we have many varieties in circulation even among the local farmers.
The ten outstanding maize varieties currently
available and in circulation in Nigeria’s maize seed supply system are, sammaz 14 ( obatampa), sammaz 11 ( AC 97 TZL
COMP 1-W), sammaz 13 (TZE E-Y), sammaz
12 (TZE E-W), 2000 SYN-W-STR, 99 TZE E-Y-STR, EV 99 DT-W-STR, EV 2000 DT-Y-STR,
TZE COMP3 DT and ACR POOL 16 DT STR ( Ajeigbe et al., 2009).
Recently, I.A.R.&T Ibadan in
collaboration with IITA Ibadan, released ten (10) maize varieties, IFE MAIZE
HYB-1-W, IFE MAIZE HYB-2- W, IFE MAIZE HYB-3-Y, IFE MAIZE HYB -4- Y, IFE MAIZE
HYB -5- W and IFE MAIZE HYB- 06, BR 9943 DMR -W- SBR OP, BR9928 DMR-Y, ILE 1-
OB- W (mayowa), and ART -98 –SW6 –OB –W (Faralokun). The first six are hybrid maize varieties
while the last 4 are open pollinated, they possess varying nutritional,
physiological, yield, and maturity date characteristics and for multi-purpose
use, with the view to improving yield
and nutrition of both man and livestock (Olakojo, 2014).
Apart from the official ones
currently in circulation, some maize varieties have been bred and released
based on specific consumer preferences. The varieties developed are varied in
grain color (white and yellow), endosperm characteristics (flint, dent,
floury), cob shape and size, diseases and pests tolerance, maturity dates as
well as nutritional qualities. Those ten
released varieties meet the major interests of the farmers for each ecological
zone, as well as the Nations “high yield” target (increased production).
However, despite the large land mass
allotted to agriculture and the hectarage found suitable to use as arable land, (that can suite maize
cultivation), production per hectare is still very low, about 1.3t/ha compared
to 8.6t/ha in developed countries (IITA, 2009).
This means that, domestic supply has not been able to match with the
demand. According to Mohammed and Zakiya (2014), yield is considered as a
complex inherited trait. One of the most important tasks in the cultivation of
maize is the introduction of hybrid maize in 1981, the hybrid maize varieties are
more tolerant to weather stress, soil factors, diseases and pests and their
yields far exceeds those of the open pollinated especially in the southeastern
region, where maize cultivation used to be once in a year due to the weather
conditions. Shull, (1908) observed that inbred lines of maize
showed general deterioration in yield and vigor, but hybrids between two inbred
immediately and completely recovers, so that, most of the time their yield
exceed that of varieties from where they
were derived.
Hybrid maize projects have made a lot
of impact in Nigeria even though most farmers do not have access to it due to
its supply system, based on the fact that, due to protection of breeders rights
and loss of hybrid vigor, they are mostly bred in such a way that they cannot
be replanted after the first harvest, rather farmers must re- purchase from the
breeder at each subsequent planting. A system that does not go well with the
traditional seed supply systems and local farmers in Nigeria who will prefer to
replant from their previous turnover.
However, farmers that have tested the yield advantages, especially
the fact that it thrives well at off seasons, with its yield advantage which
is sufficiently large enough to attract
the attention of the farmer, have held on to these hybrid varieties.
The primary objective of maize breeding programs is to increase
production per unit area with grain yield being the most important trait. According
to Viola et al., (2003), maize shows
an orderly sequence of development of its yield components, that is, the ears
per plant, grains per row, rows per ear and grain.
Therefore an appropriate knowledge of such interaction between grain
yield and its contributing components can significantly improve the efficiency
of breeding programs using appropriate selection indices.
Saif-ul-Malook et al.,
(2014) wrote that grain yield is a quantitative trait, and depends on many
other factors like plant height, plant vigor, efficient water availability,
optimum nutrient availability, enhanced solar radiation interception and
conversion of solar to chemical energy. The inability of maize farmers to
consider most of these necessary factors has become part of the reasons for low
production level and as such, maize importation into Nigeria was very high,
especially among the poultry farmers (Olakojo et al., 2007).
Other
reasons for this low yield has been attributed to the seed system in Nigeria,
that is, farmers collect seeds for planting from unknown sources, instead of
newly improved varieties. Olakojo et al.,
(2001) also pointed out other reasons for low yield as, maize diseases of the
tropical environment like, streak, downy mildew, rust, blight, leaf spot, ear
or stalk rot and brown leaf spot. Pests include stem borer and striga
parasitic weeds such as striga hermontica.
This challenge has aroused a lot of
concern at national, regional and international levels. In the bid to solve
these problems, the government of Nigeria has sponsored many maize breeding
programs. Some of the programs include,
doubling maize program, nationally coordinated maize program etc.
The
inception of the International Institute of Tropical Agriculture (IITA) is for
them collaborates with other Research Institutions and Universities including
other seed companies, for maize improvement, breeding and release of new
varieties. The varieties bred must be tested in various agro-ecological zones
for adaptability, yield potentials and disease/pest reactions, before they can
be released to farmers, (Olakojo and Iken, 2001) this is also part of
government effort to improve maize breeding. Iken and Amusa, (2004) have noted
that improved high yielding maize varieties can express their full genetic
potential only when offered optimum management resources.
This study, therefore seeks to
evaluate the yield, yield components and proximate composition of some hybrid
maize genotypes, in Umuahia, Abia state.
The specific objectives are;
1.
To study the yield and
yield components of white and yellow type hybrid maize breeding populations in
Umuahia
2.
To evaluate the proximate
composition of the hybrid maize populations.
3.
To access the level of
tolerance of the hybrid maize genotypes to various diseases and pests under
natural conditions.
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