ABSTRACT
Twenty fluted pumpkin (Telfairia occidentalis) accessions were grown in two locations (Umudike and Obio Akpa) in randomized complete block design during the rainy season of 2017 to evaluate the variability in yield, yield components and nutrient content. The following data; number of leaves, number of branches, vine length, fresh leaf weight and marketable yield were collected at 8, 10, 12 and 14 WAP. Data obtained for each trait were averaged and mean values used for statistical analysis. The analysis of variance (ANOVA) showed significant variation (p<0.05) in number of branches/plant, number of leaves/plant, length of vine/plant (cm) in Umudike and no significant variation (p>0.05) in the same traits in Obio Akpa. Although not significant (p>0.05), genotype ACC6 produced the highest marketable yield (3047t/h) and the highest leaf yield (1215t/h) at Umudike while ACC11 produced the highest marketable (2368t/h) and the highest leaf yield (1781t/h) at Obio Akpa. The mean squares of analysis of variance for the two locations revealed a significant (p<0.001) genotype, error and variance ratios for the nutritional and anti – nutritional traits, which indicated the presence of wide genetic diversity among the genotypes and potentials for exploiting the observed diversity for the improvement of Telfairia occidentalis. The estimates genotypic variances were close to each other at both locations for all the traits. These lower error variances indicated that the genotypic component was the major contributor to the total variance for these characters in the two locations. In Obio Akpa, moderate broad sense heritability and genetic advance was observed, which indicated that the influence of environmental variance is more than genetic variance. Correlation analysis showed that number of branches/plant, number of leaves/plant, length of vine/plant (cm), marketable yield, and leaf yield were significantly and positively correlated with the total leafy yield per hectare (t/h). The highest positive correlation with total leaf yield per hectare (t/h) (r= 0.741**) was recorded in vine length/plant (cm) at 14 WAP. Path analysis indicated that number of leaves/plant at 14 WAP and number of branches/plant at 12 WAP imparted significant direct influence on total marketable yield and hence these traits could be used as selection criteria for improvement of marketable yield. Principal Component Analysis (PCA) was employed to evaluate the patterns of variation in these genotypes. The first two axes of the PCA captured 98.26% of the total variance. The dendrogram grouped the accessions into four clusters, suggesting that, nearly all the fluted pumpkins cultivated in Akwa Ibom State are mainly from four genotypes.
TABLE
OF CONTENTS
Title page i
Declaration ii
Certification iii
Dedication iv
Acknowledgements v
Table of
Contents vi
List of Tables vii
List of Figures viii
Abstract ix
CHAPTER 1: INTRODUCTION 1
CHAPTER 2: LITERATURE REVIEW 7
2.1 Production Trends of Fluted Pumpkin in
Nigeria/West Africa 7
2.2 Botany of Fluted Pumpkin 8
2.3 Agronomy of Fluted Pumpkin
9
2.4 Propagation of Fluted Pumpkin
11
2.5 Pests and Pathogens of Fluted
Pumpkin
11
2.6 General Health Benefits of Telfairia occidentalis 11
2.7 Genetic Improvement of Fluted Pumpkin
13
2.8
Interrelationships between Yield and Associated Traits in Fluted Pumpkin 14
CHAPTER 3: MATERIALS AND METHODS 16
3.1 Location and Site Characteristics
16
3.2 Soil Sampling and Meteorological Data
Analysis of Experimental Sites 16
3.3 Experimental Materials and Source
18
3.4 Design of Experiment and
Experimentation
19
3.4.1 Experiment 1: Germination
studies
19
3.5 Experiment 2: Nutrient and Anti-
nutrient Contents Analysis 19
3.5.1 Sample treatment 19
3.5.2 Proximate analysis 19
3.5.3 Anti- nutrient analysis
22
3.5.4 Vitamins and mineral analysis 24
3.6 Data Collection
26
3.7 Statistical Analysis 26
3.8 Estimation of Genetic Components
27
CHAPTER 4: RESULTS AND DISCUSSION 28
4.0 Results
28
4.1 Soil Physicochemical Properties and
Meteorological Data of Experimental Sites 28
4.2
Growth and Yield Studies in some Genotypes of Telfairia occidentalis Grown at
Umudike and Obio Akpa
31
4.2.1 Growth studies
31
4.2.1.1 Number of branches/plant 31
4.2.1.2 Number of leaves/plant 34
4.2.1.3 Length of vine/plant (cm) 37
4.2.2
Yield of the Telfairia occidentalis
grown at Umudike and Obio Akpa
at 8, 10, 12
and 14 WAP
40
4.2.2.1 Marketable yield (t/h) 40
4.2.2.2 Leafy yield (t/h) 40
4.3
Nutritional Composition of some Genotypes of Telfairia occidentalis
Grown at Umudike and Obio
Akpa 43
4.3.1 Proximate composition 43
4.3.2 Mineral composition 46
4.3.3 Vitamins and carotene composition 49
4.3.4 Anti – nutrients composition 52
4.4 Genetic Component Analyses of the
Nutrient Composition 55
4.5 Inter – relationships between Yield
and Associated Traits 63
4.5.1 Correlation studies 63
4.5.2 Path coefficient analysis 65
4.5.3 Principal component analysis (PCA) 67
4.5.4 Cluster analysis 69
4.6 Discussion 73
CHAPTER 5: CONCLUSION AND RECOMMENDATIONS 87
5.1 Conclusion 87
5.2 Recommendations 87
References 89
LIST
OF TABLES
3.1: Experimental
materials and source
18
4.1: Soil
physicochemical properties of the experimental sites in 2017 29
4.2: Rainfall
distribution in Umudike and Obio Akpa in 2017 30
4.3: Number
of branches/plant of some Telfairia occidentalis genotypes grown at Umudike at 8, 10, 12
and 14 WAP
32
4.4: Number
of branches/plant of some Telfairia occidentalis genotypes grown at
Obio Akpa at 8, 10, 12 and 14 WAP
33
4.5: Number
of leaves/plant of some Telfairia occidentalis genotypes grown at Umudike at 8,
10, 12 and 14 WAP
35
4.6: Number
of leaves/plant of some Telfairia occidentalis genotypes grown at Obio Akpa at
8, 10, 12 and 14 WAP
36
4.7: Length
of vine/plant (cm) of some Telfairia occidentalis genotypes grown at Umudike at 8,
10, 12 and 14 WAP
38
4.8: Length
of vine/plant (cm) of some Telfairia occidentalis genotypes grown at Obio Akpa at
8, 10, 12 and 14 WAP
39
4.9: Marketable
yield (t/h)/ Leafy yield (t/h) of some Telfairia
occidentalis genotypes grown at
Umuudike
41
4.10: Marketable
yield (t/h)/ Leafy yield (t/h) of some Telfairia
occidentalis genotypes grown at
Obio Akpa
42
4.11: Table of
means showing the proximate content of Telfairia
occidentalis genotypes grown at
Umudike
44
4.12: Table of
means showing the proximate content of Telfairia
occidentalis genotypes grown at
Obio Akpa
45
4.13: Table of
means showing the Minerals content of Telfairia
occidentalis genotypes grown at
Umudike
47
4.14: Table of
means showing the Minerals content of Telfairia
occidentalis genotypes grown at Obio
Akpa
48
4.15: Table of
means showing the Vitamins and Carotene content of Telfairia occidentalis genotypes grown at Umudike 50
4.16: Table of
means showing the Vitamins and Carotene content of Telfairia occidentalis genotypes grown at Obio Akpa 51
4.17: Table of
means showing the Anti - nutrients content of
Telfairia occidentalis genotypes grown at Umudike
53
4.18: Table of
means showing the Anti - nutrients content of Telfairia occidentalis genotypes grown at Obio Akpa 54
4.19: Mean
squares and variance ratio obtained in analysis of variance of proximate,
minerals, vitamins and carotene, and anti - nutrient compositions of
twenty genotype of
T. occidentalis leaves grown at
Umudike 57
4.20: Mean
squares and variance ratio obtained in analysis of variance of proximate,
minerals, vitamins and carotene, and anti - nutrient compositions of
twenty genotype of
T. occidentalis leaves grown at Obio
Akpa
58
4.21: Phenotypic,
genotypic and error of variances for proximate, minerals, vitamins and
carotene, and anti – nutrients compositions of twenty genotypes of Telfairia occidentalis leaves grown at
Umudike 59
4.22: Phenotypic,
Genotypic and Error of variances for proximate, minerals, vitamins and
carotene, and anti – nutrients compositions of twenty genotypes of Telfairia occidentalis leaves grown at
Obio Akpa
60
4.23: Phenotypic
coefficient, Genotypic coefficient and Environmental coefficient of variations,
Broad Sense Heritability and Genetic
Advance of proximate, minerals, vitamins and carotene and anti –
nutrients compositions of twenty genotypes of Telfairia occidentalis leaves grown at Umudike
61
4.24: Phenotypic
coefficient, Genotypic coefficient and Environmental coefficient of variations,
Broad Sense Heritability and Genetic
Advance of proximate, minerals, vitamins and carotene and anti –
nutrients compositions of twenty genotypes of Telfairia occidentalis leaves grown at Obio Akpa 62
4.25: Correlation
coefficient between different agronomic and yield traits 64
4.26: Path
coefficient analysis (direct, indirect and residual effects) of agronomic
traits on total marketable yield of T.
occidentalis
66
4.27: Eigenvector
values for principal components using agronomic traits of Telfairia occidentalis
68
4.28: Cluster
means for eight traits in twenty genotypes of Telfairia occidentalis 70
LIST
OF FIGURES
1: Scatter
plot
71
2: Dendrogram
72
CHAPTER 1
INTRODUCTION
Fluted pumpkin (Telfairia occidentalis Hook F.) is a leafy vegetable that belongs
to the Cucurbitaceae family. The two
main species in the genus are Telfairia occidentalis
and Telfairia pedata. Although perennial in nature, it is grown as
an annual (Ogbonna, 2009). It is a climber and there is need for staking so
that the tendril curls or it’s allowed to sprawl over the ground. It is known
to be a long sprawling plant that can grow up to ten (10) metres in length or
more, with a ramifying root system in the top surface of the soil. The angular, glabrous stem, becomes fibrous
when old (Akoroda, 1990).
Fluted pumpkin is a dicotyledonous plant,
originated from tropical West Africa (Schippers, 2000). It is indigenous to
Nigeria and is widely cultivated in the wet coastal areas of Tropical West
Africa, particularly in Benin, Cameroon, Ghana, Nigeria and Sierra Leone. This leaf
vegetable is commonly cultivated in the Southeastern Nigeria (Odiaka et al.,2008). However, it is gradually
gaining acceptance in the North Central, where there is increase in its
cultivation by small farm holders as a source of income (Ndor et al., 2013).
Telfairia
occidentalis is a very important leafy vegetable
crop which is known for its high nutritional, medicinal and economic value
(Akoroda, 1990; Ehiagbonare, 2008). In ranking, it is among the three most
widely consumed leaf vegetables at homes and in restaurants across Nigeria
(Abiose, 1999).
In recent time, it has been discovered
that fluted pumpkin has the potential of protecting people from devastating
high blood pressure, cholesterol and diabetes (Ugwu et al., 2000). The tender shoot and leaves of the plants are used for
cooking of soup because of its pleasant taste but most importantly, is the
nutritional benefits of blending fluted pumpkin seeds into wheat flour for
bread making (Giami, 2003). The processed seeds can be fermented into ‘ogiri’ which
is a useful condiment for cooking of soup and sauce or it can be eaten whole (Asiegbu,
1987). The fruit pulp, which consists of 64% of the entire fresh fruit weight,
can be used as feedstuff for livestock (Essien et al., 1992); (Egbekan et
al., 1998). The pectin constituent of the pulp (1.0%) has been used in the preparation
of marmalade (Egbekan et al., 1998). Telifaira occidentalis has large seeds
which weigh 80 times heavier than melon seeds (0.15g- 12.50g), and 55% of the
weight of the dry seed kernel constitutes high quality non-drying oil. The
increasing relevance of fluted pumpkin seeds and its oil as an important
industrial raw material is creating International trade opportunities for countries
where they are cultivated. The high content of oil makes it a prospective source
of raw materials for the vegetable oil industries in Nigeria, for making
margarine and these attest to the significant increase in its production in
Nigeria (Odiaka et al., 2008). There
is an increasing high demand for fluted pumpkin seeds by nursing mothers due to
their lactation - promoting properties, which is as a result of the high
concentration of iodine, essential fatty acids and poly unsaturated fatty
acids. The oil from the seed is effective for hair treatment as it enhances
luster and hair growth (Bird, 2003). The Telfairia
occidentalis plants, according to reports, can be used in bioremediation of
heavy polluted soils (Obute et al.,
2001).
Telfairia
occidentalis has a creeping growth habit that
spreads across the ground to produce an efficient cover to the ground against
erosion (Horsfall and Spiff, 2005) and produces large fruits with many large
seeds. It is a diploid species 2n = 24 (Ajayi et al., 2006). It is a dioecious plant that has male and female
flowers borne on different plants (Okoli and Mgbeogwu, 1983). Anthesis occurs
earlier in the male plant than in the female plant (Akoroda and Adejoro, 1990).
There are more than 800 open male flowers to single opened female flower and
male flowers open in the evening. About 10 – 15% of a given female population
usually flower and the level of abortion is relatively high (Ajayi et al., 2006). Each plant may set up to
six fruits, but usually one large and one or two medium sized fruits may
eventually be carried till maturity. Even up till date, various attempts made
at finding suitable markers for accurate sexual identification of seeds or seedlings
early during growth have been proven abortive (Asiegbu, 1985. Emebiri and
Nwufo, 1996).
Ajayi et
al., (2006) suggested that, the crop is an endangered species and the
genetic diversity is valuable in crop breeding programme, as this will help in the
identification of diverse parental combinations to create segregating progenies
with maximum genetic variability (Barret and Kidwel, 1998) and facilitate
introgression of desirable genes from diverse germplasm into available genetic
base (Thompson et al., 1998).
Genetically diverse and geographically isolated lines may generate a wide range
of variation when brought together (Khantun et
al., 2010). Knowledge of genetic diversity among existing cultivars of any
crop is crucial for the long term success in breeding programme and maximizes
the exploration of the germplasm resources. This is because, it provides
knowledge of genetic relationship among breeding population and helps in
selecting desirable parents for establishing new breeding population.
An
important crop with this type of profile deserves research attention especially
in area of its genetic improvement. Crop improvement is achieved through plant
breeding programme. Selection of high yielding genotypes depends on amount of
genetic variability present and how heritable important traits like yield are
selected in a population. Improvement in yield as a quantitative trait often
requires the improvement of a secondary trait that is positively correlated
with yield (Smith et al., 1978).The success of any crop breeding
programme largely depends on the availability of vast genetic variability,
genetic advance and character association, direct and indirect effects on yield
and its associated traits (Nwangburuka et
al., 2012). Genetic diversity is important for selection of parents to
recover transgressive segregants. Determination of heritability estimates using
various methods (Obilaria and Fakorede, 1981; Wray and Visscher, 2008) will
provide information on the proportion of phenotypic variance that is due to
genetic factors for different traits but heritability estimate alone is not
sufficient measure of the level of possible genetic progress that might arise
not even when the most understanding individuals are selected in the breeding
programme (Nwangburuka et al.,
2014). The value of heritability
estimates is enhanced when used together with the selection differentia or
genetic advance (GA) (Ibrahim and Hussien, 2006).
Yield is a complex character and is a
function of various polygenic traits and their interaction with the environment
(Iqbal et al., 2013). Yield related
genes have pleitropic effects on plant development in addition to their effects
in regulating yield (Li et al.,
2016). Plant architecture plays an important role in yield potential and crop
adaptation (Cai et al., 2016).
Optimal plant architecture can improve leaf area index, photosynthetic efficiency
and harvest index, hence leading to increased yield. Crop selection based on
plant architecture has been achieved in crops like Zea mays (Zhou et al.,
2016), Oryza sativa (Zhao et al., 2015) and Phaseolus vulgaris (Silva et
al., 2013). Plant architecture - related traits are mostly quantitative
traits which are frequently affected by environmental factors. Therefore, it is
vital to measure the mutual interrelationship between various plant attributes
and determine the component traits on which selection procedure can be based
for direct and indirect genetic improvement of T. occidentalis yield. To
predict crop yield, there is need to analyze data on weather, soil and crop
managements. Although, one is likely to find good data collection on soil and
climate factors, the available information on physiological processes and crop
phenology is insufficient in T.
occidentalis (Hesketh and Dale, 1987).
The knowledge of statistics had proved
helpful in understanding these relationships and their implications for yield
increase. Statistical tools like Principal Component Analysis (PCA),
Regression, Correlation Coefficient (r), Path Coefficient Analysis,
Genotype-by-Environment (GGE) Biplot, and others had been employed in studying
the nature of relationship among yield component traits and yield and the
contribution of each trait to the yield of many crops (Uchechukwu et al., 2017).
Steel
and Torrie (1984) in their work suggested that, correlation is a significant
tool for the measurement of the intensity of association between variables in
plants. Correlation measures the degree to which characters vary together or
measures the intensity of association within and between them. Knowledge of
correlation is important in identifying important parameters in any selection
programme. An understanding of yield and its associated traits is a useful tool
in phenotypic selection and breeding of fluted pumpkin. Knowledge of
correlation among such characters like number of leaves, number of branches,
vine length, fresh leaf, total weight, petiole length, vine girth, internode
length, vine weight and yield of different genotypes from different locations
is useful in designing effective selection and breeding programme for the crop.
According
to Fayeun et al. (2012) and Nwangburuka et al. (2014) in their
work, it was revealed that some interrelationships among marketable leaf yield
components traits. In the work of Fayeun et al. (2012), number of leaves
per plant, vine length, number of branches, leaf length, petiole length ,fresh
leaf weight, vine weight, internode length and vine girth had significant and
positive correlation with marketable leaf yield. Knowledge of correlation that exists
among important characters may aid in the interpretation of results and provide
a foundation for planning more efficient breeding programme. For the selection
of a superior genotype through breeding, an understanding of the association of
yield and its associated traits is essential and their heritable variation has
to be understood. This can be done through the technique of “path co-efficient
analysis” which is a powerful multivariate statistical tool and which enables a
researcher to understand the “path” through which causal factor (yield
contributing characters) influence the yield (Therthappa, 2005). A path
coefficient is a standardized partial regression coefficient that measures the
direct influence of one variable upon another (Dewey and Lu, 1959). Path
analysis allows the researcher to test theoretical propositions about cause and
effect without manipulating variables. Variables may be assumed to be causally
related and propositions about them tested (Acquaah, 2007).
A good understanding of the association
among yield component traits and the leaf yield in fluted pumpkin will not only
reduce cost and duplication of experiments, but will increase precision in
research output and bumper yield.
Therefore, the research work was undertaken
with the following objectives; to:
i.
determine the variability
that exists among the fluted pumpkin accessions in the two locations.
ii.
determine the variation
in nutrient compositions of the T.
occidentalis across the two locations
iii.
evaluate the yield and
yield components of Telfairia occidentalis
accessions in the two locations.
iv.
evaluate the inter-
relationship(s) between different traits in T.
occidentalis.
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