ABSTRACTS OF PUBLICATIONS AND CONFERENCES
Published Articles:
Comparison of Yield and Stability Assessment of Five Coconut (Cocos nucifera L.)
Varieties in a Lethal Yellow Disease (LYD) Endemic Field overNine Different
Environments. World Journal of Agricultural Sciences 8 (3): 229-233.
J.O. Odewale, Agho Collins, C.D. Ataga, G. Odiowaya,
M.J. Ahanor, A.A. Edokpayi, M.N. Okoye and E.O. Uwadiae(2012).
ABSTRACT
Abstract: Environmental factors influenced productivity of the coconut palms and contribute
to fluctuations in nut yield. Stability measurements are important since they give an
indication of the ability of a genotype to maintain a relatively constant yield independent of
changing environmental conditions. Genotypes xenvironment interactions indicate the
inconsistency of relative performance of genotypes over environments.Assessment of the
stability of a genotype to different environmentsis useful for recommending cultivars for
known conditions of cultivation. Recently, the Nigerian coconut plantations have been
reduced to a level that they no longer meet the local requirement both in direct consumption
and industrial uses. This was due to the fact that the environment is changing and this has
affected the growth, development, physiological status and consequently the yield and
stability of the coconut.Inorder to assess the yield and stability of different coconut
varieties, nine years’ yield data of five (5) coconut palm varieties were evaluated for nut yield
performance and stability using analysis of variance (ANOVA) and some univariate stability
parameters. Result of combine analysis of variance for nut yield showed significant effects of
genotype, environments and genotype by environment interaction. The mean nut yield per
palm per year ranged from 20.571 to 83.80 nuts / palm / year.
When the genotypic nut yields were subjected to stability analysis against an environmental
index, the regression coefficient for individual varieties ranged between 0.414 and 1.486. The
values of the coefficient of determination (R2) suggested that 48.7 to 95.65% of the variation
in nut yield of the individual varieties was accounted for by the regression on the
environmental index. The orange dwarf and yellow dwarf varieties had the lowest regression
coefficient (b) value (0.779 and 0.414) nearer zero and were considered most stable for nut
yield. They were however below average performance for this trait with a nut yield of 39.049
nuts / palm / year and 34.026nuts /palm / year respectively. Two varieties: Green dwarf
(43.084 nuts / palm / year) and hybrid(44.594nuts / palm / year ) were average in terms of
yield performance for nut yield and also had average stability to environmental variation and
were therefore recommended while the tall (57.511nuts / palm / year) was the most
productive but had the least buffering ability compared to other varieties.
Key words: Yield.Buffering,Regression,Stability,Environmental index.
Pattern of genetic diversity and variability in germplasm resources of local and exotic
coconut (Cocosnucifera l.) cultivars in Nigeria.Scholarly Journal of Agricultural Science
Vol. 2(8), pp. 202-207.
Odewale, J.O., Agho Collins, Ataga, C.D., Aisueni, N.O.,Ikuenobe, C.E., M.N.Okoye.,
Odiowaya, G., Edokpayi, A.A. ,Ahanor M.J., and Uwadiae E.O.(2012).
ABSTRACT
Multivariate analysis was used to group and study the pattern of genetic diversity and
relationship among six exotic and four indigenous coconut cultivars and a hybrid. Euclidean
genetic distance between Nigeria Tall (Badagry) and Ganganbodam revealed the highest
genetic distance while the lowest Euclidean distance was between Gangabondam and
Chowghat dwarf yellow. The level of variability observed suggested a high diversity among
the cultivars. The result of the principal component analysis indicated that the contribution of
the first two factors with Eigen value greater than unity accounted for 69.5% of the total
variation. The scores of all the tall cultivars and the hybrid were negative for PC1 while the
Dwarf cultivars had positive scores for PC1. The scores of the tall, hybrid and dwarf cultivars
for PC2 appeared irregularly in comparison with PC1 and such result indicated that PC2
contained little information on classification of coconut cultivars. PCA and Cluster analysis
produced similar results. Selfing intensity and duration of female phase accounted for the first
component while the second component was primarily loaded by duration of male phase and
days of emergence to opening. The clustering pattern indicated that genetic diversity might
not be necessarily related to geographical diversity, thus selection of genotypes for
hybridization should be purely based on genetic diversity. Now that there is need to expand
the coconut genetic base and crop improvement, this investigation would play an instructive
role in coconut breeding and germplasm resources improvement of coconut in Nigeria. The
floral characters were efficient in assessing genetic divergence with selfing intensity as the
most distinguishing characters followed by days of emergence to opening as revealed
by discriminant analysis. These characteristics could be useful as markers for the selection of
female parents in yield improvement programs.
Keywords: Hybridization, coconut breeding, Euclidean distance, genetic diversity, cluster
analysis and principal analysis component.
Notes on the Floral Biology and Fruiting of Cycad circinalis in Nigeria.Greener Journal
of Biological Sciences Vol. 2 (3), pp. 040-042.
Odewale, J. O, Agho Collins and Eziashi, E. I
ABSTRACT
The Cycas circinalis was first officially introduced into Nigeria by the Nigerian Institute for
Oil Palm Research (NIFOR), Benin City. It belongs to the Division: Cycadophyta, Class:
Cycadopsida, Order Cycadales, family Cycadaceaeand genera Cycas. It was first recognized
as a separate species in 1995. It is also known as Sago palm, Fern palm, Cycad or Starch
palm. The floral biology of the plant is cone like as other cones in the Order Cycadales,
the cone has the whorl of premature pinnate fronds embedded within the cone. This cone
opens up and spreads out as the inflorescence reaches anthesis revealing the whorl of young
leaves that will form the new generation crown.
The mean number of fully formed fruits per stalk is 9.0 average fruit length is 5.24cm, fruit
circumference ranged from 8.6-9.6cm while the average circumference is 9.03. Fruit weight
range between 19.2 – 22.10g (mean = 21.6g), the length of dehusked fruit vary from 4.1 –
5.0cm, while the circumference of the dehusked fruit range between 7.1 – 8.0cm. The
average circumference of dehusked fruit was 7.53cm. The weight of the dehusked fruit range
between 9.7 – 18.6g, with a mean weight of 13.9g.
Key words:Cycas, Gymnospermous, Cone and Cycasin
Multivariate analysis as a tool in the assessment of the physical properties of date palm
fruits (Phoenix dactylifera L.) in Nigeria. Plant Sciences Feed 2(10): 138-146.
Odewale JO, Ataga CD, Odiowaya G, Hamza A, Collins A. and Okoye MN
ABSTRACT
The environment is changing and plants are constantly been affected by changes in
environmental conditions. These changes are usually visible in the yield, vegetative
characteristics and the physical properties of fruits and seeds. Knowledge of Physical
properties of date fruit is necessary for design of post harvesting equipment such as cleaning,
sorting, grading, kernel removing, and packing. The constant changes in the physical
properties of date palm fruit as a result of genotype by environment interaction normally
leads to machine failure or inadequacy of date palm processing machines after some
years, hence, the complains of machine inadequacy by most users of date palm processing
machines in Nigeria after a couple of years. There is an urgent need for a regular update on
the physical properties of date palm fruit as the environment changes so as to enable
agricultural engineers design an effective processing and handling machines for date palm
fruits using data bank of their physical properties. This knowledge will also be useful in
assessing date palm genetic diversity for crop improvement. Physical dimensions of ten
morphologically distinct date palm fruits were determined in order to access
the extent of variability for the fruit length, width and thickness of ten new accessions of date
palm were measured using a vernier calliper. Other parameters were calculated using
standard mathematical procedures. Accession means shows that fruit length ranged from 28.2
to 43.0 mm, mean fruit width from 18.01 to 27.35 mm and mean fruit thickness from 17.43 to
26.66 mm. Fruit geometric diameter varied from 5.54 to 8.66 mm, arithmetic diameter varied
from 21.21 to 32.34 while surface area varied from 1344.93 to 3124.99 mm2. Other results
showed that the mean fruit density was measured 0.81g/cm3 while bulk density and porosity
were 0.44 g/cm3 and 44.03%, respectively. The sphericity, aspect ratio and surface area were
obtained as 73.35%, 63.71% and 2359.60mm2, respectively. The mean coefficients of static
friction were measured as 0.38, 0.46 and 0.44 on galvanized iron steel, plywood, and glass
surfaces, respectively. Principal component analysis divided the 17 out of the 20 variables
determined into four components which explained 97.03% of the total variation. First
component (62.43%) strongly influenced fruit geometric and arithmetic diameter, thickness,
width, surface area, porosity, volume, density, mass, circumference and length. Second
component (19.05%) was affected strongly by width-thickness ratio, length-width ratio,
sphericity and aspect ratio. Third component (9.54%) was affected strongly by
length-thickness ratio while the fourth component (6.01%) was mainly affected by bulk
density The dendrogram generated by the un-weighted pair group method using arithmetic
averages (UPGMA) cluster analysis grouped the ten new accessions into four distinct clusters
indicating genetic diversity. This information can be used in designing effective processing
and handling machine for date palm fruit and also to plan crosses in order to maximize the
expression of heterosis for large fruit size and other traits of interest.
KEYWORDS: Date fruit, Phoenix dactylifera, Nigeria, genetic diversity, physical
properties, machine inadequacy, post-harvest.
Study of Some Fruit and Seed Traits Relationship and Assessment of Multicollinearity
in Date Palm (Phoenix Dactylifera L) Accessions of Nigeria by Correlation and Principal
Component Analysis(2013).Greener Journal of Agricultural SciencesVol. 3 (2),
pp. 164-175.
Odewale J.O., Agho Collins, Ataga C.D., Odiowaya G., Hamza A., Uwadiae E.O and
Ahanor M.J.
ABSTRACT
Collinearity (or multicollinearity) is the undesirable situation where the correlations among
the independent variables are strong. Multicollinearity misleadingly inflates the standard
errors and results in incorrect conclusions about relationships between dependent and
predictor variables. Thus, it makes some variables statistically insignificant while they should
be otherwise significant.Most explanatory variables in the biological sciences tend to
correlate and this leads to incorrect identification of the most important predictors. Just like
other crops, in date palm the seed characters most times are used as predictors of the quality
and quantity of the fruits such as the fruit weight and size which are important pricing index
of date palm fruits and so, it becomes important to develop a model to explain the
relationships between these two data sets without collinearity. The changing environments
accompany by floods and high temperature coupled with the increase in population in Nigeria
and Africa as a whole is a concern to agriculturist. Famine is fast approaching and crop
modelling is one of the solutions. The main purpose of this study is to show how we can use
multivariate analysis based on principal component scores to establish a model that can
explain the relationship between the fruit and seed traits of date palm and compare its ability
to reduce multicollinearity with the method of the ordinary least square while also studying
the variability that exist among the germplasm collections for genetic improvement. The
result of the descriptive statistics which indicated the values of the coefficient of variation for
the different characters of the fruit and seeds of date palm reveals the possibility of genetic
improvements of these characters. Principal component analysis (PCA) was applied to
predictor variables to address the problem of multicollinearity. The result of the principal
component analysis indicated that the contribution of the first two factors with Eigen value
greater than unity accounted for 86.5 % of the total variation which was well above average
and thus, explains the use of PCA in data reduction. The results showed that the principal
component regression (PCR) was sufficient in eliminating multicollinearity with a variance
inflation factor (VIF) and tolerance value (TOL) of unity and P < 0.05 and it was possible to
explain a high percentage of the total variance with a reduced number of principal
components as two principal components (PRIN 1 and PRIN 2) accounted for most of the
variability in seed characters observed among the date palm germplasm collections from
different locations. There was a high level of variation in some of the seed traits studied
which could serve as the basis for genetic improvement of date palm fruit. There was a direct
positive relationship between the groove width and the fruit traits in the multiple regression
analysis and the principle component analysis, thus, indicating the importance of groove
width in the genetic improvement of date palm fruits.
Key words: date fruit, tolerance value, variance inflation factor, multicollinearity, principal
component regression and principal component analysis.
Genotype evaluation of coconut (Cocos nucifera L.) and mega environment investigation
based on additive main effects and multiplicative interaction (AMMI) analysis
(2013).Research Journal of Agricultural and Environmental Management Vol. 2(1), pp.
001-010.
Odewale J. O., Ataga C. D., Agho C., Odiowaya G., Okoye M. N. and Okolo E. C.
ABSTRACT
The objective of this study was to assess genotype by environment interaction for nut yield in
coconut genotypes grown in southern Nigeria by the AMMI (additive main effects and
multiplicative interaction) model. The study comprised 5 coconut genotypes, analysed in nine
years through field trials. Nut yield per palm per year of the tested genotypes varied from
20.571 to 83.80 nuts / palm / year throughout the nine seasons, with an average of 43.663
nuts. In the variance analysis, the model revealed that differences between the environments
accounted for about 34.98% of the treatment sum of squares while the genotypes and the GxE
interaction also accounted significantly for 25.04% and 15.78% respectively of the treatment
SS. The mean squares for the PCA 1 and PCA 2 were significant at P = 0.01 and
cumulatively contributed to 86.48% of the GxE interaction SS, leaving 13.52% of the
variation in the GxE interaction (within 37.5% of the interaction df) in the residual.The biplot
accounts for 97.86% of the treatment SS leaving only 2.13% in the residual. On the biplot,
genotypes with high yield genetic potential had positive correlation with the seasons with
optimal growing conditions, while the genotypes with lower yield potential were correlated to
the years with unfavourable conditions. Nut yield per plant is highly influenced by
environmental factors, which indicates the adaptability of specific genotypes to specific
seasons/years. The AMMI and AMMI stability value (ASV) identified G1 and G4 as
the most stable genotypes and also identified three mega environments.E1 was identified as
stable environment as its IPCA2 score and vector was near to the source (zero). The most and
least discriminating test environments were E8 and E7 respectively. Genotypes with obtuse
angles with test environments had below average yields at those particular sites. The results
also show that the environment is changing which could be as a result of the impact of global
warming on the environment as revealed by clustering of the nine years into three different
mega environments with no definite patterns from the AMMI biplot.
Key words: AMMI, ASV, yield, biplot, genotypes, GxE interaction, PCA.
Estimates of Components of Variances for Bunch
Traits in Date Palm Crosses (Phoenix dactylifera L)
Hamza A.M.,Okolo E.C.,Ado S.G., Usman I.S.and Agho Collins(2013).Greener Journal of
Agricultural Sciences Vol. 3 (7), pp. 563-568.
ABSTRACT
A field experiment was carried out at Nigeria institute for Oil Palm Research date palm
Research substation Dutse,Jigawa state during 2004-2005 flowering season. Biparental
progenies derived from 60 crosses replicated twice were subjected to analysis of variance
using nested design for the purpose of estimating additives, genetic and dominance
components of variances of the seven bunch traits. Significant variation was observed for the
traits studied. The male components of variances (σ2m) for all the traits were negative,
indicating that the estimates were not different from zero or were very small. Positive
estimates were recorded for females within male variance (σ2f/m), while Non-significant
negative additive variances (σ2 A) were obtained for all the traits. Dominance variance (σ
2 D) showed significant positive values for number of fruits, spikelets, aborted fruits and
unfertilized florets. Positive estimates were recorded for environmental variance (σ
2e), genotypic variance (σ 2g) and phenotypic variance (σ 2ph). In allcases phenotypic
variance was much larger than the genotypic variance. Low environmental variance were
obtained for the traits indicating that the environmental condition where the experiment was
carried out is homogenous and the material could perform considerably well under similar
environmental conditions. The means performance of the males indicates that variability
exists between the males; Males 6R3 and 1R7 are good combiners with female 12R3 for
number of fruits while males 1R12 and 5R2 are good combiners with female 12R3 for
number of fruits. Female 2R8 is poor general combiners for number of fruits. Males 1R12
and 5R2 are good combiners with female 1R27 for weight of fruit while male 6R3 and 1R7
are good combiners with female 12R3 for fruit weight. Recurrent and backcross selection are
recommended for further date palm improvement programs.
Keywords: Male variances (σ2m), female within male variances (σ2f/m), additive variances
(σ2A), Dominance variance (σ2D),environment variance (σ2e), phenotypic variance (σ2ph),
genotypic variance(σ2g) and bunch traits.
Estimates of Components of Variances for Bunch
Traits in Date Palm Crosses (Phoenix dactylifera L)
Hamza A.M.,Okolo E.C.,Ado S.G., Usman I.S.and Agho Collins (2013). Greener Journal of
Agricultural Sciences Vol. 3 (7), pp. 563-568.
ABSTRACT
Date palm progress derived from 60 crosses replicated twice, subjected to analysis of
variance using nested design for the purpose of estimating fulsibs, broad sense and narrow
sense heritability’s, genetic advance and genetic advance as percentage mean for the eight
fruit traits. Positive estimates were recorded for fulsibs heritability for the traits. Broad sense
heritability for the traits was high. Narrow sense estimates were low and negative indicating
that the estimates were not different from zero or they were very small. Heritability indicates
the effectiveness with which selection of genotype can be based on phenotypic performance,
though it does not provide any indication of the amount of genetic progress that will result
from selecting the best individuals. The relatively high estimates obtained for broad sense and
medium estimates for fulsibs heritability suggest that variation in these traits may be
attributed to a high degree of additive gene action and selection for these traits would
therefore be effective and thus shows that the traits are under strong genetic control. Broad
sense heritability estimate for any one trait is useful when high genetic advance in that trait is
feasible, because high heritability coupled with high genetic advance is the true index for
effective selection. It was necessary that expected genetic advance be estimated to know what
level of improvement can be expected from selection of each of the characters examined.
Pollen source has strong influence on fruits and seed characters of date palm. Among the
palms used for this study, male 1R12 GPIII; 6R3 GPIII and 1R7 NCRP performed better than
the rest. Mass, recurrent and backcross selection are recommended for further breeding
programs in development of date palms in Nigeria.
Keywords: Fulsibs heritability, Broad sense heritability, Narrow sense heritability, expected
genetic advance and fruits traits.
Proximate Compositions Evaluation and Variability among Cultivars of Date Palm
(Phoenix dactylifera L.) inNigeria (2014). International Journal of Plant & Soil Science
3(3): 248-259, 2014.
A. M. Hamza1, Agho Collins, S. G. Ado, C. E. Ikuenobe, C. D. Ataga and J. O. Odewale
ABSTRACT
Genetic variability among the fruits of 22 date palm cultivars was studied using 6
nutritional characters to enable us classify the available germplasm into distinct groups
on the basis of their genetic diversity using their nutritional characteristics from proximate
composition. The main date palm-growing areas of Nigeria were surveyed in 2011 with
the objective of characterizing cultivars as to the quality and economic value of their fruits.
Descriptive statistics and some multivariate analysis techniques were used to classify the
22 date palm cultivars. The genotypes based on studied traits were grouped into three
clusters. Discriminant function analysis was used to confirm the accuracy of grouping that
was produced by cluster analysis. Sugar and crude protein content were identified as
important traits that could be used to differentiate the genotypes as revealed by both
principal component and discriminant analysis. Genetic distance between Daushenga 1
and Saberari 2 exhibited the greatest dissimilarity followed by Daushenga 1 and
Hausawa. Hence the use of these parents for hybridization should be given greater
emphasis for the production of transgressive segregants with high nutritional potential.
The level of variability observed suggested a high diversity among the cultivars. The result of
the principal component analysis indicated that the contribution of the first three factors
with Eigen value greater than one accounted for 73.03% of the total variation. The
moderately high ash content shows that date palm fruit can effectively serve as a source
of inorganic minerals and good adsorbent in the removal of metallic ions, odour, colours
and other particulate matter from aqueous medium of water and waste water thus making
date palm fruit an effective material precursor in water and waste water treatment among
other uses. The high soluble carbohydrate content indeed gives an indication that it
compares favourably with other fast energy giving food stuffs and thus it can be added to
some food content as an additive .This work identified the existence of inherent variability
in the local germplasm collections, and the traits that could be used to exploit the
observed variability, eliciting important relationships among the traits in the process.
Keywords: Date palm fruit; nutritional characters; cluster analysis; discriminant function
analysis; genetic diversity and principal component analysis.
Genotype by Trait Relations between Yield and some Morphological Traits of Coconut
(Cocosnucifera L.) Hybrid Varieties Based on GT Biplot.International Journal of Plant &
Soil Science 3(3): 270-280.
J. O. Odewale, Agho Collins, C. D. Ataga, E. C. Okolo, C. E. Ikuenobe, G. Odiowaya and
M. J. Ahanon (2014).
ABSTRACT
The objective of this study was to evaluate the coconut hybrid varieties based on
Genotype by Traits (GT) biplot to examine its usefulness in visualizing coconut trait
relationship and its application in genotypes comparison. The experimental design was a
randomized complete block design with two replications; each block consisted of 5 plots
with a total of eight palms per plot while the remaining palms were used as guard rows.
This experiment was conducted at the Main Research Station of the Nigerian Institute for
Oil Palm Research (NIFOR), Benin City, Edo State, Nigeria. The materials for the present
study consisted of 5 hybrid varieties of Coconut palm. Data on individual palms were
recorded on seven quantitative traits: thickness of petiole (TP), number of fronds (NFD),
number of leaflets (NL), number of fruits per palm (NF), number of bunches per palm
(NB), width of leaflet (WL) and circumference of the stem 20 cm from the soil level
(CF).The GT biplot analysis revealed close associations among the studied traits. The two
axes explained 90.4% of the total variation among the cultivars due to the various traits
measured thus reflecting the accuracy of inter-relationships among the measured characters.
Correlation coefficient between the studied traits showed that there is a strong positive
relationship between number of fruit and number of bunches. These two traits were however
negatively correlated with other traits except number of fronds. Based on the Auto Find QTL
function of GGE biplot, bunch yield and width of leaflets were identified as traits suiTable for
indirect selection for nut yield improvement. H4 was identified as an ideal genotype as it
combines several good traits in its genetic composition and thus could serve as a good genetic
raw material from which better cultivars, synthetic varietiesand pure lines can be developed.
H1 was the best in terms of nut and bunch yields, indicating that it can be used as parents in
the development of hybrid varieties and populations that are outstanding in these traits.
Keywords: Coconut; Genotype by Trait biplot; ideal cultivar; correlation coefficient.
CONFERENCES
Characterization of coconut (Cocos nucifera L.) selected mother palms based on fruit
components in Nigeria (2014).Proceedings of the 38th Annual Conference of the Genetic
Society of Nigeria.Pp.593-601.
Odewale, J.O., Okolo, E.C., Ataga, C.D., Okwuagwu, C.O., Odiowaya, G., Agho Collins,
and Yusuf, A.O.
ABSRACT
Genetic diversity among 17 mother palms of coconut (Cocos nucifera L.)collected from the
Genetic Resources Centre of the Nigerian Institute for Oil Palm Research (NIFOR) in
Badagry, Lagos State was assessed under field conditions. The seed-nuts were collected from
the palms that presented attractive yield and vegetative characteristics .Other features
considered were the type identity and group uniformity through planting history and nut yield
per tree per year from previous four year field records of the palms .The palms were
evaluated on a single plant basis using repeated observations on five replicates. Data on 5
randomly selected nuts from each palm were recorded on nine nut characters. The data were
subjected to descriptive and multivariate analysis. Studied palms showed high coefficient
ofvariation for fruit weight. The palms basedon studied traits were classified into 6 groups
indicating high genetic variability in the coconut genotypes studied. The first three principal
axes accounted for 73.9% of the total variation among the characters describing the 17
mother palms studied. Among the studied traits, nut weight, volume of water, weight of shell,
weight of copra showed positive correlation with the first component (PC1) while percentage
of dry matter showed a negative correlation. Weight of meat was positively correlated with
the second component (PC2) while Sugar content was negatively correlated with PC2. Based
on the result of the cluster analysis, genotypes belonging to clusters with high intercluster
distancehave been selected forfuture hybridization program. The role of weight of copra,
sugar content, volume of water and husk weight in the vectors were important components
for geneticdivergence in these materials. These characters could be used to facilitate selection
of female parents in the improvements of nut characters. Considering group distance the
inter-genotypic crosses between PR718 and PR3, PR718 and PR1060; PR3 and PR248might
be suggested for future hybridization program for improved nut traits.
Key words: Nut, traits, cluster analysis, genetic diversity.
Character interrelationships and path analysis for copra yield in coconut (Cocos
nucifera L.). .). Proceedings of the 38th Annual Conference of the Genetic Society of
Nigeria.Pp. 602-609.
Odewale, J.O., Ataga, C.D., Agho Collins, Ahanon, M.J., Odiowaya, G., and Okoye,
M.N.(2012)
ABSTRACT
The present study was carried out in a field located at the Main Research Station of the
Nigerian Institute for Oil Palm Research (NIFOR), Benin City, Edo State, Nigeria. The field
is located within latitude 6o33’N and longitude 5o37’E and lies 183m above sea level. The
materials for the study consisted of four hybrid varieties of Coconut palm that were planted in
2003. Data on individual palms were recorded on seven quantitative traits: number of fronds
(NFD), number of leaflets (NL), number of fruits per palm (NF), number of bunches per palm
(NB), width of leaflet (WL), circumference of the stem 20 cm from the soil level (CF) and
copra yield which was estimated in tons per hectare during 2010/11 crop season. Correlation
and path analysis was applied to investigate the relationships between copra yield and other
important yield components in coconut (Cocos nucifera L.). Copra yield was significantly
and positively correlated with number of fruits per palm per year. The path coefficient
analysis revealed that width of leaflets and number of fruits per palm per year gave the
highest direct effect on copra yield at 1.533 and 0.587 respectively. The highest indirect
contribution of all the characters on copra yield was through width of leaflets. The residual
effect at 4.2% indicates that there will be little or no contribution in the addition of more
characters affecting copra yield than the ones already included in the present study. Path
analysis revealed that number of fruits per palm and width of leaflets can be suitable criteria
to select high-yielding genotypes in coconut programs.
Keywords: Coconut, copra, correlation, regression, path coefficient analysis.