American Journal of Plant Sciences, 2013, 4, 2126-2130
Published Online November 2013 (http://www.scirp.org/journal/ajps)
Open Access AJPS
Genetic Divergence Studies in Pigeonpea
[Cajanus cajan (L.) Millsp.]
Praveen Pandey1*, Rajesh Kumar1, Vankat Raman Pandey1, Mritunjay Tripathi2
1Department of Genetics and Plant Breeding, Narendra Deva University of Agriculture and Technology, Kumarganj, India;
2Department of Biochemistry, Narendra Deva University of Agriculture and Technology, Kumarganj, India.
Received September 4th, 2013; revised October 4th, 2013; accepted October 21st, 2013
Copyright © 2013 Praveen Pandey et al. This is an open access article distributed under the Creative Commons Attribution License,
which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
The nature and extent of genetic diversity were assessed among 23 parents of pigeonpea hybrids employing Mahalano-
bis D2 statistics. Based on relative magnitude of D2, the genotypes were grouped into five different non-overlapping
clusters. Cluster III, having 8 genotypes, emerged with high est number of entries; cluster I, II and V were constituted by
four genotypes each while cluster IV, comprising three genotypes, had least number of entries. The highest contribution
in manifestation of genetic divergence was exhibited by 100-seed weight followed by pods per plant, days to maturity,
harvest index, biological yield per plant, days to 50% flowering and seed yield per plant. The maximum intra-cluster
distance was observed for cluster III, followed by cluster IV, cluster I and cluster V. The highest inter-cluster distance
was recorded between cluster II and IV followed by cluster I and IV and cluster V and II. The crossing between entries
belonging to cluster pairs having large inter-cluster distance and possessing high cluster means for one or other charac-
ters to be improved may be recommended for isolating desirable recombinants in the segregating generations in pi-
geonpea. Considering the mean performance for different characters of genotypes belonging to diverse clusters, the
promising genotypes identified were NDA 2, NDA 7-11, IPA 208 and NDA 5-14 of cluster I; NDA 3-3, NDA 98-6,
Amar and NDACMS 1-3A of cluster II; NDACMS 1-4A, NDACMS 1-6A and ICP 870 of cluster IV and NDA 96-6,
ICP 2155, NDA 8-6 and NDAGC 1010 of cluster V for exploitation as parents in hybridization programme for devel-
opment of superior pigeonpea hybrid cultivars.
Keywords: Pigeonpea; Genetic Diversity; Clustering Pattern; Polygenic Traits
Pigeonpea [Cajanus cajan (L.) Millsp.] is the second
most important pulse crop of India after chickpea, com-
monly known as Arhar, Red gram and Tur. It has been
recognized as a good source of vegetarian protein par-
ticularly in the developing countries where majority of
the population depends on the low priced vegetarian
foods. In fact, this crop has diversified uses such as food,
feed, fodder and fuel. It is a rich source of protein, car-
bohydrate, vitamins, lipids and certain minerals. Com-
pared to other food legumes, breeding in pigeonpea has
been more challenging due to various crop specific traits
and highly sensitive nature to biotic and abiotic stresses.
The final target of any plant breeding programme is to
develop improved genotypes which are better than the
existing ones in producing the economic yield. This re-
quires genetic amelioration through maximum utilizatio n
of allelic resources to develop ideal genotype.
The information about the nature and magnitude of
genetic diversity existing in the available germplasm of a
particular crop is crucial for selection of diverse parents,
which upon hybridization may provide a wide spectrum
of gene recombin ations for quantitatively inherited traits.
Darwin used the expression of divergence in characters
to denote variation in genera, species and varieties .
Genetically diverse parents are preferred for use in hy-
bridization programme because crosses involving diver-
gent parents have been found to provide greater possibil-
ity for obtaining desirable segregan ts in segregating gen-
erations. The importance of genetic diversity for select-
ing parents for recombination breeding in crops including
pigeonpea to recover transgressive segregants has also
*Corresponding a uthor.
Genetic Divergence Studies in Pigeonpea [Cajanus cajan (L.) Millsp.] 2127
been repeatedly emphasized [2-6]. Earlier workers con-
sidered distances in place of origin as index of genetic
diversity and used it for selection of parents for hybridi-
zation programme. However, the genetic diversity of the
selected parents has not been always found to be based
on factors such as geographic diversity/place of release
or ploidy level [7,8]. Hence, characterization of genetic
divergence for selection of suitable and diverse geno-
types should be based on sound statistical procedures,
such as D2 cluster analysis. Keeping in view, an experi-
ment was taken up to study genetic diversity for selecting
the diverse parents for hybridization programme aimed at
isolating desirable segregants for seed yield and other
important characters in pigeonpea.
2. Materials and Methods
2.1. Experimental Detail
Twenty three pigeonpea parental materials of hybrids (3
cytoplasmic male sterile lines and 20 restorers/maintain-
ers genotypes) were evaluated in a randomized block
design with three replications at Research Farm of Ge-
netics and Plant Breeding, Narendra Deva University of
Agriculture & Technology, Kumarganj, Faizabad during
Kharif season of 2012. The experimental site is located at
26.47˚N latitude, 82.12˚E longitudes and an altitude of
113 m above mean sea level. This site is in the eastern
Gangetic plains of India an d has sandy loam soil texture.
Each genotype was raised in single row plots of 4 m
length with intra-row and inter-row spacing of 25 cm and
75 cm, respectively. The recommended agronomic prac-
tices followed to raise good crop stand.
2.2. Data Collection
The observations were recorded on five randomly se-
lected competitive plants of a genotype for eleven char-
acters viz., days to 50% flowering, days to maturity,
number of primary branches per plant, number of secon-
dary branches per plant, plant height (cm), pods per plant,
seeds per pod, 100-seed weight, seed yield per plant (g),
biological yield per plant (g) and harvest index (%).
2.3. Statistical Analysis
The mean data on eleven quantitative characters fro m the
experiment were utilized for analysis of variance to test
the significance for each character as per methodology
advocated by . Genetic diversity was estimated by 
and the grouping of the genotypes into different clusters
were done by using the procedure of .
3. Results and Discussion
The Mahalanobis D2 cluster analysis grouped all the 23
pigeonpea genotypes of the present investigation into five
distinct non-overlapping clusters (Table 1 and Figure 1).
The discrimination of genotypes into discrete clusters
suggested presence of high degree of genetic diversity in
the material evaluated. Earlier workers have also re-
ported substantial genetic divergence in the pigeonpea
materials [4-6,12,13]. Presence of substantial genetic
diversity among the parental material screened in the
present study indicated that this material may serve as
good source for selecting the diverse parents for hybridi-
zation programme aimed at isolating desirable segregants
for seed yield and other important characters.
An examination of the clustering pattern of the 23 pi-
geonpea genotypes into five clusters revealed that the
genotypes of heterogeneous origin were frequently pre-
sent in same cluster. Although the genotypes originated
in same place or ge ographic reg ion were also fo und to be
grouped together in same cluster, the instances of group-
ing of genotypes of different origin or geographical re-
gions in same cluster were observed in case of all the
clusters. This indicated lack of any definite relationship
or correlation between genetic diversity and geographic
origin of the pigeonpea genotypes evaluated in the pre-
sent study. Therefore, the selection of parental material
for hybridization programme simply based on geographic
diversity may not be rewarding exercise. The choice of
suitable diverse parents based on genetic divergence
analysis would be more fruitful than the choice made on
the basis of geographical distances. This finding is in
conformity with the previous reports advocating lack of
parallelism between genetic and geographic diversity in
Table 1. Distribution of parents into different clusters on the basis of Mahalanobis D2 statistics.
Clusters Name of genotypes included No. of genotypes included
1 Cluster NDA 2, NDA 7-11, IPA 208, NDA 5-14 4
2 Cluster NDA 3-3, NDA 98-6, Amar, NDACMS 1-3A 4
3 Cluster NDA 3, ICP 7353, NDA 96-1, ICP 2309, NDAGC 31, NDA 7-15, Bahar, NDA 98-7 8
4 Cluster NDACMS1-4A, ICP 870 NDACMS 1-6A 3
5 Cluster NDA 96-6, ICP 2155, NDA 8-6, NDAGC 1010 4
Open Access AJPS
Genetic Divergence Studies in Pigeonpea [Cajanus cajan (L.) Millsp.]
Figure 1. Ward’s minimum variance dendrogram.
pigeonp ea [12-14].
Cluster III, having 8 genotypes, emerged with highest
number of entries. Cluster I, II and V were con stituted by
four genotypes each while Cluster IV, comprising three
genotypes, had least number of entries.
The estimates of average intra- and inter-cluster dis-
tances for five clusters (Table 2, Figure 2) revealed that
the genotypes present in a cluster have little genetic di-
vergence from each other with respect to aggregate effect
of 11 characters under study, while much more genetic
diversity was observed between the genotypes belonging
to different clusters. Since, high or optimum genetic di-
vergence is desired between the parents of hybridization
plan for obtaining higher frequency of desirable recom-
binants, the chances of obtaining good segregants by
crossing the little diverse genotypes belonging same
cluster are very low. In order to increase the possibility
of isolating good segregants in the segregating genera-
tions it would be logical to attempt crosses between the
diverse genotypes belonging to clusters separated by
large inter-cluster distances. In present investigation,
vary high inter cluster distances were recorded between
cluster II and IV followed by cluster I and IV and cluster
V and II. The lowest inter cluster distance was observed
between cluster I and II, followed by cluster III and IV
and cluster III and V. Thus, crossing between the geno-
types of the above three cluster pairs having very low
inter-cluster distances may not be rewarding owing to
little genetic diversity among their genotypes.
The intra-cluster group means for eleven characters
(Table 3) revealed marked differences between the clus-
ters in respects of cluster means for different characters.
The intra-cluster group means for eleven characters re-
vealed marked differences between the clusters in re-
Table 2. Estimates of average intra- and inter-cluster dis-
tances in pigeonpea.
ClustersCluster 1Cluster 2Cluster 3 Cluster 4Cluster 5
Cluster 1244.81 299.93 558.94 690.94 524.58
Cluster 2149.70 535.38 727.79 689.30
263.80 404.74 474.86
*Bold figures represent intra-cluster distances.
Figure 2. Cluster diagram showing Euclidean2 d is t an ce.
spects of cluster means for different characters. Cluster I
having 4 genotypes, showed highest cluster means for
Open Access AJPS
Genetic Divergence Studies in Pigeonpea [Cajanus cajan (L.) Millsp.] 2129
100-seed weight, second highest cluster means for seed
yield per plant, biological yield per plant and days to
maturity besides having lowest mean performance for
days to 50% flowering. Cluster II with four genotypes
recorded second highest cluster means for days to matur-
ity, 100-seed weight and harvest index besides having
lowest cluster means for secondary branches per plant,
pods per plant, seeds per pod and biological yield. Clus-
ter III comprising 8 genotypes, exhibited highest cluster
mean for days to maturity and days to 50% flowering
besides having lowest cluster means for plant height,
primary branches per plant and seed yield per plant. The
three genotypes of cluster IV were responsible for high-
est cluster mean for plant height, primary branches per
plant, secondary branches per plant and seeds per pod
while lowest cluster means for 100-seed weight and har-
vest index. Cluster V possessing four genotypes, has
highest means pods per plant, seed yield plant, biological
yield per plant and harvest index; second highest cluster
means for plant height, primary branches per plant and
secondary branches per plant besides having lowest
cluster mean for days to maturity. Similar findings were
also reported by [4-6].
Further, the efficacy of D2-statistics is improved by its
applicability to estimate the relative contribution of the
various characters towards genetic divergence . In
this context, the highest contribution in manifestation of
genetic divergence was exhibited by 100-seed weight
followed by pods per plant, days to maturity, harvest
index, biological yield per plant, days to 50% flowering
and seed yield per plant (Table 4).
The above discussion clearly shows wide variation
from one cluster to another in respect of cluster means
for eleven characters, which indicated that genotypes
having distinctly different mean performance for various
characters were separated into different clusters. The
crossing between the entries belonging to cluster pairs
having large inter-cluster distance and possessing high
cluster means for one or other characters to be improved
may be recommended for isolating desirable recombi-
nants in the segregating generations in pigeonpea. Con-
sidering the mean performance for different characters of
genotypes belonging to diverse clusters, the promising
genotypes for exploitation as parents in hybridization
programme were NDA 2, NDA 7-11, IPA 208 and NDA
5-14 of cluster I; NDA 3-3, NDA 98-6, Amar and
NDACMS 1-3A of cluster II; NDACMS 1-4A,
NDACMS1-6A and IC P 8 70 of cluster I V a n d NDA 96-6,
ICP 2155, NDA 8-6 and NDAGC 1010 of cluster V.
These genotypes may be recommended for crossing with
the genotypes of the clusters showing high inter cluster
Table 3. Clusters means for 11 quantitative characters in pigeonpea.
Clusters Days to
branches/plant Pods/plant Seeds/pod100-Seed
yield/plant (g) Harvest
1 Cluster 139.25 250.5 172.84 5.15 22.32 169.32 3.38 13.02 68.09 235.11 29.04
2 Cluster 143.5 250. 5 176.85 5.06 16.36 163.66 2.89 12.83 52.83 180.43 29.31
3 Cluster 145.42 252.75 172.59 5 18.98 176.22 3.34 9.58 51.35 181.13 28.29
4 Cluster 144.22 249.89 198.33 5.91 30.53 184.06 3.53 9 .41 58.91 226.16 25.79
5 Cluster 142.5 249.33 179.01 5.43 23.14 234.47 3.18 10.93 73.76 240.21 30.77
Table 4. Per cent contribution of characters towards genetic diversity.
Source Times Ranked 1st Contribution %
Days to 50% flowering 16 6.32
Days to maturity 25 9.88
Plant height (cm) 9 3.56
Primary branches/plant 0 0 .00
Secondary branches/plant 1 0.40
Pods/plant 48 18.97
Seeds/pod 1 0.40
100-Seed Wt. (g) 100 39.53
Seed yield/plant (g) 14 5.53
Biological yield/plant (g) 18 7.11
Harvest index (%) 21 8.30
Open Access AJPS
Genetic Divergence Studies in Pigeonpea [Cajanus cajan (L.) Millsp.]
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heterotic crosses and magnitude of heterosis for yield and
its components were found to be higher in crosses be-
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