Cotton Genomics and Genetics 2015, Vol.6, No.1, 1-6
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screening of CLCV in Pakistan conditions. The
development of superior cotton genotypes by
hybridizing distant parental lines has been reported
(Akter, 2009). To get particular information on nature
and extent of genetic variability depends upon the
various procedures exploited for its estimation, like
plant characterization based on agronomical,
morphological and physiological traits (Bajracharya et
al., 2006). Multivariate study based on Mahalonobis’s
D2 statistics (MDS), principal component analysis
(PCA) and principal coordinate analysis (PCoA) are
mostly utilized to estimate the extent of genetic
diversity among the germplasm (Brown-Guedira et al.,
2000). Among these biometrical procedures the main
edge of principal component analysis (PCA) is that
each genotype can be assigned to only one group and
it also reflects the significance of largest contributor to
the total variability at each axis of differentiation
(Sharma, 1998). Genetic variation for morphological
traits has been estimated using principal component
analysis, which leads to the detection of phenotypic
variability in cotton (Esmail et al., 2008; Li et al.,
2008). The objective of present research was to
evaluate the genetic diversity among cotton
germplasms specifically for resistance against CLCuD
and generally for morphological and fiber traits to
recognize the model genotypes that can be exploited
in future breeding program.
Results
Association among various studied characters
The basic statistics of different studied traits revealed
considerable amount of variability among 159 exotic
cotton genotypes (Table 1). Simple correlation coe-
fficient revealed some important associations among
the studied traits table 2.
Days to first square exhibited positive significant
association with days to first flower and nodes to first
fruiting branch while it had significant negative
association with fiber fineness and negatively and non
significantly correlated with plant height, monopodia
per plant, sympodia per plant, boll weight and staple
length. Days to first square showed positive
significant association towards nodes to 1st fruiting
branch and had negative non-significant correlation
with plant height, monopodia, sympodia per plant ,
boll weight and fiber fineness. The CLCuD exhibited
highly significant negative association with plant
height while showed negative non-significant
correlation with monopodia per plant and staple length.
The plant height had highly significant correlation
with monopodia per plant and sympodia per plant
while showed highly significant negative association
with GOT. On the other hand nodes to first fruiting
branch exhibited significant negative association with
fiber fineness and for staple length significant
negative correlation was found with fiber fineness.
Table 1 Basic statistics for various traits of 159 cotton genotypes
Traits
Minimum
Maximum Mean± S.E.
Std. Deviation
Variance
Days to 1
st
square
40
58
47.25±0.28
3.55
12.58
Days to 1
st
flower
55
74
65.12±0.34
4.30
18.49
CLCuD %
22
90
67.12±1.59
20.17
406.71
Plant height
34
121
57.23±0.96
12.21
149.05
Nodes to 1
st
fruiting branch
4
12
6.88±0.12
1.48
2.19
Monopodia per plant
0
7
2.54±0.12
1.50
2.26
Sympodia per plant
8
20
14.34±0.17
2.20
4.85
Boll weight
1.2
5.1
2.66±0.05
0.63
0.39
GOT (%)
24
44
33.81±0.29
3.63
13.14
SL (mm)
24
28.8
27.01±0.06
0.72
0.52
FF (µg/inch)
3.3
5.9
4.79±0.04
0.48
0.24
