Cotton Genomics and Genetics 2015, Vol.6, No.1, 1-6
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2 Discussion
Presence of sufficient genetic variation is a pre
requisite for an effective breeding programme to study
the nature and strength of association among yield
related traits (Irum et al., 2011). In this study the
sufficient amount of genetic variation is quite evident
from analysis of variance for all traits. PCV% was
higher in magnitude than GCV% for all the traits
which are in accordance with the results of
Mendez-Natera et al., (2012). Ali et al., (2009)
reported higher values of GCV and PCV% for seed
cotton yield. Heritability is the measure of phenotypic
variance computed from genetic variance (Songsri et
al., 2008). High estimates of heritability were present
in all the traits in present study. Farooq et al. (2014)
reported higher estimates for boll weight, moderate
estimates for nodes to 1
st
fruiting branch, monopodia
per plant and sympodia per plant. Basbeg and Gencer
(2004) reported lower estimates for bolls per plant
and seed cotton yield which are in contradiction to
the present research. Similarly, Mendez-Natera et al.
(2012) found moderate estimates for plant height,
and low values for bolls per plant, boll weight and
seed cotton yield which also contradict the present
results.
Early generation selection will be more useful in all
the traits showing higher values of broad sense
heritability (Farooq et al., 2014). The higher values of
narrow heritability show an additive genetic effect
that’s why the adoption of selection procedure for the
traits showing higher estimates is much easier
(Soomro et al., 2010). Environmental factors play a
vital role in the development of phenotypic
correlations (Ali et al., 2009).
Phenotypic correlation can be computed from the net
result of genotypic and environmental correlations. In
the present study, the seed cotton yield has significant
positive association with sympodia per plant, bolls per
plant and boll weight, while it has negative association
with monopodia per plant and CLCuV. These results
of positive association of yield components are in
agreement with the findings of Iqbal et al. (2006),
Ashokkumar and Ravikesavan (2010) and Farooq et al.
(2014). Early generation selection may be adopted for
traits having significant genotypic correlation (Farooq
et al., 2014). Significant role of strong genotypic
association was observed in the present studies. These
results are in accordance with the findings of Desalegn
et al. (2009) and Qayyum et al. (2010) who reported
the chief role of genetic effects. Positive correlation of
sympodia per plant with plant height and seed cotton
yield was reported by Ashokkumar and Ravikesavan
(2010) and Ahuja et al. (2006) which are in
accordance with the present findings Negative direct
effects for sympodial branches on seed cotton yield
have been earlier reported by Ahuja et al (2006) and
Rauf et al. (2004). The traits like nodes to 1st fruiting
branch, sympodia per plant and bolls per plant
indirectly influenced seed cotton yield through most
of the yield contributing traits. Similar indirect effects
were found in the studies of Ashokkumar and
Ravikesavan (2010).
3 Material and methods
3.1 Plant material and site characteristics
A total of 18 diverse genotypes were evaluated in the
experimental area of Cotton Research Institute,
Faisalabad during the year 2013-2014. The material
was sown on 15 th of May to observe their tolerance
ability regarding CLCuV and some yield and related
parameters
3.2 Experimental design, plot size and cultural
practices
Layout of the experiment was randomized complete
block design (RCBD) with three replications. For each
entry, plot size measured 4.572 m × 6.096 m,
comprising six rows set 75 cm apart. Distance
between plants within rows was 30 cm. Normal
agronomic and cultural practices (irrigation, weeding,
hoeing, and fertilizer applications) were adopted as
and when required.
3.3 Measurement of various traits studied
For measuring the traits ten representative,
undamaged plants were selected in each line and
marked for identification. Nodes to 1
st
fruiting branch
counted from zero node (cotyledonary node) to the
node at which first flower was appeared. Data on plant
height in centimeters were recorded from the base to
the tip of the plant. Data on monopodia and sympodia
were taken by counting the number of vegetative and
fruiting branches, respectively. Number of bolls
counted from the guarded plants upto final picking.
The bolls were picked and seed cotton yield was
