Investigating physiological and biochemical

3.4.4. Discussion 
 
Salt tolerance at vegetative stage is crucial for yielding vigorous plants for 
tolerating salt stress at later stages of growth. That is why, crop failed to reach at 
maturity at highest salinity level of 200 mM NaCl. The advantage of the utilization of 
branching and number of pods in the evaluation for salt tolerance is that both parameters 
can be determined at early growth stage. Therefore, screening salt tolerance of 
genotypes at early growth stage based on agronomic parameters can shorten the period 
for experiments to screen salt tolerance of linseed genotypes. However, it is only true if 
the changes in salt tolerance exhibit the same pattern at all growth stages (Allen et al., 
1985; Ashraf and Waheed, 1993). Because evaluating salt tolerance among genotypes 
based on grain yield needs a long period for the experiment, the work in the literature 
suggests that evaluating salt tolerance of genotypes on the basis of agronomic 
parameters, especially for parameters that initiate at early growth stage and significantly 
correlate with grain yield, can be used as more quick and feasible traits to screen large 

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number of genotypes rather than grain yield. Therefore, it is necessary to identify 
salinity-sensitive agronomic parameters that initiate at early growth stage. In our study, 
branching and pod number of linseed initiate during vegetative stages and are sensitive 
parameters to salinity in other crops such as rice (Zeng et al., 2002). The advantage of 
the utilization of both parameters in the evaluation for salt tolerance is that both 
parameters can represent the evaluation of genotypic differences for salt tolerances in 
terms of total grain yield. Thus, both parameters can be used as more quick and feasible 
traits to evaluate large number of linseed genotypes in breeding programs rather than 
grain yield. 
In the present study, the observed reduction in branching (30-37% of respective 
control) and number of pods plant
-1
(26-32% of respective control) due to salt stress 
directly affects the productivity, biomass and seed yield of linseed genotypes of 
Pakistan origin. Decreased branching due to salt stress in different oil seed crops 
(Mensah et al., 2006; Sadat-Noori et al., 2008) has been reported and might be due to 
the reduction in photosynthesis. The deleterious effect of salinity on yield attributes 
namely number of pods plant
-1
, number of seed pod
-1
was not surprising. The limited 
synthesis of photosynthates would adversely affect their partitioning to developing sink 
and thus resulting in lower values of these attributes would naturally be responsible for 
decreasing seed yield plant
-1
. Khan et al. (2007) and Muhammad and Hussain (2010) 
also reported that productivity of linseed was decreased under saline conditions.
It was interesting to note that different yield attributes played a positive role in 
increasing oil contents in linseed genotypes and a comparison among different yield 
attributes revealed that 1000 seed weight played a very important role and exhibited a 
positive correlation with percent oil contents. However, contribution of seed yield 
plant
-1
towards percent oil contents of linseed is far better than 1000 seed weight.
The decrease in seed oil content of all the four genotypes with the increase in salt 
concentration of soil parallels the situation in some salt tolerant and salt sensitive lines 
of Brassica juncea (Ashraf and Naqvi, 1992). Previously, Semiz et al. (2012) observed 
that with the increasing salinity levels reduction in water potential, plant height, fresh 
yield, biomass production, seed yield, and 1000-grain (seed) weight of fennel 

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138 
(Foeniculum vulgare Mill.). Similar results were reported in peppermint 
(Khorasaninejad et al., 2010), Brassica juncea (Shanker et al., 2011), and in soybean 
(Taher-Soula and Mohammadi, 2013). 
Results of present study revealed that all the four genotypes of linseed did not 
express tolerance in terms of grain yield at salt level of 200 mM NaCl, which proved 
their sensitivity at this salinity level. However, these genotypes produced grains at 
lower level of salinity, i.e. 100 mM NaCl. This shows that native linseed genotypes can 
be grown on soils having higher than 100 mM NaCl for biomass production and not for 
grain yield. Moreover, salt stress severely reduced the branching and pods production in 
linseed and both of them have significant role in improving seed yield in linseed 
genotypes. It was also noted that dry land (soil) salinity affected growth and 
development of linseed and crop failed to reach maturity at highest level of salinity (200 
mM NaCl). Salt stress also drastically affected number of seeds in pods and hence 
reduced the overall seed yield. Salt stress not only reduced the number of seeds in pods 
but also severely reduced the seed weight and 1000 seed weight was drastically reduced 
under salinity stress. Reduction in seed yield and seed weight played a significant role 
in the reduction of oil contents in linseed. Hence, salt stress indirectly affects seed yield 
and oil contents by affecting the yield attributes of linseed.