沙漠研究 22-1, 311 -314 (2012 )"ICAL 1 / DT X"

Journal of Arid Land Studies－Refereed Paper－

Effect of Salinity on Grain Yield and Quality of Wheat andGenetic Relationships among Durum and Common Wheat
Najla TURKI*1), Moncef HARRABI2) and Kazutoshi OKUNO1)
Abstract: Salinity is a big constraint to crop quality and production. In the major wheat growing region of the world, wheatgrowth, yield and quality are affected by salinity. To solve this problem it is necessary to breed tolerant varieties through selectionand breeding techniques. The objective of the present study was to determine the salinity impact on grain yield, protein content andthousand kernel weight (TKW) among 55 varieties and accessions of common and durum wheat (16 winter wheat varieties and 39
spring wheat accessions). The results showed that salt treatment (100 mM of NaCl solution) depressed growth and yield productionin 45 common and durum wheat varieties. While 6 varieties of durum wheat, 3 accessions of durum wheat and 1 accession ofcommon wheat were insignificantly affected by salinity. Among them were Chryssodur from Greece, Saragolla, Silur and Dakterfrom Italy, Sculptur from France, Karim from Tunisia, Algeria 70-2 from Algeria, Ethiopia 201 and Ethiopia 229 from Ethiopia, andfinally the Morocco 85 accession of common wheat from Morocco. The decrease in grain yield might be caused by the salinity,
which induced reduction of photosynthetic capacity leading to less starch synthesis and accumulation in the grain. In addition theresults showed that winter wheat is more tolerant to salt stress then spring wheat and that durum type of wheat showed more tolerance
than common wheat. Moreover it appeared that salt accumulation increased protein content in five varieties and one accession ofdurum wheat. This variation maybe related to the relatively stable nitrogen metabolism under salt stress, which might contribute to
the higher protein concentration. TKW also decreased in all 10 varieties and accessions regardless of the species. Also the variationin response to salt of the varieties and accessions was closely related to genetic diversity among these species. Indeed Simple
Sequence Repeat (SSR) markers showed the presence of two groups, African-European complex and African-Asian complex of wheat.
Key Words: Bread wheat, Durum wheat, Protein content, Salt tolerance, SSR markers

1. Introduction
Food shortage and water deficit are the greatest problem
discussed nowadays, and it is linked to both with population
growth and water allocation to different sectors, such as
domestic, agronomic and industrial uses. According to theFAO Land and Plant Nutrition Management Service, over 6%of the world's land is affected by either salinity or sodicity.
Moreover the low water quality and the poor drainage systems
are the greatest causes of these stresses, and this problem ismore acute with higher evaporation, especially in arid and semiarid zones, where saline soils are widespread that induced thedecreasing of land productivity in many countries over theworld (Atlassi et al., 2009). Furthermore salinity affects soil
fertility and due to these situations some solutions were taken
to reduce this problem through soil reclamation or growing
tolerant species; however, soil reclamation is a very expensive
process, and then the selection of tolerant varieties of crops isstill the most practical solutions when salinity is low.
Besides, a genotypic difference within and between plant

species was noted related to the response of plants to salt stress(Saudi et al., 2003).
In this study, genetic variation and salt tolerance of wheat
genotypes were investigated as result of treatment with anutrient solution of NaCl. In addition, the effect of salinity on
grain yield, protein content and thousand kernel weight (TKW)
were determined. Moreover, genetic diversity among two
wheat species was studied by using Simple Sequence Repeat(SSR) markers

2. Materials and Methods
2.1. Plant materialA total of 55 varieties and accessions of durum andcommon wheat were used in this experiment where 16 werewinter wheat and 39 were spring wheat accessions. Theexperiments were conducted at the glass house. Wintervarieties were sowed on December, 2009 however springaccessions were sowed on April, 2010. The experiments
were carried out in pots as 10 seeds per pot. After emergence,
all accessions are thinned on 6 plants per pot.

* Corresponding Author: turki.najla@hotmail.fr
Tsukuba University, Tennodai 1-1-1, Tsukuba shi, 305-8577, Japan1)

Laboratory of Plant Genetics and Breeding Science, Graduate School of Life and Environmental Sciences, University of Tsukuba2)

Laboratory of Genetics and plant breeding, Department of Crop Sciences and Biotechnology, National Agronomic Institute of Tunisia (INAT), Tunisia

2.2. Salt stress induction
3 to 4 leaves salt treatment was applied during different
ontogenetic stages under various concentrations (0 and 100mMol). Electrical Conductivity (EC) was measured by using
EC meter.
2.3. Different traits
2.3.1. At seedling stages
Chlorophyll content was measured 21 days after salt
treatment by using SPAD-502 Chlorophyll Meter which
provides rapid and non destructive measurements of leaf
chlorophyll content.
2.3.2. At tillering stage
In this stage tiller’s number were taken among accessions
and varieties under control conditions compared to untouchedtreatment and also leaves number per tiller were determined.
2.3.3. At maturity stage
Spikes number and seeds number per spike: these traits
were calculated to evaluate the salinity effect on yield.
2.3.4. Quality analysis
Thousand kernel weight (TKW) in g: the high weight of1000 kernel is considered relevant to semolina yield. Theweight was determined with manual count of 100 seeds after
removing handpicking broken kernels and others impurities.
The weight of 100 kernels was multiplied by 10 to have the1000 kernels weight.
Protein’s concentration (in µg/ml): total protein wasquantified by using BCA protein Assay Kit.
2.4. Genetic relationships among durum and common wheat
2.4.1. DNA extraction
High quality genomic DNA was extracted from leaves(stage 4-5 leaves) using the cetyl- trimethyl-ammonium
bromide (CTAB). The DNA concentration was adjusted
to 20 ng/µl. SSR markers Wmc and Gwm markers wereused to detect polymorphism among 55 varieties andaccessions of durum and common wheat
2.4.2. Statistical analysis
Statistical analysis was performed using JMP software.
To compare means values student test was used. Levels notconnected by same letters are significantly different. To show
the relationships between different genotypes, a clustering
dendogram was drawn using NTSYS software.

3. Results and discussion
3.1. Seedling stage
All genotypes were watered until stage 3 to 4 leaves; Under
standard growth conditions, salt treatment was applied under
two concentrations (0 and 100 mMol). In seedling stage,

chlorophyll content changed with two main factors: genotypes
and NaCl concentration. Most of species ranged from highly
tolerant to salt stress as for Nasr (V13) variety from Tunisia to
low tolerant, such as variety: Carioca (V6) from Italy. Somespecies are medium tolerant to salt stress such as variety
Sculptur (V3) from France. According to some researchers,
salinity reduces net photosynthetic rate, transpiration rate, andstomatal conductance in plant species, increases chlorophyll
content at low salinity and degrades chlorophyll at high salinity(Ashraf, 2004).
Our statistical analysis (student test)
mentioned that the decrease of chlorophyll content issignificant in sensitive genotypes compared to high tolerant.
These findings are in agreement with results of many
researchers, who made similar conclusion (Khan et al., 2009).
3.2.Tillering stage
In some species the number of tillers decreased strongly
with the acuteness of salt stress load that is the case for V13
and V16 varieties concerning winter type for V45 and V51
varieties concerning spring type. Concerning common
wheat, tiller’s number decreased from 5 to 3 tillers per plant
which is the case of the varieties V74, V76, V83, V86, V88,V126, V128, V131and V225; and it decreased from 5 to 2tillers in the case of the variety V187. However in the caseof durum wheat, the number of tillers under salt stress ranged
from 3 (in the case of the varieties: V1, V2, V6, V12 and V14)
to 8 (in the case of V9). In the same concept, Nicolas et al.
(1994) found that salt stress during tiller emergence can inhibit
their formation and can cause their abortion at later stages.
Furthermore, when salinity levels are greater than 7.5 dSm−1
or 50 mM NaCl, most of the secondary tillers of moderately
tolerant genotypes were eliminated, and their number was
greatly reduced (Hendawy et al., 2005).
Statistical analysis of the data revealed that tiller’s number
was significantly (P<0.05) affected by NaCl concentration’s;
wheat genotypes as we have described showed a considerable
decreasing in tiller’s number among sensitive genotypes thenamong tolerant ones. Concerning leave’s number per tiller,
statistical analysis revealed that this trait was not significantly(P<0.05) affected by various species and NaCl concentrations.
3.3. Maturity stage
In maturity stage, number of spikes was significantly(P<0.05) affected both between species and by different salt
concentration treatment.
Furthermore, this trait was highly correlated with thenumber of tillers. Based on the results revealed in our work,
we can conclude that seed’s number per spike increased withthe acuteness of salt stress. Furthermore, seed’s number per
spike was calculated only among tolerant accessions andvarieties, where we notified a great reduction of this trait
however, for the remaining this value was equal to Zero.
These results was explained by the way that NaCl stressed
wheat during apex vegetative stage, had a shorter spikelet
development stage that, resulted in fewer spikelets per spike
which leaded to the reducing of the number of grains per
spikes (Akram et al., 2002).
3.3. Quality analysis
The results of this study mentioned that thousand kernel
weight (TKW) is so much affected by salt stress amongsensitive genotypes than tolerant ones. In our work, weconcluded that TKW was strongly reduced among different
genotypes. Furthermore, according to Wardlow et al. (1980),
this trait is related essentially to the duration of grain
development. In this concept, Gill (1979) showed in his workon barley that reduced grain yield under salt stress could be due
to reduced efficiency per day to fill the grains and consequent
more effective days and also due to disturbed starch-sugar
balance.
Concerning protein content, this trait was very important toevaluate pasta and semolina quality. In this work, salt
accumulation increased protein content in five varieties andone accession of durum wheat. The highest level of protein
was indetified for the variety “Chryssodur” from Greece by
500 µg/ml. However, the lowest value was notified by thevariety “Silur” from Italy by 180 µg/ml.
This variation of protein content was related to genetic
diversity among different genotypes, in the same concept,
3.4. Genetic relationships among durum and common wheat
A total of 67 bands (alleles) on 55 genotypes (selectedbasely from different continents like Africa, Europe and Asia)
were obtained by using 160 SSR markers as showed by Table
1; we selected 10 high quality polymorphic primer pairs fromtwo sources and these primers were used for genotyping. The
number of alleles ranged from 7 to 11 and the primer“GWM131” detected the highest number of alleles.

4. Conclusion
In this study, salinity induced variations in grain yield andquality were larger among sensitive genotypes then salt tolerant
ones. These results suggested that breeding and the use ofsalt-tolerant wheat cultivars might be the most promisingstrategies for harvesting higher grain yield of best quality undersaline conditions. Finally, results showed that winter wheat
was more tolerant to salt stress then spring wheat and that
durum wheat showed more tolerance than the common wheat
and this variation was strongly related to the genetic diversity

Table 1. Number of screened SSR loci and number of alleles
detected in durum and common wheat
S ource ofSSR

Not
Polymorphic

Polymorphic

Number ofalleles

WMC

100

428

GWM

60

639

Total

160

1067v1v9v5v12v2v14v7v8v30v59v225v3v10v16v15v28v25v4v13v6v11v26v41v54v60v88v19v37v43v57v186v187v42v45v58v48v51v53v126v128v131v71v74v76v86
V47v179v49v62
v63
v81v83v144v161
v52
0.07

0.28

0.48

0.69

0.89

CoefficientFig. 1. Dendogram of 55 wheat genotypes showing the genetic
similarity based on 67 alleles detected by 10 SSRs using
UPGMA cluster analysis

among these genotypes. In this concept appears the role ofe-SSR markers in detecting polymorphism among different
genotypes of wheat that become useful for assaying molecular
genetic diversity.
In this study, many cases of null alleles were observed andaccording to some researchers Null alleles are common inwheat (Eujay et al., 2001). To estimate genetic distance moreaccurately, combined analysis were carried out using all theSSR bands together. A clustering dendogram (Figure 1) wasdrawn to show the relationships between different genotypes.
Two main groups (A and B) were observed where the first one
showed the clustering of genotypes of Africa and Europe andthe second one included genotypes from Africa and Asia. We
can conclude from this separation that African genotypes
shared some alleles (similarity) with European and Asiangenotypes. But European and Asian genotypes didn’t show
any similarity. The coefficient of similarity ranged generally
from 0.26 to 0.81. Among winter wheat, this coefficientranged from 0.48 to 0.79 however among spring wheat, it
ranged from 0.26 to 0.81. Also the similarity coefficientvaried among the same species where it ranged from 0.27 until
0.8 in the case of durum wheat while it ranged from 0.27 until
0.81 in the case of common wheat. Based on this separation,
we can conclude that African genotypes shared some alleles(similarity) with European and Asian genotypes. But
European and Asian genotypes didn’t show any similarity.
Also in this study, winter wheat genotypes were selected in thefirst group where it was absent in the second one, however
spring wheat genotypes was observed in both of these groups.
To summarize these results, we can conclude that thisseparation between all genotypes was based essentially on
geographical criteria otherwise it was difficult to separate
between durum and common wheat.

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