Salinity Effects On Germination Stage of Bread and Durum Wheat Cultivars

In this study 5 salt concentrations (3.5, 7.0, 10.5, 14.0 and 17.5 dS m) and tap water (0.3 dS m ) as control were used to determine the effects of salinity on germination stage of 5 bread wheat (Golia, Gonen, Koksal - 2000, Pehlivan and Sagittario) and 3 durum wheat cultivars (Altintas - 95, Gediz - 75 and Pinar - 2001) in the laboratory of the Department of Field Crops, Faculty of Agriculture, University of Uludag. The experiment was carried out as randomized plots design with two factors and three replications. Water uptake, root lenght and shoot lenght, dry weight of shoot, dry weight of root, germination percentage, the reduction percentage of emergence and salt tolerance index decreased significantly depend on increasing salt concentration. As a result of resistance to salt for investigated genotypes under in vitro conditions, among the bread wheat cultivars, Koksal - 2000 and Sagittario were resistant for the other genotypes and Gediz - 75 and Pinar - 2001 with the highest tolerance was being investigated in durum wheat genotypes. Correlation analysis indicated significant relationships between salt concentration and all investigated parameters. Further study is required to see the effect of salt stress on germination of these genotypes under field conditions.


Introduction
Salinity is a serious problem affecting one third of the irrigation land and limiting the yield potential of modern cultivars.It has been estimated that salts affected nearly 950 million ha land in the world (Taghipour and Salehi 2008).In Turkey, the soil salinity problem is becoming an important constraint on crop production particularly in arid and semi-arid regions (Eker et al. 2006).For example; Şanlıurfa, Kaarapınar.
In generally, EC values between 0 and 0.8 dS m -1 are acceptable for general crop growth.Soil salinity class and general crop responses for each class: soil EC value 0-0.98 dS m -1 is non saline and almost negligible effects, 0.98-1.71dS m -1 is very slightly saline and yields of very sensitive crops are restricted, 1.71-3.16dS m -1 is slightly saline and yields of most crops are restricted, 3.16-6.07dS m -1 is moderately saline and only tolerant crops yield satisfactorily, and > 6.07 dS m -1 is strongly saline and only very tolerant crops yield satisfactorily (Kara and Kara Uysal 2010).
Germination is an important phase in the life cycle of crop plants particularly in saline soils as it determines the degree of crop establishment.Moud and Maghsoudi (2008), Saboora and Kiarostami (2006) have reported that several plants are sensitive to high salinity during germination and the seedling stage.Cereals are sensitive to elevated salinity at the germination and early seedling phase of development (Ghoulam and Fares, 2001).Wheat (Triticum aestivum L.) is a moderately salt-tolerant crop.In the field, where the salinity rises to 100 mM NaCl (about 10 dS m -1 ), rice (Oryza sativa L.) will die before maturity, while wheat will produce a reduced yield.Even barley (Hordeum vulgare L.), the most-tolerant cereal, dies after extended periods at salt concentrations higher than 250 mM NaCl (equivalent to 50% seawater).Durum wheat (Triticum turgidum ssp.durum) is less salt tolerant than bread wheat, as are maize (Zea mays) and sorghum (Sorghum bicolor L.Moench.) (Munns et al. 2006).
The present study was undertaken to study the response of bread and durum wheat cultivars to different levels of salinity and to determine their tolerance to salinity at germination stage.

Materials and Methods
The experiment was conducted in the laboratory of the Department of Field Crops, Faculty of Agriculture, University of Uludag.In the study five bread wheat cultivars (Golia, Gönen, Köksal-2000, Pehlivan and Sagittario), three durum wheat cultivars (Altıntaş-95, Gediz-75 and Pınar-2001) were used as experimental materials.The features of the varities is given in Table 1.
The experiment was carried out as randomized plots design with two factors and three replications.Salinity levels with electrical conductivity of the solution at 25 0 C were adjusted to control and EC values 3.5, 7.0, 10.5, 14.0 and 17.5 dS m -1 (deciSiemens m -1 ) using different NaCl concentrations.Tap water used as a control.Three replicates of 50 seeds were germinated on filter paper in petri dishes (9 cm diameter) with 10 ml each of the respective test solution.The seeds were allowed to germinate at 25 0 C in the dark for 8 days.A seed was considered to have germinated when the emerging radicle elongated to 1 mm (Atak et al. 2006).Germinated seeds were recorded every day at the same time.The effects of salinity treatments were studied by sampling on water uptake, root lenght and shoot lenght, dry weight of shoot, dry weight of root, germination percentage, the reduction percentage of emergence (RPE) and salt tolerance index (STI).
Water uptake was recorded at 12 and 24 hours after planting.Water uptake percentage was calculated by the formula given below (Rahman et al. 2008).Water uptake (WU%) = (W2 -W1/W1)100 W1 = Initial weight of seed W2 = Weight of seed after absorbing water in particular time (12, 24 hours) The reduction percentage of emergence (RPE) was calculated according to the following formula (El-Madidi et al. 2004).RPE = (1-Nx / Nc) x 100 "Nx" is the number of emerged seedlings under salt treatments and "Nc" is the number of emerged seedlings under control Salt tolerance index (STI) was calculated by the formula given below (Bağcı et.al. 2007).
Dry weight of root and were measured after drying samples at 70 o C for 48 h in oven (Atak et al. 2006).Data were analyzed separately for bread and durum wheat cultivars.Analysis of variance was conducted with JUMP statistics package program and differences among means were compared with LSD test.

Results and Discussion
Water Uptake (WU): According to results of variance analysis, water uptake in 12 hours (for salt concentration for bread wheats) and in 24 hours (for variety and salt concentration) were significant in both bread wheats and durum wheats.Interaction between genotypes and salt concentration was also significant for durum wheats (Table 2,3).The highest water uptake in 12 and 24 hours was observed from control applications in both bread and durum wheats (Table 4,5).Among the bread wheats the highest water uptake was observed in Golia, Köksal-2000 and Sagittario cultivars (Table 4).The highest water uptake was from control level with Gediz-75 cultivar (43.05%) (53.06%) among durum wheats (Table 5).When salt concentration increase to 14.0 and 17.5 dS m -1 the water uptake ability decrease in comparison to control.Root Lenght (RL): Analysis of variance revealed that the effect of NaCl concentration on root lenght of various genotypes and differences between different concentrations were significant.However, interaction between genotypes and concentrations was non-significant in both bread and durum wheats (Table 2,3).
Among various genotypes the highest root lenght was observed from Sagittario cultivar with 8.85 cm followed by Köksal-2000 (8.43 cm) in bread wheats and Pınar-2001 and Gediz-75 (5.97and 5.58 cm, respectively) in durum wheats.Concentrations means showed that maximum root lenght was recorded under control levels for bread wheats and control and 3.5 dS m -1 levels for durum wheats.Generally root lenght decreased as NaCl concentration increased (Table 6).

Shoot Lenght (SL):
The result of variance analysis showed significant variation for shoot lenght among bread wheat cultivars and different salinity concentrations.The interaction between genotypes and concentrations was also significant for bread wheat cultivars.For durum wheats only salt concentrations was found significant (Table2,3).
Mean of shoot lenght varied between 4.17 cm and 2.63 cm for varities and 4.68 cm to 1.89 cm for NaCl concentrations.The longest shoot lenght was observed in the 3.5 dS m-1 of Pehlivan and control of Köksal-2000 cultivars in bread wheat genotypes.Among durum wheats the longest shoot lenght observed in the 3.5 dS m -1 level by 3.97 cm followed by 7.0 dS m -1 level (386 cm) (Table 7).Dry Root Weight (DRW): Analysis of variance exhibited significant differences among salt concentration for bread wheat and among various genotypes, different salt concentrations for durum wheats for dry root weight.The interaction between genotypes and concentration between genotypes and concentrations was non-significant in both bread and durum wheats (Table 2,3).Concentration means showed that maximum dry root weight was observed under conrol level in both bread and durum wheats by 0.052 g and 0.040 g, respectively.Genotypic means showed that dry root weights ranged from 0.039-0.029g for bread wheats and 0.033-0.013g for durum wheats (Table 8).0,040 a 0,029 b 0,026 b 0,022 bc 0,017 c 0,004 d Dry Shoot Weight (DSW): According to result of variance analysis, among of variuos genotypes and salt concentrations were significant in both bread and durum wheats for dry shoot weight.The interaction between genotypes and concentrations was significant for only durum wheats (Table 2,3).
Among various genotypes maximum dry shoot weight was recorded in Sagittario and Köksal-2000 by 0.044 and 0.041 g respectively for bread wheats and Pınar-2001 with 0.033g for durum wheats (Table 9).Concentration means revealed that dry shoot weight was maximum in the 3.5 dS m -1 salt concentration level followed by 7.0 dS m -1 and control level in bread wheat and maximum dry shoot weight recorded under control level followed by 3.5,7.0and 10.5 dS m -1 levels of salt concentrations.The maximum dry shoot weight was recorded in genotype Pınar-2001 under control, 7.0 and 10.5 dS m -1 salt concentration levels (Table 9).0,032 a 0,026 a 0,026 a 0,027 a 0,019 b 0,004 c Germination Percentage (GP): Analysis of variance performed on germination percentage revealed significant differences among various genotypes, different salt concentration and interaction between genotypes and concentration in both bread and durum wheats (Table 2,3).
Genotypic means reveal that the highest germination (95.44 %) was recorded in Pehlivan followed by Köksal-2000 with 92.77 % for bread wheats (Table 10).Among various durum wheat maximum mean germination observed in Pınar -2001 (Table 10).Concentration means showed that maximum germination percentage was recorded under control and 3.5 dS m -1 salt level for bread wheats and under control level for durum wheats (Table 10).
Interaction of genotypes and concentrations showed that maximum germination percentage was recorded in the genotype Pehlivan by 100% under control for bread wheats and in the genotypes Gediz-75 and Pınar-2001 by 94.66 % under control and 14.0 dS m -1 salt level (Table 10).Results showed that by increasing NaCl concentration to 17.5 dS m -1 germination percentage decreased.

Reduction Percentage of Emergence (RPE):
According to variance analysis results, the reduction percentage of emergence was significantly influenced by different NaCl concentrations in both bread and durum wheats.Similiarly, the interaction between genotypes and NaCl concentrations in both bread and durum wheats were significant.The results showed that the reduction percentage of emergence of bread and durum wheats increased depend on increasing of salt concentrations (Table 2,3).
The lowest reduction percentage of emergence was recorded from control application followed by 3.5 and 7.0 dS m -1 for bread wheats and from control application for durum wheats.The highest was observed in 17.5 dS m -1 salt level in both bread and durum wheat genotypes (Table 11).
The highest reduction percentage of emergence was observed from Golia and Altıntaş-95 and Gediz-75 among bread and durum wheats, respectively.The lowest reduction percentage of emergence recorded in the genotypes of Sagittario and Pınar 2001 by 0.24 and 8.90 respectively (Table 11).Among the bread wheats the highest reduction percentage of emergence was obtained from Golia x17.5 dS m -1 interaction (68.35 %) and Altıntaş-95 x17.5 dS m -1 interaction among durum wheats (Table 11).
Salt Tolerance Index (STI): Variance analysis results showed significant variation for salt tolerance index among various genotypes and different salinity concentrations in both bread and durum wheats.The interaction between genotypes and concentrations was non-significant for bread and durum wheats (Table 2,3).
The highest salt tolerance index was determined from control and 3.5 dS m -1 NaCl application and the lowest salt tolerance index recorded in 14.0 and 17.5 dS m -1 salt concentrations.Among bread and durum wheats the highest salt tolerance index obtained from Köksal-2000 and Gönen, followed by Pehlivan (78.18 %) and Pınar-2001 and Gediz-75 cultivars, respectively (Table 12).Correlation Coefficients: In order to identify the relationship between salinity concentrations and other parameters the correlation coefficients were calculated.Significant negative correlation coefficients were found between salinity concentrations, water uptake in 12 and 24 hours, root lenght, shoot lenght, dry root weight, dry shoot weight, germination percentage and salt tolerance index, while positive significant correlations coefficients were found between salt concentration and reduction percantage of emergence in both bread and durum wheat varities.Water uptake in 12 hours was positively and significantly correlated with water uptake in 24 hours and root lenght in both bread and durum wheats.However, significant correlations were determined only between water uptake in 12 hours and shoot lenght for durum wheats and only between water uptake in 12 hours and dry root weight for bread wheats.Water uptake in 24 hours showed significantly positive correlation with root lenght in both bread and durum wheats and significant positive correlation with shoot lenght and negative significant correlation with reduction percantage of emergence for bread wheats.Root lenght exhibited significant correlations with all parameters in both bread and durum wheats.Shoot lenght was significantly correlated with all parameters except germination percentage and reduction percantage of emergence for bread wheats.Significant possitive correlations were found between dry root weight and dry shoot weight, germination percentage and salt tolerance index, while negative correlations were found between dry root weight and reduction percantage of emergence in both bread and durum wheats.Similiar results were obtained from dry shoot weight.Germination percentage showed significantly negative corelation with reduction percantage of emergence and positive correlation with salt tolerance index.Negative significant correlation coefficients were determined with reduction percantage of emergence and salt tolerance index (Table 13).
The study showed the parameters in the germination period of the investigated wheat varities were significantly influenced by NaCl concentrations.Kara and Kara Uysal (2010) reported that nearly all plants are sensitive to high salinity during germination and first development stage.In our study, the reduction was greater at higher NaCl concentrations for the both bread and durum wheat varities for all of the investigated parameters compared to control.
Decreases in water uptake was observed by increasing NaCl levels.Similiarly, a number of studies have demonstrated that water uptake in wheat is significantly reduced under salt or water stress conditions (Sabora and Kiarostami 2006;Moud and Mahgsoudi 2008;Akbarimoghaddam et al. 2011).However, Atak et al. (2006) reported that water uptake of cultivars did not vary much with NaCl levels.Seed absorbed water much faster during the first 6 hours.In our study, the means of water uptake in 12 hours of bread wheat cultivars also did not vary much with incerasing NaCl levels.Root and shoot lenghts are the most important parameters for salt stress because roots are indirect contact with soil and absorb water from soil and shoot supply it to the rest of the plant.For this purpose, root and shoot lenght provides an important clue to the response of plants to salt stress (Bahrani and Hogh Joo 2012).In the study, generally root and shoot lenght decreased as NaCl concentration increased and salt stress inhibited the growth of shoot more than root in both bread and durum wheat genotypes.Similiar observations have been reported in Atak et al. (2006), Moud and Mahgsoudi (2008), Akbarimoghaddam et al. (2011), Bahrani and Hagh Joo (2012).
As NaCl concentration increased, it affected dry root and shoot weight.Reduction of dry weights relatively depended on shoot and root lenghts.The similiar results reported by Ghoulam and Fores (2001) and Akbarimoghaddam et al. (2011).Kara and Kara Uysal (2010) obtained that from dry shoot and root weight showed that shoots and roots were inhibited severely salinity levels, however roots were more inhibited than the shoots.
In the study the results showed that by increasing NaCl concentrations, germination percentage decreased.Similiar decreases in germination percentage have been reported in the study of Sharma et al. (2004), Khan et al. (2005), Akbari et al. (2007), Abdel-Ghani (2009).However, Muhammad and Hussain (2012) negate all the above mentioned reports in their study.
Increasing NaCl levels in both bread and durum wheat genotypes decreased in the reduction percentage of emergence.Similiar results determined by Kara and Kara Uysal (2010).
Increasing NaCl levels decreased to salt tolerance index of bread and durum wheats.In the study the decreases reduced at 3.5 ≤ (dS m -1 ) NaCl concentrations.Similiar findings observed by Bağcı et al. (2007) and Kara and Kara Uysal (2010).Correlation analysis indicated significant relationships between salt concentration and all investigated parameters.A few non-significant relationships determined in the study between water uptake in 12 hours with dry root weight for durum wheat, dry shoot weight, germination percentage, reduction percentage of emergence, salt tolerance index, between water uptake in 24 hours with shoot lenght (for durum wheat), dry root weight, dry shoot weight, reduction percentage of emergence and salt tolerance index.The correlation coefficients were found significant between the other investigated parameters.Similiarly, Shahzad et al. (2012) reported positively and significantly correlations between shoot lenght and root lenght, shoot dry weight.Bahrani and Hagh Joo (2012) reported a negative correlation between germination percentage and root lenght, shoot lenght, dry root and shoot weight, which is line with the present findings.Bağcı et al. (2007) explained that the correlation coefficients were significant between salt tolerance index and dry root weight, dry shoot weight and germination percentage.The results of the current study in agreement with those results.
In the study, salt stress affected all investigated parameters.It can be concluded that to select cultivars for better salt stress tolerance at germination stage root and shoot elongation may be used as breeding criterions.The results in the study also indicated that among the measurements needed for a reliable ranking of genotypes for salt stress tolerance, an important emphasis should be given to the germination percentage and the determination of the salt tolerance index based on dry root and shoot weight.Munns et al. (2006) reported as durum wheat is less salt tolerant than bread wheat.In the study compared to bread and durum wheat varities, durum wheat varities were seen less salt tolerant, relatively.The genotypes Köksal-2000 and Sagittario were resistant for the others genotypes in bread wheat varities and Gediz-75 and Pınar -2001 with the highest tolerance was being investigated in durum wheat genotypes while Gönen and Golia in bread wheat genotypes and Altıntaş-95 with the largest susceptibility to salt stress for the investigated parameters.Further study is required to see the effect of salt stress on germination and seedling growth of these genotypes under field conditions.

Table 1 .
(Anonymous 2014)the varities used in the study., with green leaves color and semi-upright structure.Spike is medium density, stringy and white in color.Grains are small, egg-shaped and dark red in color and glassy properties.1000grainweight is 34-36 g.Good bread quality.Blending ability and fertilizer reaction is good.In artificial and natural conditions resistant to yellow rust, leaf rust and septoria.Recommended for Southeastern Anatolia Region, Cukurova and Trakya(Anonymous 2014).GönenMedium plant height with green leaves and a flat structure.Spikes are parallel-sided, white, dense structure and is stringy.The grains are round, hard and white in terms of color feature and mixed with durum wheat for its glassy feature.1000-grainweight is 30-32 g.Blending ability and fertilizer reaction is good.In artificial and natural conditions, moderately resistant to yellow rust and tolerant to leaf rust.Recommended for Aegean Region and the area of Coastal Belt(Anonymous 2014).

Table 2
WU 12: Water Uptake in 12 hours, WU 24: Water Uptake in 24 hours, RL: Root Lenght, SL: Shoot Lenght, DRW: Dry Root Weight, DSW: Dry Shoot Weight, GP: Germination Percentage, RPE: Reduction Percentage of Emergence, STI: Salt Tolerance Index Table 3. Analysis of variance for the parameters investigated in 3 durum wheat cultivars in response to salinity stres WU 12: Water Uptake in 12 hours, WU24: Water Uptake in 24 hours, RL: Root Lenght, SL: Shoot Lenght, DRW: Dry Root Weight,DSW: Dry Shoot Weight, GP: Germination Percentage, RPE: Reduction Percentage of Emergence, STI: Salt Tolerance Index

Table 4 .
Mean values of the parameters of water uptake in 12 and 24 hours for bread wheat cultivars, different salinity levels and interactions Bread

Table 5 .
Mean values of the parameters of water uptake in 12 and 24 hours for durum wheat cultivars, different salinity levels and interactions Durum

Table 6 .
Mean values of the parameters of root lenght for bread and durum wheat cultivars, different salinity levels and interactions

Table 7 .
Mean values of the parameters of shoot length for bread and durum wheat cultivars, different salinity levels and interactions

Table 8 .
Mean values of the parameters of dry root weight for bread and durum wheat cultivars, different salinity levels and interactions

Table 9 .
Mean values of the parameters of dry shoot weight for bread and durum wheat cultivars, different salinity levels and interactions

Table 10 .
Mean values of the parameters of germination percentage for bread and durum wheat cultivars, different salinity levels and interactions

Table 11 .
Mean values of the parameters of reduction percentage of emergence for bread and durum wheat cultivars, different salinity levels and interactions Bread

Table 12 .
Mean values of the parameters of salt tolerance index for bread and durum wheat cultivars, different salinity levels and interactions