فهرست مطالب اشکبوس امینی

Black rust is one of the important fungal diseases that widely affects the quantity and quality of wheat in many regions of the world. The damages caused by black rust disease can be more than other pathogens in wheat and its importance is such that millions of hectares of healthy fields with high production potential can be destroyed in less time. Destroy it completely in one month. Resistance is one of the genetic characteristics of the host that plant breeders use to produce cultivars. Lines that are recognized as resistant in a survey can be used as a source of resistance in another breeding program. Genetic resistance reduces or eliminates the consumption of chemical poisons, and as a result, it is considered as the most economical and healthiest method of combating plant diseases. Accordingly, in order to statistically investigate some physiological markers related to resistance to black rust disease, 24 bread wheat genotypes including 8 cultivars and 16 promising lines were studied. In this study, two varieties MV-17 (disease-resistant variety) and Morocco (disease-susceptible variety) were selected as controls in this study due to their different behavior in resistance to wheat black rust.

Material and Methods: 

This experiment was carried out in 2019 in the greenhouse of the Research Institute of Plant Breeding and Seed Preparation under the conditions of infection and non- infection with the native race TKTTF of wheat black rust disease and in the form of a randomized complete block design with four replications. Physiological traits including relative leaf water content (RWC), cell membrane stability (MP), electrical conductivity (EC), chlorophyll content (SPAD) and chlorophyll fluorescence were measured and recorded.

At the probability level of 1%, a significant difference between genotypes was observed and the interaction effect of disease x genotype was significant for all traits, which indicates the non-homogeneous difference of genotypes for the studied traits in two conditions of infection and non- infection. Also, for all measured traits, there was a significant difference between two different levels of disease infection, which shows the effect of the black rust pathogen on the relative content of leaves, membrane permeability, electrical conductivity, chlorophyll concentration, primary fluorescence, fluorescence It has maximum, variable fluorescence and photochemical efficiency of photosystem II. The results showed that pathogen contamination increases the relative water content, chlorophyll concentration, membrane permeability, initial fluorescence, maximum fluorescence, variable fluorescence, photochemical efficiency of photosystem II and decrease in electrical conductivity. Based on all studied physiological traits of genotypes MV-17, C-98-17, C-98-11, C-98-5, C-98-12, C-98-18, C-98- 16, C-98-3 and CD-94-9 were identified as the genotypes that showed more resistance to the disease agent. There was a high correlation between initial fluorescence, maximum fluorescence, variable fluorescence, photochemical efficiency of photosystem II, membrane permeability and electrical conductivity in response to stem rust. Based on Ward's cluster analysis and detection function analysis, the genotypes were divided into four separate groups in the conditions of infection and non-infection with black rust. They were placed in a group. While, in the condition of no disease contamination, 6, 9, 4 and 5 genotypes were clustered in four separate groups, respectively.

This study showed the effect of East Azerbaijan stem rust TKTTF race on the physiological traits of winter cultivars and lines of wheat. This race caused changes in the studied physiological traits in both experimental conditions, from this output it can be concluded that the resistant lines are more resistant to the disease than the commercial variety and are recommended as selected lines in breeding programs should be used. It is worth mentioning that according to the results of the grouping of genotypes and also the placement of valuable genotypes in terms of relative water content traits, membrane permeability index, chlorophyll content, initial fluorescence, maximum fluorescence, variable fluorescence, and photochemical efficiency. Photosystem II and electrical conductivity in the first and second groups in the conditions of disease infection and non- infection, it was concluded that the results of cluster analysis had a good relationship with the results of variance analysis and comparing the average of the studied traits. The results showed that the physiological traits measured in response to black rust disease have diversity. Therefore, possible genotypes with resistance to this pathogen can be identified by using the changes of these traits. Also, considering the relationship between the results obtained from the evaluation of physiological and pathological traits, the possibility of using physiological traits as indicators related to resistance to wheat black rust disease was benefited. In other words, the physiological indicators used were able to detect the existence of diversity and response to resistance to black rust disease and they can be used as physiological indicators related to resistance to black rust disease of wheat. Examining different traits in different environmental conditions has shown that the way the genotypes act and respond to the pathogen changes with the change of environmental conditions. For this purpose, these studies should be carried out in several years and in different environments. It is also recommended to carry out the above test using agricultural traits at the stage of the sorghum plant as well as biochemical traits related to the disease.

 Yield under stress conditions has never been an accurate criterion for selecting drought-tolerant genotypes, and the goal of preparing drought-tolerant cultivars has always been to create cultivars that relatively tolerate stress better compared to other genotypes and in the same agricultural conditions, they show less yield loss. In most studies, only the seed yield is considered for the field selection of crops, while some researchers believe that in order to be more efficient in breeding compatible and superior cultivars in arid and semi-arid regions, the indicators that are effective in identifying the stability of cultivars under drought stress conditions should be identified and used them as selection index in addition to seed yield, therefore, the relative uield status of genotypes in drought stress conditions and water conditions is a starting point for identifying and selecting genotypes for improvement in dry environments. In semi-arid regions where the distribution of rainfall is not proportional, the yield potential in stress conditions is not considered the best criterion for drought tolerance, but in addition to yield stability, the comparison of yield in stress and optimal conditions is a more suitable criterion for the reaction of genotypes to moisture stress. Due to the fact that most of the studies related to indicators in crop species and especially wheat are done only in one place and one year and finally in a specific environment and the results are generalized to all environments and the variable effects of year and place are not taken into account in the calculation of indicators. In this regard, this research was carried out to evaluate the genotypes of autumn wheat in terms of drought tolerance, to select the best drought tolerance indices and to identify drought stress tolerant cultivars in different regions of the country's cold climate.

In this research project, 20 genotypes under normal irrigation and water deficit conditions in the form of randomized complete block design (RCBD) with three replications in the research stations of Karaj, Mashhad, Miandoab and Arak, in the crop years of 2017-2018 and 2018-2019 were investigated. In order to investigate the drought tolerance of the genotypes, different tolerance and stress sensitivity indices were determined for the genotypes under investigation and the genotypes were grouped based on the sensitivity and tolerance to drought by each of these indices. Principal component analyzing was also used in order to summarize the data and draw a diagram based on the first two components and identify the desired indicators. Finally, biplot analysis was used to group genotypes and indices based on drought tolerance criteria.

Stress decreased the Yield of genotypes, but the amount of reduction was different in different genotypes. The average grain yield for all genotypes under normal irrigation conditions and drought stress at the end of the season was 7.002 and 5.215 tons per hectare, respectively, which showed that the stress conditions caused a decrease of about 25% in grain yield compared to normal irrigation conditions. The environmental and agricultural conditions of different regions and the studied years caused differences in the estimated indices so that the ranking of genotypes changed based on different indices in different years and regions therefore, it is better to carry out studies on stress tolerance indices in several places and several years so that the process of functional changes of different cultivars and genotypes is correctly determined and as a result, there is more confidence in the calculated tolerance and sensitivity indices. Genotypes G4, G2, G16 and G5 showed higher yield in both conditions. STI, MP, GMP, MSTI1, MSTI2, YI, HM, and RR had a positive and significant correlation with grain yield under normal and stress conditions, and therefore, they can be used for more favorable selection of drought tolerant genotypes.  Principal component analysis showed that indicators can be grouped using the first two components. The first principal component explained 53.16% of the changes in the total data and had a positive and significant correlation with yield in normal and stress conditions as well as MP, STI, GMP, YI, MSTI1, MSTI2, HM and RDY indicators. Due to the high correlation of this component with yield under normal and stress conditions, this component was named as the yield potential component under normal and stress conditions. The second estimated component justified 42.33% of the total data changes and showed a positive and significant correlation with yield in normal conditions and SSI, TOL, ATI, SSPI and RR indices. It seems that this component is able to identify genotypes that have high yield under stress conditions. Biplot analysis showed that HM, MP, STI, MSTI1, MSTI2, GMP, RDY, YI, and SNPI indices had a positive and high correlation with performance under stress and normal conditions. So that the sharp angles between these indices showed their positive and very high correlation with each other. RDI and YSI indices had a negative correlation with performance in normal conditions and RR, SSI, TOL and SSPI indices had a negative correlation with performance in stressful conditions.

 In order to achieve varieties resistant to drought stress by using indices, in order to prevent the mutual effects of the environment in the genotype, the experiments should be carried out in many years and places so that the effects of the environment in the calculated indices can be reduced and more reasonable results can be obtained. Finally, G4, G2, G16, G5 and G17 genotypes can be selected as genotypes with high performance under normal and stress conditions.

In order to estimate the heritability and genetic diversity of some seedling biometric traits in response to black rust (stem rust) disease, 24 wheat genotypes in the 2020 at the research greenhouse of the Seedling and Seed Breeding Research Institute was evaluated in the form of a randomized complete block design with four replications under the conditions of infection and non- infection to the native race TKTTF black rust. Based on the results, the genotype ´ disease condition interaction, was significant for all traits at the 1% probability level. Also, a significant difference between the genotypes in terms of seedling height, seedling fresh weight, seedling dry weight, and seedling fresh weight to dry weight ratio was observed. The results showed that pathogen infection causes a decrease in seedling height and an increase in seedling fresh weight, seedling dry weight, and seedling fresh weight to dry weight ratio due to the presence of pustules caused by disease. Under black rust infection, the highest heritability was observed for seedling dry weight (42.85%) and the lowest heritability was related to seedling height trait (8.78%). In the absence of black rust disease, the highest heritability was observed for the ratio of fresh weight to dry weight of seedlings (53.66%) and the lowest heritability was related to seedling height (51.25%). The results showed that black rust infection affects seedling traits and the diversity between genotypes can be used to improve wheat genotypes.

It is necessary to develop new sustainable high-yielding cultivars in drought-prone areas. The yield of cultivars in different environments is different and their yield rating varies from one environment to another. Reduction of interaction effects and production stability in different environments is one of the goals of breeding program and introducing cultivars in different regions. The purpose of this study was to evaluate the genotype ×environment interaction effect in different cold climate regions of Iran and to determine the superior genotypes and introduce the most stable wheat genotype in these conditions.

To investigate of the stability of 17 wheat genotypes along with Mihan, Heydari and Zarineh cultivars (check cultivars) under water deficit conditions, these genotypes were tested in a randomized complete block designwith three replications in the research stations of Karaj, Hamedan, Mashhad, Jalgarokh, Miandoab and Ardabil in the two crop years 2018 to 2019. In order to check the stability of genotypes, AMMI and GGE-biplot analysis were used.

AMMI analysis showed that the first ten main components were significant and in total explained nearly 97% of the changes in the genotype × environment interaction and the two main components, the first and the second, contributed 46% to the expression of the genotype × environment interaction. Based on SSiASV and SSiWAAS indices G2, G19 and G4 were identified as the best genotypes, respectively. The G3 was the most stable genotype. GGE-biplot analysis showed that G16, G1, G3 and G7 had the highest general stability compared to other genotypes. G16 can be considered as a desirable genotype that has high average yield and high yield stability. G12 and G9 genotypes were in the next ranks. On the other hand, the ideal environment was not observed, but the environments of Mashhad, Ardabil and Karaj in the first year can be introduced as the closest environments to the ideal environment for the selection of superior wheat genotypes in water deficit condition in the cold climate of the Iran.

G3 was the most stable genotype, and then G16, G1 and G7 had the most general stability compared to other genotypes, so that G16 was identified as the desired genotype with high average yield and high yield stability. The environments of Mashhad, Ardabil and Karaj in the first year can also be used to select superior genotypes.

Stem rust or black rust is one of the most important fungal diseases that widely affect wheat yield and quality in the world. Therefore, the selection of genetic materials resistant to stem rust in the breeding programs is necessary. In this study, 24 winter wheat genotypes including eight varieties and 16 elite lines were evaluated at the adult plant and seedling stages using a randomized complete block design under the influence of local stem rust race TKTTF. Disease indices including the type of infection, the severity of infection, the coefficient of infection, the area under the disease progress curve (AUDPC), the relative area under the disease progress curve (rAUDPC), and genotype reaction were recorded. Significant differences were observed among the genotypes for all disease indices. Based on all indices, MV-17 and C-98-17 were resistant and C-98-14, C-98-9, Bolany, and Morocco were susceptible. Pearson’s correlation coefficients revealed a significant positive correlation between field type of infection, the severity of infection, the coefficient of infection, AUDPC, and rAUDPC at the field, and between greenhouse type of infection and genotype reaction at the greenhouse. Based on cluster analysis by Ward’s method, all the genotypes were classified into four groups (R, MR, MS, and S) in the adult plant stage and into two groups (R and S) at the seedling stage. The resistant genotypes can be used in the breeding programs for improvement of the stem-rust-resistant genotypes.

Studying the nature of the genotype×environment interaction provides the possibility of identifying stable and compatible genotypes for breeders, and it has always been one of the important issues in the production and release of new stable and high-yield cultivars in breeding projects. The current research was conducted with the aim of identifying the response of genotypes in each of the studied areas, based on AMMI and GGE biplot models and better understanding of the genotype×environment interaction and determining the level of public and private stability of cultivars. Twenty facultative and winter wheat genotypes were cultivated and evaluated in nine regions (18 environments) during the two crop years of 2017 to 2019 in a randomized complete block design with three replications. In order to analyze the compatibility and stability of genotypes, AMMI and GGE biplot models were used. The results of AMMI analysis showed that the main effect of genotype, genotype×environment interaction effect and the first six principal components were significant at the 1% probability level. The first and second principal components explained about 51% of the sum of squares of the genotype×environment interaction effect. Based on SSiASV and SSiWAAS simultaneous selection indices, genotypes G13, G1, G3, G2, G6, G16, and G7 were identified as the best genotypes. Biplot analysis showed that the genotypes G1, G3, and G6 with average yield had the highest general stability compared to other genotypes. None of the genotypes can be considered as desirable genotypes that have high average yield and high yield stability, but genotype G16 and in the next stage the genotypes G1 and G13 were close to the ideal genotype. Polygon biplot model divided environments into two environmental groups (macro environment) and genotypes into four groups. The first environmental group included Kar1, Kar2, Qaz1, Qaz2, Ham1, Ham2, Mia2, Egl1, Jol2, Ard2, and Ara1 environments, with G16, G17, and G4 genotypes having the highest yield. The second environmental group included Mas1, Mas2, Mia1, Ard1, Jol1, Ara1, and Egl2 environments, and in this macro environment G2, G11, G7, and G12 genotypes had the highest yield. Finally, the examination of the relationships among the environments showed a very high correlation among the investigated environments, which indicated the similar behavior of the genotypes in the most of the tested environments.

Considering the importance of maize production and the impact of water deficit stress on reducing the yield of maize, estimating the genetic components and heritability of traits for determine the breeding method under water deficit stress is essential in breeding programs. The generations drived from a cross between two inbred lines of maize including B73 (maternal line) and MO17 (paternal line), SC704 (F1) as well as F2, BC1, BC2 and F3 generations in order to estimate the genetic effects and heritability of yield, yield components and morphological traits were studied. Seven maize generations using the generations mean analysis under the full irrigation, mild and severe water deficit conditions were evaluated. The experiment was conducted in the form of randomized complete block design with 20 replications per experimental unit during two cropping seasons (2018-2019) at the Agricultural Research Station of University of Tabriz. The results of two-year combined analysis of variance and mean comparisons under three different irrigation regimes showed that water deficit stress significantly reduced all of the studied traits (except root/shoot ratio). The generations mean analysis showed the high contribution of non-additive gene effects for the genetic control of grain yield, ear diameter, number of kernel row, ear weight (in full irrigation conditions), 100 grain weight, plant height, fresh shoot weight and biological yield traits. According to these results, selection in the advanced generations and the breeding method based on hybridization can be effective to improve these traits. Also, the significant contribution of additive gene effects in controlling the inheritance of ear length, ear weight (in both stress conditions) and root/shoot ratio traits indicated that selection in early segregating generations and inbred parents can be effective for breeding of these traits and taking advantage of additive variance. Hybrid SC704 and inbred MO17 compared with the inbred B73 showed the lowest variation percentage under the water deficit stress conditions, which indicated their high yield potential and stability in the stress conditions.

Salt stress affects 20% of global cultivable land and is increasing continuously owing to the change in climate and anthropogenic activities. Globally, wheat is cultivated on non-saline and saline soils, covering an area of approximately 214.79 million hectares (Becker-Reshef et al., 2020). Salinity stress negatively affects the growth and development of wheat leading to diminished grain yield and quality. For this reason, it is important to develop effective strategies to improve yield through salt tolerance. The breeding of salinity-tolerant cultivars through selection and breeding techniques is one of the effective methods in the production and exploitation of saline soil and water.

In order to study the effects of salinity stress on grain yield, phenological and morphological traits and salinity tolerance indices among bread wheat elite lines, two separate experiments in a randomized complete block design with three replications were conducted in two saline and normal environments during two cropping years of 2019-2021. 20 wheat cultivars and elite lines cultivated at the South Khorasan Agricultural and Natural Resources Research and Education Centre. After determining the grain yield in both conditions, MP, GMP, TOL, HARM, STI and SSI indices were calculated and using SAS software, their correlation with grain yield was investigated and using STATISTICA software, the three-dimensional distribution of each cultivar and line was plotted. Combined analysis of variance was performed to determine the main and interaction effects in the two years of the experiment and the means were compared by Duncan's multiple range test at the level of 5% probability. Bartlett's uniformity test was performed before the combined analysis of variance. Analysis of variance and mean comparison was performed using SAS-9.0 software and cluster analysis was performed by Ward method through StatGraphics program.

The reaction of wheat lines were different in two environments and salinity stress reduced grain yield. The experimental results showed that different wheat lines react differently to salinity stress. Salinity stress decreased grain yield and morphological traits in all lines compared to normal conditions. Salinity stress shortens intermediates and reduces plant height and consequently leaf and shoot dry weight by reducing cell proliferation and reducing dry matter accumulation (Dura et al., 2011).The difference between cultivars and lines in terms of all phenological, morphological and grain yield in two years of the experiment was significant, which indicates the existence of appropriate diversity in the wheat elite lines. The existence of this genetic diversity can be very useful for selecting high-yielding wheat cultivars in salinity conditions. In the first year of implementation, Narin, line No. 3 and Barzegar with an average of 6494, 6227 and 6072 kg/ha, respectively, in normal conditions and Barzegar, line No. 18 and Narin with an average of 6361, 6166 and 5805 kg/ha respectively, had the highest grain yield under salinity stress. In the second year of the experiment, line number 16, 10 and 4 with an average of 5388, 5305 and 5155 kg/ha in normal condition and Narin, Barzegar and line No. 3 with an average of 4930, 4611 and 4180 kg/ha respectively, had the highest grain yield under salinity stress. Naturally, wheat lines grain yield under salinity stress was lower than their yield under normal conditions. Under these conditions, the plant leaf area of is greatly reduced, which reduces the photosynthetic capacity of the plant, and as a result, the amount of dry matter produced and ultimately the grain yield of the plant is reduced (Munns et al., 2002).

For selecting wheat cultivars and lines in the areas that are most exposed to salinity stress, YI, HM, GMP, STI, MP, RSI and YSI indices and in areas not exposed to salinity stress, MP and STI indices are suggested. Barzegar and Narin check cultivars and line number 10 were determined as the most tolerant and lines No. 14, 13 and 20 as the most sensitive lines to salinity stress by different indices. Cluster analysis of lines based on STI index led to the placement of Barzegar and Narin cultivars and lines No. 3, 4 and 18 in the first cluster in which the mentioned lines have fewer days to heading and in contrast more days to maturity, grain filling period, thousand-grain weights and higher grain yield.

Bread wheat is one of the most important food crops that is grown in different climatic conditions across the world. One of the important factors for this wide adaptability is the role of vernalization genes in different wheat genotypes. Therefore, identification of allelic variations of these genes provides an opportunity to determine growth habit, prediction of cold tolerance and adaptability of bread wheat genotypes to different climatic conditions. In this study, growth habit of 40 promising bread wheat genotypes was evaluated in the field and glasshouse during two and one cropping seasons, respectively. Allelic variation in VRN-1 and VRN-3 loci was also determined using nine locus-specific primer pairs. In VRN-A1 locus; Vrn-A1a, Vrn-A1b, Vrn-A1c and vrn-A1 alleles had frequencies of 7.5%, 7.5%, 10% and 67.5%, respectively. In this locus, three genotypes did not produce any band. In VRN-B1 locus; dominant and recessive alleles had frequencies of 52.5% and 47.5%, respectively, and in VRN-D1 locus; dominant and recessive alleles had frequencies of 60%, 40%, respectively. In VRN-3 locus; the majority of genotypes (97.5%) had recessive allele (vrn-B3). Results of this study indicated that different alleles of VRN-A1 locus had more influence on field growth habit as compared to VRN-B1 and VRN-D1 loci, and different combinations of these alleles resulted in range of various field growth habits from true spring to true winter. The results of this study can be used in the national bread wheat breeding programs for pyramiding favorite alleles of vernalization genes to improve adaptability of bread wheat genotypes for different target agro-climatic zones of Iran.

To identify bread wheat genotypes with higher grain yield and stability in saline regions of Iran, 17 elite genotypes along with three salinity tolerant control (Ofogh, Narin and Sistan) were evaluated in five regions including Birjand, Yazd, Zabol, Isfahan and Kerman, during two consecutive cropping seasons (2016-2018) under saline conditions. In all regions, the experiments were performed based on the randomized complete block with four replications. The result of combined analysis of variance indicated that the interactions of year×location×genotype were significant. To dissection of genotype-by-environment interaction (GE) and yield stability of genotypes, AMMI analysis and several parametric and non-parametric statistics were estimated. Based on AMMI2's biplot and stability statistics, G1, G2, G3, G6, G9, G10 and G20 genotypes were identified as the most stable genotypes. The results of correlation analysis showed that among all stability statistics, only ASV had a positive and significant association with grain yield. Taken together, our results revealed that G9 genotype had the highest grain yield (4.60 t. ha–1); hence, this genotype can be recommended as a high-yielding and stable genotype for cultivation in saline-prone regions of Iran.

In order to evaluate variation and reaction of 40 wheat genotypes to salinity tolerance and assess the association of 27 microsatellite markers with salinity tolerance and morpho-physiological traits measured under normal and salt stress conditions, the present study was conducted. The results of analysis of variance in two environments showed significant difference among genotypes for all traits, indicating genetic variation among them. Based on the results of combined analysis of variance, the effect of the environment for all traits and the effect of Genotype × environment on most of the traits was significant and it was determined that the response of the evaluated genotypes to salinity stress was different In two environment, the highest variation was belonged to grain yield and its component and biological yield. Cluster analysis in salinity stress based on traits with significant genotype × environment, classified the genotypes into 3 groups i.e. tolerant moderate and sensitive. Association analysis using 27 microsatellite markers, SSR markers with 11 traits measured in two normal conditions and salinity stress for all genotypes was conducted through a mixed linear model (MLM) The study of population structure as a precondition for communication analysis showed that there are 2 probable subgroups (K = 2) in the population studied, which was confirmed by the results of the plot formula. The decomposition of the association analysis using 27 SSR markers with 11 traits measured in two conditions based on mixed linear model (MLM) was carried out using the population structure matrix. Based on the results, 29 locations had a significant relationship with the evaluated traits in the normal environment, while in the salinity stress environment, this number increased to 40 locations. The existence of common markers among some of the studied traits such as the significant associate between S16-1 and 3 traits in normal conditions and with 5 traits in the salinity medium can be due to the polytrophic effects of these markers and possibly the connectivity of genomic locations controlling these traits. S6-3 and S12-1 markers were identified as markers that associated with grain yield in salinity condition and S11-4 marker was identified as marker that related with biological yield in both environmental Conditions. Finally, given the results obtained, if the results are confirmed in other genetic fields, these markers can be used in corrective programs.

Wheat is mostly cultivated at rainfed condition in Iran, so, water deficit stress has much effect on yield reduction. Hence, breeding activities are necessary for introduction of wheat tolerant genotypes to water deficit stress. In order to estimate the heritability and genetic correlation between traits of 36 wheat genotypes, an experiment was conducted in two separate conditions (water stress and non-stress) based on a randomized complete blocks design with three replications. Studied traits in wheat genotypes under water stress and normal condition showed significant differences for environment, genotype and genotype× environment interaction at 1 and 5% level of probability. The results of the factor analysis showed that the 6 first factor in normal condition explained 81.13% of total variance, and the 5 first factor in stress condition explained 74.96% of total variance. Estimation of genetic correlations based on REML approach revealed that biological yield, harvest index and number of grains per spike had the highest correlation with grain yield and these characteristics are of important for selecting the varieties with high yield under non-stress and stress conditions. Estimation of heritability based on REML approach showed that number of days to heading had the highest amount of heritability in both normal and stress conditions.

Salinity stress is a serious threat of plant growth and production over the world. Soil salinity is the major problem, which affects the yield of wheat crop. It is commonly observed in arid and semi-arid regions of the world (Atlassi et al., 2009). Crop growth reduction due to salinity is generally related to the osmotic potential of the root-zone soil solution. The relative salt tolerance of wheat crop is 7.0 dS∙m−1 and its yield decrease is 25% at 9.0 dS∙m−1 (Kramer and Amtmann, 2012). The reduction in growth and yield varies between cultivars (Sultana et al., 2000). The varietal differences in salinity tolerance that exist among crop plants can be utilized through screening programs by exploiting appropriate traits for salt tolerance. The recently developed cultivars form a much diversed genetic base and may therefore possess a wider range of salts stress tolerance. In order to study the effects of salinity stress on grain yield, yield components, morphological traits and concentrations of Na+ and K+ of eight wheat cultivars and elite lines, two separate experiments in randomized complete block design with three replications were conducted at two places of Amirabad (saline condition) and Mohammadieh (none saline condition) in 2009-2010. Four elite lines including MS-88-8, MS-88-16, MS-88-17 and MS-87-8 and four salt tolerant cultivars including Ofogh, Arg, Bam and Kavir investigated. The first experiment conducted at the Research Farm of Birjand University located in Amirabad region which texturally the soil was sandy clay loam, with pH=8.2 and EC=13.69 ds.m-1. The second experiment conducted at the South Khorasan Agricultural and Natural Resources Research and Education Center located in Mohammadieh region which texturally the soil was loam, with pH=8 and EC=4.79 ds.m-1. Investigated traits were including flag leaf area, spike length, peduncle length, plant height, number of grain per spike, thousand grain weight, biological yield, grain yield, harvest index, Na+ and K+ concentrations and stress indices. Data analyses were performed using two-way analysis of variance with SAS 9.1. Means of treatments were compared according to Duncan test at the 5% level. Results showed that salt stress led to significant reduction on all morphological traits and had the most effect on plant height. Salt stress had no effect on number of grain per spike, 1000 grain weight, and Na+ and K+ concentration in shoot. Biomass and grain yield in salt stress condition decreased 38.2 and 44.5 percent, respectively. MS-87-8 and Ofogh with grain yield of 4.02 and 3.72 ton/ha were better than Bam and Kavir checks and same as Arg. The best indices for selection of tolerant cultivars were HARM, STI and GMP, which Arg and MS-87-8 identified as the most tolerant based on them. The results of this experiment showed that salinity significantly reduced grain yield, biomass and morphological traits of wheat cultivars and promising lines. Meanwhile, Arg cultivar and then MS-87-8 line had the highest grain yield and identified suitable for saline condition. Due to the presence of salinity resistance genes, they can be used for breeding of cultivars with high potential yield and also to cultivate in saline conditions.

Salinity stress is one of the major abiotic stresses in arid and semi-arid regions of the world, such as Iran. High genetic diversity for salinity tolerance has been observed in Iranian bread wheat genotypes. In this study to finding interrelationships between different traits and performance evaluation of wheat genotypes was used biplot method. In this study, 110 bread wheat genotypes were evaluated in two conditions (non-stress and saline stress) at the research field of the National Salinity Research Center (NSRC). The salinity of water used in irrigation in saline and non-stress conditions was 10 and 2 dS.m-1 respectively. The results revealed that there was a strong positive association between biological yield and harvest index with seed yield in both non-stress and saline conditions. Therefore, it seems that biological yield and harvest index could be used as a suitable criterion in selecting for increased seed yield in wheat in both non-saline and saline conditions. In this research among 110 studied bread wheat genotypes, promising advanced lines Salt22, Salt29 and Salt30 were identified as the most salinity-tolerant genotypes that these lines can be utilized for salt-affected areas and as donor parents in wheat breeding programs for further improvement of germplasm for salinity tolerance.

Salinity stress is one of the major abiotic stresses in arid and semi-arid regions of the world, such as Iran. High genetic diversity for salinity tolerance has been observed in Iranian bread wheat genotypes. In order to analyze genetic diversity and determine the most effective characteristics on salinity tolerance, 110 bread wheat genotypes were evaluated in two conditions (non-stress and saline stress) at the research field of the National Salinity Research Center (NSRC). The salinity of water used in irrigation in stress and non-stress conditions was 10 and 2 ds.m-1, respectively. The results showed that there was a significant genetic variation between studied genotypes. According to cluster analysis based on agronomical and morphological traits, genotypes were divided into 4 categories in both non-stress and stress conditions. According to the results of the means comparison of the groups in non-stress and saline stress conditions, the genotypes No. 2, 5, 7, 8, 9, 10, 11, 12, 13, 31, 35, 38, 73, 81, 97 and 98 were identified as the most salinity-tolerant genotypes. These genotypes can be utilized for salt-affected areas and also as donor parents in wheat breeding programs for further improvement of germplasm for salinity tolerance. Also, the results of factor analysis in saline stress condition indicated a positive relationship between biological yield, harvest index and chlorophyll content with seed yield. Generally, it can be concluded that chlorophyll content trait due to the low cost and easy and non-destructive measurement than other traits could be used as a suitable criterion in selecting for increased seed yield in saline stress conditions in field.

To study the effects of salinity stress on some wheat characteristics, twenty advanced genotypes were evaluated in controlled (hydroponic culture) and field conditions. Field experiment in randomized complete block design (RCBD) was conducted in saline conditions (Ecwater = 9ds/m and Ecsoil = 12ds/m) at the research farm of Birjand station. The hydroponic culture experiment was conducted in factorial based on RCBD with three replications, in which the first factor was salinity of sodium chloride levels of 0 and 12ds/m and the second factor the same twenty wheat genotypes. In filed experiment, ANOVA results showed significant effects of genotype on grain yield, days to heading and maturity, spike length, peduncle length, spike seed number and weight, thousand grain weight, biological yield and harvest index. Genotype no. 18 (1-66-22//PBW154/3/HALT) was recognized as a tolerant genotype due to the highest grain yield and biomass, while genotype no. 12 (Bow"s"/Vee"s"//1-60-3/3/Cocoraque75/4/Inia) was evaluate as a susceptible genotype in field experiment. In Hydroponic culture, the salinity had significant effects on plant height, biomass dry weight, leaf width, leaf length, leaf area, root dry weight and chlorophyll contents. The interaction effects of genotype and salinity were also significant on some traits. In hydroponic experiment, genotypes no. 4, 5, 14, 17 and 18 having higher biomass and chlorophyll contents, compared to the check cultivars, were determined as superior and tolerant genotypes, while genotype no. 12 was susceptible to solinity stress. The results of hydroponic experiment relatively comfimed the results of field experiment.

In order to investigation of different levels of salinity stress effects on germination, vegetative and some germination indices an experiment was performed in factorial form using a completely randomized design with 3 replications at Seed and Plant Improvement Institute Karaj. First factor encompass 20 genotypes (including narin, Ofough and Arg varieties as checks) and second factor four levels of salinity treatment (0 ,8, 12 and 16 ds/m), were used. Traits germination percent, germination rate, radicle length, plumule length, seedling length, plumule /radicle length ratio,dry weight of radicle , dry weight of seedling, plumule /radicle dry weight ratio, germination uniformity ,seed vigor index and salinity tolerance index (TI) were studied. Results analysis of variance showed that between genotypes, salinity stress and their interaction for all traits had significant difference. The most and the least of TI was belonged to genotype no.10 (Ti=83.13%) and genotype no 8 (Ti=54.82%) respectively. Salinity tolerance index (TI) had positive and significant correlation with germination percent, germination rate, plumule length, dry weight of seedling, plumule /radicle dry weight ratio and seed vigor index. Based on cluster analysis genotypes were divided into 3 different groups. Finally based on salinity tolerance index and all of germination traits, and results of cluster analysis, genotypes no 5,20, 10 and 14 were determined as the most tolerant genotypes and better than checks cultivars, that can be recommended to using of this genotypes for future breeding programs tolerance to salinity stress, and genotypes No. 8, 11 and 17 as the most susceptible genotypes.

In the major wheat growing countries, wheat growth and yield are negatively affected by salinity and breed tolerant cultivars through selection and breeding techniques is necessary to solve this problem. Relationship among yield, and its related traits in 23 wheat cultivars and promised lines were studied under salt stress conditions using a randomized complete block design with three replications at research field of Birjand University. Bread wheat cultivars and promised lines cultivated at two cropping seasons of 2010 and 2011 and irrigated with 10.81 ds.m-1 irrigation water during each season. Investigated cultivars and lines were significantly different in almost all traits except for days to heading and peduncle length. Correlation analysis showed that grain yield was significantly related to all traits except for number of spike per square meter and grain weight per spike. Regression analysis using step-wise method revealed that 81 percent of total variation exists in grain yield have been determined by grain filling period, plant height, and spike and peduncle length, in which grain filling period alone determined 54% of the variations. According to path analysis, grain filling period had the highest direct effect and peduncle length had the highest indirect effect via plant height on grain yield. These four traits are suggesting as suitable traits for selection of high-yield wheat lines under salt stress conditions.

In order to evaluate allelic diversity of microsatellite markers in QTL regions associated with salinity tolerance and to assess relatedness of these markers with yield performance of Iranian wheats under normal and salt stress conditions, twenty-five wheat genotypes (comprising tolerant and sensitive Iranian landraces, commercial cultivars and breeding lines), were studied using 45 microsatellite primers. Results of yield mean comparison showed that there were significant differences among genotypes in both environmental conditions. Under stress conditions, genotypes no 25 (Pishtaz/Karchia) and 16 (Sissons/3/Alvd//Aldan/Ias58) had the highest and lowest grain yields, respectively. Based on grain yield mean under both stress and non-stress conditions as well as tolerance and susceptibility indices, the genotypes were classified into tolerant, moderately tolerant and sensitive groups. From 45 microsatellite primer pairs used, 27 markers were polymorphic. In total, these markers generated 95 alleles, from which 89 alleles were polymorphic, possessing 2-7 alleles with the average of 3.52 alleles per locus. The polymorphic information content (PIC) varied from 0.077 to 0.454 with the average of 0.258 and the Marker Index (MI) ranged from 0.151 to 1.19 with the average of 0.79 for different primers. Cluster analysis based on molecular data, could completely separate sensitive and tolerant genotypes and relatively was concordant with grouping of genotypes based on field results. Principal coordinate analysis (PCOA), mostly confirmed the results of cluster analysis. Results of molecular data demonstrated that SSR markers: gwm291, gpw345, wmc249, barc353.1, cfa2170.2, gwm339 and wmc326 had higher PIC & MI values and can be considered as suitable microsatellite markers to assess the genetic diversity among the wheat genotypes in salinity stress breeding programs.

Effects of salinity on morpho-physiological traits of twenty-five hexaploid wheat genotypes (landraces, commercial cultivars, promising breeding lines, and Arg, Bam, Ofogh and Sistan as checks), were studied. Bread wheat genotypes were evaluated in randomized complete block design with three replications in each of the environmental conditions (saline and non-saline conditions) at the research filed station of Birjand, Iran in 2012-2014 cropping seasons. Combined analysis variance revealed significant differences among grnotypes for the studied traits. In saline condition, the maximum grain yield (5517, 5322, 5317 kg.ha-1) obtained in genotypes No. 25, 22 and 20, respectively and in non saline condition the maximum grain yield (7869, 7728 and 7706 kg.ha-1) obtained in genotypes No. 1 (Sistan), 20 an 25, respectively. Results showed salinity led to decreased Kﳖ ratio of flag leaf, grain yield, biological yield, flag leaf area, length of penultimate, length of peduncle, plant height and increased Na content of flag leaf and canopy temperature as compared with non-stress condintion. In saline condition, grain yield was significantly and positively correlated with grain yield in non-stress, biological yield (BY), Kﳖ ratio, chlorophyll content (SPAD), relative water content (RWC), harvest index (HI), length of spike, length of peduncle, thousand grain weight (TGW), while it was negatively correlated with Na content of flag leaf. Stepwise regression analysis in saline condition showed BY, HI, Kﳖ ratio, Na content of flag leaf, length of spike and width of flag leaf justified the majority of grain yield variation and can be used for indirect selection of grain yield. Factors analysis identified five factors which explained 80.46% of the total variation. On the basis of these results, it is concluded that criteria such as BY, HI, Kﳖ ratio, Na content of flag leaf, length of spike, chlorophyll content, RWC and TGW could be considered as effective criteria for selecting to improve grain yield in the national wheat breeding programs for tolerance to salinity stress. Genotypes No. 25, 22, 20, 21, 24, 13 and 23 were determined as more tolerant genotypes even more than check cultivars. These genotypes have salt tolerant parents shuch as: Karchia, Sakha8 and 1-66-22 in their pedigrees.

Applying an appropriate statistical analysis is complementary for conducting a robust experimental design in plant and animal breeding. In these experiments 33 Iranian bread wheat genotypes, cultivated in a randomized complete blocks design with three replications in two normal and saline conditions were evaluated at the field of National Salinity Research Center located in Yazd province, Iran. The restricted maximum likelihood (REML) was used to evaluate the different genotypic variance-covariance structures and to estimate the genotypic and phenotypic correlations of some of Iranian wheat traits under two normal and salt-stressed conditions. The Using different estimation by REML method the traits of grain yield, biological yield and harvest index had different and significant values across two conditions, this genetic variability can be used for salinity tolerance of bread wheat in breeding programs.. In addition, genotype by environment interaction for all traits was not significant, especially for grain yield as important trait for evaluation of salinity tolerance in wheat. The means comparisons of genotypes showed that the SALT22, SALT29 and SALT28 had the highest values and line No. 6, Shahpasand and line No.13 had the lowest values for grain yield, respectively. There were significantly positive genetic correlation between yield with biological yield (0.97) and harvest index (0.94) in combined analysis and negative genetic correlation for days to maturity with grain yield (-0.32) in saline condition by REML estimator. So, the selection of early maturing genotypes with higher yield in the saline condition, especially in the location of conducted experiment (Yazd) is achievable and selection can be done to improve the performance of salinity stress.

To evaluate reaction of 25 wheat genotypes to salinity stress، this study was conducted under salinity stress (EcSoil = 9. 8-12. 8 ds/m and EcWater = 8. 8-10 ds/m) and non-stress (EcSoil = 3. 3 ds/m and EcWater = 2. 1 ds/m) conditions using RCBD with three replications at Birjand research station in 2012-13 and 2013-14 cropping seasons. Combined analysis of variance showed that there were significant differences among genotypes for grain yield and other concerned characteristics. Role of the yield components was different in genotypes with higher grain yield. Correlation coefficients of stress indices with grain yield in non-stress and stress conditions showed that STI، MP and GMP were desirable for identifying high yielding and tolerant genotypes in two conditions، and the best index was STI. By drawing of biplot، genotypes were placed into tolerant، moderately tolerant and non-tolerant groups. Based on cluster analysis، genotypes were divided into four different groups. Finally based on salinity tolerance indices،، SDR of indices and results of biplot، genotypes No. 25، 22، 20 and 13 were determined as the most tolerant genotypes and better than check cultivars، that were placed in area with high yield potential، low sensitive to salinity، and near to MP، GMP and STI vectors، and genotypes No. 16، 9 (Moghan 3)، 10 (Shiroodi) and 17 as the most susceptible genotypes.

In wheat Na+ exclusion and K+/Na+ have shown to be associated with salinity tolerance، therefore in order to identify QTLs with additive effect for Na+ and K+ concentration traits in roots and shoots of wheat، 319 bread wheat recombinant inbred lines (RIL F7)، derived from a cross between Roshan cultivar (salt tolerant) and Falat cultivar (salt sensitive)، along with their parents and 2 checks (Arg and Moghan3) were studied in 2 separate randomized complete block designs (normal and stress) with 3 replications in greenhouse in 2012. Traits measured included shoot and root Na+ and K+ concentration، K+/Na+ ratio in root and shoot and root to shoot Na+ and K+ concentrations. Linkage map was constructed with 730 markers (709 DArt markers and 21 SSR markers). The linkage map spanned 4505. 71 cM with an average distance of 6. 17 cM between adjacent markers. A total of 31 additive QTLs were identified by QTL Cartographer program using single-environment phenotypic values. Results indicated that the biochemical pathways for Na+ and K+ accumulation are highly likely to be independent. Also، results indicated that shoot Na+ concentration and root to shoot Na+ and K+ concentrations could be used as selection criteria between tolerant and sensitive cultivars in salt stress condition.

In order to determine response of wheat recombinant inbred lines to salt stress, a study conducted with 319 bread wheat recombinant inbred line (RIL F7) derived from a cross between Roshan cultivar (salt tolerant) and Falat cultivar (salt sensitive), with their parent and 3 check (Arg, Bam and Kavir) were studied in an alpha lattice design with 2 rep and two location (normal and salt affected) in Yazd during 2012. In order to evaluation of inbred lines to salinity tolerance, 8 indices including SSI, TOL, MP, GMP, Harm, STI, SDI and MSTI were calculated based on inbred lines yield in normal and stress environments. Correlation analysis show that MP, TOL, STI and GMP had highest correlation coefficient with seed yield in normal condition, while Harm, MSTI, GMP, STI and MP had highest correlation coefficient with seed yield in stress condition. Principal component analysis for salinity tolerance indices identify two components, first component called yield stability and tolerance to salinity stress, the second component called sensitivity to salt stress and yield potential. MP, GMP and STI were the best indices for identifying superior lines. Using biplot of two first principal components, inbred lines 313, 164, 151, 5, 33, 41, 115, 117, 42, 20, 107 and 132 were identified with high seed yield and salt tolerance.