فهرست مطالب s.a. mohammadi

Salinity stress is one of the most important environmental stresses that decrease crop growth and yield. Barley is an important crop known as the salt-tolerant plant in cereals. In this study, the salt stress-responsive root transcriptome of tolerant (Afzal) and susceptible (Yusef) cultivars was investigated. The sequencing of mRNA transcripts (termed RNA-Seq) was performed using the Illumina HiSeq platform after filtering for RNA with 3chr('39') polyadenylated tails to include only mRNA. The Tuxedo pipeline was used to identify the altered expression of transcripts. Sequencing results showed that, after initial trimming of the reads, more than 20 million reads (92%) remained for all samples, of which 88% were aligned with the barley genome. Bioinformatics analysis showed the altered genes expressions in various processes such as membrane antiporter and transporter activity, an antioxidant, wide range of kinase and phosphatase cascades, internal signal transduction, metabolism of carbohydrates, amino acids, and lipids, binding processes, response to plant hormones, catalytic activity, and cell wall organization. Gene network analysis revealed that key genes, including proteins involved in systemic acquired resistance, peroxidase family proteins, cyclin-dependent protein kinase, phosphatidylinositol kinase, auxin-carrying proteins, mannose 6 phosphate isomerase, helicases and transcription factors play an important role in salt tolerance. These data can be used as a valuable source in future studies for genetic manipulation of barley and development of salinity tolerant cultivars.

For mathematically-oriented investigators, DNA is a string. Therefore, they consider a DNA sequence as a string of symbols whose correlation structure can be characterized almost completely by all possible base-base correlation functions at any range, short or long or their corresponding power spectra. Long-range correlations between bases in the DNA sequence are a statistical feature found in the genome of many eukaryotes. The existence of long-range DNA correlations indicates the existence of DNA rearrangement or duplication processes. These types of phenomena are not directly applicable to breeding and are mostly used in evolutionary studies. Our basic assumption in this study was that by extracting long-range DNA correlations between all the different nucleotides within a gene, it is possible to achieve a degree of correlation between them in the first place and possibly better run SNP-based researches. Due to many furious issues, not all investigations of a complete characterization of long-scale correlation structure of DNA sequences were motivated by biology arena. Rather, many such investigations were motivated by the issues of mathematical modeling, cryptography language code detections, dynamical systems, stochastic processes, and noise detections. Perhaps due to this reason, long-scale correlation structure has not yet become part of the toolbox in the “mainstream” DNA sequence analysis in human genetics and breeding settings. Prediction of DNA correlations from a sequence with finite length could be done with, frequency-count estimator, indirect Bayesian estimator, direct Bayesian estimator. Here we followed the ideas by CorGen theory.

24 genes selected out of genes affecting milk yield of dairy cow. The number, length and length of each exon and its position on the chromosome were obtained from the NCBI gene bank and the sequences were saved in FASTA format. Using software previously designed in #C language, according to the research request, the accession numbers of the studied genes was entered and the appropriate output was obtained. CorGen software was used to calculate the long-range DNA correlations of the genes involved in milk production.

The results showed that there is a significant level of long-term correlation in DNA sequence of a number of genes such as EZR, FGG, KRT6A, RAB1A, EIF3L, TBC1D20, ZNF419, S100A16, MRPL3, TPPP3, PHF10. The reduction power of the fitting function of the power function was based on the long-range correlations obtained from genes of different lengths, in the range of 0.146 and 0.643, so it can be concluded that reducing the range of long-range correlations by increasing the interval between DNA sequence intervals does not follow a random process. And so, the fractal geometry of nature is also seen in these genes. This research was an attempt for the first to address long-DNA correlation in dairy cattle genes. There are at least two goals for this job. First, there has been discordant on the result of correlation structure in DNA sequences. Due to this matter of what the actual result is, some researches still believe that DNA sequences do not exhibit any feature long-range DNA correlation which cannot be explained by the basic known stochastic processes such as random sequence or Markov chain - with the first one having no correlation inherently in its theory and the second one considers only short-range correlations. Resolving this disagreement can be straightforward once everybody agrees to use the same measure of correlation, use the same estimator, and apply this estimator of the correlation to the same sequence. The second is to highlight more biologically-motivated study of correlation structure of long range DNA sequences especially in animal breeding. Although this research does not accomplish this task, the intention was to at least put forward the issue. Most of the current studies of correlation (especially the long range one) in DNA sequences are based-base base statistical correlations. This base-base correlation won't not be a powerful tool to reveal the correlation on a global scale or between larger blocks in DNA-sequences.

The genes studied have been shown to have high complexity and mode of invariant on their DNA. This type of analysis can be generalized to the work of breeding setting. A more complete characterization of long-range correlation between base pairs at both short and long distances became possible only as long DNA sequences became more commonly available. Now thanks to stupendous growth of DNA generating technologies, almost the entire whole genome of an organism can be sequences in low cost price with high speed time. Therefore, a raw data shall be available for many researchers who are looking for to check new DNA correlation hypotheses in handy DNA sequences. The claim of DNA base-base statistical correlation at long distances in DNA sequences is sought to be still a few steps away from finding a Naive organization principle of the genome.

The genes studied have been shown to have high complexity and mode of invariant on their DNA. This type of analysis can be generalized to the work of breeding setting. A more complete characterization of long-range correlation between base pairs at both short and long distances became possible only as long DNA sequences became more commonly available. Now thanks to stupendous growth of DNA generating technologies, almost the entire whole genome of an organism can be sequences in low cost price with high speed time. Therefore, a raw data shall be available for many researchers who are looking for to check new DNA correlation hypotheses in handy DNA sequences. The claim of DNA base-base statistical correlation at long distances in DNA sequences is sought to be still a few steps away from finding a Naive organization principle of the genome.

Comparative genomics has revealed a high degree of collinearity between related species, which allows transferability of interspecies and intergenus   markers. The aim of this study was to examine the transferability of barley microsatellite markers among species of Triticum and Aegilops genus for determination of their genetic relationships. The experiments was carried out in faculty of agriculture, university of Tabriz, Iran, in 2016. Among 165 evaluated barley microsatellite primer pairs in 40 genotypes from nine species of Triticum and Aegilops genus, 62 (37.57%) showed successful amplification at least in the genome of one species and 50 (30.3%) were polymorphic. Using 50 polymorphic primer pairs, 223 alleles were amplified and number of alleles varied from 2 to 14 with an average of 4.46. The mean of polymorphic information content and genetic diversity were 0.55 and 0.6, respectively. The studied genotypes were assigned into four groups using Nieghbor-Joining clustering algorithm and Guckes Cantor evolutionary distance coefficient. The species of Triticum and Aegilops genera were grouped separately, and within each genus, grouping was in accordance with their genome structure. In principal coordinate analysis, two first coordinates explained 24.63 and 21.86% of molecular variation, respectively, and distribution of the genotypes based on two first coordinates was in concordance with grouping of cluster analysis. The results indicated that the transferable barley markers could be successfully utilized in wheat and its wild relatives genetics and breeding studies.

This study was conducted to investigate the response of four barley cultivars (Reyhan03, Yousef, Afzal, and Khatam) to salinity stress at 0 (control), 100, 200 and 300 mM levels as a factorial experiment, within the randomized complete block design in three replications in a greenhouse, using the Hoagland solution. The physiological and biochemical properties including dry weight and RWC, photosynthesis pigments, K+/Na+, osmotic adjustments (soluble sugars, glycine betaine, proline), hydrogen peroxide and antioxidants enzymes (catalase and peroxidase) in root and shoot of barley cultivars were evaluated in saline and non-saline conditions. To determine the relationship between growth performance and the physiological and biochemical properties, the correlation between the properties and causality analysis was examined. Results obtained from comparing the mean among the treatment combinations showed that the salinity stress reduced the dry weight, photosynthesis pigments, and K+/Na+, while it increased the soluble sugars, glycine betaine, proline, H2O2, catalase and peroxidase in the root and shoot of barley cultivars. Correlation analysis indicated that potassium in the shoot had the most positive and significant correlation coefficient (r= 0.86) with the dry matter of shoot. The stepwise regression analysis showed that the root dry weight, catalase of root and shoot, H2O2 of shoot and K+/Na+ of shoot contributed to the performance. Causality analysis revealed that the root dry weight, K+/Na+ of shoot, and catalase of shoot were highly important as they had a direct positive and significant impacts on the performance of shoot dry matter.

High density linkage maps are essential for precise mapping of gene loci controlling quantitative traits. In the present study, a high density linkage map of spring wheat recombinant inbred lines population derived from a cross between Yecora Rojo and No. 49 was constructed using genotyping by sequencing (GBS) method. To identify single nucleotide polymorphisms (SNPs), sequencing of parents and recombinant inbred lines was carried out at three lanes of Illumina Hiseq 2500. In total, more than 36 thousand SNP were identified of which 804 SNPs were not aligned to any wheat chromosome. Among these SNPs, 3042, 3977 and 769 SNPs were belonged to A, B and D sub genomes, respectively. After removing SNPs with ≥20% missing data and minimum allele frequency ≤0.05 as well as loci segregating from 1:1 Mendelian ratio, in total 5831 polymorphic SNPs identified and assigned to 21 chromosomes of wheat. These markers spanned 3642.14 cM of the wheat genome with an average marker density of 0.62 (markers/cM).

To develop high yielding and environmental stresses tolerant wheat genotypes, quantitative trait loci (QTL) were mapped for various traits and nucleotide diversity of yellow (Yr) and leaf (Lr) rusts genes and resistance gene analogues in resistance and susceptible wheat cultivars and vernalization genes in Iranian wheat landraces were evaluated for development of SNP markers. Population structure of wheat landraces were assessed using microsatellites, vernalization, leaf rust resistance and low molecular glutamine subunits genes. Based on the identified genes and markers toolkit and genomic breeding values, QTL isogenic recombinant inbred lines and genotypes and varieties with multiple genes and QTLs were selected and crossed for development of multi-parental population. Selection of desirable genotypes was started from F3 generation based on grain yield and its components, yellow rust resistance under natural infection, shape and size of flag leaf. The selected genotypes at different generations were evaluated under normal irrigation and rainfed conditions. Under rainfed condition, in the selected F5 genotypes, length of spike varied from 10 to 19 with an average of 13.78 cm and number of grain per spike ranged from 38 to 180 with a mean of 94.20 grain. Under normal irrigation, length of spike and number of grain per spike of the selected genotypes varied from 13 to 24 with a mean of 16.33 cm and 20 to 90 with a mean of 128.14 grain, respectively. The results of this project indicated that application of genomics methods and techniques could increase the efficiency of development of high yielding and environmental stresses tolerant cultivars.

Alternative splicing is molecular processes which lead into transcriptome and/or proteome plasticity in plants and animals. These functions accomplished through the producing of proteins isoforms, affecting RNA function, making changes in transcription factors and enzymes characteristics. One of the most important and beneficial influence of alternative splicing is giving the living organism the ability to tolerate variety of biotic and/or abiotic stresses. In this review paper we have discussed some of the functional aspects of Alternative Splicing in the plants.

To identify the QTLs affecting grain weight and yield, 148 doubled-haploid (DH) population derived from a cross between Clipper (high yield) and Sahara3771 (low yield) were screened under controlled conditions. The experiment was conducted in CRD with 3 replications. The new 30 ISSR marker loci were added to a backbone of 466 loci on the Clipper × Sahara DH linkage map. The map spanned 1460 centimorgans (cM) and had a mean density of 2 loci per 3 cM. The QTL analysis led to identification of 5 QTLs on 2H, 4H, 5H and 6H chromosomes for grain yield. These QTLs could explain 57% of the total phenotypic variation, and the QTL on chromosome 2H (ksuF2-mwg892) with 20% had the largest effect. For grain weight, 3 QTLs were identified, and the QTL on 2H could explain 69% of total phenotypic variation. The identification of QTLs with large effects on grain weight and yield illustrates the usefulness of molecular markers in gene mapping and suggest that marker-assisted selection will be feasible in the near future in barley breeding programs.

During evolution, various compounds against herbivors were developed in plant species. Disturbance in digestive system by plant enzyme inhibitors is one of the effective methods in integrated pest managment programs. In this study, the effects of total Goebelia alopecuroides and Vicia ervilia seed extracts and their fractions were assessed against proteolytic activity of cotton bollworm. Total extracts of G. alopecuroides was effectively inhibited digestive proteinase of cotton bollworm compared with that of V. ervilia. The inhibitory effect of G. alopecuroides on Bovine trypsin and chymotrypsin as well as insects’ trypsin and chymotrypsin was higher than that of V. ervilia. Total seed extracts of V. ervilia significantly decreased digestive chymotrypsin activity. Ammonium sulfate precipitation of seed extract also showed significant inhibitory effect among the fractions. The fifth fraction of G. alopecuroides showed the highest inhibititory efect agianst digestive proteolytic activity of cotton bollworm and bovine trypsin. The first fraction of V. ervilia significantly inhibited total proteolytic activity.The first fraction of both plants seed extracts inhibited digestive trypsin of cotton bollworm compared to the other fractions. The third fraction of V. ervilia and the forth fraction of G. alopecuroides showed higher inhibitory effect on digestive chymotrypsin of cotton bollworm comperd with the other fractions. Comparing crude extracts effects of both plant species on laboratory and wild populations of cotton bollworm showed that wild ones was susseptible compared with the laboratory population.

Leaf rust is one of the important wheat diseases which damages its production. Development of resistant varieties is an effective، environmentally friendly and low costly method for reducing disease damage. The aim of this study was to isolate and sequence Lr29 and Lr47 genes transferred to wheat from Agropyron elongatum and Triticum speltoides، respectively، in seven wheat lines with different levels of resistance to leaf rust. Using a specific primer pair، a fragment with length of 396 bp was isolated and sequenced from Lr47 gene in the studied lines having five open reading frames (ORF). The second ORF encoded a protein with length of 37 amino acids which showed 36% homology with wheat agglutinin antimicrobial protein. Alignment of the Lr47 sequence with NCBI data revealed 99% homology with Triticuma estivum sucrose synthase type I gene sequence. Nucleotide diversity of Lr47 gene was 0. 0041 and five single nucleotide polymorphism were identified among the seven lines. Bolani showed a large deletion with length of 48 nucleotide at 3’ non-coding end of the gene which could differentiate this line from the others. The length of isolated fragment from Lr29 gene was 160 bp which showed 91 and 90% similarity with acetyl CoA carboxylase gene from wheat and Aegilop stauschii، respectively. Twenty eight single nucleotide substitutions with nucleotide diversity of 0. 0589 were detected in Lr29 gene. Synonymous/non synonymous substitution ratio in Lr47 and Lr29 gene indicated negative and positive selection in the studied line for these genes، respectively.

To evaluate response of bread wheat recombinant inbred lines to drought stress, an experiment was conducted using split plot based on completely randomized blocks design with three replications at research station of agriculture college of Islamic Azad University of Tabriz during 1389. The main factor included three irrigation levels (80, 120 and 160 mm evaporation from class A pan) and sub-factor consisted of 23 recombination inbred lines along with their parents (Super head and Roshan varieties). In this study five stress tolerance indices i.e. Stress Susceptibility Index (SSI), Tolerance Index (TOL), Mean Productivity (MP), Geometric Mean Productivity (GMP) and Stress Tolerance Index (STI) based on grain yield of the lines were calculated under stress and non- stress conditions. Highest Mean Productivity, Geometric Mean Productivity and Stress Tolerance Index at 120 and 160 evaporation were common belonged to the lines number 212, 224, 255, 277 and Roshan variety. Line number 244 had the minimum SSI and TOL at 120 mm, whereas line 241 had the lowest SSI and TOL under 160 mm. The study of correlation between the indices and mean grain yield showed among the criteria MP, GMP and STI are reliable indices for screening of the lines under stress and non-stress conditions. At cluster analysis based on quantitative criteria for stress resistance at 120 and 160 mm evaporation, lines number 224, 255, 277 and Roshan variety were grouped in superior cluster.

Water deficit stress is one of the most important abiotic stress reducing wheat yield world wise which affect its sustainable production. To map gene(s) controlling drought tolerance related traits in wheat, 142 recombinant inbred lines derived from a cross between Azar2 (drought tolerant) and 87zhong291 (high yielding) was evaluated under rainfed and supplementary irrigation conditions. The measured traits were grain yield, 1000 grain weight and number of spikelet per spike. Parental polymorphism was assessed using SSR and ISSR markers and 24 SSR marker and 16 ISSR polymorphic markers were used for analysis. Linkage analysis was performed to assign these markers to the population linkage map consisted of 45 SSR and AFLP markers. The linkage map span 1310 cM of wheat genome with 19.55 cM distance between two neighboring markers. Based on composite interval mapping, 10 and 18 QTLs were identified for grain yield, under rainfed and supplementary irrigation conditions, respectively. Under rainfed and supplementary irrigation, five and nine QTLs were mapped for number of spikelet per spike. For 1000 grain weight, four QTLs under rainfed condition and nine QTLs under supplementary irrigation were detected. Two and four QTLs detected for grain yield and 1000 grain weight, respectively, were stable under both conditions. For the studied traits, number of common QTLs were identified which could be due to gene linkage or pleiotropic gene effect. The common QTLs for grain yield and number of spikelet per spike (18.26%) as well as for grain yield, number spikelet per spike and 1000 grain weight on linkage group 2 and the common QTL for number spikelet per spike and 1000 grain weight on linkage group 3 with determining more 15% of these trait phenotypic variance were identified as major QTLs. Some of the markers were tightly linked to the QTLs which could be used for selection of drought tolerant lines.

Iran is one of arid and semi-arid regions of the world. Wheat as a strategic agricultural products faces water deficiency in most areas of the country. Therefore, identification of the resistant varieties to drought stress is one of main aims for breeders. To assess effect of drought stress at heading on 72 spring wheat recombinant inbred lines derived from American Yecora Rojo (high yielder, dwarf and early maturity) as paternal parent and Iranian No. 49 line (tall and late maturiting) as maternal parent cross were studied. The experiment was conducted at the Research Station of the University of Tabriz using a randomized complete block design with two replications during 2009 growing season. Based on the results from combined analysis of variance significant difference was observed among lines for all of traits studied, except for harvest index, grain number per spike and days to heading. There was significant difference between normal and drought stress conditions. Since the interaction between line and conditions was insignificant for all traits, it does therefore, provide the possibility of comparing the lines without regard to irrigation levels. Based on the means of, the traits it was found that the lines 96, 122, 123 and 155 were superior. MP, GMP and STI indices were recognized to be suitable indices to identify superior lines. With respect to these indices, lines 96, 122, 123, 138, 149 and 155 were found superior as compared with remaining lines. Based on stepwise regression analysis of grain yield with other traits, respectively grain number per spike, number of spikes/m2 and 1000 kernel weight were inserted into final model as effective variables on grain yield, which made 81/9 percent of the grain yield variation. Path analysis of grain yield and related traits, based on stepwise regression, demonstrated the significant positive direct effect for grain number per spike, number of spikes/m2 and 1000 kernel weight on grain yield. Cluster analysis, also showed that, lines under study were grouped into two clusters; superior lines for studied traits assigned to group one.

An investigation was carried out in order to study the genetic variation of barley genotypes in terms of winter survival, LT50 and leaf soluble carbohydrates under field and greenhouse conditions using 40 barley genotypes in the research station and greenhouse of Faculty of Agriculture, University of Tabriz, Iran. The field evaluation was performed in the form of randomized complete block design in two years and percentage of winter survival was estimated. Multivariate analysis of variance indicated significant differences among genotypes for the traits measured in greenhouse and laboratory. Combined analysis of variance showed significant differences among genotypes for percentage of winter survival, but the effects of year and genotype × year interaction were significant for this character. The greenhouse experiment for percentage of plant survival was carried out in the form of split plot design on the basis of randomized complete blocks with two replications. Barley genotypes were assigned in subplots and five freezing temperatures (-8, -11, -13, -15 and -17°C) were assigned in main plots. Other traits measured in the greenhouse, such as LT50, percentage of seedling dry weight, soluble carbohydrates content before and after hardening and leaf length and width were analyzes based on randomized complete block design. Significant differences were observed among barley genotypes in terms of survival percentage at temperatures -8, -11, -13, -15 and -17°C, LT50, percentage of seedlings dry weight, leaf width and the soluble carbohydrates content after hardening. The heritability of field survival percentage, LT50 and leaf width were high. The heritability of soluble carbohydrates content after hardening and the percentage of seedling dry weight were moderate. The highest and lowest heritability were observed at temperatures -8°C and -17°C, respectively. Percentage of survival at temperature -15°C had the largest squared genetic coefficient of variation and other traits had low squared genetic coefficient of variation. It can be concluded that genotype #38 (Athenise) was susceptible to cold stress and considerable number of genotypes had desirable characteristics for cold tolerance from which genotypes #36 (Schulyer) and #15 (EC83-12) can be recognized as more cold tolerant genotypes with regard to percentage of winter survival and LT50.

A field experiment was conducted in 2008, to investigate the effects of different irrigation treatments (I1,I2,I3 and I4: well-watering on the bases of 70mm evaporation from class A pan and irrigation disruptions at flowering stage, grain filling stage and during flowering and grain filling stages, respectively) on growth and yield of three pinto bean cultivars (Talash, Khomain and COS16). The experiment was arranged as split-plot based on randomized complete block design in 3 replications, with the irrigation treatments in main plots and pinto bean cultivars in sub-plots. Dry matter accumulation, crop growth rate, relative growth rate and grain yield per unit area decreased, due to water stress at reproductive stages. The percentage of grain yield reduction under irrigation disruption during flowering and grain filling stages compared to well-watering condition was about 40.25%. The most reduction was happened at water disruption during flowering and grain filling stages. Dry matter accumulation and crop growth rate of Talash was higher than for Khomain and COS16. Grain yield of khomain was slightly higher than that of other pinto bean cultivars. However, this difference was not statistically significant.

Wheat is the most important crop plant in Iran and self sufficiency in wheat production is one of the economical and food safety policies in the country. In spite of efforts have been carried out in this area, the mean of wheat yield in Iran is less than its world average. To identify high yielding wheat lines with optimal characteristics and determination of traits to use as selection index, 180 recombinant inbred lines derived from a cross between Norstar (winter wheat) and Zagros (spring wheat) cultivars were evaluated in a randomized complete block design with two replications. During the experiment, grain yield, number of grain per spike, 1000 grain weight, spike length, number of fertile tiller, plant height and winter survival were measured. Analysis of variance revealed significant differences among the lines for all the studied traits except winter survival and transgressive segregation was observed for grain yield, number of grain per spike, number of spike per m2, plant height and spike length. In path analysis, 1000 grain yield, number of grain per spike and number of spike per m2 with positive direct effects on grain yield determined about 93. 2 درصد of this trait variation. Considering high heritability of these characters compared with grain yield, they could be use as indices in selection of high yielding lines. Based on grain yield per m2, 14 lines were superior to Norstar (high yielding parent). Considering optimal characteristics of these lines, they could be evaluated at multi-environment experiments for selection of high yielding genotypes.

Fusarium head blight (FHB) caused by Fusarium graminearum is one of the important diseases of wheat. Traditional breeding for the disease resistance is difficult and expensive. DNA markers linked to FHB resistance genes can be useful in accelerating disease breeding programs. The objective of the study was to identify the SSR markers linked to FHB resistance QTLs in wheat. A population of 167 F2:3 families from the cross Wangshuibai (resistant) /Falat (susceptible) was developed. F2 individuals، F3 families and the parents were evaluated for Type II resistance (resistance to the disease spread within the spike) in greenhouse. The parents and two resistant and susceptible bulks from F2 plants (including 15 plants in every bulk) were screened with 341 SSR Markers. 125 markers showed polymorphism between the two parents and 16 markers showed polymorphism between both parents and two bulks. The 16 markers were used to genotype 30 individuals in two bulks. Eight markers showed significant polymorphism and were used for screening the population and QTL analysis. Furthurmore، seven markers linked to the polymorph markers were used for screening and identifying QTL. Using F2 phenotypic and genotypic data، three QTLs for FHB resistance were identified on chromosomes 2AL، 3BS and 3AS. By evaluating F3 families، two QTLs controlling FHB resistance were confirmed on chromosomes 3BS and 2AL. SSR markers linked to the QTLs can be useful in marker assisted selection for FHB resistance in wheat.

Freezing resistance is a quantitative trait which is affected by 10 out of 21 wheat chromosomes. In order to identify the microsatellite molecular markers linked to freezing resistance QTLs in bread wheat, a set of 280 F2:3 families derived from a cross between cv. Norstar (winter type and frost resistant) and cv. Zagros (spring type and sensitive to low temperatures) was evaluated at 11 temperatures under controlled conditions. The LT50 was used as a frost resistance index. Parental polymorphism was assessed using 200 microsatellite primer pairs and 41 polymorphic markers were used to screen F2 individuals. QTL analysis revealed association of LT50 with seven microsatellite markers, Xgwm357, Xgwm148, Xgwm666, Xcfa190, Xgwm499, Xgwm292 and Xgwm174 located on chromosomes 1A, 2B, 5A, 5B and 5D. In total, these markers determined 27% of frost resistance variation in the population. QTL detected on chromosome 1A was the first report about the contribution of this chromosome in frost resistance.

Milk thistle (Silybum marianum) is one of the most important medicinal plants and has found special place in pharmacy industries. Irregular harvest of this plant from natural habitats results in the destruction of its genetic resources. In order to optimize in vitro culture of milk thistle، this study was carried out in a factorial experiment based on completely randomized design with four replications، two genotypes (Budakalszi from Hungry and Moghan ecotype) and cotyledon and hypocotyle explants in MS medium supplemented with four kinetin and 2-4 D combinations. Seeds were germinated in MS medium without hormones under 26˚C and darkness conditions. After callus induction، the calli were subcultured four times into the fresh media. Analysis of variance revealed that in all of the subcultures، Budakalszi cultivar was superior to Moghan ecotype with respect to callus fresh weight and diameter. Callus fresh weight and diameter were also higher in the calli obtained from cotyledon compared with the hypocotyls explant. With the increase in hormone levels، callus weight and diameter were increased. In all of the four subcultures، maximum callus growth was observed in the medium supplemented with 2 mg/l 2-4 D and 2 mg/l kinetin. Analysis of somaclonal variation in the calli obtained from different culture conditions and subcultures using RAPD markers revealed different banding patterns among samples from explants of the two genotypes in different culture and subculture conditions.

To determine chromosomal regions controlling important agronomic traits in rapeseed, eight winter rapeseed cultivars along with their F1 hybrids resulted from a complete diallel cross were evaluated using simple lattice design with two replications. Significant difference was observed among genotypes for all the studied traits. General combining ability was significant for all the traits except percentage of oil and specific combining ability was only significant for 1000 grain weight. Parental polymorphism evaluation by 78 polymorphic microsatellite markers resulted in 359 alleles with allele number ranging from 2 to 9 and an average of 4.22 alleles per locus. Polymorphic information content ranged from 0.21 to 0.84 with an average of 0.60 and gene diversity showed variation from0.24 to 0.86 with an average of 0.65. Based on molecular data, the highest and lowest similarities were observed between Orient and Geronimo and Sunday and Geronimo cultivars, respectively.Genetic distance between parental lines was separated into general and specific genetic distance based on Griffing’s method, mixed model B. Analysis of phenotypic and genotypic data relationships revealed significant and positive correlation between general molecular distance and general combining ability for pod number per main branch. Stepwise multiple regression analysis identified one to eight informative markers for the studied traits and chromosomal region associated with marker Na12-G08 showed the highest additive effect on number of pod in main branch. The most of positive markers detected for yield and yield components showed over-dominance geneeffect.

To evaluate the response of hulless barley promising lines to water deficiency stress, 15 genotypes were assessed under three irrigation regimes (complete irrigation and water stress at booting and grain filling stages) at field and greenhouse conditions using split-plot design arranged in randomized complete blocks with three replications. The result of analyses revealed significant differences among the genotypes for all of the studied characters. Based on the combined data mean comparison, genotypes 1, 2, 3, 5, 6, 11 and 12 showed the highest yield. However, among these genotypes, the minimum yield reduction under the stress conditions compared with the normal irrigation was observed in lines 3 and 10. Therefore, these lines can be used as promising genotypes in breeding program for improvement of drought tolerance and as parental lines for mapping of genes involved in drought tolerance. Genotype ranking based on the characters evaluated at the field and greenhouse revealed the highest ranks for genotypes 1, 3 and 5. The result indicated that these lines have other desirable characters such as harvest index, biomass and tiller beside high yield.

Drought is one of the most important abiotic stresses affecting food production under dryland-rainfed conditions. In the present study, fluorescence parameters as non-destructive methods were used to assess drought tolerance in winter bread wheat. A population of 142 recombinant inbred lines in F8 generation, derived from a cross between Azar2 (Winter type) and 87Zhong291 (Facultative type), was used. Experiment was conducted using randomized complete block design with three replications under rainfed (drought stress) and supplementary irrigation during 2006-2007 seasons at Maragheh Experiment Station of the Dryland Agricultural Research Institute (DARI). The chlorophyll fluorescence characters including minimal fluorescence level from dark-adapted leaves (Fo), maximal fluorescence level from dark-adapted leaves (Fm), variable fluorescence level (Fv), maximum quantum efficiency of PSII photochemistry (Fv/Fm), non-photochemical quenching (NPQ), photochemical quenching (QUE), leaf water potential related to drought resistance (LWP), yield of photochemical energy conversion (YPEC), and performance index (PI) were measured. There were significant differences among genotypes with respect to chlorophyll fluorescence parameters under both conditions. Average grain yield under drought and irrigated conditions were 928 and 2547 Kg/ha, respectively. Under drought condition, grain yield ranged from 272 to 1935 Kg/ha. It varried from 3805.4 and 3804.9 Kg/ha under supplementary irrigation. Grouping of geneotypes based on grain yield revealed significant differences between high and low yielding groups with respect to chlorophyll fluorescence parameters only under drought condition. Based on regression analysis, significant and positive relationships were observed between grain yield and all chlorophyll fluorescence characters except QUE under droght condition. QUE had negative and significant association with grain yield. However, no significant linear relationships was found between grain yield and chlorophyll fluorescence parameters under irrigated condition. Correlation analysis indicated positive or negative significant correlation between chlorophyll fluorescence parameters. The results of present study indicated that chlorophyll fluorescence parameters along with morpho-physiological characters could be used as selection criteria in breeding wheat for drought tolerance.

Low temperature is one of the most important abiotic stresses which decrease the production and the yield of crops. It is important to identify the nature of genetic control for breeding of cold tolerance. In order to estimate the genetic parameters related to cold tolerance in bread wheat, seven cultivars, namely: Norstar, Capplle-Desprez, Morgan, Desconsoide, Sardari, Kohdasht and Zagros along with their 21 half diallel hybrids were evaluated under controled conditions in freezing temperatures and survival percentage and LT50 of genotypes in each temperature was recorded. Analysis of variance showed significant difference among genotypes. Therefore, diallel analysis was performed based on Griffing’s mixed model B of method II. Genetic analysis revealed significant general combining ability for plant survival percentage whereas specific combining ability was not significant. This indicated the role of additive the effects in control of cold tolerance. The high narrow heritability (87.08) and low degree of dominance (0.28) also showedthe small contribution of dominance effects in controlling this trait. Among parental genotypes, Norstar showed the highest general combining ability (0.402) and also maximum mean for survival percentage (88.2).

In order to compare heat indices at various phonological stages of corn affected by different levels of densities and interference periods of sorghum, a factorial experiment was conducted on the basis of randomized complete block design with three replications in the growing season of 2002 at the Research Station of the Faculty of Agriculture, University of Tabriz, Iran. Studied factors consisted of different interference periods of sorghum (0, 14, 28, 42 days after corn emergence), and sorghum densities of 4, 8, and 12 plant/m2. Corn density was 7.8 plant/m2. Results showed that the best thermal indicator was the classical index to evaluate the effects of density levels and various interference periods of sorghum on corn phonological stages in Tabriz area. This index had the highest correlation with the grain yield at all corn phonological stages such as tasseling, silking and physiological maturity. Also, when winter crops were planted after corn harvesting or ripening or seed filling duration, it can be recommend to use general thermal heat index. If the aim of artifical pollination is to produce hybrid genotypes. Three indices of growth degree day, crop heat unit and heat unit can be used due to their similar results. Finally, if the aim is to determine the silking, it would be better to use crop heat unit or heat unit.

Genetic maps with high genome coverage are becoming increasingly useful in both basic and applied genetic researches. In the last decades, the advent of DNA markers has brought about a magnificent revolution in the production of genetic map, especially in wheat. In the present study, AFLP markers were used to saturate linkage map of 107 doubled haploid individuals produced through Fukuho _Komugi × Oligo – Culm crosses received from Japan International Research Center of Agricultural Science (JIRCAS). The framework of genetic map was used as base map for next analysis. AFLP analysis was performed with MseI / PstI as digestive enzymes. The average percentage of polymorphism with AFLP markers was around 16.6%. Data analysis was performed by computer program known as Mapmaker / EXP, Ver. 3.3. In this program, the maximum distance criterion was 50 cM and the minimum LOD equated 3. The drawing of chromosome schema for the linkage groups was performed by Draw map, Ver 1.1. In this analysis, 115 AFLP markers were divided into 10 groups in addition, some of the markers remained unlinked. The supplementary data analysis along with specific SSR markers identified the chromosome loci of the markers. Ultimately, 71.1% of the markers were assigned to genome A, 16.5% to genome B and only 3% to genome D. The AFLP markers filled 11 gaps in 7 chromosomes (2A, 3A, 7A, 2B, 3B, 5B and 7B). The low coverage of genome D was due to the limited polymorphism and its conservation in different populations. Among the chromosomes, maximum number of markers (60) was assigned to the chromosome 7A. The distribution of the markers on this chromosome was not uniform. Such a distribution was related to the grouping AFLP markers within heterochromatin region, particularly around the centromere.