Chrysanthemum (Chrysanthemum morifolium) is one of the most important ornamental plants which plays a significant role in the development of gardening industry in the world. The knowledge of genetic diversity is one of the prerequisite criteria for Chrysanthemum breeding with important economic goals. Molecular markers have a significant share in elucidation of inter and intra species genetic diversity. To this end, genetic diversity of a number of Iranian cultivars was molecularly investigated by sequencing a part of rDNA, using ITS4 and ITS5 primers. Genetic distance between Chrysanthemum cultivars ranged from 0.05 to 10.15, demonstrating the power of ITS region in revealing the genetic diversity among cultivars of morifolium, suggesting Iranian cultivars have been genetically improved from morifolium species. Genetic diversity assessment of Iranian Chrysanthemum cultivars demonstrated that presumably inter, intra species or even inter population hybridization may have been involved in creating enormous genetic diversity among Chrysanthemum cultivars.

Plant Breeding has utilized a wide range of techniques and methods to improve the quality and quantity of plants. The molecular markers are the tools that have provided a new perspective for plant breeding advancements. This article has reviewed the various advantages and uses of molecular markers and the utilization of the high potential of natural polymorphisms within communities, combined with the abilities of conventional plant breeding methods. The marker attributes are not subject to environmental influence and their high frequency of these markers in their number, high structural diversity are as part of their benefits in identifying identities, determining the genetic diversity of species and studying relationship between populations. They may aid in discovering more information about protecting and maintaining genetic stock collections, identifying varieties, determining genes with chromosomal location and the number of genes controlling traits. Genome sequencing, the preparation of physical and genetic maps, genomic fingerprinting of plants are some of the other applications of this tool in plant breeding. The high efficiency of selection with the help of markers in selection of genotypes has been emphasized as the parent of crosses and selection with the help of a marker in breeding programs and genomic selection. New technologies offers new opportunities to shape genetic variation in the improvement of specific plant breeding programs. Nowadays development of next-generation sequencing technology, genome sequencing and high throughput approaches for markers have facilitated EST-derived simple sequence repeat (EST-SSR) marker development as well as single nucleotide polymorphism (SNP) marker. These markers can be successfully employed in accelerating research and plant breeding programs.

In order to analyze the genetic components of agronomic traits among 116 F9 recombinant lines derived from crosses of Ahlamitarom × Sepidroud rice cultivars, an experiment was conducted as a randomized complete block design in research farm of Gonbad Kavous University of Agriculture with three replications in 2016 and 2017. Genetic linkage map provided with 80 SSR markers, 28 iPBS Markers (79 polymorphic alleles), 7 IRAP markers (17 polymorphic alleles) and 26 ISSR markers (70 polymorphic alleles), which covered 1275.4 cM of the rice genome. QTL analysis was performed by Composite Interval Mapping. In two years, 15 QTLs detected for the studied traits. The additive effected varied from 6.725 g for grain weight up to -85.626 g for grain weight. Also, R² for the detected QTLs explained from 11.3% to 20% of the total variation. The highest R² was related to grain weight in the first year of experiment. Among the detected QTLs, qGWs on chromosome 1, were found to be stable and large effector QTLs for rice (Oryza sativa L.) grain weight, and can be used in marker-assisted breeding and selection programs after validation.

Estimation of genetic diversity and evaluation of plant germplasm is the most important step in collection and management of plant genetic resources. Also, comparison of different DNA-based genetic markers in diversity evaluation and then advising the most efficient markers is very important. In order to investigate genetic variation among Persian oak (Quercus brantii Lindi.) populations of Lorestan province (Iran), 20 genotypes were collected from different geographical and climatic regions. After DNA extraction, polymerase chain reactions (PCR) were used for study of polymorphism using three markers including ISJ, ISSR and SCoT. Genotyping was performed using the polymorphic bands obtained from all three markers separately, and also by combining the data of three markers. PCR results of the primers showed 91 polymorphic bands with an average of 71% per locus. The ISSR marker with 44 bands had the most polymorphic bands. Genotypes were discriminated by ISJ, ISSR and SCoT markers in 5, 6 and 5 groups, respectively, and using the combined data of three markers, genotypes were classified in 5 groups (each group included more than one genotype) and 3 group (each group included one genotype).  The results showed that the obtained clustering by different markers were nearly consistent with clustering of genotypes based on the climatic origin of genotypes. The most similarity between the groupings was between ISJ and ISSR markers with 89%. Overall, the results indicated the usefulness of markers used to estimate genetic distances between different oak communities.

In order to identify QTLs controlling agronomically traits, landrace Tarom and rice Tarom mutant were crossed. SSR, ISSR, iPBS and IRAP markers were amplified in 250 F₂ individuals to prepare the linkage map. Number of tillers, 100 grain weight, number of filled grains, number of unfilled grains, plant height, panicle length, number of branches, stem diameter, grain length, grain width, grain shape, straw weight, days to maturity, flag leaf length and flag leaf width were measured for 250 individuals. The linkage map covered 970.9 cM of rice genome. The distance between two adjacent markers was calculated to be 12.77 cM. Based on the results, a total of 13 QTLs were identified for the evaluated traits. For all studied traits, alleles transferred from the parents to the QTLs detected increased grain yield. Most QTLs were detected for days to flowering. Three QTLs were located on chromosomes 10 and 4 (two QTLs) for days to flowering. qLDF-4a and qLDF-4b had a negative additive effect and the parent alleles of the mutant landrace Tarom reduced the number of days to flowering. These QTLs explained 11.6% of the phenotypic variance. Since the population under study was derived from a cross between landrace and mutant Tarom cultivars and the resulting population varied only in the mutated genes; so, the QTLs detected in this study were more accurate in location and expression levels, and after validation of them, they could be recommended for marker assistant selection breeding programs.

Cultivar identification in micro-propagated date palm seedlings is laborious so that application of molecular markers to facilitate and acceleration of the procedure seems inevitable. Given the need for control the originality of micro- propagated date palm seedlings, the aim of this study was evaluation of SSR markers usability to cultivar identification in micro-propagated date palm seedlings. Original samples of Green Ghanami, Red Ghanami, Gantar, Deiry, Ostaemran, Barhi, Medjool, Zahedi and Piarum cultivars were used control. Taking into account the rigidity of leaves and subsequently high consumption of liquid nitrogen to powder leaves, an efficient method for powdering of leaves using Tissue Lyser II instrument was optimized. Eight SSR primer pairs were used for polymerase chain reaction. The Results showed that by using these molecular markers and reliable controls, determination of micro- propagated date palm cultivars is feasible. Clustering of cultivars showed that all of them were differentiated using five SSR primer pairs including mPdCIR025, mPdCIR057, mPdCIR070, PDAG1003 and DP175. Also, barcoding of scored band illustrated that c1 allele (230 to 240 bp) for Piarum cultivar and d3 allele (220 to 230 bp) for Medjool cultivar were exclusive. Totally to make the results referable, cultivar identification diagram was drawn up.

Due to world population incline and the increasing wheat consumption as human main staple food, as well as high amount of waste of bread which is mainly due to its low quality, the wheat breeding programs to improve bread quality are of great importance. Therefore, evaluating the wheat grains quality and the genetic variation of bread-making quality traits among lines derived from crosses becomes imperative. To this end, the gliadin protein banding pattern of 28 recombinant inbred lines, their corresponding parents and 10 other commercial cultivars were examined via A-PAGE method. The variation between and within the lines and cultivars was determined using AMOVA according to the protein bands. The results of this study revealed high variation for gliadins coding loci with total mean of 73.96%. The percentage of polymorphism was estimated to be 91.67 and 56.25 for lines and commercial cultivars, respectively. The minimum and maximum number of gliadin bands were 12 and 25 bands, respectively. Also, based on PhiPT statistics, the significant difference was observed (P<0.05) between commercial cultivars and recombinant inbred lines in terms of gliadin banding patterns. Cluster analysis and PCoA via banding pattern of gliadins led to formation of three and four distinct groups, respectively. The highest variation was observed in ω-gliadins, suggesting that they may have a role in observed variation among genotypes and their bread making-quality traits.