Journal of Plant Molecular Breeding
Volume:3 Issue: 1, Winter and Spring 2015

Association analysis is a useful method for evaluation of significant association between molecular marker and phenotype of trait. This study was performed to evaluate association between traits related with powdery mildew resistance and molecular markers. This investigation was performed using 77 barley genotypes and AFLP markers. In phenotypic evaluation, reaction of seedlings to powdery mildew was evaluated and the infection type and intensity were assessed based on 0-9 scale as the most important traits associated with resistance. Also in this study, the genetic diversity of genotypes was evaluated using seven combination primers EcoRI/MseI. The average percentages of polymorphism and polymorphic information content were 92.37% and 0.43, respectively. General evaluation of the statistics of genetic diversity showed that among seven primer combinations, three combinations of E90-M160, E100-M160, and E100-M150 were higher value than others and had a more obvious effect in the detection and separation of barley genotypes. Association analysis was performed using four statistical models of GLM and MLM applying TASSEL software. In the complete MLM model, 33 markers showed significant association in the 5 percent probability level with traits and the highest coefficient of determination was related to marker E80-M150-3 that explained 14% of variations of infection intensity. E80-M510-3 and E80-M160-22 markers were showed significant association (pr<0.05) with both characteristic the severity and type of infection that can represent the effective role of this genomic region in resistance to powdery mildew. If the results are confirmed, it can be a suitable candidate for conversion to SCAR specific marker.

Castor (Ricinus communis L.) is one of the most ancient medicinal oil crops in the world. It has been vastly distributed in different parts of Iran. In the present study, the inter simple sequence repeat (ISSR) markers were used to evaluate the molecular genetic diversity among and within 12 castor accessions collected from 7 regions of Iran. Totally, 16 ISSR primers amplified 166 loci, of which 116 loci (69.89 %) were polymorph, indicating high genetic variability in castor germplasm. An accession-specific ISSR band was detected in ‘80-29’accession. Genetic distance among accessions ranged from 0.2 to 0.056. Analysis of molecular variance revealed a higher level of genetic variation within (80%) than between (20%) accessions. A model-based Bayesian approach subdivided 60 genotypes from 12 accessions into 6 subgroups. UPGMA dendrogram based on Nei’s genetic distance classified 12 accessions into 4 groups. The result indicates that there was no association between geographical origin and ISSR patterns. The results suggest that ISSR technique is a useful tool for studying genetic diversity in castor germplasm.

Having knowledge about genetic relationships among accessions is necessary for developing breeding strategies to produce improved cultivars. In present study, genetic diversity and inter-relationship among 29 genotypes of citrus were comparatively analyzed using morphological and RAPD markers. Significant variability was observed among citrus genotypes for 61 quantitative and qualitative morphological characters of leaves, fruits and seeds. Furthermore, the RAPD markers revealed a high polymorphism rate (91.82 %). A pair-wise similarity value between genotypes ranged from 0.14 to 0.97 with average of 0.62. Both morphological and molecular analysis indicated a high degree of variation among studied genotypes. In current research, genotypes “pummelo” and “mandarin” were confirmed as true species of citrus in distinct cluster. Results of present study proved that both of morphological and molecular markers are potential tools for determining genetic diversities and genetic relationships of citrus genotypes and can be used in citrus breeding programs.

Direct regenerations by using mature cotyledonary node as a explants has been shown to be time-saving and convenient strategy for micropropagation of soybean. So we have evaluated regeneration protocol through single shoot using cotyledonary node as a rapid and efficient protocol for two soybean cultivars and one mutant line. Cotyledonary nodes explants obtained from 7-days-old in vitro seedlings. After 28 days, the percent of regeneration and after 42 days, regeneration area were calculated. The results showed that percent of regeneration and regeneration area of mutant line was significantly more than two cultivars, L17 and Williams. After shoot induction, plants were transferred to shoot elongation medium followed by transferring plants to rooting medium. The results showed that the percent of rooting was not significantly affected by genotypes. In another experiment to test kanamycin sensitivity of regenerated shoots, it was found that kanamaycin with 150 mg/L concentration is lethal for regeneration of soybean shoots from cotyledonary node explants. The results showed that regeneration efficiency of mutant line was significantly more than two other cultivars. Kanamaycin sensitivity of regenerated shoots showed that kanamycin at 150 mg/L or above can be used as a selective agent for all three tested cultivars transformation.

Dog rose (Rosa canina L.) is one of the most important ornamental and medicinal plants which are used as a rootstock for ornamental roses such as Rosa hybrid and Rosa floribunda. In vitro propagation of rose has a very important role in rapid multiplication of species with desirable traits and in production of healthy and disease-free plants. Micropropagation of Rosa canina L. was revised, using its nodal segments under different combinations of BAP (0, 0.5, 1, 1.5 and 2 mgl⁻1), GA3 (0 and 0.5 mgl⁻1) and NAA (0 and 0.5 mgl⁻1) on Murashige and Skoog (MS) and Van der Salm medium (VS) in proliferation stage and using different combinations of NAA and IBA (0, 0.3, 0.6 and 0.9 mgl⁻1) and ½ VS medium in rooting stage. The highest shoot proliferation was obtained on VS medium containing 2 mgl⁻1 BAP. Furthermore, the highest root induction obtained in ½ VS containing 0.6– 0.9 mgl⁻1 of NAA or IBA. The present study presents an in vitro protocol for R. canina.

Plants are naturally exposed to frequent changes in environmental conditions such as salt stress affecting their growth and development, and consequently a considerable reduction in total productivity. Monodehydroascorbate reductase (MDHAR), a key enzyme in ascorbate-glutathione cycle, serves as an important antioxidative enzyme in scavenging of reactive oxygen spices (ROS). In this study, MDHAR gene from Aeluropus littoralis was isolated using specific primers by RT-PCR and its expression variation was investigated at 0, 150, 300, 450 and 600 mM of NaCl through Real-time PCR. The results indicated that A. littoralis MDHAR gene compromised 1436 bp without any introns, showing a high similarity with Sorghum bicolor. The only alteration of MDHAR expression was observed at 300 mM NaCl, i.e. cytosolic MDHAR in both shoot and root was increased 1.3 and 1.4 fold compared to control samples. It could be concluded that accumulation of MDHAR reduces at Nacl concentrations higher than 300 mM.

Rice as one of the most important agricultural crops has a putative potential for ensuring food security and addressing poverty in the world. In the present study, in order to provide basic information to improve rice through breeding programs, Inter Simple Sequence Repeat marker (ISSR) was used For DNA fingerprinting and finding genetic relationships among 32 different cultivars. In this study, 12 out of 17 used primers amplified 184 distinct and reproducible fragments with high value of polymorphism (88%). also, for fingerprinting the cultivars 29 loci were used that generated high polymorphic bands among the cultivars. Results indicated that similarity index varied between 39% and 88.4 %, furthermore, PIC value with an average of 23% ranged between 0.1 (for primer #3) to 0.34 (for primer #2). Clustering based on Jaccard coefficient similarity index and UPGMA algorithm divided the cultivars into 6 main sub-clusters in cut-off point of 64% similarity index. The two Italian rice cultivars ‘Ribe’ and ‘Roma’ were the closest cultivars in addition, ‘Vialone nano’ and ‘Anbarbu’ showed the highest dissimilarity. In total, high genetic divergence was observed among the cultivars also, poly (GA)-containing 3-anchored primers amplified the highest number of bands. According to similarity and cluster analysis, it could be inferred that crosses involving Anbarbu cultivar are the most promising ones to improve rice through breeding programs. In fact, results of this study would be promising as a genetic marker for the identification of rice cultivars and an important source of knowledge for subsequent rice researches.