Iranian Journal of Genetics and Plant Breeding
Volume:7 Issue: 2, Oct 2018

The barley leaf rust has been important in recent years in Iran. In order to identify the genetic resources of resistance to this disease, 207 Iranian barley landraces were studied. The germplasms were investigated at the field of Iraqi-Mahalleh research station in Gorgan as the disease hotspot under natural incidence over three years. The results showed that four genotypes including KC18638 and KC18643 from Golestan and KC19087 and KC 19093 from Gilan expressed immunity response in all three years of the experiment and 31 accessions were immune in two years. The results of principal component analysis in three years showed that 90.69% of the variations in the data were justified by the first three principal components. The results of this study indicated the possibility of racial variation in the studied disease hotspot. These findings show the importance of tracing the changes in the disease hotspot which is necessary for planning, breeding and cultivation of cultivars with effective resistance. Also, the resistant genotypes identified in this research can be used as genetic resources of leaf rust resistance in breeding programs.

Molecular phylogenetic is the branch of phylogeny that analyzes hereditary molecular diversity, mainly in DNA sequences, to increase data on an organism‘s evolutionary relationships. Due to the taxonomic levels of the study, various molecular markers are applied in molecular phylogeny. The selection of molecular instrument is of paramount matter to ensure that a proper level of variation is meliorated to respond the phylogenetic question. In this review, we have been trying to discuss about gene markers used in the plant phylogeny at various taxonomic levels. The current gene markers used in phylogeny include: the ribosomal nuclear genes, low copy nuclear genes and the extra-nuclear genome (mitochondrial and chloroplastic genomes). Conserved regions could be used at higher taxonomic levels in phylogenetics studies and regions with more changes could be applied between closely related taxa. One of the most common sequences for studying the phylogenetic relationships at the generic and infrageneric taxonomic levels in plants is the internal transcribed spacer (ITS) region of the 18S–5.8S–26S nuclear ribosomal cistron. Chloroplastic gene sequences have been used extensively at the family level and above but chloroplast non-coding sequences such as introns and intergenic spacers are used more frequently at lower taxonomic levels. Low-copy nuclear genes are most useful at the interspecific and intraspecific levels where cpDNA and/or nrDNA cannot provide adequate resolution. Evidence offers that for more strongly reconstruction of phylogeny, several discrete genes are needed. Now, uses of next generation sequencing (NGS) techniques are reported. Techniques for NGS are an alternative to prevalent methods that let access to hundreds of DNA regions.

Castor is one of neglected African oil crops with little research attention in Nigeria. In the present research, eighty-six castor genotypes were evaluated at three locations in Niger State, Nigeria. The aim was to estimate the extent of genetic variability and also to examine the associations among the seed yield and its components. The treatments were laid out in an Alpha Lattice Design with three replications. The results revealed significant effects of genotypes on most of the studied traits. Days to 50% flowering ranged between 34 days and 125 days, and had a mean of 69.21 days. The minimum of 7.33 g and maximum of 64.12 were recorded for 100 seed weight. Seed yield ranged from 144.45 Kgha-1 to 1 349.92 Kgha-1 with the average yield of 646.04 Kgha-1. Spike length and 100 seeds weight showed a high Genotypic Coefficient of Variation (GCV) and also high Phenotypic Coefficient of Variation (PCV). Significant positive correlations were observed between the seed yield and plant height at flowering, branches per plant, length of spike, spike per plant, days to maturity and 100 seeds weight. The path coefficient analysis revealed positive direct effects of seedling establishment, spike length, spikes per plant, plant height at first raceme maturity, days to first raceme maturity and 100 seeds weight on the seed yield. Highest positive direct effect on seed yield was recorded in spike length, followed by spikes per plant and seed weight, respectively. Significant positive correlations and high positive direct effect were observed between spike length, spikes per plant and seed weight. The findings revealed the importance of spike characters for the selection of desirable castor genotypes for increased seed yield.

This study was conducted to assess the efficacy of SCoT and DAMD molecular markers in genetic diversity of three moss species and compare them with ISSR marker. Another objective was to evaluate the suitability of these DNA markers in species identification (delimitation) in three moss species, including Neckera complanata, Homalothecium sericeum and Neckera crispa. To prevent ecological impact on results, all samples were collected from one locality. PIC and MI in three markers showed closely ranged values. Our results revealed that the average values of Rp and the number of species-specific bands in SCoT primers were more than those of DAMD and ISSR. It showed considerable capability of SCoT marker in discriminating individuals. The highest value of genetic parameters Na (1.08), He (0.15) and I (0.23) were obtained with SCoT marker showing the power of this marker in genetic diversity analysis. Moreover, dendrograms produced from SCoT and DAMD data indicated similar results in the placement of closely related species. ‏SCoT markers were shown to be more efficient than DAMD and ISSR markers based on the multiplex ratio (EMR), Rp, genetic diversity parameters (Na, He, I) and the number of species-specific bands. The findings demonstrated that the SCoT and DAMD markers could be applied for the estimation of genetic relationships and separation of two closely related genera. This is the first report of its type on the genetic diversity of mosses by application of SCoT and DAMD.

Estimation of genetic diversity is an important factor in germplasm conservation and characterization. In rice breeding programs, genetic diversity information on specific regions of genome can be very useful for the application of marker assisted selection (MAS) and for gene mapping. A total of 152 rice lines were considered for breeding programs using microsatellites (SSR) technique. The total number of polymorphic alleles was 206 with an average of 2 alleles per SSR locus. The PIC value for the SSR loci ranged from 0.479 to 0.5 with an average of 0.498. The highest PIC value was observed for primers RM60, RM6832, RM3838 and RM592. RM1, RM237, RM154 and RM84 had the lowest PIC values in a decreasing order. Nei’s gene diversity ranged from 0.479 to 0.5 with an average of 0.498. Using Shannon’s diversity index, a mean genetic diversity of 0.691 was obtained. The lowest diversity was found for RM1, RM237, RM246, RM154 and RM279 in an ascending order and 27 SSR markers had the highest value (0.693). Cluster analysis using the UPGMA method based on Jaccard’s similarity coefficient classified all lines into three clusters. Association analysis by general linear model (GLM) method revealed that 62 SSR markers showed a significant association with 10 studied morphological traits. Twenty eight markers were associated with more than one trait. These may be further investigated in rice breeding programs to be introduced as informative and useful markers. Results showed the potential of SSR markers to identify rice lines at the DNA level. The information will help the selection of lines to serve for efficient rice breeding programs.

This study was carried out to compare agro-morphological traits and nutritive value of 25 tall fescue (Festuca arundinacea) ecotypes grown in Tehran, Iran. The experiments were carried out in a split plot design during 2016-2018 growing seasons. The results showed that there was a significant genetic variation in existing germplasm. The highest heritability was related to dry forage yield and collar diameter (88%). The low heritability levels of forage quality related traits indicated that environmental effects play a greater role in controlling this trait. The mean comparison showed that Isfahan ecotype 11 had the highest number of fertile shoots, dry forage yield and diameter of collar while ecotypes of Shahrood ecotype 9 had the highest percentage of dry mater and Dauphine genotype with 16.05% had the highest protein percentage. The number of fertile shoots (NFS) had a positive and significant correlation with dry forage yield (DFY) and plant height (PH). DFY was positively correlated with NDF (0.71) and negatively correlated with CP (-0.62). In AFLP analysis out of the 463 scored bands, 339 (68%) were polymorphic. PIC values ranged from 0.34 (EcoACA-MseCTA) to 0.10 (EcoAGC-MseCAC). The results showed that genetic distances between ecotypes based on agro-morphologic characters and nutritional values were correlated based on AFLP (r=0.41, P=0.05) results. Based on cluster analysis all genotypes were classified into 4 genotypic groups. Considerable genetic variation and high heritability estimates indicate that direct selection for increasing forage yield could be promising. However, breeding nutritional values of forage quality might be more difficult due to environmental effects.

Production of genetically and phenotypically stable plantlets is the main purpose in commercial strawberry tissue culture. In this study, different tissues of Fragaria ananassa cv. Camarosa including stipule, apical meristem, leaf and petiole were cultured in Murashige and Skoog (MS) medium supplemented with different concentrations of N6-benzyladenine (BA) (0.5, 1, 2, 3 mg/L) and indole-3-butyric acid (IBA) (0.1 and 0.5 mg/L). For apical meristem explants, the best regeneration rate (7.6 shoots per each explant) was obtained in the medium containing 1 mg/L BA and 0.1 mg/L IBA. Whereas stipule explants showed the highest regeneration rate in the medium containing 2 mg/L BA and 0.1 mg/L IBA. For leaf and petiole explants, the medium containing 2 mg/L BA and 0.5 mg/L IBA had the best hormonal combination. To determine the genetic variation, micropropagated plants from different tissue (after 8 subcultures) were analyzed by the inter-simple sequence repeats (ISSR) molecular marker. Among the 18 pre-selected primers, 10 displayed clear, reproducible and informative bands. A total of 88 distinct bands with a polymorphic rate of 46% were produced in the molecular profile of different explants. The highest and the lowest similarity values to maternal plants belonged to stipule and petiole explants with a similarity index of 0.738 and 0.645, respectively. Vitroplants derived from stipule and apical meristem showed the highest genetic stability with respect to maternal plants. With respect to genetic stability and regeneration rate, apical meristem can be recommended as suitable explants with the highest genetic fidelity. The findings of this study could be applied for commercial scale multiplication of strawberry, and also demonstrate that ISSR markers are eligible for detection of somaclonal variations.