جستجوی مقالات مرتبط با کلیدواژه « توده های بومی » در نشریات گروه « بیوتکنولوژی و ژنتیک گیاهی »

Evaluating the population structure is essential for understanding diversity patterns, choosing proper parents for crossing, accurate identification of genomic regions controlling traits, and evolutionary and kinship relationship studies. In this research, the genetic structure of a wheat population was studied in a panel consisting of 383 Iranian wheat genotypes of hexaploid (cultivars and landraces) and tetraploid species based on distance-based methods (principal component analysis and discriminant analysis of principal component). For this purpose, 16270 single nucleotide polymorphism (SNP) markers obtained by the GBS technique were used. According to the results, almost a quarter of the total variance was belonged to the diversity between populations, and the Fst coefficient between cultivars and landraces was equal to 0.15. In contrast, the above coefficient between tetraploid samples and hexaploid landraces was high and equal to 0.44. Genome D had the lowest value of Fst index and chromosome 4B showed the highest Fst coefficient, and other genetic diversity indices. Although the PCA biplot distinguished hexaploid wheat cultivars from landraces, it was unable to distinctly separate tetraploid genotypes from other genotypes. Accurate evaluation of the population structure with the DAPC method was able to identify and separate the predetermined successfully groups, suggesting that the DAPC approach maximizes the differentiation between groups and minimizes the changes within the group. Partial admixture between cultivars and landraces of hexaploid wheat can be related to gene exchange between these two groups or perhaps their wrong labeling at the time of collection. In general, the results of this study provided valuable information about the genetic differentiation of Iranian tetraploid and hexaploid wheat, which can be used in future wheat breeding programs. Further, protecting these genotypes in gene banks is necessary for different strategies.

To investigate the broad-sense heritability of some Haloxylon traits, an experimental design was performed using native populations collected from different provinces of Iran. 32 native populations were planted based on a randomized complete block design with three replications in Shaheed Zendeh Ruh's research station in Kerman. During three years, seven traits including main stem length, collar diameter, number of tillers, sub-stem length1, sub-stem length2, the small and large diameter of the canopy on shrubs were examined. The data were assessed by simple and combined analysis of variance. For all traits, the difference between the mean of genotypes and years was significant (p < %1). The genotype× year interaction effect was significant for all other traits except the number of tillers, which indicates different effects of genotypes in different years. Heritability of traits was estimated based on simple and combined analysis of variances. The amount of heritability was ranged from 75 to 87% for simple analysis and 51 to 64% for combined analysis, which indicates a decrease in heritability in a combined analysis. This is due to the genotypes by the year interactions effects. In both methods, the main stem length and number of tillers had the highest and lowest broad-sense heritability and coefficients of genetic and phenotypic variation, respectively. Due to the high genetic diversity among the studied Haloxylon genotypes, it will be possible to select the best rootstocks for making windbreaks in desertification projects.

Genetic diversity is necessary for plant breeders to obtain new cultivars either with high yield, better quality, more adapted to abiotic stress or more resistant to pest and pathogens. Retrotransposons are current component of plant genomes. Ubiquitous, activity and abundant of retrotransposons thorough the plant genome, make them useful molecular marker. We used inter-retrotransposon amplified polymorphism (IRAP) markers to assess genomic diversity levels and survey the activity of LTR retrotransposon elements in 10 confectionary sunflower populations. Out of 25 single and combined IRAP primers, 11 primers produced scorable and polymorphic banding patterns. A total of 116 loci were amplified by using 11 IRAP primers on confectionary populations. 110 loci out of 116 were polymorphic. The lowest (0.74) and highest (0.88) Nei genetic similarity was observed between Hamedan and Mashhad and Marand and Esfahan populations, respectively. Cluster analysis based on UPGMA algorithm grouped the studied populations in 3 main classes. Analysis of molecular variance revealed that the high part of total variation was due to within populations. So it will be better to do selection within populations in breeding programs. The results showed that retrotransposons are active in sunflower genome and they are inserted in sunflower genome as head-to-head, head-to-tail and tail-to-tail orientations. Our results showed that retrotransposon-based molecular markers can be used as a valuable tool for genomic assessment in sunflower.

Iran is one of the main centers for genetic diversity of sainfoin (Onobrychis Mill.). A total of 198 landraces of sainfoin (O. vicifolia Scop. Syn O. sativa Lam.) genetic resources, collected from all over the country were subjected in the study. The materials were sown in an experimental field and evaluated based on their agro-morphological traits. A high degree of genetic diversity for most of the agro-morphological traits was observed. Days to flowering revealed a diversity of 40 days. Therefore, the germplasm can be used as suitable materials for improving different classes of seed ripening. There were suitable genetic diversity for susceptibility to leaf powdery mildew and pod shattering traits. Result of regression analysis implied the stem color as a character for fast screening on high yield forage selection. According to the result of cluster analysis based on K-means and factor analysis, landraces were grouped into 3 distinct clusters. Clusters relations and main traits in each cluster have been disscused. A remarkable collection of sainfoin germplasm was evaluated; therefore, it can provide suitable materials for future sainfoin breeding programs.