جستجوی مقالات مرتبط با کلیدواژه "genetic diversity" در نشریات گروه "اکولوژی"

Wetlands, as fragile water sources, are constantly affected by climate change and human activities. Recently, human intervention and the reduction of surface water in the catchment area of Lake Urmia have altered the microflora and physicochemical parameters of the wetlands, which need to be investigated. Results showed that phytoplankton populations of Darga-Sangi wetland consisted of Chlorophyta (2 classes, 10 families, and 22 genera), Cyanobacteriata (1 classes, 3 families, and 4 genera), Streptophyta (1 classes, 2 families, and 2 genera), Ochrophyta (2 classes, 2 families, and 2 genera), and Basillariophyta (4 orders, 6 families, and 10 genera ). In addition, pH value, Biological Oxygen Demand (BOD), and Chemical Oxygen Demand (COD) were investigated. The highest amount of BOD5 of Darga-Sangi wetland was estimated to be between 78 and 98 mg/l, while the highest amount of COD was 159 and 198 mg/l during the summer season. The results indicate that the high influx of organic and mineral substances into the wetland has affected its enrichment which resulted in blooming of microalgae and hence, rising ecological concerns. The bacterial load in this wetland puts it in an unfavorable condition, which can be dangerous for native and migratory organisms.

Iranian mangrove forests provides valuable information to prevent genetic erosion in the gene pool of these ecosystems. The aim of this study was to investigate the genetic diversity among mangrove forests located in four different regions of Iran, based on morphological characteristics and microsatellite markers. Cluster analysis of molecular data, using neighbor joining algorithm classified the 60 mangrove trees, sampled from different coastal areas, into four groups. Analysis of molecular variance showed that the majority (77%) of the variance explained by among-population variation and the highest values of genetic diversity parameters including number of effective alleles, Shannon’s information index, and Nei’s genetic diversity were obtained for the Qeshm population, indicating that region is the most diverse population among all the studied populations. Baced on the morphological analyses significant differences were observed between all populations in terms of height, diameter at breast height, collar diameter, leaf size, pneumatophore length and pneumatophore diameter. The present study, provides useful information about genetic diversity of mangrove habitats which can be used in evolutionary studies and conservation efforts for these valuable plant ecosystems.

In order to study of 13 primary chromosomal recombinant lines of hexaploid Tritipyrum in comparison with seven Iranian and two Afghan bread wheat cultivars and five promising triticale lines in hot and arid climate of Yazd as spring planting was carried out as a RCBD design with four replications on the farm of Yazd University. Some morphophenological traits were evaluated. The results showed that there was a significant difference between all studied genotypes in terms of all traits. The results of phenotypic correlation coefficient showed that heading and physiological maturity day had the highest negative and significant correlation with grain number and grain weight per spike. Tritipyrum cultivars with the highest average days to the physiological maturity, due to exposure to high temperatures, had a lower height than bread wheat and Triticale cultivars. La (4B/4D)/b showed the highest mean spike length. According to the type of cultivation and climate studied although Tritipyrum lines had the highest values for spike length, but they had the lowest values for the number of grains per spike and grain weight per spike. The results of principal component analysis showed that the first component determined 73% of the total variance. It can be concluded that the traits of stem elongation, heading, dough development and days to physiological maturity had the greatest impact on diversity. The genotypes studied in this study were classified into four clusters. In the first group, 12 Tritipyrum lines were included. Five Triticale lines and eight bread wheat cultivars were placed in the third group. The two-dimensional graph obtained from principal component analysis showed that the 12 Tritipyrum lines are superior to the other studied lines and cultivars in terms of phenological traits. Bioplate analysis, while explaining 82.2% of the total changes in the first two components, showed that the primary Tritipyrum lines include ma/b، St/b، La/b and (ka/b)(cr/b)f3 can be used as superior lines for some of the measured traits in future studies.

The coasts of Imam Khomeini port are one of the most important hot spots of mangrove plantations across Iranian coast of Persian Gulf and Sea of Oman, so this is very important to conserve this valuable ecosystem. For this purpose, 75 individual from 3 populations, keeping the minimum distance of 30 to 50 meters from each other, has been collected and investigated using 15 ISSR markers. This study aims to investigate genetic diversity of plantations and natural stands of Avicennia marina, using ISSR. 14 primers produced 284 bands in 75 individual of Avicennia marina from three populations. The results showed a relatively high genetic diversity at the species level (P = 69.48%, He = 0.199, SI = 0.308). Genetic diversity in the plantation population (P = 55.99%, He = 0.179, SI = 0.272) was lower than the two natural populations, Nayband Bay (P = 85.21%, He = 0.232, SI = 0.364) and Qeshm Island (P = 67.25%, He = 0.184, SI = 0.288). The AMOVA revealed that most of the genetic variation was accounted for within populations (82%) with only 18% among the populations studied, indicating that the genetic diversity of the plantation population was fairly conserved. The dendrogram based on the genetic distances showed two major clusters, separating the natural populations from the plantation population. The highly significant genetic differentiation between plantation population and natural populations, highlights the need to enhance genetic diversity of plantation stand by continued periodical planting of significant amount of seedlings from highly diverse natural populations.

Haloxylon salicornicum (Moq.) Bunge ex Boiss is a shrub that grows in large parts of the central regions of Iran. Due to the high adaptability of this species to the severe environmental conditions and its importance in the stabilization of sand dunes, Dust control and medicinal functions recognition of its genetic diversity and the selection of superior genotypes is very important. A set of 12 inter simple sequence repeat (ISSR) markers were used to evaluate genetic variation of 30 genotypes from 3 locations in Yazd province. Out of 12 primers, 4 primers were able to produce 39 reproducible bands that out of which, 32 bands were polymorphic (79.5%) with a mean PIC value of 0.39. The number of alleles in each individual locus varied in the range of 7-15 with the mean of 9.75. Primers ISSR 826 and with 9 alleles and ISSR7 with 7 allels showed the highest and lowest number of loci, respectively. The mean average rate of Nei’s gene diversity (h') and Shannon’s diversity index (I) were 0.451 and 0.643, respectively Using cluster analysis based on UPGMA algorithm and Jaccard's similarity coefficient, the isolates with 45% similarity level were divided into 5 groups. Shanon index, Principal coordinates analysis (PCoA), and analysis of molecular variance (AMOVA) revealed significant difference among isolates selected from three regions. Analysis of molecular variance showed that the highest genetic diversity rate (89%) was disturbed between isolates and genetic variety within different isolated was determined as 11%. Based on these results in this work it can be demonstrated a high genetic diversity within the populations will be due to the closely distributed Haloxylon community in these studied regions.

In order to investigate the effect of late-season drought stress on some physiological traits, yield and yield attributes, a two-year field trial was carried out at the research field of Seed and Plant Improvement Institute, Karaj, Iran, on 2015-2017 growing seasons. Factorial arrangement of the treatments was set up as randomized complete block design with three replications. Experimental factors consisted of irrigation regimes (normal irrigation and withholding irrigation from silique setting stage until the end of the growing season) and 17 new winter genotypes of rapeseed. Several physiological traits included relative water content (RWC), total chlorophyll, proline as well as grain yield and yield attributes as dependent variables were measured. Results showed that amount of total chlorophyll under withholding irrigation was reduced (21.65 percentage) reduced compared to the normal irrigation, while leaf proline content was increased by 28.04 %. According to the findings of this study, superior genotypes were not necessarily top in terms of proline. Averaged over both years, Artist genotype produced highest grain yield (5043.25 kg.ha-1) under normal irrigation condition, while L72 and HL3721 had highest grain yield (3915.25 and 3892.45 kg.ha-1, respectively) under withholding condition. It is worth noting that this advantage was mainly revealed to increased source capacity (number of silique plant-1, silique length and number of seed silique-1) as well as the superiority of chlorophyll content and relative water content of the leaf.

This research was conducted in order to induction of genetic diversity through radiation with gamma rays in potato cultivars for tolerance to deficit water stress under in vitro condition in Karaj Nuclear Agricultural Research Institute and Laboratory of Zar-Gostar-Arta Technology Company, during 2016 and 2017. From each cultivar of Jeli, Esprit, Banba, Milva and Agria, 3000 plantlets reproduced and were irradiated with 25 Gary of gamma rays. After evaluation, 2517 genotypes were survived. The first experiment was factorial based on completely randomized design with three replications. The first factor was potato genotypes and the second factor consisted of four concentrations of poly-ethylene-glycol including 0, 150, 220 and 275 g.l-1. After evaluation under normal and water deficit stress, 66 genotypes were selected. In second experiment 66 selected genotypes and 5 cultivars as control totally 71 genotypes were conducted based on factorial design based on completely randomized design with three replications. The first factor was 71 potato genotypes and the second factor consisted of four concentrations of poly-ethylene-glycol including normal (0 g.l-1), mild (150 g.l-1), severe (220 g.l-1) and very severe (275 g.l-1) and were investigated in terms of plant height, leaf number per plantlet, root number per plantlet, node number per plantlet, internode length, micro-tuber number and weight per plantlet and micro-tuber average weight. The Esprit-G8 genotype under normal and mild condition and Milva-G3 genotype under severe condition had the highest micro-tuber weight per plantlet. In normal condition, Esprit-G8 genotype and under mild and severe conditions, Milva-G1, Milva-G3, Banba-G5, Banba-G6, Banba-G7, Banba-G9 and Esprit-G8 genotypes had the highest in terms of leaf, node and micro-tuber number per plantlet and were selected as tolerant genotypes to deficit water stress.

In order to investigate the genetic polymorphism among 18 important Iranian and two foreign cultivars of safflower, RAPD marker was used. In this experiment 17 primer sets (ten mer) were used for amplification in reactions. Out of 279 markable bands, 256 bands were found in the range of 100 to 3000 bp. Cluster diagrams produced by means of the unweighted pair-group method arithmetic average (UPGMA) divided the lines into 4 main classes. Class 1 included two exotic genotypes and class 2 included two Iranian landrace lines and one bred cultivated Iranian. Class 3 included 13 wild and local domestic Iranian genotypes. One improved Iranian line (kw4) and Isfahan line placed in class 4. The most genetic diversity (0.863) was observed between Iranian landrace (KW4) and exotic genotype (S710). But in most Iranian landraces, the genetic diversity was low (0.241). The result showed that there is a relationship between the genetic diversity and geographical distances in exotic and indogenous genotypes. But this reletion is not among indogenous cultivars. That might be due to originating from the same parent.