principal component analysis

The aim of this study was to determine properties of soil Citrullus colocynthis habitat. First implement the distribution status of this plant in Nimroz city and by establishing two transects, each with a length of 250 meters and at a distance of 50 meters, a plot of 3× 3 meters was determined according to the type of cover. Also the characteristics of cover percentage, bare soil and litter were determined. forty soil samples were taken from habitats of this plant and control areas from a depth of 0-50 cm and analyzed some soil properties. T-test and principal component analysis (PCA) method were used to compare the soil properties and to determine the factors affecting the establishment of plant species. Results showed that there is a significant difference between the mean of acidity, carbon, total calcium and magnesium, sodium, sodium adsorption ratio, soluble sodium, total cations, absorbed phosphorus and potassium, clay, silt and sand in the two studied areas. But between other data, it is not statistically significant. The multivariate analysis indicate that the plant tends to settle in soils with higher organic matter, phosphorus, potassium and clay and the variables of sodium content, sodium uptake ratio, total cations and sand percentage are the most important obstacles to the establishment of this plant in study area. Conclusion the soil characteristics of this plant, its ecological needs are low in the harsh ecological conditions of the region and can be adapted to poor soils.

This study aimed to compare the morphological characteristics of northern Caucasian bleak (Alburnus hohenackeri) populations in the Caspian basin using geometric morphometrics. Geometric morphometrics in fishes examines the changes in their appearance among different groups or under different environmental conditions by using anatomical reference points on their body. The data encompassed 487 fish samples from the Caspian Basin, including the Aras, Shalmanrud, Mazoboon, Noor, Sorkhrud, Goharrud, Kaparbordrud 1, Kaparbordrud 2, Gorganrud 1, Gorganrud 2, Lamir, and Hajibakandeh rivers. Photographs were taken from the left side of the lateral surface of these samples, and then 13 landmarks were digitized using tpsDig2 software. The data obtained from Procrustes analysis were analyzed with multivariate statistical methods such as PCA, CVA, and cluster analysis. The comparison of geometric morphometrics revealed a significant difference between the Aras River population and the other populations. The main differences were related to the shape of the body, the size and shape of the head, the position of the mouth, the position of the fins, the height of the body, and the length of the tail stem. This difference between the Aras River population and other rivers may be due to variations in habitat and geographical separation. Alternatively, it is possible that the observed differences indicate distinct species. On the other hand, the other populations overlapped with each other, and no significant difference was observed between them. This similarity in morphometrics could be attributed to similar habitat conditions.

During 2020-2021, to investigate the morphological variation of Chelon auratus, a total of 170 specimens were collected using beach seine nets from the shores of Astara (23 specimens), Anzali (33 specimens), Kiashahr (23 specimens), Langaroud (27 specimens), Roudsar (7 specimens), Chalous (30 specimens), Mahmoudabad (14 specimens), and Sari (13 specimens). At the sampling sites, after imaging from the left side of the specimens, 14 landmark points were defined and digitized on the two-dimensional images using the tpsDig2 software. The obtained data, after generalized Procrustes analysis, were analyzed using multivariate statistical analyses including principal component analysis (PCA), canonical variate analysis (CVA), and cluster analysis (CA). The deformation patterns of each population were illustrated in relation to consensus shapes on the deformation grids. The results showed significant differences in the body shape of the studied populations (P<0.05). These differences, related to head length, body depth, dorsal fin position, and caudal peduncle length, suggest the separation of populations in response to environmental conditions.

High increase in societies’ needs to wood and its products followed by decrease in forests lands leads to give special importance to forest plantation. The study aims to consider the impact of pure and mixed plantation of Eucalyptus and Ziziphus on above-ground growth features and soil properties in Laleh Park in Dezful . A complete randomly design was conducted with two treatments of pure plantation of Eucalyptus cameldulensis, and mixed plantation of Eucalyptus and Ziziphus with three repetitions. In total, 42 sample plots were determined. The quantity characteristics were diameter at breast height , diameter of collar , height of tree , crown coverage, slender coefficient , Form quotient, volume, leaf dry mass , leaf area index , total growth ring width , and wood density. To determine the chemical and physical properties of soil, three soil samples from each plot at the depth of 0 to 30 cm were collected and a mixed sample was transformed to the laboratory for the further works. The results showed that DBH, DC, H, V, TWR of Eucalyptus cameldulensis in pure plantation was significantly higher than those of mixed plantation. According to the analysis of main components and growth features of Eucalyptus cameldulensis, two groups were separated across first and second axes as each of them indicated high adaptation with place of sampling (mixed or pure mass). The measuring soil properties between two plantations showed that potassium, nitrogen, phosphor, organic carbon, and saturation moisture content were significantly more than that in pure plantation.

To evaluate the effect of drought stress on grain yield, yield component, morphologic and phonological traits on 30 genotypes of wheat, an experiment in the form randomized complete block with three replication at 2 levels of irrigation (normal and stress), was carried out. Results showed that the studied genotypes were significantly different in terms of grain yield, 100-seed weight, number of seeds per pod, number of pods per plant, day to maturity, and seed size under stress and non-stress conditions. According to the results, it can be seen that Kavir, Pishtaz and Helmand cultivars showed the lowest yield reduction and Navid, Karim and Alvand cultivars showed the highest grain yield decrease among all cultivars. The analysis of tolerance index correlation showed index of tolerance stress, using mean and using numeral mean are the best indexes for identifying genotype with high yield in this test According to the results of phenotypic correlations, stepwise regression, path analysis and principal component analysis in both normal and stress conditions, it can be concluded that, expected that the traits of number of spike in plant, total spikes weight, biological yield, main spike of weight, were most important and effective traits affecting yield and considering that among the genotypes, The highest diversity was observed for these traits, therefore selecting and breeding for these traits can ideally be improved the yield Genotype grouping in both conditions was conducted based on studied traits with UPGMA method, in both conditions investigated genotypes were grouped in five clusters.

Salinity is one of the most significant environmental stresses for sustainable crop production in the world's agricultural lands. Tomatoes are sensitive to salinity, and it is possible to create a tolerant genotype by evaluating the diversity among tomato genotypes under salt stress and using this diversity in tomato breeding programs. Based on this, in the current study, 22 tomato genotypes were evaluated under salt stress in a randomized complete block design with three replications. In this research, different stress tolerance indices were used to evaluate genotypes under salt stress. Stress Tolerance Index (STI), Tolerance Index (TOL), Geometric Mean Productivity (GMP), Mean Productivity (MP), Harmonic Mean (HM), Yield (Y), Yield Stability (YSI) and Stress Sensitivity (SSI) were calculated based on the total dry weight under control and stress conditions. The results of analysis of variance and mean comparison showed that there is a statistically significant difference between the studied tomato genotypes for two traits, total dry weight and total fresh weight, in two conditions of salt stress and control. These results confirmed the existence of diversity between genotypes in their morphological characteristics. The YP trait showed the highest correlation (0.9) with the MP index and the YS trait showed the highest correlation (0.91) with the HM index, and these indices are suitable for evaluating tomato genotypes under salt stress in the seedling stage. Based on bi-plot analysis, the G10 genotype was the most tolerant genotype, and after that, the G2, G22, G19 and G5 genotypes showed tolerance to salt stress. The cluster analysis divided the genotypes into three separate categories, which showed different behaviors during the transition from a non-stressed environment to a stressed environment. Based on tolerance indices and grouping methods, genotype G10 was identified as a tolerant genotype to salt stress, which can be used as a parent in hybridization and selection of tolerant genotypes.

The aim of this study was to investigate the body shape and morphological comparison between the populations of wild (marine) and farmed common carp using geometric morphology. For this purpose, 65 pieces of fish including 23 wild common carp and 42 farmed common carp were sampled. The samples were then photographed and 16 landmarks were identified on the images. Procrast analysis was used in order to remove the amorphous data from coordinate landmarks. Principal component analysis (PCA) and discriminant function analysis (DFA) tests were used. The results showed that the two populations of wild and farmed common carp are completely separated from each other using PCA and the first three components accounted for about 64.41% of the total changes. Based on DFA for morphometric characteristics, individuals were correctly placed in their original population. The results of this study showed a significant difference in body depth and body width of wild and farmed common carp using geometric morphometric method, so that the farmed common carp had deeper body (related to the displacement of landmarks 5 and 12), a wider body (related to the displacement of landmarks 5,6,10,11 and 12) and also a shorter tail stem (related to the displacement of landmarks 6, 7, 9 and 10) than wild common carp.

The expansion of industries, the development of cities, the increase in population, and the excessive human intervention in nature have led to the destruction and pollution of the environment. Soil pollution, especially soil pollution with heavy metals, is one of the environmental issues of concern to many researchers. The geographical distribution of heavy elements in the soil, either naturally or through human activities, will bring issues and problems. Heavy metals can enter the soil environment through the weathering of parent materials or external pollutants. For some metals, such as lead, pollution from external sources is much more than from natural sources. Among the natural factors, parent materials are the main factors that determine the concentration of heavy metals in the soil, and among the unnatural factors, industrial and agricultural activities are among the main sources of heavy metals entering the soil and are known as human sources. Human sources of heavy metal entry are divided into primary and secondary categories. Heavy metals are added to the soil as impurities along with primary sources including sewage sludge, chemical fertilizers and pesticides. Secondary sources include the entry of heavy metals through mines, industrial activities or through deposition from the air. The purpose of this study is to identify the sources of heavy metals (chromium, cobalt, zinc, vanadium, copper, lead, nickel, antimony, arsenic and cadmium) in the surface soil of Hamedan province (0-20 cm) using multivariate statistical methods. (Analysis of main and cluster components).

In this study, to investigate sources of ten heavy metals (Cr, Cd, Zn, V, Cu, Pb, Ni, Sb, As, Cd,) in soil surface layer in Hammadan province, a systematic random method was utilized for soil sampling and 286 soil samples were collected from 0-25cm depth. For this purpose, first, the region was divided into 5 x 5 km grids. In the next step, based on the knowledge of the study area and the variety of uses and activities, the grid spacing was 2.5 x 2.5 km in the areas where the intensity of land use was high, and the grid spacing was 10 x 10 km in the areas where the intensity of land use was less. And the intersection of networks was considered as sampling points. A total of 286 soil samples were collected from the study area by a combined method in sampling after spotting, at the sampling site a plot of 20x20 meters (macroplot) and inside it three plots of 3x3 meters (microplot) was applied, then 5 soil samples were taken crosswise from each microplate from a depth of 0-20 cm and after mixing the soil, a 2-3 kg composite sample was taken from it. Also, by completing the sampling form, information about the use of the sampling location, the type of cultivation (irrigated or rainfed), the appearance of the land, the type of product, geographical coordinates andthe nearest village was completed. Soil sampling was done from pristine and untouched areas, mountainous areas, salt marshes, irrigated or rainfed agricultural lands, vineyards, gardens and lands around villages.Soil samples were dried and prepared for analysis after passing through a 2 mm sieve. Extraction was done to determine the total concentration of heavy metals in the soil using HCl and HNO3. The concentration of heavy elements lead, zinc, arsenic,antimony, chromium, cobalt, vanadium, nickel and copper was measured using ICP-MS device and cadmium was measured by graphite furnace method and using atomic absorption device.In this study, the mean, median, skewness, skewness and Kolmogorov-Smirnov statistics were used to examine the distribution and test the normality of the data at the 95% confidence level. Principal component analysis is used to classify relationships between measured variables. In cases where the number of evaluated variables is large, it is difficult to analyze them through the correlation coefficient.In this study, the accumulation method was used to group the variables. This method starts with one variable, so at the beginning of processing, the number of groups is equal to the number of studied variables (target variables). Then, the similar and homogeneous groups are combined with each other and with decreasing homogeneity, all the subgroups are piled up and condensed and finally form a single group.

Results of multivariate statistical analysis showed that the main origin of the chromium, cobalt, nickel, zinc, lead and vanadium is parent material and copper cadmium, arsenic and antimony have common origins of natural material and anthropogenic sources (agricultural activities). Finding appropriate information about possible resources of heavy metals can be used for the monitoring and evaluation processes of agricultural soils in the study area. The results obtained from measuring the concentration of total heavy metals in the surface soil of Hamadan province showed that by using factor analysis, the source of heavy metal accumulation can be identified. The results of factor analysis showed that chromium, cobalt, nickel, iron, zinc, lead, and vanadium were the first factor with the highest connection, according to the results of factor analysis. The close correlation between these elements could explain their shared origin. The high concentration of these components in the surface soil of the mother matter appears to be the key reason, according to the geological structure and agricultural maps of the study area. However, because of the high consumption of chemical fertilizers (average urea fertilizer consumption is 500-700 kg/ha per year, potash fertilizer consumption is 200-330 kg/ha per year, and phosphorus fertilizer consumption is 300-558 kg/ha per year), and the possibility of these elements in the chemical structure of urea, phosphate, and potash fertilizers, increasing the element concentration in the soil by them is not far from the mind. Copper, antimony, cadmium, and arsenic are among the components present in the second factor. According to the geological structure and land use map, the high concentrations of these elements are due to both natural and human activity (agricultural activities). The results of a cluster analysis confirm these findings. Overall, the findings of this study revealed that studying the relationship between heavy metals, investigating their origins, and analyzing them using multivariate statistical methods (factor analysis and cluster analysis) would be very accurate and simple.

Gambusia holbrooki Girard, 1859 is considered as one of the non-native and invasive species in the inland waters of Iran. This species occurs in most inland basins and aquatic bodies of Iran and has even been found in brackish waters. Extensive adaptations of this species to its different habitats caused numerous changes in its biological characteristics and morphological traits. The present study was performed to investigate the sexual dimorphism of G. holbrooki in the Gamasiab River, Kermanshah Province, Iran. 59 fish specimens were collected from the river in September 2017. After taxonomic confirmation and sex determination, 29 morphological traits were measured in fish samples using a caliper and their meristic traits were recorded. In total, 37 characters (including 8 meristic traits and 29 morphometric traits) were examined. After obtaining morphological data, Principal Component Analysis (PCA) and Discriminant Function Analysis (DFA) were utilized to compare morphological traits between male and female individuals. The results showed that the 59 specimens were comprised of 30 malea and 29 femalea. On the basis of the results, all morphological traits, except the caudal peduncle length, dorsal fin base length and a post-anal length, showed significant sexual dimorphism (p <0.05). The results of DFA and PCA analysis showed that males and females were completely different from each other in terms of morphometric traits. These findings indicate that there is a sexual dimorphism in G. holbrooki of the Gamasiab River. The sexual dimorphism observed in this fish species is due to the sexual selection and increase of reproductive success.

Sesame as one of the most important oilseed crops has high industrial, food, and medicinal potentials. Drought stress challenges sesame production, especially at the germination and seedling stages. To screen sesame genotypes for drought tolerance at the germination stage, a factorial experiment was performed in a completely randomized design with 3 replications. The studied factors included 4 drought levels induced by polyethylene glycol (concentrations of 0%, 20%, 25%, and 30%) and 15 sesame genotypes. Based on the results of ANOVA, the effect of genotype, drought, and their interaction on all studied traits including germination rate, germination speed, vigor index 1 and 2, radicle length, plumule length, and seedling fresh and dry weight was significant (P<0.01). Significant reduction (P<0.05) was observed in all levels of stress compared to the control in the studied traits. Germination rate, radicle length, and plumule length (with 10%, 17%, and 18% reduction, respectively) showed less sensitivity to drought stress at weak level (20% concentration), while the most negative effect was obtained for vigor index 2, seedling dry weight and seedling fresh weight (with 52.5%, 47.3%, and 34.4% reduction, respectively). On the other hand, the highest decrease was observed in plumule length, vigor index 1 and 2 (98%, 97%, and 96%, respectively), under severe drought (30% concentration). The calculated drought tolerance indices of each trait were used for principal component analysis and biplot visualization. Thus, genotypes were divided into 5 categories based on tolerance. Dashtestan 2 and Darab 1 genotypes were selected as the most tolerant and Qaem, Yekta, Sudan, and Kerman genotypes were selected as the most sensitive genotypes. The findings of this study can be used in future studies and breeding programs of sesame for drought tolerance.

Water fern (Azolla filiculoides) is one of the most dangerous invasive aquatic plant species in the temperate and tropical regions of the world. 4 different sites were selected in Guilan and Mazandaran provinces to examine the habitat suitability of Azolla. 15 physical, chemical and structural variables at each site were monthly sampled simultaneously with biological data (based on 24 presence instances and 24 absence instances of Azolla) during one year (2017-2018). The results of the Mann-Whitney test showed that except water and air temperature, ammonium and turbidity (p > 0.01 for all), a significant difference was observed between the presence and absence of Azolla and the remaining variables (p < 0.01 for all). The obtained results of the principal component analysis showed that water depth, phosphate and electric conductivity were the most influential factors in the first to third components, respectively so that they had the major effect on the habitat suitability of Azolla in the sampling sites. The results of generalized linear model showed that there was a significant difference between the presence and absence of Azolla in the sampling sites and all variables used in the principal component analysis (p < 0.01).

Rice is one of the most important food crop which is the staple food for more than half of the world population. The purpose of this study was to evaluate the physical and chemical properties such as plant height, panicle length, number of effective tillers, total number of grains, number of filled grains, number of unfilled grains, 1000-grain weight, biological yield, economic yield, harvest index, chlorophyll index, growth period, total Phenol (TP), antioxidant capacity based on 2,2-Diphenyl-1-Picryl Hydrazil (DPPH) with 30 rice genotypes in a randomized complete block design in the experimental field of Amol Rice Research Institute. Results showed that Amol 1 and Bijar rice varieties had significantly higher antioxidant activities and total phenolic than the other samples examined in this study, respectively. The highest total number of grains, number of filled grains and 1000-grain weight were observed in genotype IR56. The genotypes were grouped into five clusters based on agronomic traits using UPGMA method. The highest mean of yield was related to the fourth cluster and the lowest of this attribute was related to the fifth cluster. Principal components analysis (PCA) explained 79.01% of variation and economic yield, total number of grains, and number of filled grains played the main Experimental Field role. Two principal components accounted for 43% of the raw data of the yield-related traits. The results of this research indicated that use of economic yield, total number of grains, and number of filled grains could be applied as a breeding strategy to obtain high yield rice cultivars.

6 different sites (4 sites situated in wetlands and 2 sites located in river) were selected in the Guilan and Mazandaran provinces to study the habitat suitability of Myriophyllum spicatum L. Monitoring of biotic data (36 presence and 36 absence data) was monthly carried out simultaneously with abiotic data (a set of physical, chemical and structural variables) during one year (from July 2017 to May 2018). Based on the results of Mann-Whitney, except water temperature, biological and chemical oxygen demand, ammonium and nitrite (p > 0.01), a significant difference was observed between the presence and absence of plant and the remaining of variables (p < 0.01). According to the results of principal component analysis (PCA), among 8 variables used in this method, flow velocity, total suspended solid and bicarbonate were the most important variables in the first three components, respectively so that they had the major effect on the habitat suitability of plant. According to the results of canonical correspondence analysis (CCA), the presence of plant in wetlands can be because of increasing of carbon dioxide, bicarbonate, dissolved oxygen and phosphate and the absence of plant can be attributed by increasing flow velocity, total suspended solid, electric conductivity and water depth while different seasons of year didn’t have much effect on the presence of absence of plant. Based on the results of the generalize linear model (GLM model), there was a significant difference between the presence and absence of plant and 8 variables (p < 0.01).

The current morphometric research was conducted collecting Rhamnus cathartica and Rhamnus pallasii from the natural habitats in North and West of Iran. In order to clarify the relationships in studied species and understand taxonomicall values, 58 morphological characters were employed (26 quantititative and 32 qualitative characters) using numerical taxonomy, Principal Component Analysis (CPA), and cluster analysis. In this study, leaf shape, color fruit have been found to significantly contribute to the determination of the studied species (Rhamnus pallasii & Rhamnus cathartica). The results confirmed more diversity in Rh. pallasii and three sub-species. But, in Rh. Cathartica, diversity features in the two varieties were not effective. Rh. × spathulifolia were collected from sandy hill of North of Iran which was determined by morphometric features e.g., leaflet, abaxial, adaxial leaflet trichrome, and fruit color. Overall, Rh. × spathulifolia can not be considered.