جستجوی مقالات مرتبط با کلیدواژه « بعد همبستگی » در نشریات گروه « اکولوژی »

The objectives of this research were to evaluate the relationships between traits of different sesame genotypes and determine the most important traits affecting on the grain yield under control and humic acid application. This experiment was carried out under control and humic acid application (250 gr humic acid per 1000 liter water). Each experiment was conducted using randomized complete block design with three replications in Abarkouh. Sesame genotypes were including Varamin 2822, Halil, Dashtestan 2, Dashtestan 5, Darab 1, Darab 14, Yazd, Jiroft 13 and Safi Abad. Grain yield under both conditions had significant positive correlation with biological yield, harvest index, 1000 seed weight, oil percentage, protein percentage, number of branches and number of seeds per capsule. By stepwise regression, number of branches and 1000 seed weight under control condition and number of seeds per capsule under humic acid application were entered to the stepwise regression model. The result of path analysis showed that number of branches under control condition and number of seeds per capsule under humic acid application had the most positive direct effect on grain yield. Studied genotypes using cluster analysis classified into three groups. Number of branches under control condition and number of seeds per capsule under humic acid application was one of the most important traits in sesame genotypes. According to cluster analysis, Dashtestan 2 and Darab 14 were better genotypes and so these genotypes could be used for achieving to high yield in sesame..

Drought stress is one of the abiotic factors that restricts crop growth and performance in most regions of the world. It causes changes in the growth of medicinal plants regarding the quantity and quality of their active ingredients. Fennel belongs to Apiaceae family that is growing in most parts of Iran. Essential oil that obtained from its seeds used in various industries of pharmaceutical, food, and cosmetics. Wide germplasm resources, genetic diversity among species, low water requirement and drought resistance have been factors for increasing importance of this plant. Despite of tendency to use and produce natural products, and importance of medical application of fennel, few studies have been existed and resulted in using local mass for cultivation in Iran. Studies suggested that for yield improvement, selection should be emphasis on plant height, primary branches, total plant branches and the number of effective umbrella in plant. The purpose of this research is to evaluated the morpho-phenological and quantities characteristics of different ecotypes of fennel and selection criteria for resistance and compatibility under water stress.

This experiment was conducted in a randomized complete block design with three replications at two locations of normal and end-of-season drought stress at the agricultural research farm of University of Birjand during 2014-2015 growing season. Ecotypes contained: Birjand, Mashhad, Nishabur, Gonabad, Bojnoord, Ilam and a Roman cultivar. Drought stress was treated before flowering by evaporation pan (Type A). Traits such as number of days to 50% flowering, days to 50% maturity, plant height, height of the main umbrella, the number of main branches per plants, the number of umbrellas, effective number of umbrella per plants, the number of seeds per main umbrella, the number of umbelets in main umbrella, Internodal length, internodes number and grain yield were measured. Analysis of variance and drawing By-Plot was carried out with GenStat 12 software. Cluster analysis and Pearson correlation coefficient analysis was performed using SPSS software.

Analysis of variance showed that the genotypes were significantly different for all traits except for the number of branches and the number of umbrella per plants in 1% probability levels. This result indicates that there is genetic variation in these genotypes for evaluated traits in normal and drought conditions. Correlation coefficient analysis showed a significant correlation between investigated traits under both normal and stress conditions. Result of cluster analysis was similar under both normal and stress condition and investigated ecotypes of fennel were divided to two distinct groups. Under normal condition, the highest seed yield was related to Birjand ecotype. Under drought stress condition, however, the highest seed yield corresponded to Mashhad, Nishabour, Khousf and Bojnord ecotypes while Romi and Ilam ecotypes where located in middle class for seed yield trait and lowest seed yield was related to Gonabad ecotype. Based on bi-plot analysis of genotype×traits, under normal conditions ecotypes such as Ilam, Gonabad and Khoosf had the highest value in plant height, internode length, days to maturity and the main branches. Under stress conditions, ecotypes such as Bojnoord, Mashhad, Nishabur and Roman had the best grain yield. Ilam and Khoosf showed moderate yield.

There was a significant difference between yields of different genotype under both normal and stress conditions that is related to the number of fertilized umbels and the number of umbels per plant. Under drought stress conditions genotypes such as Mashhad, Nishabur, Khosf and Bojnoord had the highest performance and belong in one class, while Ilam and Roman genotypes were in middle classes and Gonabad genotype stay on in lowest yield. The number of umbels per plant, the number of seeds per plant and umbels can be as effective traits on grain yield and can be the best criteria for selection in breeding programs.

The landscape metrics are used to quantify the spatial properties of landuse patches and classes as a useful tool in assessing effect of human activities on flooding processes. This study aims to evaluate the efficiency of HEC-HMS model in flood simulaion of Amoughin watershed and exploring the relationships of landscape metrics and the flood components. The HEC-HMS model was runned with SCS-CN (loss module), SCS-Unit hydrograph (rainfall-runoff transformation) and Muskingum (routing). The model parameters were optimized using 6 events considering Nash-Sutcliffe objective function and three excluded events used during validation. The components of simulated hydrographs were defined by 25-year design rainfall. The landscape metrics were quantified using Fragstat and appropriate landscape metrics slected by PCA. The correlation and regression analysis were performed in R programming. The value of Nash-Sutcliffe criterion was 0.63 in validation which proves the accuracy of model in flood simulation. The results showed a positive relationship between Qp, runoff volume and base time with total area (TA) and MESH metrics. Relationship of Qp with TA, patch density (PD) and slope were evaluated as positive (p-value

Despite the significant advances in Numerical Weather Prediction (NWP), the prediction of precipitation is still challenging. Considering the importance of accurate prediction of precipitation in hydrological applications and prediction of flood, In this paper, in order to determine WRF resolution impacts for precipitation, model precipitation prediction was evaluated for three domains with resolution of 36, 12 and 4 km in 5 cases of heavy precipitation resulted in flood (more than 50mm at 24 hours) at KARKHE and KAROON basins. At first, atmosphere conditions investigated synoptically at the time of heavy precipitation in the study area by ECMWF data with resolution of 0.75 degrees. In order to study the quality of the model in terms of synoptic, Jet Stream at 200hPa, Relative Humidity and Horizontal Flux Moisture at 700hPa were drawn for three domains with different resolutions and were compared with their respective maps with reanalysis data. Then, WRF model accumulated precipitation output has been compared with accumulated observations for 22 synoptic stations at KAROON basin and 20 stations at KARKHE basin. In order to verify the WRF model output in prediction of precipitation, the statistical index of correlation coefficient was calculated. Also, for a closer look, average and accumulated precipitation maximum was determined for three domains. Results showed that in a synoptic study when heavy precipitation occurs, model prediction is consistent (For example, in terms of the direction of motion of the wind, the maximum, the center of measurement and curvature in the Jet stream of 200 hPa and the relative humidity of 700 hpa) for all three domains with different resolution. Also, comparing precipitation observation and prediction, the 4 km domain is more accurate with higher correlation coefficient. In general, the prediction of precipitation for the WRF model is acceptable In terms of increasing accuracy in predicting rainfall and flood for a domain with a 4 km resolution. So, the model prediction in the third domain with 4-km resolution compared to the second domain with a resolution of 12 km has improved in terms of the average precipitation of 7% and in terms of maximum precipitation of 5%. Also, the percentage of improvement of the third domain of the model compared to the first domain of the model with a resolution of 36 km for the average and maximum precipitation of catchments is 12% and 22%, respectively.

In this research the chaocity of precipitation time series in daily, weekly and monthly scales in the Pole-Kohneh and Ghourbaghestan Stations located in Qarah-Soo watershed is investigated. In order to reassure about the absence of stochastic behavior of the time series, method of surrogate data is applied. Thereafter, the aperiodicity of the time series is investigated using power spectrum analysis. The results of chaocity investigation indicates that according to correlation dimension method and Lyapunov exponent, the daily scale is not chaotic but weekly and monthly scales are chaotic (existence of the largest Lyapunov exponent and correlation dimension between 4 to 7). Also, the phase space reconstruction is done using time delay and embedding dimension method (embedding dimensions of 7 to 10 and time delay of 2 to 4 for Pole-Kohneh Station; embedding dimensions of 9 to 19 and time delay of 2 to 3 for Ghourbaghestan Station). Findings of the research indicate the stochasticity of short term precipitation time series (daily) and chaosity of medium term precipitation time series (weekly and monthly).

In order to investigate the effect of seed rate on seed yield and yield components of three rapeseed varieties, a split- plot experiment was conducted in randomized complete block design with four replicates during 2008-2009 at Baykola Agricultural Research Station, Neka, Mazandaran province. In this experiment four seed rates (5, 7, 9 and 11 kg.ha-1) as main plots, three rapeseed cultivars (Hyola 401, RGS-003 and Sarigol) as sub plots were assessed. Each plot was included six lines with five meter length and distance between lines was 30 cm. Results showed that the effect of seed rates on seed yield and number of pods per plant was significant. The highest grain yield (4829 kg.ha-1) was related to the lowest seed rates. The effect of varieties on the secondary branch number, 1000-seed weight of pods per plant and seed yield were significant. Hyola 401 with 5033 kg.ha-1 was performed better than RGS-003 and Sarigol (PF) with 4357 and 4066 kg.ha-1 seed yield, respectively. Significant positive correlation of seed yield with 1000-seed weight, number of pods per plant, number of seed per pod indicating that Hyola 401 with highest yield components at the different plant density had the highest seed yield.