Bayzid Yousefi; Sedigheh Zarekia
Volume 29, Issue 4 , January 2023, , Pages 562-578
Abstract
To evaluate the genetic diversity and relationships among traits of herbaceous milkvetch, 10 genotypes belong to five species including Astragalus vegetus. A. brevidens, A. brachyodontus, A. effusus and A. cyclophyllus in Sanandaj in a randomized complete block design with three replications were studied. ...
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To evaluate the genetic diversity and relationships among traits of herbaceous milkvetch, 10 genotypes belong to five species including Astragalus vegetus. A. brevidens, A. brachyodontus, A. effusus and A. cyclophyllus in Sanandaj in a randomized complete block design with three replications were studied. Seed sowing was done in November 2018 and morphological traits of plant in spring 2020 were measured. Analysis of variance released significnant (p≤0.01 and 0.05) difference for milkvetch populations (G) for all studied traits. In 2020 (two years old plants), the mean of plant establishment was about 26%, the number of primary branches was 3.2, plant height, the tallest stem length and crown diameter were 16.9, 19.2 and 15.4 cm respectively, the length and width of the root were 17.4 and 6.2 cm, respectively, the average of fresh weights of the whole plant, arial and root parts were 2.3, 1.9 and 0.4 g and the average of dry weights of the whole plant, arial and root parts were were 0.9, 0.7 and 0.2 g respectively, average dry to fresh weight ratio was 0.38. Average of leaflet per leaf was 7.7, so mean of length and width of leaf and leaflet were 7.5, 3.7, 2.3 and 0.5 cm respectively. Up to this stage, the accession of A. effusus Darreh Shohada (West Azerbaijan) and three accession of A. vegetus (Zereshk of Qazvin, Saral of Kurdistan and Qarehbagh of West Azerbaijan) were superior ones in terms of forage production and other studied traits. The weight of the plant was positively correlated with plant vigor, length and width of leaf (p≤0.05) and with plant height, crown diameter, number of primary branches, length and width of root, arial and root weight at 1% probality level. The results of stepwise regression of forage yield on other traits showed that plant weight, establishment percentage, plant height and crown diameter at 1% and the length of leaf and root at 5% probality level (R2adj = 91.1%) were forage yield components. Therefore, in order to achieve higher forage, the genotypes with larger aerial parts and deeper roots should be selected.
Mohsen Yousefi; leila kashi zenouzi
Volume 22, Issue 2 , August 2015, , Pages 240-250
Abstract
The aim of this study was to determine some factors affecting dust storms phenomenon using different methods. In order to determine the best-input combination, variable reduction techniques such as factor analysis (maximum likelihood, principal component analysis), Gama test, and multivariate forward ...
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The aim of this study was to determine some factors affecting dust storms phenomenon using different methods. In order to determine the best-input combination, variable reduction techniques such as factor analysis (maximum likelihood, principal component analysis), Gama test, and multivariate forward regression analysis were used. Each of these methods presented different combinations used by feedforward neural network model, with Levenberg–Marquardt algorithm and multivariate forward regression with R²=0.87 and RMSE=0.04 was selected as the best suitable combination of neural network model. In addition, monthly and seasonal data were applied by neural network using the best-input combination, and the simulation of dust storm phenomenon was done in summer and spring during the months of April, May, June, July, August and September with a higher correlation coefficient and lower mean square error, due to the good distribution of the dust storm data. The results showed that based on these methods used in this study, dominant wind speed, horizontal visibility, continuity and average of wind speed were the most important factors affecting dust storm phenomenon in Yazd province.