جستجوی مقالات مرتبط با کلیدواژه "hydro" در نشریات گروه "زراعت"

Germination is the first and the most stages for sainfoin (Onobrychis viciifolia) growth; which it has specially sensitivity to environmental stresses such as alkalinity. The current study was conducted to evaluate the effectiveness of seed pre-treatment methods on improving of sainfoin tolerance to alkali stress in germination, early growth and its recovery as a factorial experiment based on a completely randomized design in College of Agriculture, Shiraz University in 2013. The first factor was four seed pre-treatment methods (seed with pod, seed without the pod, pre-chilling of seed without pod and hydro-priming of seed without pod) and the second factor was five alkali stress levels (pH= 6.7, 7.9, 8.9, 9.8 and 10.7). Alkali stress levels were prepared using two neutral salts (Na₂SO4 and NaCl) and two alkaline salt (NaHCO3 and Na2CO3). The results showed that germination percentage was decreased as alkalinity (pH) levels were enhanced; so that, there were no germinated seeds in 9.8 and 10.7 treatments. Alkali stress reduced initial germination percentage (51.9%), final germination percentage (51.8%), plumule length (55.7%) and radicle length (72.2%). Under all alkalinity conditions, the lowest seed germination and seedling growth were observed in with pod seed, followed by pre-chilling treatments; while their highest were achieved in without pod seeds and hydro-priming treatments. The highest recovery was observed in without the pod, followed by hydro-primed seeds. Recovery was observed in Pre-chilled and with pod speeds up to 7.9 and in hydro-primed and without pod speeds up to 8.9.

Drought is a climatic anomaly that associates with a significant decrease (lack) of precipitation and water resources availability, which spreads on vast temporal and spatial scales, and significantly affects various aspects of life and environment. One of the most common methods of drought assessing and monitoring is calculating drought indices (DIs). Drought areal and temporal extent and its severity are determined by these indices. In this study, an aggregate drought index (Hydro-Meteorological) has been developed for the assessment of hydrological and meteorological droughts in Sarbaz river basin located in southeastern of Iran. The Aggregate Drought Index (ADI) comprehensively considers all physical forms of drought (meteorological, hydrological, and agricultural) through selection of variables that are related to each drought type. In this case, monthly values of Stream flow Drought Index (SDI) and Standardized Precipitation Index (SPI) indicators were used for four similar reference periods with principle component analysis and aggregate hydro-meteorological index was defined based on its first component. The study time span was set between 1981-82 to 2010-11, which begins of October in Iran. Results based on the aggregate drought index (ADI) revealed that a long period of hydro-meteorological drought occurred from 1999-2000 to 2005/06 in southeast of Iran, in which, 2003/04 water year has been extremely a drought year. The ADI methodology provides a clear, objective approach for describing the intensity of drought. This index is appropriately able to represent the behavior of Hydro-Meteorological droughts and recommended as an integrated index for assessing and monitoring of regional droughts. Finally, different states of hydro-meteorological drought have been extracted based on conventional regional thresholds, and have been modeled by Markov chain. This made the estimation of drought state transition frequency possible, and made the prediction of next drought state time more real. State transition frequency matrices, are the main instruments for predicting drought states in real time. Results of validation tests and conforming the predicted results with real data indicate that predicting hydrological drought state transitions in the study area using Markov chain method is valid.

Seedy watermelon (Citrullus lanatus) is a crop that is planted in as a second crop after winter crops some parts of country. This crop is more attended by farmers due to the short time between planting and maturity, low production costs and greater profitability rather than other spring crops. In order to evaluate the interaction effects between weeds and seed priming on growth indices on different seed lots of seedy watermelon (Citrullus lanatus).
this experiment was conducted in factorial design based on complete randomized block design with three replications in Research Farm of Faculty of Agriculture of Ferdowsi University of Mashhad in 2013. First factor included three seed lots of Seedy Watermelon (Kalaleh, Neishabour and bojnord), second factor included seed hydropriming in two levels (primed and non-primed seeds) and third factor was weedy and weed free conditions. The studied traits were include plant height, Leaf area index, fruit setting, fruit number per plant, Seed number per fruit, 1000weight and seed yield.
results showed that weeds had effect on growth and yield components of seeds, which caused reduction in seed yield in seedy watermelon lots by 79%. Seed priming reduced the effects of weeds on leaf area index and thousand kernel weights, but didn’t have any significant effect on seed yield, but increased seed yield rather than control treatment. In general, the most seed yield and thousand kernel weights were observed in Neishabour lot with 1581 kg per ha and 144 gr, respectively.
based on the results of the experiment on weed interference all traits, especially grain decreased significantly with the removal o the weeds can be to a certain extent or in the presence official said grasses weeds can also be performed using the appropriate varieties as well (Neishabour seed lots) as the preparation of seed germination as well as providing good condition (seed priming) can be achieved optimal performance.

The study was conducted to evaluate the effect of seed priming on root growth of two barley cultivars (Hordeum vulgare L.) under salinity stress was performed in phytogel. The treatments included two cultivars of barely (Yusuf and Maquie), levels of seed priming (control, hydro-priming and priming with 4.35 g l-1 of urea) and four levels of NaCl salinity stress (0, 0.2, 0.3 M). The experiment was conducted in Factorial experiment based on a completely randomized design (CRD) with three replications. The results indicated that salinity and seed priming were significantly effects on length, volume, density, fresh and dry weight and rate of root development of barley. Also, the effect of cultivar was significantly in volume, fresh weight and density. Salinity stress reduced length, volume, density, fresh and dry weight and rate of root development. However, the most of barely traits which were affected by seed priming were improved in 0, 0.1 and 0.2 salt Molar levels and priming with urea had the most positive impact on root traits. In the highest salinity level, none of seed priming treatments had not significant effect on root traits. The most effective of Hydro-priming was obtained in the absence of stress. In most of salinity treatments Yusuf cv. in compared with Maquie cv, had more fresh weight and volume root was higher fresh and In general, seed priming could be used as a solution to improve root development of barley seedlings until 0.2 Molar NaCl salinity stress.