Afzalinia S.,Agricultural and Natural Resources Research Center of Iran |
Zabihi J.,Shiraz University
Soil and Tillage Research | Year: 2014
Area cultivated using conservation tillage methods has recently increased in Iran and soil compaction increment is one of the most challenging issues in this new technology. In addition to the soil compaction status at the end of growing season, soil compaction variation during the growing season is also important because of its potential effect on the crop growth and yield. Therefore, soil compaction variation during the corn growing season under different tillage methods and its effect on the crop yield was investigated in this study. The research was conducted in the form of a split plot experimental design with nine treatments and six replications. Main plots were tillage methods including: (1) conventional tillage method (CT); (2) reduced tillage (RT); and (3) zero tillage or direct drilling (ZT). Soil depth ranges of 0-0.10, 0.10-0.20, and 0.20-0.30. m were considered as sub plots. Soil bulk density (BD) and soil cone index (CI) were measured during corn growth season (eight measurements for bulk density and five measurements for cone index) as indices of soil compaction. Corn silage yield, thousand kernels weight, and grain yield were also determined in this research. Collected data were analyzed using SAS statistics software and Duncan's multiple range tests were used to compare the treatments means. Results indicated that tillage methods and soil depth had a significant effect on the soil bulk density so that the maximum soil bulk density was obtained from ZT method and soil depth range of 0.10-0.20. m. The difference between soil bulk densities in different tillage methods was statistically significant from the beginning of growth season to two month after the first irrigation (sixth measurement); while, this difference was not significant from the sixth measurement to the end of growth season. Soil cone index was also significantly affected by tillage methods and soil depth in such a way that ZT method and 0.20-0.30. m soil depth range had the maximum cone index. Although, the difference between tillage methods for corn yield and yield components was not statistically different, ZT method decreased corn thousand kernels weight, silage yield, and grain yield compared to the CT method for 11.1, 2.4, and 18.2%, respectively. © 2013 Elsevier B.V.
Faraji A.,Agricultural and Natural Resources Research Center of Iran
International Journal of Plant Production | Year: 2010
An alternative means by which to examine the importance of assimilates supply to flower and pod formation is to analyze the relationships of leaf area index (LAI), above-ground dry matter (ADM), leaf area duration (LAD) and crop growth rate (CGR) around flowering with flower number and pod/flower ratio. For this objective, an experiment was conducted at Agricultural Research Station of Gonbad, Iran in 2005-2006 and 2006-2007. The experiment was a randomized complete block design arranged in split plot. Two cultivars of spring type canola (Hyola401 and RGS003) as subplots were grown at 5 sowing dates as main plots, spaced approximately 30 days apart, to obtain different environmental conditions and assimilates availability around flowering. The experiment was conducted at two conditions, i.e. supplemental irrigation and rainfed. In both main (MR) and branch (MR) racemes, flower number increased as LAI and ADM at the beginning of flowering increased. The reduction in flower number with reduction of LAI and ADM is evidence that canola plants can adjust to carbohydrates availability by altering the number of potential resource demanding sinks. Pod/flower ratio was quadratically related to ADM at the beginning of flowering. A significant positive linear relationship was found between LAD and CGR during flowering period and pod/flower ratio. Therefore, potential and actual pod number was related to cumulative dry matter production of the crop until the beginning of flowering and until the end of flowering, respectively.
Hassanpanah D.,Agricultural and Natural Resources Research Center of Iran
Potato Research | Year: 2010
Water deficit is the most important abiotic stress factor in crop production. Evaluation of the response of different potato cultivars to water deficit stress is necessary to release cultivars for regions with water deficit. A split-plot experiment with three replications was carried out during 2005 and 2006. The main factor consisted of three levels of irrigation (irrigation after 25%, 35% and 50% discharge of the available water, i.e. normal conditions, mild stress and severe stress, respectively), and the split factor included seven potato cultivars (Agria, Savalan, Satina, Caesar, Kennebec, Marfona and Santé). Cultivars Savalan, Caesar and Kennebec had higher total and marketable tuber yield, water use efficiency, and values for stress tolerance indices than the other cultivars, both under mild and severe stress conditions. Cultivars Caesar and Kennebec were selected as tolerant cultivars; cultivars Savalan and Satina were identified as moderately tolerant cultivars whereas cultivars Agria, Marfona and Santé proved to be susceptible to water deficit. © 2010 The Author(s).
Karimizadeh R.,Agricultural and Natural Resources Research Center of Iran |
Mohammadi M.,Agricultural and Natural Resources Research Center of Iran
Australian Journal of Crop Science | Year: 2011
The objectives of this study were to evaluate the ability of five selection indices to assess drought tolerance of durum wheat genotypes under a variety of environmental conditions and the relationships of canopy temperature depression (CTD) with drought indices. Eight durum wheat genotypes were planted in the rainfed and supplementary irrigation conditions for two years (2007-2009). Five drought tolerance indices including stress susceptibility index (SSI), stress tolerance index (STI), tolerance index (TOL), mean productivity (MP) and geometric mean productivity (GMP) were calculated. Canopy temperature depression (CTD) was used to estimate crop yield and to rank genotypes. CTD was measured at three stages, from the emergence of fifty percent of inflorescence (Zadoks Growth Scale54) to watery ripe stage (ZGS71). The results showed that the average values of CTD in durum wheat genotypes changed from 3.3 to 5.7°C at the ZGS69 stage. Genotypes in this stage (ZGS69) had highly significant differences and average of CTD showed that durum wheat canopy was the largest value in all ZGSs under both conditions. The significant and positive correlation of YP, MP, GMP, SSI, STI and CTD showed that these indices were more effective in identifying high yield genotypes under both conditions. Results also showed that CTD has played an important role to search physiological basis of grain yield of wheat, and can be successfully used as a selection criterion in breeding programs.
Ardakani A.S.,Agricultural and Natural Resources Research Center of Iran
Nematology | Year: 2013
The toxicity of three nanoparticles, silver (AgNP, 20 nm), silicon oxide (SiO2NP, 11-14 nm) and titanium oxide (TiO2NP, 20 nm), to the root-knot nematode, Meloidogyne incognita, was studied in laboratory and pot experiments. Application rates of all nanoparticles were 1.5, 3, 6, 12.5, 25, 50, 100, 200, 400 and 800 mg nanoparticles (ml water)-1 for laboratory experiment to determine their effects on motility and mortality of second-stage juveniles (J2). In pot experiment, 0.02, 0.01, 0.005, 0.0025, 0.00125 and 0.0007% (w/w) of nano-silver and nano-titanium were applied to examine effects on nematode activity and plant growth components of tomato (Solanum lycopersicum). Results showed 100% J2 immobility and mortality in treatments of 800, 400 and 200 mg ml-1 of AgNP; the LC50 for AgNP was 100 mg ml-1. J2 mortality was 48, 16 and 7.3% in 100, 50 and 25 mg ml-1 of AgNP, respectively. J2 mortality was 4.3 and 2% in 800 and 400 mg ml-1 of TiO2NP, respectively. No J2 mortality was seen in all other treatments after 24 h exposure. In a pot experiment, all treatments of AgNP and 0.02% TiO2NP completely controlled M. incognita. Treatments of 0.02, 0.01 and 0.005% of AgNP as well as 0.02% of TiO2NP were toxic to tomato plants and significantly reduced tomato root and stem length and fresh weights in comparison to control. © 2013 Koninklijke Brill NV, Leiden.
Taleshi S.A.R.,Agricultural and Natural Resources Research Center of Iran
Biodiversitas | Year: 2014
Diversity index is the useful criteria for evaluating sustainability of forest ecosystems. Current study carried out in Alder (Alnus subcordata C.A. Meyer) stands that located in north forests of Iran. The aim of the study is express the plant diversity indices and positive role of the trees both natural and plantation forms. Data of Alder trees and associated species were recorded in sample plots which lay down in study area randomly. The abundance, density, percentage of frequency of each species was calculated by standard methods. The results of analysis revealed that, 47 species (21 trees and shrubs species and 26 herbaceous species) were abundant in 80 sample plots both in natural and plantations Alder stands. Whilst the results showed that the number of species in natural area (44 species) was more than plantation stands (37 species). Comparison of species distribution in different physiographical situation showed that some species such as Alnus subcordata, Parrotia persica, Rubus hyrcanus and Prunus sp. recorded in spread rang of physiographic variables as elevation, slopes and aspects. The biodiversity criteria as Shannon H' and Simpsons D and 1/D indexes showed that they were more in natural stands than plantation areas.
Khaj H.,Agricultural and Natural Resources Research Center of Iran
Advances in Environmental Biology | Year: 2014
In recent years, Iran has had significant growth in aquaculture as well as some activities on propagation and breeding of native fish have been conducted. Hygiene principles, development of diagnosis methods, prevention and cure of diseases are necessary. Otherwise, sooner or later, aquaculture industry may be jeopardized and suffered by heavy and irreversible losses. Parasitic diseases are one of the dangerous and important diseases among fish and aquatic organisms. Chilodonella is one parasite that infects skin and makes disease. This study aimed to investigate outbreak of Chilodonella in fish pods of Sistan region, located in south of Iran, and their prevention and cure. To implement this project, studying Chilodonella in Sistan ponds including warm and cold water was carried out in the early autumn of 2010 in collaboration with the Fishery office of Sistan region. It lasted about a year and a half. In the beginning, Zahak station was studied for reproduction of warm water fish. 200 pieces of 17 ponds in Zahak consists of carp, grass carp, silver carp, bighead and Russian fed were caught alive and transferred to the laboratory in order to conduct this study. Initially bioassay of fish had been done and then their characteristics were recorded in special forms prepared for this goal. Subsequently, the parts of fish body such as skin, gills and fins were prepared and parasites were observed by microscopes. Although there are a large number of parasites in Sistan region, the results of this study showed that there was found no Chilodonella among fish in experimental ponds. © 2014 AENSI Publisher All rights reserved.
Hassanpanah D.,Agricultural and Natural Resources Research Center of Iran
Biotechnology | Year: 2010
This experiment performed according to the factorial design and on the base of completely randomized design in three replications in 2007. Factor A included four levels of osmotic pressure (0, -1, -2 and -3 bar) and factor B included seven advanced potato cultivars (Agria, Savalan (397007-9), Satina, Caesar, Kennebec, Marfona and Sante). The PEG 6000 was used for exerting the water deficiency stress on the plantlets. The attributes such as germinating ability and root producing was measured. In this stage the cultivar that produced the roots, had moved to the greenhouse. The plantlets were planted in soil bed with mixed of Punce and Biolan with 1:1 v/v. The applied experimental design was factorial on the base of completely randomized design in three replications. Factor A has four levels of osmotic pressure and factor B included seven advanced potato cultivars. After two months, was harvested the mini-tubers and the attributes was measured such as mini-tuber average size, mini-tubers weight and number per plant. The variance analysis results showed that significant difference between osmotic pressure levels, cultivars and their interaction as attributes mini-tubers number and weight per plant and mini-tubers average size in 1% probability. The Caesar and Savalan cultivars had the most number and weight of mini-tuber per plant in -1 bar and Caesar and Kennebec cultivars in -2 bar osmotic pressures. The MP, GMP, STI and MSTI selected Caesar as better cultivar in normal and stress conditions. Results of cluster analysis showed that cultivars grouped in three clusters. The first cluster included Agria, Sante and Marfona (susceptible cultivars), the second cluster Satina, Savalan and Kennebec (moderately tolerance cultivars) and the third cluster Caesar (tolerance cultivar). © 2010 Asian Network for Scientific Information. © 2010 Asian Network for Scientific Information.
Faraji A.,Agricultural and Natural Resources Research Center of Iran
International Journal of Plant Production | Year: 2012
Oil concentration (OC) in canola (B. napus L.) is determined during seed filling period (SFP), and the variation in OC is greatly related to environmental conditions during that period. To determine factors affecting OC in canola, 12 field experiments were conducted at Agricultural Research Station of Gonbad, Iran, during 2000-07. The experiments were carried out under different growing conditions. The regression functions were fitted to the data of each group of genotypes, over years and experiments. Increasing SFP was a determinant factor for increasing OC. Oil concentration was affected by the duration of SFP, which was maximized when plants of both genotypes (open pollinates and hybrids) were exposed to lower temperatures. There was a linear negative relationship between air temperature during SFP and OC. High temperatures, accelerated the rate of plant development, lowered the length of SFP, and reduced OC potential. In both group of genotypes, the variation of OC was explained by rainfall during SFP, and temperature and radiation interactions during the period, as showed by photothermal quotient (PTQ). There was a positive logarithmic relationship between PTQ during SFP and OC. The relationships of OC with duration of SFP, and temperature, PTQ and rainfall during SFP over years, sowing dates and genotypes showed that these variables are generally applicable in canola OC determination.
Arabzadeh N.,Agricultural and Natural Resources Research Center of Iran
Asian Journal of Plant Sciences | Year: 2012
Soluble carbohydrates (sugars) are considered as important metabolites in plants under drought stress. In order to study the trend of changes of this osmolyte when encountering with dryness, the seeds of two species of Haloxylon persicum and Haloxylon aphyllum were planted in vase and their grown twigs underwent drought stress after a one year care and a one month compatibility with the greenhouse environment. The study of changes of this osmoiyte in branchlet and roots of the twigs of these two types of haloxylon was planned within the format of a completely randomize design with two treatments of species and fifteen tension treatments (lack of irrigation of twigs). The Two Species of Haloxylon persicum and Haloxylon aphyllum and the levels 0 (control), 2,4.and 28 days of lack of irrigation were determined as treatments of experiment. The analysis of data in two sides analysis variance was conducted and the averages were compared by using Duncan's test. The study of data of branchlet and root showed that with the possibility of 99%, the effect of drought stress on the increase of the rate of soluble sugar of branchlet and root of both types of haloxylon was meaningful. In addition, between these two species at the same level of reliability, there was a difference. The study of the effect of drought stress on changes of the quantities of total soluble sugars showed that the changes of this factor are of more similarity with changes of soluble sugar of root and they almost obey the same model. The increase of rate of branchlet soluble sugars, root and total soluble sugars were in proportion with the intensity of tension. © 2012 Asian Network for Scientific Information.