Showing 5 results for Rouhani
F. Padasht Dehkaei, Sh. Mansouri Jajaei H. Rouhani,
Volume 8, Issue 1 (spring 2004)
Abstract
One hundred and two microorganisms were isolated from 85 paddy soil samples of different locations in Guilan Province. Antagonistic effects of the microorganisms were tested against Gibberella fujikuroi on PDA medium. Twenty one microorganism isolates were selected for seed treatment in blotter test. Seven isolates that were satisfactorily effective in reducing pathogen colonies formed on seeds and seedlings were tested in controlling disease in a greenhouse experiment with split plot design. The antagonists were Bacillus subtilis, B. circulans, Bacillus sp., Trichoderma harzianum, T. virens (2 isolates), and F.23 (unidentified). Results showed that all antagonists effectively reduced the disease in sterilized soil compared with control but overall effectiveness of B. subtilis, T. harzianum, and T. virens was higher than others and lower than the fungicide treatment (thiophant methyl thiram W.P. 80% , 2g/L). It was found that when seeds were treated with antagonists prior to inoculation with the pathogen, the effectiveness of antagonists was significantly better than when they were applied after seed infection with the pathogen.
E. Karimi, H. Rouhani, D. Zafari1, Gh. Khodakaramian, M. Taghinasab,
Volume 11, Issue 41 (fall 2007)
Abstract
In order to study the biological control of carnation vascular wilt disease caused by Fusarium oxysporum f.sp. dianthi, 141 bacterial strains were isolated from carnation rhizosphere, and their antagonistic activity was evaluated against fungal pathogen in dual culture method. Among the tested strains, 16 strains showed antagonistic activity seven of them with more activity were selected for further investigation. Based on phenotypic features, strains E31 and E57 were identified as Bacillus cereus E76, E93, E102 and E121 as Bacillus subtilis and E130 as Pseudomonas fluorescens bv. III. All bacterial strains inhibited mycelial growth of F. o. f. sp. dianthi by production of non-volatile and volatile metabolites under laboratory condition. Microscopical analysis showed that all strains caused deformation of pathogen mycelium, and metabolites of these strains reduced conidia production rate and as well as the ability of conidia germination. In the in vivo tests, in sterilized and nonsterilized soils, the effect of bacterial strains was studied on disease severity, percentage of healthy plants and the growth rate of plants using soil inoculating and root-dipping into bacteria-methyl cellulose mixture methods. The E57 and E121 strains, in both methods, and E130 in root-dipping method showed highest effect on decreasing of disease severity and increasing of healthy plants percentage. Strains E57, E121 and E130 significantly increased total dry weight of carnation. Maximum dry weight was obtained by E57 and E130 in soil inoculating and root –dipping methods respectively.
N Rouhani, H Yang, S Amin Sichani, M Afyuni, S.f Mousavi, A.a Kamgar Haghighi,
Volume 12, Issue 46 (1-2009)
Abstract
Iran, with an average annual precipitation of about 252 mm (413 BCM) and renewable freshwater resources of 130 BCM, has irregular distribution of water resources. With a high population growth rate, agriculture remains the greatest water user in Iran but its production still does not meet the total food demand of the country. Due to unreliable water availability, the competition for water from other sectors and the increasing demand for food and better diets, Iran will experience water stress. In this study, virtual water trade in relation to water resources availability has been assessed as a way of relaxing water stress in Iran. The results showed that from the 21 food products, cereals, pulses, nuts and oilseeds are water-intensive crops according to their estimated virtual water content, while fruits, vegetables and industrial crops are not water-intensive. Considering the volume of virtual water entering the country through food imports, more water will be available for other essential uses. However, the virtual water trade has been developed rather unconsciously regarding water use and crop water productivity during the past two decades. For instance, wheat with a share of 58.5% in the virtual water import to Iran, was the dominant imported crop during 1983-2003. By importing 10.4 Mt of wheat, 11.6 BCM of water has been saved within the country during 1999-2003. However, Iran became self-sufficient in wheat production in early 2005. Consequently, this latest drive for self-sufficiency in the production of wheat, as a water-intensive crop, put tremendous pressure on domestic water resources. The trend in crop trade in terms of quantity and virtual water for other groups of crops has also been shown in the study. Seemingly, crop production and import have been greatly influenced by the weather conditions. With the increasing water scarcity, the role of virtual water in food security is expected to rise continuously in Iran. Thus, conscious virtual water trade as a policy measure in water management and judicious adjustment in agricultural structure will ensure sustainable food security and water availability in Iran.
E Mahdikhani Moghadam, H Rouhani, M Flahi Rastegar,
Volume 13, Issue 48 (7-2009)
Abstract
Sugar beet cyst forming nematode (Heterodera schachtii) is one of the most important pathogens of the sugar beet in Iran. For biological control of Heterodera schachtii, 10 isolates of Trichoderma related to two species T. harzianum and T. virens were examined in laboratory and green house on eggs and cysts for two years. Results obtained from the laboratory assay showed that isolates of Trichoderma parasitized 60% eggs on average. Among them two isolates T. harzianum Bi and T. virens VM1with % 76.18 and %72.55 parasitism, respectively, showed more efficiency compared with the control. In green house, experiments were carried out in autoclaved and non autoclaved soils (field soils) separately with 12 treatments and 3 replications including non infested control (using Ragbi nematicide in field soils experiment), and infested control treated with isolates of Trichoderma using Randomized Complete Design. Then analysis of variance for the bio-control potential of isolates, final population of nematode, fresh and dry root weight, fresh and dry leaves weight inoculated with isolates of Trichoderma was carried out. The results revealed a significant difference (P<0.05) between treatments and control according to Duncan,s Multiple Range Test. T. harzianum Bi and T. virens VM1 decreased population of nematodes, and increased yield in autoclaved and field soils. In autoclaved soils, the two isolates (T. harzianum Bi and T. virens VM1) decreased population of nematodes by %76.68 and %72.65, respectively compared with the control. The Ragbi nematicide, T. harzianum Bi and T. virens VM1 decreased population of nematodes by %81.65, %75.15 and %72.85, respectively compared with the control in field soils experiments.
H. Sadoghi, T. Rajaee, N. Rouhani,
Volume 24, Issue 4 (Winter 2021)
Abstract
Identification and investigation of changes in the area under cultivation of various crops seem to be essential for the management supply of crop production. In this study, r to identify and investigate change of the area under cultivation in major crop Hoseynabade Mishmast region in Qom province, we used the time series images of OLI and ETM sensors of landsat 8 and 7satellites, according to the crop calendar of this region. By using the vegetation index (NDVI) in the decision tree algorithm, the thresholds of this index were adjusted according to the major crops of this region; then a map of the cultivation pattern of the crop of this region was prepared. In order to evaluate the results, the statistics of the provinces agricultural jihad were used during 2005, 2009, 2014 and 2019 crop years. The results showed that by using the threshold of NDVI index, crops in this region in 2005 included wheat and barley and alfalfa, and their areas had an error of 17/1 and 6/1 percent in comparison with the statistics of agricultural Jihad, respectively; in 2009, wheat and barley, alfalfa and corn had an error of 0/5, 9/6 and 0/1 percent. Also, in 2014, wheat and barley, alfalfa, corn and sophie crops had an error equal to 4/9, 0.4, 11/4 and 2/4 percent, and the same crops in 2019 had an error 0/04, 11/6, 1/4 and 17/5 percent; that error was not significant. According to the results, the appropriate efficiency NDVI index in estimating crop cultivation area was determined by their phenology. Also, in 2009 and 2014, corn and sophie crops were added to the regions crops, and the area under crops cultivation in 2019 was increased, as compared to 2014.
