JOURNAL OF RESEARCH IN AGRICULTURAL SCIENCE
Year:2012 | Volume:8 | Issue:1 (14)|Papers Count:12

Gully erosion is a serious problem of land degradation in pasture land of Sothern Iran. To study the causes of gully erosion initiation, the Abgendi Watershed with the highest amount of gully erosion was selected as a semi-arid area in Iran. In this area, 35 gullies were randomly chosen and the influences of SAR and EC, as the indexes of alkalinity and salinity on gully erosion, were investigated. The role of sodium in calculating SAR, and the effective role of sodium to soil dispersing, It can increase the susceptibility of soil to water erosion. Moreover, concentration of soluble salts (are measured by electrical conductivity), such as sodium cations are attached to each soil clay particle in the arid and semi-arid areas. To accomplish this study, soil sampling from headcut and gully walls in two depths of 0-30 cm (top layer) and 30cm to the bottom of gully (sub-layer) was carried out. One main objective of the present study was to determine the effects of these two chemical factors on gully erosion development. Based on gullies volume (as a dependent variable), the gullies were classified into four groups and were compared in terms of EC and SAR. The results indicated that the gullies with volume of more than 200 m3 (big gully group), in comparison to the gullies with volume less than 50 m3 (very small gully group), have greater EC and SAR. The amounts of EC and SAR of big gully group were significantly higher than very small gully group. Moreover, for the purpose of further analysis, the gullies were classified and compared in terms of EC and SAR. The results indicated that there is a significant difference between gullies volume groups in terms of EC and SAR as well. The gullies with EC>8 dS/m and SAR>8, compared to the gullies with EC<4 dS/m and SAR<4, have significantly greater volume and length.

Nitrification is an important biological process in soils which, ammonia convert to nitrite and subsequently to nitrate, oxidation of ammonia accomplish by Autotrophic and Heterotrophic oxidizer bacteria. In this study, Heterotrophic oxidizer bacteria enumerated in two soil and wastewater samples with different characteristic and displayed that heterotrophic nitrifers in soil samples were higher than number of those in wastewater samples. Different pollutants have effects on nitrification process, one of these are phenol that inhibitor for this process. Phenol is pertaining to poly aromatic hydrocarbons which are toxic chemical material for human and another organism. Add phenol with different concentrations to media of ammonia oxidizer bacteria and investigated decrease of ammonia removal percentage and percentage of nitrite product in soil and wastewater samples. This decline in ammonia removal and nitrite product was surveyed in heterotrophic nitrification. The percentage of elimination ammonia in soil samples were about 67.9% in the absence of phenol and decreased to about 47.5% in 32 ppm phenol. The percentage of ammonia elimination in wastewater samples were about 91.3% in the absence of phenol and decreased to about 71.6% in 32 ppm phenol. In soil samples was separated to two heterotrophic ammonia oxidizer bacteria, single and double rod with gram-positive test, this separation was because of vivid decreasing of ammonia removal percentage and in wastewater samples separated bacteria were gram-positive double rod and gram-positive cocci. Heterotrophic ammonia oxidizer bacteria in soil sample were had low resistance to phenol than heterotrophic ammonia oxidizer bacteria in wastewater samples and decreased the ammonia removal percentage in lesser phenol concentration.

In this study simultaneously 6 major mastitis-causing pathogens (Staphylococcus aureus, Streptococcus agalactiae, Streptococcus dysgalactiae, Staphylococcus epidermidis, Streptococcus uberis, and Escherichia coli), using multiplex-polymerase chain reaction (M-PCR) with self-designed primers were evaluated. Four quarters of the first, third, and fifth parities in industrial, semi-industrial, and traditional dairy cattle farms of Isfahan province in Iran were sampeled. Results revealed a significant effect of farm type on mean somatic cell count (SCC) (P<0.001). A significant difference in mean SCC between different parity levels, but not between different quarters (Left Front, Left Rear, Right Front, and Right Rear) were also observed. M-PCR method could identify 92, 84 and 39% of infected udder quarters with high, medium and low SCC levels. Moreover, the technique facilitates the identification of low levels of pathogens at the start of infection, when the subclinical effects are not yet visible. Compared to contagious pathogens, environmental pathogens showed a higher incidence in quarters with low SCC. Among the pathogens detected by M-PCR, the shares of contagious pathogens in apparently healthy quarters with low SCC, quarters with medium SCC, and quarters with high SCC were 26.3, 45.9, and 50.5%, respectively. Meanwhile, the shares of environmental pathogens in the same quarters were 73.5, 54, and 49.3%, respectively.

In a 4x3 factorial completely randomized experiment, four Pleurotus strains including P. florida, P. ostreatus A., P. ostreatus M and P. ostreatus T, were cultured on wheat stubble (WS), date palm leaf (DPL) and potato dextrose agar (PDA) as well. Growth rate of the mycelium was measured for two weeks of incubation. At the first week of incubation, growth rate of P. ostreatus A. And P. ostreatusM. were higher (P<0.05) than P. florida and P. ostreatus T., whereas it was inverse during the second week of incubation. An interaction effect (P<0.05) was found between strains with substrates. During the first week of incubation, the highest amount of mycelial running rate was shown by P. ostreatus A and P. ostreatus T on PDA followed by P. florida. In addition, P. ostreatus A and P. ostreatus T had significantly (p<0.05) more growth rate on DPL than WS. However, the final cumulative growth rate was not statistically different among the strains or the substrates. The dry mater (DM) and organic matter (OM) losses were different (P<0.05) between the substrates but no significant variation was shown among the strains. The crude protein (CP) was increased in the biomass obtained from fungal treatment but it was significantly (p<0.05) different among the strains on the different substrates. In conclusion, P. ostreatus A. and P. ostreatus T. showed a substantial mycelium running ability in wheat straw and date palm leaf to producing higher crude protein.

The early blight of tomato disease, caused by the fungus Alternaria solani, affects the tomato plant, Lycopersicon esculentum, by causing brown leaf spots and concentric black circles on the tomato fruit. In this experiment, it was tested to see if various essential oils have any inhibitory effect on the growth of the Alternaria solani fungus and are able to replace the fungicides, such as azoxystrobin and pyraclostrobin, that are being used or have been used worldwide against the early blight of tomato disease. Three essential oils fromCarum copticum (ajowan), Zataria multiflora (Shirazi thyme), and Satureja hortensis (savory)- were tested in vitro in a 200 and 400 ppm dosage to examine their effects on the growth of A. solani. The 200 ppm dosage of Carum copticuminhibited the growth of A. solaniby 99.5%, while the 400 ppm dosage allowed absolutely no growth of the fungus over the period of twelve days. The essential oils of Zataria multiflora and Satureja hortensis were not very effective on inhibiting the growth of the pathogen. The 400 ppm of Satureja hortensis even fostered the growth of the fungus. Consequently, Carum copticum can potentially replace the substances that are commercially used to treat the early blight of tomato disease.

The leaves and petioles of Malva sylvestris L. were analyzed for their proximate composition, fatty acid composition, mineral content, total flavonoids and mucilage. The antioxidant capacities of samples were estimated using Folin-Ciocalteu (FC), Trolox equivalent antioxidant capacity (TEAC), 2,2'-diphenyl-1-picrylhydrazyl (DPPH), ferric-reducing/antioxidant power (FRAP) radical scavenging assays. The anti-nutritive compounds, tannin and nitrate were also quantified. The results showed that linolenic, linoleic, palmitic and oleic acids were measured more than 82% of total fatty acids in leaves and petioles. GC-MS analysis of methanolic extract revealed that 2-methoxy-4-vinylphenol was the major compound in the extract. Analysis of variance was showed that genotype and plant part were important sources of variability in the measured properties. Finally, antioxidant capacities of the Malva sylvestris L. were compared with spinach.

Alternaria brown spot is one of the most important worldwide diseases of citrus. This disease caused by Alternaria alternata (Fr.:Fr.) Kessl, and causing serious economical losses in citrus yield. Citrus cultivars vary genetically in their degree of brown spot resistance. In this research, susceptibility of 13 citrus cultivars including "Orlando tangelo, Minneloa tangelo, Clementine mandarin, Fortune, Page, Unesi, Kino, Local tangerine, Sweet orange (Thomson and Local orange), Sweet lemon, Lime and Sour orange to Alternaria brown spot was analyzed. The results revealed that Page, Orlando tangelo and Mineola tangelo were highly susceptible to A. alternata and showed severe brown spot symptoms on leaves. Based on Disease rating Index (DRI) these cultivars were placed in sensitive class (S). However, Sour orange and Clementine with the least DRI were designated as resistance varieties (R). In molecular method, the total DNA was extracted from leaves with CTAB-phenol chloroform method and DNA fragments were amplified by RAPD-PCR using 2 single, random 10mer oligonucleotide primers; AL3 and P12. In sour orange and Clementine mandarin an 850 bp fragment by P12 and a 1250 bp fragment by AL3 primer were amplified and there was not observed any fragment in these regions in other citrus cultivars. Based on results of molecular marker and pathogenicity test, sour orange and Clementine are resistance to Alternaria brown spot and have resistant gene (amplified by P12 and AL3 primers). This is the first report of resistant gene in citrus cultivars to Alternaria alternata in Iran.

Application of botanical and biological methods in plant disease controls are unique techniques in reducing environmental pollutions. Trichoderma species are effective agents in biocontrol strategies and identifying their useful isolates for further studies seems to be helpful. The purpose of this study was to assess the in-vitro biocontrol efficacy of some native Trichoderma isolates against Pythium aphanidermatum an important causal agent of sugar beet root rot disease in North Iran. Evaluations were conducted in Shahrood Agricultural Research Center, North Iran during 2007. Collected Isolates of Trichoderma belonging to four species (T. harzianum, T. longibrachatum, T. erinaceum and T. koningii ), among which T. erinaceum is a new fungus for Irans' mycoflora. Results of lab tests including dual culture technique, assessment of volatile and non-volatile effects on pathogen' colony growth indicated the effectiveness of all ten isolates against P. aphanidermatum. In dual culture T. harzianum-2733 and T. longibrachatum-2734 were best in reducing the colony growth of P. aphanidermatum by 57% compared to control. Volatile antibiotic compounds of T. longibrachiatum-2737 and non-volatile antibiotic compounds of T. harzianum-2739 were best among Trichoderma isolates and controlled the colony growth of the pathogen by 66 and 87% respectively.

Heteroptera with more than 80 known families is one of the most important suborder in class of insects and this is a large and diversity group of insects. A faunistic survey was carried out to collect and identify of Heteroptera members in 2008-2011. Among collected Specimens 8 species was new record for Isfahan province, which was marked by one asterisk (*) and 2 species to new record for Iranian fauna by two asterisks (**) species in Isfahan regions were as listed bellow:1.Anthocoridae Orius albidipennis (Reuter)O. pallidicornis (Reuter)2.Lygaeidae Nysius cymoides (Spinola)Geocoris pallidipennis (Costa)3.Miridae Lygus gemellatus (Herrich-Schaffer)Deraeoris serenus (Douglus and Scott)4.Nabidae Nabis palifera* (Seidenstucker)5.Pentatomidae Dolycoris baccarum (Linnaeus)Perilus sp.** (Stall)6.Reduviidae Coranus aegyptius *(Fabricus)Zelus sp.**(Fabricus)7.Rhopalidae Brachycarenus tigrinus *(Schilling)

Owing to the fact that Iran has a suitable climate and a variety of climate conditions in the north, south, east and west of the country, plus the existence of four separate seasons and greenhouses around the country, it has the potential to grow plants and flowers in every seasons of the year. In addition, Iran’s strategic situation in the Middle East region and the accessibility to target world markets (neighboring countries) has turned the export of plants and flowers to on of the main non-oil exports. This study has firstly focused on the existing defects and the proceeds to explore different ways to overcome those defects. Finally, a solution is proposed to achieve more effective interaction between urban unions and the national union on one hand, and the packaging and shipping section of the Trade Promotion Organization of Iran (TPO), plus the national aviation on the other hand.