INTERNATIONAL JOURNAL OF AGRICULTURAL SCIENCE AND RESEARCH
Year:2011 | Volume:2 | Issue:2 (3)|Papers Count:8

Brown spot disease caused byAlternaria alternata (Fr.: Fr.) Keissl is a serious problem for production of tangerines and tangerine hybrids in Iran. The Tangerine pathotype causes brown spot disease on young leaves and immature fruits of limited varieties of mandarins and tangerines (Citrus. reticulata Blanco). Specificity in the interaction between tangerine and the pathogen is determined by a host- specific toxin (HST), called ACT-toxin. Culture filtrates of isolates of Alternaria alternatawere selectively toxic to tangerine leaves, related toxic compounds were isolated from culture filtrates of Alternaria alternata. The biological characteristics of ACT-toxin matched the criteria for HST. ACT-toxin was purified by chromatography analysis, and H-NMR data showed the presence of ACT-toxin related structures. These results suggest that collected isolates produce ACT-toxin which is toxic to specific host plants (tangerines). This host specific toxin rapidly affects plasma membrane integrity of susceptible genotypes and plays a critical role in the infection process, pathogenicity and host specificity of the pathogen.

Sunn pest is one of the most important cereal pests that affect both grain yield and quality of cereal in Iran. One potential control strategy is to use entomopathogenic fungi suchas Beauveria bassianaVuillemin as mycoinsecticide to control this pest. Naturally infested Sunn pests in Kermanshah province were collected and brought to laboratory.10 isolates were selected for further analysis in the laboratory. Isolate characters such as colony growth, conidia production, virulence and dose response were studied under laboratory conditions. Colony growth increased linearly overtime at 27o C. Isolate IR-K-43, IR-K-23 and IR-K-10 had the largest growth rate of 3.6 mm/day. Isolate IR-K-36 with 4.6×108 conidia/cm2 was the highest conidia producer. All of the selected isolates showed pathogenicity against Eurygaster integriceps Puton. Five Iranian isolates IR-K- 40, IR-K-58, IR-K-10, IR-K-53 and IR-K-43, and one Turkish isolate SPT 22 were high virulent isolates causing mortality ranging between 88.7–94.4 %. Isolate IR-K-40 along with isolate SPT 22 from Turkey was selected for dose response study. The lethal concentration required to kill 50% of insects (LC50) was 2.9×107 conidia/cm2 for both isolates. The results of this study showed thatB. bassiana can be isolated from Sunn pest overwintering sites in Kermanshah. In addition the selected isolates were pathogenic towards Eurygaster integriceps Puton under laboratory conditions. These results will help in selection and development of these fungi for Sunn pest, E. integriceps management in the future.

Canola producers in the Province of Qazvin were surveyed in order to explore their perception about technical skills influencing the production of canola. Based on the perception of respondents, the results showed that the contact with agricultural service centers would encourage farmers to produce canola. The results showed that there were relationship between perception of respondents about canola production and working experience in canola production, areas under cultivation of canola and social factors as independent variables.

The purpose of this research was to assess the role of educational factors in protecting urban landscapes in Tehran Metropolitan. This is a quantitative research, applied and descriptive-correlation method was used. The research population consisted of all participants in educational courses held by Tehran municipality (N=300) and 172 of them selected by using simple random sampling method. To gather data in the field a questionnaire was employed. The content and face validity of the research instrument was confirmed by specialists in the field of agricultural extension and education. Cronbach Coefficient was applied for the purpose of reliability and 0.90 was obtained. Findings indicated that there was a statistically significant relationship between communication channels, interest of participants, skill of participants, teaching methods, participants' motivation, educational content program, educator, educational objectives and people motivation and dependent variable. The obtained results from multiple regressions could explain the variance of dependent variable (participant's motivation to protect urban landscapes) from independent variables showed that communication channels, skill and interest of participants contribute to the variation of dependent variable.

Investment in research is indeed a "rational" investment. Thesis issues and projects in higher education are the sources of research at educational institutions and have an evident role in helping professionals and researchers. However, lack of fit scientific methods along with the ignorance of the proper processes of science has somewhat diminished the importance of research. This study points out the dire need to examine "standards" which are based on the statistical competency in graduates. Preliminary survey investigations and content analysis of Ph.D. dissertations (N1=69) and master thesis (n=246 out of N2=648) in agricultural extension, education and rural development in Iran showed that the applied statistical procedures were rarely eligible and appropriate. For this study were used combines quantitative methods (survey) and qualitative (content analysis). In the end, student could improve knowledge content about statistic when consideration and using from sequential statistics by agricultural extension and education students, can give them holistic view from using statistical test to exploit of mix and together statistical test.

Tomato is one of the sensitive fruits to mechanical impacts and physical tensions. The most mechanical damages arise from handling which results in reducing tomato quality. in this study, impact energy effect has been studied in 3 different levels 0, 0.14 and 0.25 J by a pendulum impact apparatus, on changes of physicochemical properties of tomato, hybrid variety Shiva F1, including ripening factor, wet content physical properties such as texture resistance versus shearing force, color and shelf life during a period of shelf life for 20 days in Temperature 11±1oC and relative humidity 94±2 percent. It is found that when mechanical energy increase, like something results from increasing shelf life, texture resistance decrease versus shearing force. However increasing impact energy not only reduces firmness texture and wet content in production but also increasing ripening factor and its color during storing time. Results show the least shelf life and most unsuitable changes in 0.25 J samples.

A model of the Iranian wheat market is specified and fitted to data from 1981-2008. Several diagnostic tests were employed in the analysis to determine the specification of the model. Despite the simplicity of the model and data problems, an examination of the econometric model leads to several conclusions with possible important policy implications for the wheat economy in Iran.The general results rejected adaptive expectation (AE) model in favor of partial adjustment (PA) to examine the supply response. The estimated short run price elasticity is not fairly low and is -0.2 because wheat is a strategic good that government has the responsibility of its supply, so with increasing its price, government follow some strategies to decrease the amount of wheat that had been supplied, on the other hand, price elasticity of supply is not low and is significant at five percent level that it denotes that the amount of supply affected largely from producer price in last period. The results obtained from production function is that all the factors have positive effect on production except fertilizer that have negative effect on wheat production and with decreasing the amount of fertilizer in wheat production, yield will increase. The demand function showed that wheat is a Giffen good and barley is an appropriate substantial good for wheat. Income elasticity of demand for wheat can obtain from this model and it is -0.77. It means that each 1 percent increase in consumer income contributes to the annual decrease in demand for wheat approximately 0.77 per cent. This indicated that wheat is an Inferior good in Iran either. The coefficient of trend variable and its significance and sign showed that consumer taste and preferences to wheat is going to increase year by year. The import demand function of wheat that estimated in this study showed that import doesn’t influence from domestic price ratio and gross domestic product and the unique parameter that can decrease the amount of import is domestic production.

In this study, the effect of edible coat (carboxy methyl cellulose) before osmotic dehydration and different drying methods on sensory and physical properties of dried apple (V. Golden delicious) rings was investigated. The coated and non-coated samples pretreated with 50% sucrose osmotic solution and dried in freeze drier (-40 to -50oC, 0.026-0.017 mbar, 24 hr), vacuum drier (70oC, 200 mbar, 8-10 hr), air dryer (60oC, 1.5 m/s, 2-3 hr). Sensory evolutions, Rehydration ratio (RR), color changes (DE), shear strength (SS), true density and shrinkage present of dried samples were determined. Effect of using edible coats before osmotic process was significant on the SS, RR and color changes. As the lowest shrinkage, color changes, RR, and highest SS were found in freeze dried apples. The air and vacuum dried samples had the highest RR and true density, respectively. The best sample in sensory evolutions was coated and freeze dried samples.