Showing 64 results for لک
I. Malek Mohammadi, A. Shafii Alavijeh,
Volume 4, Issue 2 (summer 2000)
Abstract
Mutual understanding among officials and followers has been a point of concern in behavioral management. Natural resources extension which, from the very first step, is concerned with the exploration of practical problems is in serious need of an atmosphere of mutual understanding between agents and clientele. In this research, attention was drawn toward the measurement of mutual understanding between executives and nomads regarding nomads’ problems in utilizing natural resources and breeding cattle in Isfahan Province. For this purpose, initially, understanding between nomads and natural resources administrators (extension agents and specialists) regarding their respective problems were measured and compared. The research population of the study consisted of two groups. The first, involved 32 administrators, extension agents and specialists, and the second, 75 nomad families. Two different questionnaires were developed for the study as research instruments in which 52 items regarding nomad problems were included. Each part of the population was asked to rank the items accordingly. Then, some nonparametric tests such as Kruscall Wallis and Mann Whitny U tests were applied to compare the mean rank for each item within and between the two groups.
Results showed that the administrators and nomads had different attitudes in only two of the 52 items. Administrators had no statistically significant different attitude in 52 problems. Eliminating the discriminating items, the attitudes in only two groups were compared and results showed that they had no significant difference in the remaining 48 items. Therefore, extension agents can follow these problems based on their mean rank priority in their developmental projects. This method of data reduction and understanding field constraints can be applied to the studies dealing with planning agricultural and/or natural resources development projects through extension education.
J. Keramt, S. Malek,
Volume 5, Issue 1 (spring 2001)
Abstract
Molasses are produced in large amounts by sugar cane and sugar beet factories every year. However, they are considered as the waste product of the crystallization plants. Thus, although they contain significant amounts of materials with deep black colour which can be separated as food colour, molasses are very cheap and feasible to be used for this purpose. Aliquots of diluted molasses, after adjusting the pH, were passed through the column followed by extraction with acidified alcohol. The highest yield of extraction (76.3%) was obtained by using diluted molasses (10° BX) and 150 ml of Amberlite resins. The solvent was removed and the solid colour was obtained by evaporating the water using a freeze drying system.
The colour was characterized by determining its solubility, amount of ash, and sugar content and its colouring ability. Also, the stability of the colour under different conditions of acidic pH, temperature, and visible light was investigated. In addition, the colour values of the colour solution were measured by Hunter lab system.
The colour was compared with the imported caramel which is used in the black soft drinks of Zam Zam. Both had almost the same values of λmax. Also, their sensitivities to pH changes were similar. Samples of soft drinks made by using the prepared colour were compared with those made by caramel under different conditions of storage such as temperature and light. On the whole, the colour was found to be a very suitable replacement for caramel in the production of black soft drinks.
Also the colour was used as partial replacement for cocoa powder in making chocolate milk. The taste panel showed that cocoa powder can be replaced by the colour powder by 20% with almost no detectable differences. The caramel from molasses is safe and can be used as a food colour. The cost of production was estimated at about 10 Rials per gram of caramel. Thus, from an economical point of view, industrial production of caramel from molasses is profitable.
M.r. Lak, M. Shamsbakhsh, M. Bahar,
Volume 6, Issue 1 (spring 2002)
Abstract
During the summer of 1998, leaf and pod blight symptoms of bean were observed in Arak, The survey in the following year showed that the disease had an increasing trend in bean-growing regions of Markazi Province. It appeared that more severe losses occurred in fields equipped with sprinkler irrigation system. Symptoms of diseased plants consisted of formation of irregular necrotic lesions on leaves surrounded by yellow halo. Under favourable conditions, these lesions gradually expanded and heavily infected leaves became blighted. The primary symptoms on infected pods were the development of water soaked spots which later turned to dark or reddish blotches. In attempts to investigate the causal agent, two types of a Gram negative bacteria with raised, yellow and translucent colonies were isolated from leaves and pods of blighted beans. All strains produced Xanthomonadin pigment and their inoculation on young bean plants induced disease symptoms similar to those observed under field conditions. Based on morphological, physiological and biochemical properties, the predominant pathogenic type was identified as Xanthomonas axonopodis pv. phaseoli. However, the other strain with the same properties, but capable of producing melanin pigment in nutrient media, was assigned to X. axonopodis pv. phaseoli var. fuscans.
M. Noshadi, S. Amin, N. Maleki,
Volume 7, Issue 1 (spring 2003)
Abstract
Increasing application of herbicides such as atrazine raises concerns about soil and groundwater pollution. This study investigated spatial and temporal variation of atrazine concentration and its transportation in the Daneshkadeh soil series (Fine, mixed, mesic, Calcixerollic Xerochrepts) at the experimental field of Agricultural College, Shiraz University. The risk of soil and water contamination due to applying atrazine was also assessed. The PRZM-2 model was evaluated for the simulation of the atrazine concentration. The experiment had 3 plots, 209 m2 each (19 by 11 m). Atrazine was applied on corn at a rate of 3.5 kg a.i./ha per plot. During the growing season, soil samples were collected from each plot 7 times through 1 m soil depth with 0.10-m increments. The observed data showed temporal reduction of atrazine concentrations in the soil profile. The maximum depth of atrazine traced was about 50 cm below the soil surface. Statistical parameters ME, RMSE, EF, and CRM were obtained to compare PRZM-2 predicted and observed soil residue concentrations. For all data, the mentioned parameters were calculated and found to be 2.78 mg/kg-soil, 12.73 mg/kg-soil, 0.49, and 0.25, respectively. The simulation results were in close agreement with the observed data. Therefore, PRZM-2 could be used for simulation of atrazine transport and groundwater pollution.
A. Kashi, S. Hosseinzadeh, M. Babalar, H. Lessani,
Volume 7, Issue 4 (winter 2004)
Abstract
Watermelon (Citrullus Lanatus) cv. Charleston Gray is one of the most important cultivars grown in Iran. It has some good quantitative and qualitative characteristics but unfortunately is sensitive to Blossom End rot. To solve this problem, this experiment was conducted in a factorial manner in randomized complete block design with four replications in Research Station and Laboratories of Department of Horticulture, College of Agriculture, the University of Tehran, during 1997 & 1998. In this experiment, black polyethylene mulch was used and calcium nitrate was foliar sprayed at concentrations of 0, 4, and 6 g/L. Results indicated that mulch could increase yield by 85% over two years due to weed growth suppression and conserving soil moisture for a longer time. Foliage fresh weight, number and average weight of fruits per plant and precocity were also significantly affected by black polyethylene mulch. Furthermore, mulch reduced the number and weight of fruits affected by Blossom End rot by about 13% and 12.5% (average of two years), respectively. Calcium nitrate addition during both years had no significant effect on the measured fruit characteristics nor on Blossom End rot.
D. Hashemabadi, A. Kashi,
Volume 8, Issue 2 (summer 2004)
Abstract
The effects of 4 different levels of nitrogen (0,120,150, and 180 kg nitrogen per hectare) and one level of poultry manure (10 tons per hectare) on the quantitative and qualitative characteristics of an autumn grown cultivar of cucumber [Cucumis sativus, cv.'super dominos] were studied in DarrehShahr, Ilam. The experiment was conducted in a completely randomized block design with 3 replications.
The results showed that treatments affected yield, number of nods and plant fresh weight and the highest yield was 41/287 ton/ha in the plots receiving poultry manure. Also 180 kg of pure nitrogen increased yield compared to control. Effect of treatments on fruit length, diameter, and fruit dry matter was different. Plant length, number of nodes, and plant fresh weight showed a positive and significant correlation with plant yield.
G. R. Mesbahi, J. Jamalian, H. Golkari,
Volume 8, Issue 2 (summer 2004)
Abstract
Mayonnaise is a food emulsion containing egg yolk as emulsifier and some sort of gum as stabilizer. Iran is a main producer of tragacanth gum in the world which could be a potential replacement for imported gums used in making mayonnaise .The objective of this study was to investigate the possibility of substituting this gum for imported stabilizers in the formulation of mayonnaise sauce. To do this, tragacanth powder was added to the sauce at the levels of 0.1, 0.2, 0.4, 0.6, 0.8 and 1% . Emulsion stability and apparent viscosity of the sauces were determined and compared with that of the commercial one to find the right concentration of tragacanth. This concentration was used to produce mayonnaise on a commercial scale and then its physico-chemical characteristics, microbiological stability, and organoleptic properties were compared with commercial mayonnaise. The shelf-life of the sauce samples were also monitored bimonthly up to 4 months at two different temperatures (5 and 25 oC) by measuring apparent viscosity, moisture content, pH, microbial count, and organoleptic parameters. The results were compared with those obtained for commercial sauce. The results indicated that the characteristics of tragacanth-containing mayonnaise were similar to those of the commercial one and that the former was acceptable to consumers. Therefore, gum tragacanth at the right concentration could be a suitable subsitute for the stabilizers and thickeners already used in making mayonnaise sauce.
A. Jafari Malekabadi, M. Afyuni, S. F. Mousavi, A. Khosravi,
Volume 8, Issue 3 (fall 2004)
Abstract
In recent decades, the use of nitrogen fertilizers has increased irrespective of their effects on soil properties, agricultural products and, particularly, on environmental pollution. Nitrate easily leaches from soils into groundwater. The objective of this study was to determine temporal and spatial nitrate concentrations in groundwater in agricultural, industrial and urban regions in some parts of Isfahan Province. Water samples were collected monthly from 75 agricultural, industrial, and urban wells of Isfahan, Najaf-abad, Shahreza, Natanz and Kashan during January-May 2001. The results indicated that NO3-N concentrations in most of the regions studied were higher than the standard level (10 mg/l) and nitrate pollution must be reckoned among the most serious problems of sustainable agriculture and exploitation of groundwater resources. Average NO3-N concentration in different wells ranged from 1.03 to 50.78 mg/l (4.64 to 228.5 mg/l as nitrate). The average NO3-N concentration in groundwater of Najaf-abad, Shahreza, Isfahan and Natanz-Kashan was 17.56, 14.6, 16.04, and 8.24 mg/l and 95.5, 100, 84 and 33.3 % of total wells in these regions had nitrate concentrations above the standard level, respectively. Maximum NO3-N concentration was detected in the agricultural region south of Najaf-abad (64.6 mg/l). Nitrate pollution in most of the sampling areas was mainly linked to agricultural activities. The average NO3-N concentration in groundwater of all agricultural, industrial, and urban regions, except for urban regions of Natanz and Kashan, were above the standard level. Generally, nitrate concentration level in groundwater increased with time and was maximum in March and April.
M. R. Bahreini Behzadi, F. Eftekhari Shahroudi, L. D. van Vleck,
Volume 9, Issue 1 (spring 2005)
Abstract
Data from the birth weight (BW), the average daily gain from birth to weaning (ADG) and the weaning weight (WW) of 1182, 1099 and 1099 lambs were respectively collected and applied to estimate the maternal effects on heritabilities as well as on the determination of the environmental factors. The data were collected from Shahrbabak Sheep Breeding Research Station within five year, from 1993 to 1998. The effects of the year of birth, the age of the dam and its sex on all the traits were significant. The type of birth had no effect on BW but it was significant for the other two traits. Estimates of (co)variance components and genetic parameters were obtained by restricted maximum likelihood, using single and two-trait animal models. Based on the most appropriate fitted model, direct heritability of BW, ADG and WW were estimated at 0.10± 0.06, 0.21 ±0.08 and 0.22± 0.09, respectively. The maternal heritability for the three traits was also estimated at 0.27± 0.04, 0.15 ±0.05 and 0.19 ±0.05, respectively. Direct genetic and phenotypic correlations between BW and ADG BW and WW ADG and WW were estimated at 0.85 and 0.41 0.82 and 0.48 and 0.99 and 0.99, respectively. Ignoring maternal effects in animal model caused overestimation of direct heritability. Thus maternal effects are significant sources of variation for early growth traits and their ignorance in the animal model causes inaccurate genetic evaluation of the lambs.
M. R. Lak, H. R. Dorei, M. K. Ramazani, M. H. Hadizadeh,
Volume 9, Issue 3 (fall 2005)
Abstract
In orther to determine the critical period for weed control in the Chitti bean (Phaseolus vulgaris) line KS-21467 a field study was conducted at the Bean Research Station of Khomein by a randomized completele block design in 2001 and 2002. The treatments included weed free and weed infested period until 20, 28, 36 and 44 days after planting (DAP) with two weed free and weedy checks. The results indicated that the critical period at 5% allowable yield loss was 20-53 DAP (between first-trifoliate and flowering stages) in 2001 and 35-51 DAP ( between blossom and flowering stages) in 2002. Weed dry weight decreased averaglly 81% in weed-free period until 44 DAP compared to the weedy check. Yeild decreased averaglly 63% in weedy check compared to the weed free check. Weed competition increased the height of bean, wherease 100-seed weights and the number of seeds per pod were not substantially affected. There was a negative and significant correlation of weed dry weight with the number of pods per plant, the number of seeds per plant and yeild.
M. Kavoosi, M. J. Malakouti,
Volume 10, Issue 3 (fall 2006)
Abstract
Potassium is one of nutritional element that has an important effect on the quantity and quality of rice plant. Knowledge about the K critical level and plant response to different application rate of K, can effectively help with the proper use of this element. Therefore, in this study potassium (K) critical level for rice (Khazar variety) and prediction equation for grain yield were determined in 21 rice fields of Guilan provience during 2001-2002. After land preparation, 6 experimental plots (4×5m) were constructed in each selected field. Nitrogen and phosphorus were applied before transplanting, based on soil test from urea and triple superphosphate, respectively. Potassium was applied in different rates including 0, 100, 200, 300, 400, and 500 kg ha-1 of K2O as muriate potassium. Khazar variety was transplanted in a space of 25×25cm, just after fertilizing of plots. Plots were harvested in 5 m2 at the end of maturity stage from the first node above the ground, and grain and straw were measured separately. Statistic analysis was done on grain weight based on 14% moisture. The results showed, that effect of different K fertilizer application in 5% and the effect of soil type in 1% were statistically significant on the grain yield. The mean increase of grain yield in responsive fields to K application was 982 kg ha-1. The results also showed that the responses of rice fields with available K less than 100 mg kg-1, 100-160, and more than 160 mg kg-1 to KCl application were high, moderate and low, respectively. Potassium critical level based on 90% relative yield was determined as 110 mg kg-1 of soil . In final relative yield, prediction equation, available potassium, potassium content of irrigation water, and rate of KCl fertilizer application entered positively in the equation, while available phosphorus showed negative effect on relative yield.
M. Haghighat Afshar, M. Babalar, A. Kashi, A. Ebadi, M. A. Asgari,
Volume 10, Issue 3 (fall 2006)
Abstract
Some strawberriy cultivars (Fragaria x ananassa Dutch. cv. Aliso, Selva, Gaviota and Camarosa) were grown hydroponically with five NH4:NO3 mM concentration ratios (0/6 (S1), 0.25/6 (S2), 0.5/6 (S3), 1/6 (S4), 2/6 (S5) and constant nitrate concentration in three replicates for two seasons: Summer and Winter, in greenhouses of Agriculture Faculty of Tehran University. The results are reported as Follows: In summer shoot dry weight and shoot/ root ratio were highest in 0.25 and 0.5 mM NH4-N and were constant in remaining solutions with higher ammonium concentration. Increasing ammonium concentration resulted in decreasing the root dry weight. Aliso and Selva had the highest shoot and root dry matter respectively. Gaviota had the highest runner. In winter, shoot dry matter was highest in plants grown in S5 solution. Increasing ammonium from 0 to 0.5 mM decreased fruit yield but more ammonium in S4 and S5 solution increased yield. Root and fruit dry matter were highest in Selva. Yield and Fruit fresh weight were highest in Gaviota. Camarosa had the highest shoot dry weight. In summer shoot dry weight was significantly higher than in winter. Due to the high yeild, commercial use of the S5 solution and the cv. Gaviota is recommended.
A. Nekouei, M. Rahimmalek,
Volume 11, Issue 41 (fall 2007)
Abstract
Flora identification of each region plays an important role in the maintenance of natural resources of each country and it is a prerequisite to supplementary phylogenetics and genetic diversity studies. During February 1994 to August 1995, in a two-week interval, vineyards in two districts of Isfahan province, namely Zarinshahr and Tiran & Karvan were visited and weed samples were collected in flowering stages. All collected specimens were identified using specimens present in Herbarium of colleges of agriculture and natural resources of Isfahan University of Technology and other available references. The analysis revealed that in Tiran and Karvan, 84 species belonged to 71 genera and 26 families and in Zarinshahr 62 species belonged to 51 genera and 23 families. Species dominance in both districts belonged to Asteraceae and Gramineae families. Analysis of plant life forms using Raunkiaar method showed that Therophytes with 79.5% and Geophytes with 8.3% were the most frequent life forms in both Zarinshahr and Tiran & Karvan regions.
S.h. Lack, A. Naderi, S. A. Saidat, A. Ayenehband, G.h. Nour – Mohammadi, S.h. Moosavi,
Volume 11, Issue 42 (winter 2008)
Abstract
In order to study the effects of different levels of irrigation, nitrogen and plant population on yield, yield components and reserved dry matter remobilization of seed corn (SC. 704 hybrid) a research was conducted at the experimental field in Khuzestan Natural Resources and Agricultural Science University in summer, 2004. This research was made based on three split-plot field experiments, RCBD. Each of the irrigation treatments implemented separately in each experiment have been as follows: Optimum irrigation, Moderate stress and Severe stress (irrigation after drainage 50%, 75% and 100% of available water based on 70%, 60% and 50% of field capacity, respectively). In each experiment three nitrogen levels consisting of 140(N 1 ), 180 (N 2 ) and 220(N 3 ) Kg N ha-1 were applied in main plots and subplots which consisted of three plant populations (D 1 =6, D 2= 7.5 and D 3= 9 plant m-2). There were three replications for each experiment. The results of the combined analysis of variance indicated that the effect of water deficiency stress, nitrogen and plant population on grain and biological yield was significant. With increasing severity of drought stress, the grain and biological yield decreased. The maximum grain yield was estimated to be 1017.04 gm -2 which was related to optimum irrigation treatment. Grain yield reduction was mainly due to reduction of grain per ear and 1000 seed weight. The increase of nitrogen consumption caused an increase in grain yield. The positive effect of nitrogen application on grain yield considerably decreased as a result of the increased water deficiency in soil. The response of grain yield to plant population was positive. The contrary to interaction effects of irrigation and nitrogen, and irrigation, nitrogen and plant population, the interaction effects of irrigation and plant population and also nitrogen and plant population on grain yield were significant. The results indicated that the difference between different levels of irrigation in the case of dry matter remobilization rate was significant. The least and the highest remobilization rate of reserved dry matter was related to optimum irrigation and drought moderate stress treatment, respectively. The efficiency and contribution of remobilization in grain yield increased in response to increasing severity of drought stress, but these traits significantly reduced as a result of nitrogen consumption. Remobilization rate and contribution of reserved materials to grain yield in the highest density (D3) were significantly more than other densities. According to the results of this study, under drought stress conditions, the decrease of inputs consumption, in addition to the decrease of costs, will be followed by the increasing efficiency use of the resources.
E. Karimi, A. Lakzian, K. Khavazi, A. Asgharzadeh, G.h. Haghnia,
Volume 11, Issue 42 (winter 2008)
Abstract
It is important to investigate the genetic diversity and evaluate symbiotic effectiveness of the indigenous rhizobial population. It helps understand the responses of indigenous isolates to different rhizobial inoculants. In spite of the importance of bacterial diversity, there are a few scientific reports about it in Iranian soils. Genetic diversity of 150 isolates of Sinorhizobium isolated from Hamadan soils was studied by using PCR / RFLP 16S-23S rDNA technique. The results showed that all isolates clustered in three different groups. Group (I) formed 122 isolates and they were quite similar to Sinorhizobium meliloti from viewpoint of genetic characteristics. Twenty five isolates were clustered in Group (II) and they belonged to Sinorhizobium medicae. Group (III) had two isolates and they were new species and quite different from the other groups. Shannon diversity index was different within eleven different land units (Medium gradient mountains, Level lands, Plateau, Foot slopes, Depressions and Composite land) and there was a correlation between Shannon index and some soil properties. Difference in Similarity index showed that Sinorhizobium groups in each land unit were different.
M. Falaki, H. Shabanali Fami, H. Iravani , H. Movahed Mohammadi,
Volume 12, Issue 43 (spring 2008)
Abstract
The continuous rapid development of telecommunications and computer-based information technology (IT) is probably one of the biggest factors of change in agricultural extension, which will facilitate and reinforce other changes. There are many possibilities for the potential applications of the technology in agricultural extension, about which attitudes of extension professionals is highly important. The present study was conducted to assess the attitude of extension professionals which can affect the adoption of IT by extension system. The population of the study consisted of 1145 extension professionals working throughout the country in different provinces. Using a stratified random sampling technique, 241 extension experts were selected as the sample for the study. The reliability and validity of the tools of study were confirmed by a pilot study and expert judgment. The results of the study indicated that the respondents had higher knowledge on word processing softwares, windows and file management in the area of computer application. In contrast, in the area of internet application they were mainly interested in getting information from specialized sites, searching by search engines of Yahoo and Google and exchanging e-mails. Correlation analysis showed that there was a significant relationship between the attitude of extension professionals and their age, educational attainments, knowledge of IT, its application and English language proficiency. Meanwhile, there was a significant difference between attitudes of male and female extension experts towards IT.
M. Rahimmalek, B.e. Sayed Tabatabaei, S.a. Mohammadi,
Volume 12, Issue 43 (spring 2008)
Abstract
Genetic maps with high genome coverage are becoming increasingly useful in both basic and applied genetic researches. In the last decades, the advent of DNA markers has brought about a magnificent revolution in the production of genetic map, especially in wheat. In the present study, AFLP markers were used to saturate linkage map of 107 doubled haploid individuals produced through Fukuho _Komugi × Oligo – Culm crosses received from Japan International Research Center of Agricultural Science (JIRCAS). The framework of genetic map was used as base map for next analysis. AFLP analysis was performed with MseI / PstI as digestive enzymes. The average percentage of polymorphism with AFLP markers was around 16.6%. Data analysis was performed by computer program known as Mapmaker / EXP, Ver. 3.3. In this program, the maximum distance criterion was 50 cM and the minimum LOD equated 3. The drawing of chromosome schema for the linkage groups was performed by Draw map, Ver 1.1. In this analysis, 115 AFLP markers were divided into 10 groups in addition, some of the markers remained unlinked. The supplementary data analysis along with specific SSR markers identified the chromosome loci of the markers. Ultimately, 71.1% of the markers were assigned to genome A, 16.5% to genome B and only 3% to genome D. The AFLP markers filled 11 gaps in 7 chromosomes (2A, 3A, 7A, 2B, 3B, 5B and 7B). The low coverage of genome D was due to the limited polymorphism and its conservation in different populations. Among the chromosomes, maximum number of markers (60) was assigned to the chromosome 7A. The distribution of the markers on this chromosome was not uniform. Such a distribution was related to the grouping AFLP markers within heterochromatin region, particularly around the centromere.
A. Maleki, S. S. Mohtasebi, A. Akram, V. Esfahanian,
Volume 12, Issue 44 (summer 2008)
Abstract
Occupational safety and health of agricultural workers have not yet received their due attention in developing countries. This is particularly true in the case of tractor drivers who operate tractors in unfavorable conditions and in a high level of seat and tractor vibrations. Therefore, an investigation of vibration sources and finding the methods for decreasing them are of considerable importance. In this research, vibrations that the tractor operators of different weights are exposed to while operating any of the three commonly used tractors in Iran during plowing with moldboard plows, disk harrows or routine road travel at two forward speeds were examined. Acceleration data of tractor body and its driver, while riding the tractor, were measured and recorded. Later, Fast Fourier Analysis, and root mean square of weighted accelerations for the cases of driver health and comfort were analyzed and evaluated. Results revealed that the level of forward speed did not have any significant effect on vibrations introduced to drivers body, however, the average of acceleration vectors on different tractors and their drivers’ bodies revealed a significant influence (P<0.01). Moreover, with increasing a driver’s mass, the average of acceleration vectors on his body decreased. For example, a driver of 55 kg mass, bore a maximum acceleration vector of 9.8 m/sec2, while a driver with 100 kg mass, had a minimum acceleration vector of 3.3 m/sec2. In a comparison of permissible riding hours/day, JD3140 and U651 tractors recorded maximum and minimum, respectively. Also acceleration vectors for different tractor operators compared with international standards showed that the comfort level for these tractors was extremely low.
H. Khoshghalb, K. Arzani, M. J. Malakouti, M. Barzegar,
Volume 12, Issue 45 (fall 2008)
Abstract
Changes of the main sugars and organic acids content in Asian pear (Pyrus serotina Rehd.) Cultivars ‘KS’9 and ‘KS’13 grown in Tehran were studied from fruit set to maturity. The main sugars and organic acids content in fruits were determined 1 and 2 months before harvest, at the time of harvest and 1, 2 months after harvest time using High Performance Liquid Chromatography (HPLC). Fruits were stored at 2˚C and 80-85% relative humidity (RH). There were significant differences between cultivars and time of fruit harvest in terms of sugars and organic acids content. In both studied cultivars, fructose, glucose and sorbitol increased from the first fruit sampling to one month after harvest (1 to 9% FW) and then decreased. Sucrose content decreased from 2 months before harvest to 2 months after harvest time (3 to 0.75% FW). In both studied cultivars organic acids content increased at the time of pick-up and then decreased. The highest organic acids contents in the studied cultivars were malic and ascorbic acids (345 and 41.1mg 100g-1FW in ‘KS’9 and control, respectively). The relationship between low sugar and organic acid content in fruits showed the highest correlation (0.8 to 1) in both cultivars among low flesh firmness, low total soluble solid (TSS), low dry weight and high internal browning determined in this study. Results indicated that high content of sugars and organic acids in fruit led to delayed internal browning. Asian pears with a low ascorbic acid concentration are probably more susceptible to internal browning. High correlation was observed between high sugars content and high fruit colour.
M. Gholamhoseini, M. Aghaalikhani, M.j. Malakouti,
Volume 12, Issue 45 (fall 2008)
Abstract
In order to study the effect of various amounts of nitrogen (N) and Iranian natural zeolite on the quantitative and qualitative forage yield of winter canola (Brassica napus L.) in light soil, a field experiment was conducted on research farm of Tarbiat Modares University, Tehran, during 2006-2007. Treatments were arranged in the form of RCBD with 3 replications. The experimental treatments were based on factorial various levels of zeolite (0, 3, 6 and 9 t.ha-1) and nitrogen (90, 180 and 270 kg ha-1) in urea form. Seeds of canola (Brassica napus L. cv. Okapi) were sown on October 2, and fresh forage was harvested at the time of silique formation (170 DAP). Results showed that the effect of N and zeolite on forage quantitative attributes including biomass, leaf and stem dry weight and leaf area index were statistically significant. In addition, forage qualitative traits including crude protein percentage and calcium percentage in plant mass were significantly affected by N and zeolite. Increasing application of N fertilizer caused increase in N leaching, and with increasing zeolite application, N leaching reduced. The interaction of two factors for all parameters was not significant. The most increasing effects on forage yield and quality were gained using 270 kg N ha-1 in combination with 9 t. Zeolite ha-1. More detailed studies are strongly recommended to investigate the effects of integrated application of chemical fertilizer and natural zeolite.
