Agricultural Sciences and Technology
Year:2001 | Volume:15 | Issue:1|Papers Count:19

Bitterness in citrus juices has been a big problem since 1932. The bitterness in citrus juices, especially sweet lemon, is due to either naringin or limonin component or both. Enzymatic and surface adsorption are the most popular debittering methods. Because enzymatic methods are very expensive and also cannot eliminate both bitter components, adsorption method is more applicable. In this study polystyrene divinylbenzene was used, to make continuous flow column as fixed bed. Sweet lemon juice was passed through the column, as down flow with two flow rates. Debittered lemon juice under these conditions was evaluated for physical and chemical characteristic and compared with control sample. The results show that polystyrene divinylbenzene resin only absorbs limonin but doesn’t have any effect on the other fruit juice components such as vitamin C or sugars. The flow rate of 15 bed volumes per hour was chosen as a suitable flow rate for the debittering process. Fruit pulp was added to debittered fruit juice, to recover initial properties of the juice. The results of taste panel showed that debittered fruit juice containing 2% pulp was the best fruit juice among tested samples.

Dodder (Cuscuta campestris Yunck) is a troublesome weed in vineyards which is hard to control. The effects of Treflan, Sonalan, Tramat and Dacthal for dodder control in vineyarsd were evaluated. Due to the hard seed coat, the dodder seeds are not able to grerminate. Treating the dodder seeds in concentrated sulfuric acid softens the seed coat so they are able to germinate. The optimum temperature for dodder seed germination and hypocotyl growth is 20-35°C. Tramat inhibited dodder seed germination while Tref1an, Sonalan and Dacthal were absorbed through epicotyl and hypocotyl and inhibited seedling emergence. The experiments conducted in the vineyards showed that Treflan at 3 Kg a. i./ha before shoveling and 1.5 Kg a. i./ha after shoveling, Sonaln 2.5 Kg a. i./ha before shoveling and 1.25 Kg a.i./ha after shoveling and Tramat 1.2 Kg a.i./ha before shoveling and 0.6 Kg a.i./ha after shoveling could control dodder in vineyards effectively. In this study the effect of Dacthal was weaker than other herbicides. All herbicides were soil incorporated after treatment.

During 1995 - 96 faunistic studies were carried out on the mites of cotton fields in Moghan plain. A total of 9 species, 18 genera and 8 families belonging to the order Mesostigmata were collected and identified. The first part of it which is presented here in this paper includes 4 families named Rhodacaridae, Digamasellidae, Phytoseiidae and Ascide with 9 genera and 6 species as follows: Amblydromella iranensis Dan. & Den., Neoseiulus oryzacolus Dan., Phytoseius tropicalis Dan., Typhodromus sp., Rhodacarellus epiginalis Sheals, Digamasellus sp., Dendrolaelaps zwoelferi Hirschm, Proctolaelaps hystricoides and Asca sp., one species (Proctolaelaps hystricoides) is new record for the mite fauna of Iran, all others are new for the Moghan plain. With regard to the gernera and species diversity of the family phtoseiidae, further studies about this family in order to identify the important bio-control agents of the region are needed.

The effect of planting date and time of irrigation termination on yield and yield components of cotton, var. Varamin, was studied in an experiment conducted in 1996 in Torbat-Djam. The experimental design was a randomized, complete block with a spilt-plot arrangement with 4 replications. Main plots were time of irrigation termination (cut-out, 2 and 4 weeks after cut-out) and subplots were planting dates (29 Apr., 9 and 19 May). Results showed increased seed cotton and lint yields in first planting dates, compared with thired one, were associated with higher cottonseed number and weight, lint index and boll size; however, lint percent and number of bolls showed no difference in different planting dates. Irrigation termination in a later date, caused highest cottonseed, lint weight and lint yields. Planting date and irrigation termination interactions had no effects on bolls number, lint percent and lint weight, but later termination of watering and earlier planting, together, increased cottonseed number and weight, lint index, boll size and therefore seed cotton seed and lint yields.

In order to investigate the effect of different tillage methods and residue management on agronomic criteria of maize, an experiment was conducted during growing seasons of 1375-76 and 1376-77. This experiment was on the basis of a split - split plot design with 4 replication. Treatments were different combination of 2 levels of residue (a: without residue, b:3 ton residue/hectar) 3 levels of tillage methods (a: no tillage, biminimun tillage, C: conventional tillage) and 3 different rotations (l):wheat - corn wheat - sesame, (2):wheat - sesame - wheat - corn, and (3):wheat - fallow - wheat - corn. Cultivar used was 301. Rotations, tillage methods and residue application had no effect on maize yield. Number of ears/plant, number of kernels/ ear, kernel weight/ear, 100 kernel weight and protein content were not affected by tillage methods and residue treatment; however, total harvest index in conservation tillage methods (no tillage and minimum tillage) without residue, was increased. Corn yield was not affected by rotation. Hypothetical substitution of Corn with sesame in rotation (1) and (2) could cause a significant increase in economic output.

The objective of this study was to evaluate the quality and shelf life of raisins and dried apricot under different packaging materials and storage conditions. Three different plastic films (polyamide, P. V. C polypropylene cellulose, and BOPP), which are commonly used in food packaging, were compared with samples packed in cardboard boxes which are currently used for dried fruits packaging in Iran in presence or absence of air. All different treatments were then stored at 15 and 30°C for eight months. The moisture content, degree of browning, and microbial load were then determined at 0, 4, and 8 months. Furthermore, texture, color, appearance, flavor, and total acceptance were determined by the sensory method using the multiple points hedonic test. Results shown that the type of packaging material had a significant effect on the moisture content, degree of browing, texture, appearance, flavor, total acceptance (P<0.01), and color (P<0.05) of all treatments. There was no significant difference between the vacuum packed and other samples except in moisture and texture of dried apricots (P<0.05). Storage temperature and time had a significant effect on all of the evaluated properties (P<0.01).

A field study was conducted in the College of Agriculture at Ferdowsi University of Mashhad to investigate the effect of irrigation by municipal treated wastewater on the yield and quality of tomato. Five irrigation treatments were applied in a clay loam soil in a randomized block design as follows; T1 - Irrigation by treated wastewater during all growing season, T2 - Alternate irrigation by treated wastewater and well water, T3 - Irrigation with well water and use of animal manure, T4 - Irrigation with well water plus fertilizer (urea), T5 - Irrigation with well water only. The results showed that tomato yield in all of the treatments exceeded that of check (T5). Maximum yield and total fresh and dry weight of plants were obtained from T1 and T3 respectively, in comparison with T5. Concentration of micronutrients and heavy metals in plant tissues of each treatment were higher than check. However, Fe concentration was highest in all treatments while cadmium concentration was lowest. Microbial contamination was considerably higher in T1 and T2 treatments.

A study was conducted to determine the critical period in silage corn (Zea mays) during 1998 in tehran (in Aburihan Campus). Treatments included weed free and weed infested period up to 3 leaf; 6 leaf; 10 leaf; 14 leaf; tassseling plus 1 week and to the end of growth season (weed free and weedy check). Treatment were replicated, four times in a complete randomized block design. Results based on Gompertz and logistic equation showed a critical period of weed control for forage yield from 4-5 to 12 leaf stages (based on 5% of acceptable damage); and for grain yield (5% of acceptable damage); from 4 to 13 - 14 leaf stage of corn development. Correlation between dry matter of weed and corn was shown that between this two variables there was a negative relation.- Number of weed in early season increased and then decreased.

The present study was carried out to evaluate the potential fungicidal properties of seeds, roots, stem and levaves of several plant species such as: Peganeum harmlala, Nigella sativa, Satureja hortensis, Sesamum indicum, Trachystermum copticur, Uninum sp., Deserunia sophia, Spinacia oleracea, Coriandrum sativum, Anethum cymbacarpum, Gosipyum hirsutum, Alium porrum and Teverium polium under laboratory conditions. Four species of soil borne fungi, including Fusarium graminearum, Fusarium equisets, Pythium aphanidermatum and Rhizoctonia solani were also used in this investigation, The inhibition was assessed by measuring fungal colony diameters at 20°C on PDA after 24, 48, 72 and 96 periods. Another experiment was also carried out with T.copticum seed extract and wheat seedlings in a green house. In addition, the effects of time duration and autoclaving on T.copticum seed extracts were also investigated. The results of this experiment revealed that only T. copticum seed extract could inhibit the fungal growth completely, the rest showed various degree of fungicidal activities and some like cotton even had stimulating effect on germination and growth of the fungi. Unlike seeds, the extract of the above ground plant parts. roots, time duration and autoclaving had no significant effect on the fungal growth. In green house, T. copticum extract caused considerable reduction in the percentage of the infected wheat seedlings.

The efficiency of Trichogramma brassicae Bezdenko (Hymenoptera: Trichogrammatidae) (reared on Heliothis zea Boddie eggs) as parasitoid of the sugarcane stem borers; Sesamin cretica Led. and S. nonagrioides botonephaga T. & B., was assessed under laboratory and greenhouse conditions. Data on seven biological characteristics are presented. The laboratory results showed that T. brassicae reared on H zea eggs parasitized 50 % of S. cretica eggs compared to 58% eggs of S.nonagrioides. In T. brassicae rearedon S. cretica eggs percentages of emergence (87%), female progeny (71 %), deformed females (2.5%), longevity (2.3% d), and developmental time (8.6 d) did not differ significantly from those reared on H. zea eggs (93, 69%, 3.2%, 2d and 8.5 d, respectively). However, the body length (0.39 mm) of T. brassicae femles reared on S. cretica eggs was greater than those reared on H. zea (0.33 mm). In the greenhouse conditons, T. brassicae paraitized an average of 56.4% of the S. cretica eggs distributed on the sugaracane plants. About 21.6% of the eggs were dessicated, probably due to puncturing by the parasitoid, compared to 4.1 % in the control treatment. Results showed that Trichogramma has the potential in controling sugarcane stalk boreres in a field IPM program and sustainable agriculture.

In order to study the effect of late planting dates and optimum plant density on yield and growth pattern of se 604 corn hybrid, an experiment was conducted in 1995-1997 at Ramin Agricultural Research and Education School, which is located 36 km north of Ahwaz city. The design of the experiment was a split plot in which main plots were consisted of 3 planting date (August 15, September 1, and 15) and subplots of 4 plant densities (70, 80, 90 and 100 thousands plants in hectare) with completely randomize block bases. The experiment replicated 4 times. Analysis of variance showed that there was significant difference between planting dates and highest yield (12.31 t/ha) was obtained from August 15 planting date. The highest yield (9.82 t/ha) was obtained from 80 thousands plants ha-1. Among yield components, number of kernels per row and kernel weight showed the highest sensitivity to planting date. Number of kernels per ear row and kernel weight in August 15 were higher than that of September. Different plant densities influenced yield components. Seventy thousands plants ha-1, due to wider spaces between plants, effected on yield components considerably. The variations in the out put of leaf, stem, ear and total dry matter as a function of time followed second - degree equation, in such a way that after reaching to maximum point it tended to decline. Maximum plant dry matter was obtained from the 80,000 plants ha-1 and planting date at August 15 (about 100 days after sowing). Thus, August 15 and 80,000 plants per ha -1 recommended to this area.

Germination of seed and establishment of seedling in sugar beet could be influenced by chemical inhibitors of seed coat, seed hardness and impermeability to water and oxygen as well as seed reserves. Uniform seeds of cv 9597 were studied using a completely randomized design with 4 replications. Samples of 100 seeds were washed by distilled water, diluted hydrochloric acid and diluted hydrochloric acid which was neutralized by sodium hydroxide at the end of washing treatment. Each of the above treatments was applied at 2, 4 and 6 hours. Samples were sterilized by diluted sodium hypochlorite solution. Germination percent and the rate of germination in germinator and sand medium were calculated. Results showed that the type of treatment for washing couldn’t influence the percent and the rate of sugar beet germination seed in the germinator. But the rate of germination in sand medium increased significantly through water treatment. In addition, the time of applied treatments influenced the percent and the rate of germination in germinator and sand medium significantly. Interaction effects between the type of treatments and the time of washing also influenced the percent of germination in germinator and the rate of germination in sand medium significantly. Such that, the 6 hours washing with distilled water increased the percent of germination in germinator 1.87 times and the rate of germination in sand medium 43% in comparison with control, non-washed seed treatment.

Crop seed germination and seedling growth are exposed to drought and salinity in some areas specially in arid and semi-arid regions and combined effect of these stresses on germination and emergence is of considerable interest. A growth chamber study was conducted to investigate seed germination of wheat (Triticum aestivum), sugar beet (Beta vulgaris) and chickpea (Cicer arietinum) in reduced water potential (distilled water as control, 0.32, 0.56, and 0.80 MPa). Negative potentials were simulated by using concentrated macronutrient solution (NPK), NaCl, CaCl2 and polyethylene glycol (PEG-6000). Treatments were arranged in a completely randomized design using a 4×4×3 factorial experiment with four replications [4 levels of water potential, three species, and four types of osmoticum]. In each treatment 50 seeds were planted in a 11 cm diameter petri dish. Parameters examined in germinating seeds were rate of imbibition per day, rate and duration of emergence and elongation and weight of radicle and plumule. For all three species duration and rate of germination increased with increasing negative water potenital, but the sensitivity of species were quite different, wheat seeds were emerged fastest at all water potentials and osmoticums, followed by chickpea and then sugar beet. Although sugar beet is a salt resistant crop’its seed germination and dry matter build up in radicle and plumule reduced more than other two crops by water potential. Different osmoticums in the same water potential showed significant differences in rate and duration of germination as well as radicle and plumule length and weight particularly in sugar beet and chickpea. At all three species concentrated macro nutrient NPK showed better performance than others and PEG-6000 had the most inhibitory effect on seed germination. Differences between NaCl and CaCl2 generally became less pronounced. These results suggest that PEG-6000 may exert specific effect and concentrated NPK could be a suitable alternative for PEG.

Morphology, biology and host stages preference of Ecarsia formosa Gahan (Hymenoptera: Aphelinidae) and characteristics of egg, three larval instars, pupa and adult were studied in Isfahan. The average of growth period of parasitoid from egg to adult in 1st to 4th nymphal instars, prepupa and pupa of its host, the greenhouse whitefly, Trialeurodes vaporariorum Westwood (Homoptera: Aleyrodiae) was determined 20.3 ± 0.82, 17.4 ± 0.54, 16.1 ± 0.4, 15.1 ± 0.51, 14.8 ± 0.41 and 14.3 ± 0.52 days respectively at 24 ± 1°C, RH 65 ± 5% and 16.8 (L:D). The 3rd and 4th nymphal instars were the best stages for parasitism. Host feeding of parasitoid was further on 2nd nymphal instar and pupa. The average of growth period in 4th nymphal instar of host for egg, 1st, 2nd 3rd larval instars together and pupa was 3.3 ± 0.25, 1.8 ± 0.77, 3.2 ± 0.26 and 7.9 ± 0.39 days respectively. The full developed larva, primitive pupa, pupa with white, white - red and black-red eyes and adult were appeared 8.15 ± 0.42,9.15 ± 0.29, 10.35 ± 0.33, 12.4 ± 0.39, 14.55 ± 0.33 and 16.15 ± 0.72 days after ovipositing, respectively. This parasitoid is thelytokous parthenogenetic insect. Males were rarely observed. The size of parasitoid (width of head capsule) was positively corre1eted with the size of its host. The most number of parasitized nymphs was limited to middle regions of host plant, lantana camera.

In this research producing fruit milk with apple concentrate or puree was studied. In preliminary experiments milk with puree or concentrate and essence of apple was mixed with different proportions. In order to determine the best formulation the samples were judged by experienced panelists. In addition to determine the best combination of temperature - time for samples pasteurisation, three different conditions were applied as follows: 75°C for 15 minutes. 85°C for 10 minutes and 95°C for 5 minutes. In later stages on the basis of preliminary results apple milk beverage was produced and packed in doy-pak packages. Samples were stored in the refrigerator for 6 weeks in order to evaluate shelf life. During this period; pH, color and appearance, taste, odor and microbial characteristics were determined weekly. Results showed that the mentioned period of organoleptic quality of the samples waw maintained unchanged and the results of microbial experiments for existence of mould, yeast and excrete and non - excrete coliforms was negative.

The present study conducted to evaluate effects of climate changing on yield and other growth characteristics of irrigated and rainfed chickpeas and sunflower. For this, mean monthly climatic variables, temperature, radiation and rainfall, were predicted for Tabriz under doubled CO2 concentration using two general circulation models (GISS and GFDL)/ The results were then used to reconstruct long term climatic data of Tabriz. Using these data as the inputs of crop simulation model OSBOL, the effects of climate changing on growth, development, yield and water requirement of chickpeas and sunflower were evaluated. Based on GISS and GFDL predictions mean annual temperature rise was 4.6 and 4.3°C, respectively and mean annual precipitation was increased by 32 and 1%, respectively. However, mean annual radiation was not change in the models prediction. The results obtained by GTSS model showed that doubling CO2 concentration will led to mean temperature rise by 3.7 °C, 40% increase in mean rainfall and a reduction in mean radiation by 3% during the first 5 month of growth. However, the GFDL model predicted an increase in mean temperature and radiation by 4.7°C and 4% respectively and 12% reduction in mean rainfall within the same period. Crop simulation results showed that climate changing caused reduction of day to maturity and harvest index, and increase of yield, biomass and to a lower extent water requirement of irrigated sunflower. In rain fed conditions, increase of sunflower biomass was fallowed by a reduction of days to maturity and harvest index. Yield prediction of simulation model by GISS was in contrast with GFDL model. For irrigated chickpeas, results showed that doubling CO2 concentration led to reduction of days to maturity, biomass, yield and water requirement; but harvest index remained unchanged. Simulation results indicated that biomass, yield and harvest index of rain fed chickpeas will increase in changing climate conditions, while days to maturity will decrease.