JOURNAL OF RESEARCH IN AGRICULTURAL SCIENCE
Year:2007 | Volume:3 | Issue:1|Papers Count:13

Research was conducted in Yasouj alfalfa fields during years 1997 - 99 to identify the natural enemies and pathogenic agents of the alfalfa weevil, Hypera postica (Gyll.), (Col.:Curculionidae) and the following species were identified:1-The parasitoid wasp, Anaphes = (Patasson) sp. In the course of investigation, this parasitoid wasp caused a mean of parasitism of 3.1% on the eggs in the alfalfa fields.2-The parasitoid wasp, Bathyplectes sp. Thorn. During 1997 - 99, this parasitoid wasp caused a mean of parasitism 30.5% on the larval instars of the alfalfa weevil in the alfalfa fields.3-The predatory bug, Geocoris megacephalus. This predatory bug was observed in some alfalfa fields feeding on the first larvae instars of the alfalfa weevil, but its density was very low. In laboratory rearing each predatory bug consumed an average of 1.1 alfalfa weevil first instar larval.4-The predatory bug, Nabis sp. This predatory bug was consumed of larval instars of the alfalfa weevil. The population density of this predator in-the alfalfa fields was low. 5- Chrysoperla carnea The population density of this predator in the alfalfa fields was low prior to June in three years (1997-99), but was increased gradually.6-The lady birds, Coccinella septempunctata L. The population density of this predator in the alfalfa fields in three years was increased gradually from June. The adult and larvae of this predator consumed of eggs and larvae of the alfalfa weevil.7-The pathogenic fungus, Beauveria bassiana (Bals.). This fungus caused a mean mortality of 38.1% on the overwintering adult alfalfa weevil in the alfalfa fields. Under the laboratory condition an average of 86% adult, 56% larvae and 38.5% of the pupae were killed by the pathogen after artificial inoculations. It is therefore, recommended to conduct more research on the effectivness of the spore dusting of the B. bassiana into the alfalfa fields after the harvest to control overwintering adults. Also mass rearing and release of the C. carne a in the spring should be investigated as a potential nonchemical control method. After confirmation of the effectiveness of these control measures in the fields studies they can be used in an I.P.M program of the alfalfa weevil, in the Yasouj region.

This experiment, with a completely randomized factorial block design and 6 replications, was conducted to evaluate the key role that calcium plays in the shelf life and the quality aspects of the "Red Delicious" apples. For purposes of the experiment, a balanced application of fertilizer either broadcast or applied in manure pits within the tree shade area along with 4 foliar applications of a 0.5% solution of calcium chloride during the growing season were tested on apple trees of somewhat uniform characteristics. The results showed the yield improvements with manure pit application as compared to the control, but the differences were not statistically significant. The quality aspects of the fruits especially the fruits texture had improved as a result of the foliar applications of calcium chloride solutions. More specifically, 4 foliar applications of calcium chloride solution during the growth stage significantly (at 5% level) increased the apples calcium content and at the same time increased the texture hardness from 1.15 kg/cm2 for the control to 1.34. The ratios of N/Ca were almost normal for the fruits. Decreases in texture hardness, titrable acidity, juice content percent, and increases in the pH of the apple juice and in the ratios of total soluble solids to acid content were observed 245 days after storage. Considering the results of this experiment, we can make the following conclusions: The higher efficiency of manure pit application of plant nutrients over broadcast applications became clear. At least four applications of calcium solutions on apple fruits are recommended for the growing season in order to increase the fruits texture hardiness, its calcium content and its storage life.

In comparison to other horticultural crops, Citrus species are among saline sensitive plants. One way to increase saline tolerance is grafting sensitive cultivars onto tolerant rootstocks. Sweet lime (Citrus limetta) is one of the most sensitive species to salinity of soil and water, and under such conditions, drastic reduction occurs in vegetative growth and yield. The present study was conducted to evaluate salinity tolerance of sweet time grafted on different rootstocks including Sour orange (c. aurantium), Sweet lime (c. limetta), Mexican lime (c. aurantifolia), Volkameriana (c. volkameriana) and Bakraii (c. reticulata ´ C. limetta). One year old seedlings of rootstocks were planted in pots containig native soil (pH=8.2) and after full establishment, were budded with sweet lime scions. The four levels of salinity imposed were: 0, 20, 40 and 60 mole L1¯ NaCl for ten weeks. At the end of the experiment, chlorophyll content, solute leakage and relative water content of leaves, fresh and dry weight of scion were measured. The results showed that chlorophyll content, solute. leakage and relative water content of leaves, fresh and dry weight of scion were differ among rootstocks. Under salinity treatments different changes occurred in chlorophyll content, solute leakage, relative water, fresh and dry weight of scions among rootstocks. Generaly it was concluded that under the conditions of this experiment, Volkameriana, and to some extent Bakraii, could induce salinity resistance in sweet lime scions.

The present study was designed to investigate the possibility of tomato (Lycopersicon esculentum L.) and lettuce (Lactuca sativa L.) seeds invigoration by osmoprime with Polyethylene glycol. To osmopriming seeds of both tomato and lettuce were soaked in osmotic solution of Polyethylene glycole-6000(PEG-6000) with different water potentials (-0.4, -0.8 and -1.2 MPa) for 24, 48 and 72h. Both seed groups responded approximately similarly to osmopriming treatments. Maximum invigoration was observed in seed osmoprimed with-0.4 MPa osmotic potential for 24h followed by osmopriming for 48h as indicated by lower values of time to start germination, higher germination rate and final germination percentage as well as radicale and hypocotyle length. However, osmopriming for 72h with -1.2 MPa osmotic solutions behaved similarly to or even more poorly than that of control.

Limited water resources and the cost for irrigation and personnel cost may limit extending the grown area of the turf. The purpose of this research was to examine the effects of different irrigation regimes (every day, every two days, every three days and every four days) and four soil compositions including 100% agronomic soil, 75% agronomic soil + 20% sand + 5% animal manure, 50% agronomic soil + 40% sand + 10% animal manure, 25% agronomic soil + 60% sand and 15% animal manure on growth and quality characteristics of mixed turf grasses grown under Isfahan conditions and to determine the most economical irrigation level which would provide an acceptable turf grass quality level. Treatments including agronomic soil and every day irrigation represented the existing irrigation level practiced by turf management. During the growth, color, uniformity, height, length and width of leaf, fresh and dry weight of shoot and root and shoot and root ratio was measured. The best color quality during the experimental period was obtained from the agronomic soil and irrigation after 2 and three days, however there was not a significant difference between soils and irrigation treatments regarding color quality. The results regarding the plant height showed that every day irrigation and 25% agronomic soil had the highest values. Also the great values of leaf width and leaf length was obtained in everyday irrigation and 25% agronomic soil. Fresh and dry matter was greater in everyday irrigation and 25% agronomic soil but was less in irrigation after 4 days and 100% agronomic soil. It was concluded that irrigation after four days would be enough for irrigation of turf and the combination of this irrigation treatment and agronomic soil could decrease plant growth and conserve water and diminish moving cost compared to the current everyday irrigation schedule.

Alternaria black rot, caused by Alternaria citry is an important problem in commercial storage of citrus. It can also be a problem for the processing industry by contaminating the juice. Sweet orange is one of the sensitive citrus to Alternaria decay. In order to study the effect of chemical treatments and storage condition on postharvest life of Valencia orange, this experiment was conducted in factorial arrangement based on CRD with four replications. Fruits were harvested in mid January. After washing and inoculation with Alternaria citri spores, groped in two bulk and treated with Sodium Carbonate, Sodium Bicarbonate, Thiabendazole, Benomile, 2, 4-D at different concentrations for 5 minutes. Control treatment fruits at two levels included non washed and washed with tap water. After treatments, fruits were kept in polyethylene bags individually. One grope of the fruits were stored in ambient storage and others stored in cold storage at 6oC for 4 months. The results showed that the percentage of decayed fruits was different in treatments and storage conditions. In cold storage decayed fruits were smaller and fruits had better appearance. Among treatments, Sodium carbonate 1000 mg/l had significantly the highest effect on decreasing fruits decay. The large amount of decayed fruits was observed in Benomile 500 mg/l treatment. Generally, it was concluded that Sodium carbonate 1000 mg/l, Thiabendazole 1500 mg/J and 2, 4-D 150 and 200 mg/I and stored at 6oC were the best treatments to control Alternaria induced decay.

Barkhar and Meymeh Township with an area of 7372 Sqm between 50o and 34’ to 52o and 5’ of east length and 32o and 43’ to 33o and 45’ of north width is located in the North of Isfahan. The climate of this region is semi-desert viz hot and dry in summer and cold and dry in winter. Amount of precipitation had varied about 50-200 mm during ten years. This research was made to study the flora of Barkhar and Meymeh Township, and 504 plant species belonging to 56 families and 284 genera were recognized. The genus of Ephedra from Gymnosperms belonging to Ephedraceae family with 3 species was seen. The other available species in the region belonging to Angiosperms. Among the available families in the region were 49 families belonging to Dicotyledones Angiosperms and 6 families belonging to Monocotyledones Angiosperms. The Asteraceae family with 85 species and 43 genera was the largest and then, Fabaceae with 54 species and 14 genera, Chenopodiaceae with 46 species and 22 genera, Poaceae with 42 species and 31 genera and Brassicaceae with 40 species and 25 genera were the most important families. The genus of Astragalus with 31 species, was determined to be the most various genus in the region.

In order to compare of inheritance, combining ability and genes action in the genetic control of 1000-seed weight, harvest index, biological yield and seed yield of bread wheat cultivars, a study was conducted on eight cultivars using method 2 in fixed model of Griffing. Parents and crosses (36 treatments) were planted in randomized complete block design with three replications. Analysis of variance showed highly significant difference between treatments for all the traits. GCA and SCA mean of squares were highly significant for all the traits that designated importance of additive gene effects in inheritance of traits studied. The GCA/SCA ratio was significant for 1000-seed weight, harvest index and biological yield that reveal a greater portion of additive gene effects in genetic control of these. The GCA/SCA ratio is non-significant for seed yield that emphasizes the great importance of non-additive gene effects for this trait. In conclusion, genetic improvement of 100-seed weight, harvest index and biological yield is possible at early generations by selecting from the best crosses, while selection for seed yield is better that delayed until advanced generations and increase of it's heritability.

In order to study of wastewater and water ratio, fertilizer and manure effects on quantitative and qualitative parameters of wheat (Triticum aestivum), this experiment was done in Qaen (Aghilae Agriculture Honarestan) during the 2004 growing season. The experiment was done as Randomized completely block design with seven treatments and four replications. The treatments included 100, 75, 50 and 25 persent of wastewater and well water ratio, chemical fertilizer plus well water, manure plus well water and well water (check). The results showed that water, treatment had a significant effect on the number of kernels/spike number of tiller/plant and stem diameter at %1 probably level and on spikelet /spike and number of leaves /plant at %1 probably level. Application of 75 persent wastewater as a irrigation water, caused to increase grain and biological yield signicantly (with 7.2 and 4.45 ton/ha, respectively). Because this treatment had the highest spike/m2, kernels/spike, tillers/plant, length of spike and leaves/plant, which are the important components of yield. In addition, the application of 50 persent wastewater treatment had the highest seed protein with 15.5 persent as compare to other treatments. Inconcluded, the results of this study showed that 75% waste water is the best treatment for wheat.

During the period of growth and development, plants get involved in different kinds of environmental stress. One of the kind of these, is water stress, which is causes absorption problems for plant nutrition. But some kinds of useful terricolous fungi such as Mycorrhiza can effect on this process. The experiment was carried out to determine symbiotic effect of Mycorrhiza and also effect of this microorganism in water stress on absorption of elements in corn plant. This experiment was carried out in Factorial by using a Randomized Complete Block Design in three replications in Research and Educational Station of Islamic Azad University of Firouz Abad during 2004 growing season. Four irrigation treatmeats were designed at the different soil moisture points. These points were selected at 75, 55, 35 and 15 persent of plant available water. Each irrigation treatmant was splited into two paces of without mycorrhizae and application of mycorrhizae. The results showed that water stress can effect significantly on nitrogen and phosphorous absorption. But Mycorrhiza increased significantly the absorption of nitrogen and phosphorous, while it did not effect significantly on potassium absorption.

Aerobic composting is the decomposition of organic substances in the presence of oxygen. The aim of composting process is converting and stabilizing organic materials biologically and eliminating pathogen in order to use as a soil amendment. The composting of sewage sludge differs from composting any other materials because the feed substrate is mostly water. Because of the high moisture content, sludge cake generally lacks structural strength to maintain a property shaped windrow and the porosity necessary to assure aerobic conditions in the composting material. Amendments can also be made to increase the quality of degradable organics in the mixture. Amendments, used with dewatered sludge, include sawdust, straw, peat, rice hulls, manure, solid wastes, tree trimming and a variety of other waste organics. The ideal amendment would be dry, with a low bulk weight and be easily degradable. In the process of sludge composting, recycling compost can be used to as an amendment in order to decrease bulk weight. The composting recycling with amendment has been used in some cases. A major adaptation that has allowed the windrow system to be applied to wet organic substances is the concept of recycling dry compost to blend with wet feed. The quality of recycled material is adjusted to obtain mixture moisture content of 60 percent. In this study, composting of dewatered sewage sludge with sawdust as bulking agents has been studied and in the next period using composting recycling as bulking agents evaluated. Aerobic compost of sewage sludge as windrow was investigated. The results indicated that composting of dewatered sewage sludge with saw dust and compo sting recycling, as bulking agents is capable.

This study was conducted to evaluate the effects of different levels of canola meal and calcium on the performance of broiler chickens. Canola meal was substituted by 0, 25 and 50 % of soybean meal protein. Calcium was used as 100, 110 and 125% of NRC recommendation. Two hundred and fifty-five broiler chicks (Ross 308) were fed isoenergetic and isoprotein diets in a completely random design with 7 treatments and 3 replicates in a 6 weeks period (from 7 to 49 d). The feed intake, weight gain, feed conversion ratio in different periods, carcass components, tibia ash and calcium, blood serum calcium at 49 d and calcium digestibility at 35 d were measured. The feed intake was not affected by different levels of canola meal and calcium during different stages of growth and the whole experiment. Addition of canola meal and calcium resulted in significant differences in weight gain and feed conversion ratio in the starter (P<0.05), but no statistically significant differences were observed in the grower and finisher. The levels of canola meal and calcium had a significant effect on carcass yield and liver weight (P<0.05), however no significant difference on abdominal fat was determined. With the change in levels of canola meal and calcium and their effects, tibia ash differences were significant (P<0.05), but no significant effects were observed on tibia ash calcium, blood serum calcium and calcium digestibility. The results of this study showed that the best level of substitution was obtained by 50% canola meal and 100% calcium in diet.