IRANIAN JOURNAL OF AGRICULTURAL SCIENCES (JOURNAL OF AGRICULTURE)
Year:2007 | Volume:38 | Issue:2|Papers Count:24

Peach potato aphid, Myzus persicae (Sulzer) is an important agricultural pest throughout the world. Due to extensive and repeated application of insecticides, this aphid has developed different resistance mechanisms. Resistance mechanisms to pirimicarb and oxy- demeton methyl were surveyed. Insecticide bioassay was carried out on seven populations, collected from north provinces, as well as Karaj, using topical application method. The results of bioassay indicated that Talesh, Tirtash, Plangar and Karaj populations are susceptible to pirimicarb and oxy- demeton methyl. The results of inhibition assay showed that I50 of pirimicarb for Karaj, Rasht and Resistant populations are 1.365×10-8M, 1.366×10-8M and 1.89×10-5 M, respectively. Also I50 of oxy-demeton methyl for Karaj, Rasht and Resistant populations are 7.566×10-7M, 8.236 ×10-7M and 2.11×10-6M, respectively. The insensitivity ratios of acetyl cholinesterase from resistant population to pirimicarb and oxy-demeton methyl were 1384.6 and 2.7 respectively. The results suggested that acetycholinesterase of resistant population is insensitive to pirimicarb and oxy- demeton methyl.

Potassium is one of the most essential macro elements from the viewpoint of uptake rate, as well as physiological and biochemical processes in plant rice. This experiment was carried out to evaluate the relative K extractability of 16 chemical extractants for selection of the best extractor or extractors. A determination of the critical K level in Khazar cultivar in 21 paddy fields of the Guilan province was also investigated. Fields selected were of a wide range of clay content, cation exchangeable capacity, organic matter and ammonium acetate extractable K. The treatments included 6 K levels (0, 100, 200, 300, 400 and 500 kg/ha as K2O) supplied from KCl (1/2 at transplanting, 1/2 max. tillering) in a randomized complete block design with three replications. Results indicated at that K application increased grain and straw yield, as well as K uptake in straw. Mean maximum and minimum K extracted, were through 1N HNO3 (239mgkg-1) and 0.05 M HCl (11mgkg-1) extraction respectively. High correlations were observed among 1M, 0.5 M and 0.25 M NH4OAc and 1 N HNO3 extractants with relative grain yield of: 0.80**, 0.79**, 0.81** and 0.87** respectively, and K uptake by straw of: 0.73**, 0.73**, 0.75** and 0.81** respectively. Moreover, high correlations were observed among water, Morgan, and Kelovana extractants with K concentration in straw of: 0.75**, 0.72**, and 0.71** respectively. The critical K concentrations were evaluated for extractants that had the highest correlation with plant yield. The critical K concentration based on 90 percentage of relative yield by 1M NH4OAc, 0.5 M NH4OAc and 0.25 M NH4OAc was 120mg kg-1 and for 1N HNO3 was 210 mg kg-1.

During the years 1997-1998, thirty-one Agrobacterium isolates were obtained from gall and sap of infected grapes as well as from soil in vineyards of Fars and Kohkilouyeh and Boyerahmad province. Two pathogenic and one non- pathogenic isolates of Agrobacterium tumefaciens Biovar1 were selected and their cell protein patterns compared through gel electrophoresis. A pathogenic and one non- pathogenic isolate of A. vitis and A. tumefaciens Biovar1 were selected from which antisera were prepared. Serological studies based on agar gel diffusion placed bacterial isolates in 4 serogroups while slid agglutination test placed the isolates in 6 sergroups. A comparison of cell proteins pattern showed that A. vitis and A. tumefaciens Biovar1 isolates were heterogenous, even though similar protein bands existed among the isolates.

In order to study the effects of two kinds of clinoptilolites (calcic and potassic) on ruminal parameters, four fistulated mature male sheep were used in a changeover design as balanced latin squre. The formulated diets included: 1) Control, 2) Control + 4% calcic clinoptilolite, 3) control + 4% potassic clinoptilolite and 4) control + 2% calcic and 2% potassic clinoptilolite. The experiment was comprised of four periods. Each period included adaptation (two weeks) and sampling (one week). Sampling was made from ruminal fluid for measurement of pH, ammonia nitrogen, total volatile fatty acids (tVFAs), ruminal total and cellulolytic bacterial population as well as from ruminal fungi population at 0, 3, 6 and 10 hours after morning feeding. The results showed that calcic clinoptilolite increased pH, tVFAs and ruminal cellulolytic bacterial population significantly (P<0.05).

Density is one of the important and widely used quality indices for agricultural products. Differences in density have been utilized for inspection of quality, structure, stiffness, maturity and seed viability. Density is calculated through measurement of mass and volume of an object. Mass can be measured precisely and quickly with the use of a digital scale. Volume measurement, however, is not so easy. There are two typical methods for measuring volume: the gas displacement method and the liquid displacement method. The liquid displacement method is simple and easy, but agricultural products or foodstuff, especially dairy products, may be damaged by immersion into liquid. The gas displacement method of measuring density does not affect food seriously. However, it requires quite a long time for measurement. A volume measurement system for foodstuffs through a Helmholtz resonator has been used to eliminate the above-mentioned problems. It had already been reported that this volume measuring system performed well (r2=0.97) while measuring volumes of water, clay, beans, apple and grapes. However, variations of resonance frequency as a function of volume are too small (0.1 Hz/cc) and need special analysis methods as well as expensive hardware. Therefore, in this research, one of the standing waves of a special Helmholtz resonator is used for estimation of walnut volume. This standing wave produced a wide range of variations for resonance frequency in response to walnut volume change (about 22Hz/cc). In this case one can employ the well-known Fast Furrier Transform (FFT) method together with inexpensive hardware for analyzing signals. Uncertainty of volume measurement by this method for spherical objects was ±0.47cc. Volumes of individual walnuts were measured non-destructively and with more precision than in the liquid displacement method. Correlation between the two methods was high (r2=0.98). This method and the instrumentation may easily be calibrated and used for other agricultural and food products where the water displacement method is not applicable.

To assess the effect of starting time of feeding milk replaced (MR), thirty-two newborn Holstein calves (initial weight 43±0.7 kg) were used. The animals were divided into four groups (n=8) in which the control group (g1) was fed cow milk. The other groups were offered MR either on 5 (g2), 13 (g3) or 20 days (g4) after birth. The whole trial lased for two months. The average daily gain (ADG), starter intake (SI) and water intake (WI) were measured fortnightly. Fecal scores (FS) were determined daily throughout the trail. The data were statistically analyzed using completely randomized design. At the end of the trail, there was no significant difference observed in the performance of calves in any of the groups. However, animals in g3 had the highest ADG, SI and WI among those fed MR.

Maternal effects on growth traits of 3872 lambs born from 182 rams and to 2274 ewes during 1994 - 2002 in Moghani Sheep Breeding Station were investigated using maternal model and restricted maximum likelihood procedures. Traits were birth weight (BWT), and body weights at 3 (BWT3M), 6 (BWT6M), 9 (BWT9M) and 12 (BWT12M) months of age. With or without taking into effect. The maternal effects, six different animal models were fitted and likelihood ratio test applied to determine the most appropriate model. For BWT, direct additive genetic, maternal additive genetic and maternal permanent environmental effects without a fitting of covariance between direct and maternal additive genetic effects were important. For this trait, estimates of direct heritability (h2a ), maternal heritability (h2m) and maternal permanent environmental variance as a proportion of the phenotypic variance ( pe2) were 0.172 ±0.022, 0.058±0.045 and 0.131±0.038, respectively. For BWT3M and BWT6M, the important sources of variations were direct as well as maternal additive genetic effects. Estimates of h2a and h2m were 0.044±0.037 and 0.075 for BWT3M, and 0.083±0.024 & 0.075±0.040 for BWT6M. None of the maternal effects influenced BWT9M and BWT12M. For these traits, h2a figures were 0.376±0.037 and 0.227±0.059, respectively. Direct additive genetic correlations varied from 0.209 (between BWT and BWT6M) to 0.604 (between BWT and BWT3M). These estimates for maternal additive genetic correlations ranged from 0.574 (between BWT and BWT6M) to 1.000 (between BWT3M and BWT6M). The corresponding estimates for phenotypic correlations varied from 0.168 (between BWT and BWT12M) to 0.843 (between BWT6M and BWT9M).

Most apple cultivars are fruitless on their own, and only if they are pollinated by another compatible cultivar, sufficient fruit set and a suitable crop will result. This experiment was conducted to select the most proper pollinizer for two commercial Iranian apple cultivars of Golab-kohanz and Shafee-abady, favorite because of their special taste and aroma. The effects of five pollinizers, Golab -sahneh, Golab-kohanz, Shafee-abady, Nayon-arangeh, Khorsijan and also open pollination on quantitative and qualitative characteristics of Golab-kohanz and Shafee-abady apple cultivars were studied. The results showed that pollinizers significantly affected the percentage of fruit set, fruit weight and total sugar content in Golab-kohanz c.v. The highest percentages of fruit set; fruit weight and total sugar content were obtained from pollination by Shafee- abady. Pollen sources had significant effect on the percentage of fruit set, fruit weight, diameter, shape, seed number and total sugar content in Shafee-abady c.v. Golab-kohanz as a pollinizer resulted in the highest percentage of fruit set, fruit weight, diameter and sugar content. Fruits, produced by open pollination, carried the highest number of seeds. Golab-kohanz and Shafee-abady were self-incompatible and had a poor fruit set following self-pollination. According to the results Shafee-abady and Nayon-arangeh cvs. are the best pollinizers for Golab-kohanz, while Golab-kohanz and Golab-sahneh are found to be the most appropriate pollinizers for Shafee-abady.

Field study was conducted to evaluate plant density as well as planting time on the vegetative and reproductive traits of Tareh Irani. The experiment was a factorial one designed in the framework completely randomized blocks of three replications at the research farm of Agricultural Faculty of Tehran University in 2003. Plant density consisted of 7 levels (133, 200, 266, 400, 533, 800 and 1600 plant per experiment unit), while planting time of two levels (5 April and 5 September). Results indicated that yield of biomass decreases with increasing plant density, the density of 1600 plants per m2 yielding the lowest. Maximum seed production, seed biomass, and biomass yields were obtained from the densities of 133 and 200 plants per m2. Although crop yield was high in high-density treatments but it did not show any significance with others. Spring cultivated plants produced more flowering stalks and seeds. The weight of a thousand seeds and the amounts of Ca, Mg, K, P, Na, protein, lipid, TSS, and vitamin C were not affected by planting density.

Spinach (Spinacia oleraceae L.), an annual plant of the chenopodiaceous family, has been grown in Iran for about two thousand years. There are many various landraces of this plant in Iran, but no research has so far been carried out for identification and evaluation of these landraces. For an evaluation of genetic diversity of Iranian spinach landraces, 29 genotypes were collected from different regions of Iran, their quantity and quality traits being evaluated. Results indicated that there are highly significant differences among most of the studied landrace characteristics at 5 and 1% levels. The plants produced different ranges of leaf number before flowering. In landraces evaluated, the plants produced 12-23 leaves before flowering. Also according to the time of flowering, they were classified as: early, moderate and late flowering. Results indicated that the time of flowering varied from 135 to 180 days after planting and before they entered the reproductive phase. Among landraces the percentage of female plants varied from 39.00 to 68.33. The mean yield in the studied landraces was 715.8 to 2707.3 gm-2. According to cluster analysis, landraces were classified into 4 clusters with 7, 9, 7, and 6 landraces, respectively. Evaluation of poloidy levels of landraces indicated that all were diploid (2n= 12). The results of this research showed that native landraces of Iranian spinach are of high variations, and can be used as valuable genetic resources for breeding programs.

In this research it is intended to select suitable explants and to determine the most suitable treatment for surface sterilization as well as hormonal composition in the production of sugarcane callus, using Murashige and Skoog medium (MS). To supply primary leaf primordial and shoot tips, stem tips (5 cm long) of sugarcane cultivar N. CO.310 were selected. The experiment was carried out in a completely randomized design with three replications (each replicate consisting of ten treatments). The fresh weight of callus was used as an index, and the means of treatments were compared while using Duncan multiple range test. The research indicated that production of desired callus, from leaf primordial, was not possible either in the presence of 2, 4-D in combination with Naphthalene acetic acid (NAA) or Benzyl amino-purine (BAP) growth regulators. However, it had a meaningful effect on callus weight increase in the presence of NAA in 1 mg/L (P£1%). Formed calli in NAA medium demonstrated primary signs of organogenesis, although, in the first subculture, formed calli in NAA media did not illustrate a meaningful increase in the weight of calli, as compared with the first five weeks. Most of the calli-produced root likes organs. In another experiment effect of different concentrations of 0, 0.5 and 1.0 mg/L of NAA and IBA in callus production were compared. Statistical analysis illustrates that there are significant differences among effects of IBA and NAA. Also, the different concentrations of IBA exhibited significant differences on callus formation (P£1%). At the end of the fifth week, fresh weigh of callus significantly increased (more than in the other treatments) in one milligram per liter concentration of IBA. The results indicate that in terms of color and structure, no significant differences exist among calli produced from leaf primordial and shoot tips.

Chelcheragh lily is a wild attractive species that grows naturally in Damash area in Ammarloo region, Guilan province, Iran. Asiatic hybrids, as commercial lilies, have been resulted from different Asian species. For establishment and mass production of disease free bulblets during a short period of time, experiments were conducted in a factorial arrangement of explant sites (scale base and apex), combination of BA and NAA, each at three levels (0, 0.01, 0.1 mg/l) in a completely randomized design with three replications. Hypoclorite, ethanol and hot water treatments were employed for disinfection. To decontaminate explants 53oC and 55oC hot water was employed for Chelcheragh and Asiatic hybrid respectively. The highest numbers of bulblets as well as the highest weight of bulblets were obtained from Chelcheragh lily while the Asiatic hybrid explants produced a lot of roots. Chelcheragh lily produced the highest number of bulblets on MS basel medium with no growth regulators and MS supplemented with 0.01 mg/l NAA. The highest weights of bulblets were obtained on medium supplemented with 0.01 mg/l NAA. Asiatic hybrid showed the highest number and weight of bulblets on MS supplemented with 0.1 mg/l NAA and 0.1 mg/l BA. Both lilies emerged with the highest number of roots on MS medium containing 0.1 mg/l NAA. Effects of bulblet sites were not significant on number of bulblets, but the highest weight of bulblets and a large number of roots were obtained from base segments of scales. Developmental patterns of lilies were not similar. The explants of Chelcheragh produced large bulblets without any leaves whereas; Asiatic hybrid emerged with leafy scales.

Growth inhibitor Paclobutrazol (PBZ) is a triazol, reported to be of the potential to protect plants against several environmental stresses. This study was conducted to evaluate the alleviatory role of paclobutrazol under water stress conditions. Treatments were drought stress (100% and 40% of potential evapotranspiration) and through soil application PBZ (0, 0.25 and 0.75 gr a.i. pot-1) Three years old olive cultivars `Bladi’ and `Mission’ grown in 16 liter polyethylene pots in clay loam soil were employed. A factorial experimental design, based on randomized complete block design (RCBD) of four replications was applied. Measured growth parameters of root, shoot and leaf fresh & dry weight as well as height were found out to be reduced under water stress. Paclobutrazol reduced shoot and leaf fresh & dry weight but did not have any significant effect on root fresh & dry weight. This effect could be an important mechanism to assist plants to increase root to shoot ratio. The number of stomata per mm2 of leaf area was increased in water stress treatments’ but application did PBZ not have any significant effect. Although water stress caused a reduction in leaf relative water content but Paclobutrazol, in either cultivar, increased relative leaf water content. Both Paclobutrazol application and water stress increased temperature in either side of the leaves. Also, results indicated that both water stress and PBZ application increased proline content of the leaves.

Fertility status and distribution of mating type alleles of M. grisea were studied in some rice growing areas of Mazandaran. One hundred and seventy monoconidial isolates were isolated from different cultivars of rice in various areas. Fertility status and mating type of each isolate were determined through pairing with hermaphroditic standard isolates of mat1-1 and mat1-2 on rice flour agar (RFA). Cultures were incubated for10-25 days at 21oC under continuous illumination. Globose perithecia of long neck were formed at the contact line of two about 10-25 days after incubation in these conditions. Of the 170 isolates, 131 (about 79%) were fertile, all male-fertile, carrying just mat1-1 allele. About 21% of the isolates were sterile and did not produce visible perithecia in pairing with all the standard isolates. No examined isolate carried mat1-2 allele. With regard to that only, one mating type allele was found in the rice growing areas of Mazandaran, all the isolates being male-fertile, formation of the perfect state among rice isolates seeming to be impossible or very rare.

This study investigates the effects of manure and biofertilizer (Rhizobium inoculant) on lentil yield in dryland areas of Qazvin province, Iran. Simulated erosion plots established from three years before were employed in the experiment. The soil surface removal treatments consisted of blank, 5, 10, 15, and 20cm of surface soil removal (E0, E5, E10, E15, and E20 respectively). At the selected site a split-factorial plot was designed. Manure fertilizer treatments were 0, 10, and 20 Mg/ha at watered site and 0, 5, and 10 Mg/ha at dryland site. Each treatment was conducted with and without Rizobia inoculant. The lentil crop (Lens Culinaris) was planted in Mar. 2004. Precipitation was 116 mm for plant growth period and 390 mm for total year (Sep.23, 2003 - Sep.22, 2004). This experiment was performed at two similar sites, adjacent together, one as watered and the other as dry farming site .At watered site, for avoiding the drought conditions of the area, three supplementary irrigations were applied during the growth season, each 13 mm. The crops were harvested in July, plant number per square meter being counted. After drying, grain, dry matter and chaff weight, as well as thousand-grain weight were determined. Data were analyzed using SAS and Excel software. The results did not show any significant effect for simulated erosion. Manure fertilizer increased the dry matter and grain content somewhat at 10 Mgha-1 of manure while decreasing them slightly at 20 Mg ha-1 in the watered site, but these results were not significant as compared to control.

Scarlet mite, Brevipalpus obovatus is one of the important and cosmopolitan species of pests, active on many crops, fruit and ornamental plants. This mite was recorded for the first time on tea in 1961 from northern regions of Iran and recently reported from other parts of the country. The mite is able to make damage to all varieties of tea. In this research, biology of B. obovatus was studied under laboratory conditions at three different temperatures of: 20.5±2 oC, 25.5±2 oC, 29.5±1 oC; 80±5% RH, and 12 hrs of photoperiodism in incubator, and with leaf disc method. The effect of temperature on different growth period of mite including: larval period, nymphochrysalis, protonymph, deutochrysalis, deutonymph, teliochrysalis, preovipsition period, oviposition, end of oviposition, egg number as well as death time was studied. Average number of eggs deposited by the female was directly correlated with longevity of mites. Maximum number of eggs was 82 and the longest life span 107.5 days at 20.5±2 oC. The average life cycle of one generation (egg to egg) at 20.5±2 oC, 25.5±2 oC and 29.5±1 oC was completed within 39.8, 28.9 and 24.2 days, respectively.

A greenhouse experiment was conducted to study the effects of Zn-fertilizer on soybean yield and to determine its critical level in some selected soils of Mazandaran province. The soils were collected from 20 sites of eastern portions of Mazandaran province. They contained a wide range of CaCO3 (5-34%) and DTPA extractable Zn of 0.52 to 2.9 mg/kg of soil. In a randomized complete block design of three replications, 0 and 20 mg/kg of Zn as zinc sulphate were applied to l0 kg of soil in each pot. Pershing variety of soybean was planted at the rate of 7 seeds/ pot and then thinned but to 3 plants after l0 days .The growth period was duration of 8 weeks. The aerial parts of plants were harvested at the end of the growth period, while the dry matter, nutrient concentration and uptakes were taken as plant responses. Plant samples were analyzed for Zn. The results indicated that zinc sulphate application significantly increased the dry matter (from 16.6 to 19.7 g/pot). Zinc application also increased leaf Zn content and Zn uptake by 69.9 and l04 percent, respectively. Based on these pot experiments, zinc critical levels in these soils were 1.30 and 1.10 mg/kg applying Mitcherlich Bray and Cate Nelson methods respectively, and for obtaining 85% relative yields. A comparison between the values obtained shows that both methods provide similar results.

Data collected of 1722 lambs born from 1992 to 1999 in the one herd of Kurdish sheep in Bijar were used for estimation of genetic progress, phenotypic, genetic and environmental trends. Mixed model methodology based on a univariate and multivariate animal model was used for prediction of breeding value. Genetic, phenotypic and environmental trends were estimated by regressing means of breeding value, phenotypic value and differences between these values on year of birth, respectively. Total genetic progress after 8 years for birth weight (BW), weaning weight (WW) and 6-month weight (6MW) were 230, 970 and 882 gr, per year, respectively. Genetic trends for BW, WW and 6MW were 18±9, 128±55 and 129±71 gr per year, respectively. Also the phenotypic trends for BW, WW and 6W were 37±39, 380±431 and 173±308 gr per year, respectively. The environmental trends estimates for respective weights were 55±45, 252±308 and 301±359 gr per year, respectively.

An experiment was conducted to evaluate the effects of different levels of pigment in diets, containing three sources of fat, with or without enzyme, on egg yolk color and laying hens performance. All the diets were isocaloric and isonitrogenous. This experiment was arranged in a completely randomized design (CRD) with a 3×2×3 factorial arrangement. The experiment consisted of 18 treatments with three replicates containing 6 Hy-line W36 laying hens from 23 to 31 weeks of age. The treatments consisted of three basic diets containing sunflower oil, tallow and fatty acids with or without enzyme and three levels of pigments (0, 1100 ppm red with 125 ppm yellow pigment, 1500 ppm red with 225 ppm yellow pigment). The different traits were evaluated daily or periodically. The main effect of pigment levels, enzyme and sources of fat as well as their interaction on egg production, egg weight and feed conversion were not significant. Main effect of pigment, sources of fat and enzyme for these traits were not significant either (P<0.05). The main effect of pigment level, enzyme and sources of fat as well as their interaction on blood cholesterol were not significant (P<0.05), but the differences between averages of three sources of fat were significant (P<0.05), but the main effect of fat on yolk cholesterol was significant (P<0.05), while the main effect of fat on yolk color was significant (P<0.05).

The experiments were conducted in two parts under laboratory and field conditions. Laboratory tests were performed in 5 treatments under choice and non-choice feeding conditions. In the single feed experiments M. socialis consumed on an average 4.7±0.36 g/animal Baraki-pellet, 4.5±0.4 g/animal Lanirat and 4.2±0.3 g/ animal Baraki-wax block. Food preference was determined as 45.39%, 21.58%, 19.44% and 13.57% for carrot, Baraki-pellet, Lanirat and Baraki-wax block respectively. Toxicity symptoms like nose and anal bleeding were observed from the 4th day and 100% mortality was observed from the 6th day up to the 10th day of the experiment. In the second part, the experiments in the field were performed using completely randomized block design in four replicates with three experimental blocks and one control, each about 1000 m 2. Five g/complex burrow of Baraki with pellet and wax block formulations and Lanirat with granular formulation were used in the three experimental blocks respectively, the fourth block being kept as control without any rodenticide use. Percent efficacy was estimated using Henderson and Tilton (1955) formula. Ninety one, 82 and 64% efficacies were observed for the above-mentioned formulations respectively.