Showing 495 results for Ni
Mohammad Reza Ebadi, Javad Pour Reza, Mohammad Khorvash, Kambiz Nazer Adl, Abbas Almodares,
Volume 1, Issue 2 (10-1997)
Abstract
Sorghum grain is an important cereal to be cultivated in tropical and sub-tropical areas. The extension of its cultivation and application in animal and poultry diets may reduce the need for imported corn. In order to determine the nutritive value of sorghum, 36 sorghum grain (SG) varieties and one type of corn were grown at the same location. The grains were analyzed for their nutrient composition. Results from of proximate analyses showed that the ash, crude protein (CP), phosphorous (P) and acid detergent fiber (ADF) contents of SG were 1.72±0.54, 11.6±1.18, 0.34±0.03 and 8.35±3.93, respectively. The ether extract (EE) of SG was lower than Iranian and imported corns. Iranian corn had higher amounts of CP (10.7%), EE (5.9%) and CF (3.3%) than the imported one (7.8, 4.2 and 2.25). Tannin contents of low and high SG varieties were 0.021% and 0.998%, respectively. The apparent and true metabolizable energies (AME and TME) of SG were decreased due to increasing the tannin contents. The values of TMEn (3853, 3771 and 3213 Kcal/kg) showed significant differences (p < 0.05) among low, medium and high tannin sorghum (LTS, MTS and HTS) varieties. However, in comparison with the SG, the corn had higher amounts of TME (3853, 3771 and 3213 VS. 3947 Kcal/kg). LTS had the highest AME (3453 Kcal/kg) among all the grains, while there were no significant differences (P > 0.05) between MTS (3458 Kcal/kg) and the two corn grains (3406 Kcal/kg).
Mahmoud Kalbassi, Akbar Gandomkar,
Volume 1, Issue 2 (10-1997)
Abstract
The moisture content of urban solid wastes in Iran is very high. A large volume of leachate is, therefore, produced in the process of converting these wastes into compost. The leachate contains relatively large amounts of organic matter, plant nutrients, soluble salts as well as small amounts of some heavy metals. The effects of urban solid waste leachate on growth and yield of corn and heavy metals and nutrients concentrations in plant as well as the effects of leachate residual on soil were studied in a field trial conducted in two sites (Zeinal and Lavark) in central Iran (Isfahan). The treatments included applications of 0, 400, and 800 metric tons of leachate/ha as the main plots and two leaching treatments (0 and 15 cm leaching) as the sub-plots in a split plot design. Application of the leachate decreased crust formation and greatly improved germination and growth of corn in both sites. Biological yield of corn increased from 2.4 to 4.1 and 5.3 tons/ha in Zeinal field and from 8.1 to 13.4 and 15.0 tons/ha in Lavark field for 400 and 800 tons/ha of leachate applications (as compared to the control field), respectively. Leaching increased corn yield only in Zeinal field. Uptakes of N, P, K, Fe, Mn, Zn and Cu by corn increased as a result of leachate application. Concentrations of Fe, Mn, Zn, Cu, and Cl in plant tissues also increased but no toxic symptoms were observed in plants. Concentrations of Pb, Cd, Cr, Co, and Ni in aerial tissues of corn did not increase as a result of leachate application. The residual effects of leachate application on soil were a decrease in pH and corresponding increases in organic matter content, in electrical conductivity and in available amounts of N, P, K, Fe, Mn, Zn, and Cu. It is concluded that garbage leachate has the potential to be used as an organic liquid fertilizer and soil amendment to improve soil productivity.
Rahim Honarnejad, Alireza Tarang, Abdolhossain Sheykh Hossainian,
Volume 2, Issue 2 (7-1998)
Abstract
Seven Iranian and foreign cultivars of rice were crossed in a half-diallel. Parents with F2-generations were transplanted in a randomized complete blocks design with 3 replications and evaluated for length to breath ratio of paddy and brown rice, head rice and crust, grain yield, percent of head rice and broken rice, amylose content, gelatinization temperature and gel consistency. The ANOVA table showed significant differences among genotypes, general combining ability effects for all traits and specific combining ability effects for length to breath ratio of paddy and brown rice, percent of head rice and broken rice, so representing additive and non-additive effects in genetic control of the traits involved, respectively. The graphical analysis of the results showed partial dominance for length to breath ratio of paddy and brown rice, grain yield, amylose content, gelatinization temperature and gel consistency. Because of additive gene effects, genetic advance from selection would be high for these traits. The genetic control of brown rice weight is complete dominance, and for weight of head rice and rice crust weight over dominance involved. So, genetic advance by selection for these traits would be poor. In the genetic control of higher length to breath ratio of paddy and brown rice, brown and head rice weight, grain yield and amylose content recessive genes are involved. Domsiah for higher to breath ratio of paddy and brown rice and Sepidrud for brown and head rice weight had the most recessive genes. IR28 for higher grain yield and Sepidrud for less crust weight had the most recessive genes.
Masoud Ezzat-Ahmadi, Hamdollah Kazemi, Mohammad Reza Shakiba, Mostafa Valizadeh,
Volume 2, Issue 2 (7-1998)
Abstract
Effect of different times and levels of nitrogen fertilizer application on growth and grain yield of spring wheat cultivar “Ghods” was studied during 1993-1994 growing season at Karkadj, Agricultural Experiment Station, College of Agriculture, University of Tabriz, using a split plot design with three replications. Main plots were assigned to five levels of N fertilizers (0, 40, 80, 120 and 160 kg/ha) and subplots to five times of applications [all of N fertilizer at planting (T0) 1/2 at planting + 1/2 during tillering stage (T1), 1/2 at planting + 1/2 during heading stage (T2), 1/3 at planting + 1/3 during tillering and 1/3 at heading stages (T3) and 1/4 at planting + 1/4 at tillering + 1/4 at stem elongation and 1/4 at heading (T4)]. Results showed that different levels of N applications affected grain yield and biological yield significantly, while the effect of split application and also N levels × times of application interaction on these two traits were non-significant. Growth stages of wheat were not significantly affected by different N Levels and times of application. Dry matter accumulation, leaf area index, and crop growth rate, in response to growing degree days during growing season, increased when higher levels of N fertilizer were applied. Leaf area index and crop growth rate initially increased up to anthesis and then decreased. Crop growth rate decreased to zero level at soft dough stage and then became negative. Variations in relative growth rate and net assimilation rate, in relation to growing degree days, decreased when different levels of N fertilizer were applied at early part of growing season it was maximum while at later growth stages decreased and finally became negative, Times of N application and level × time interaction during growing season did not affect the growth indices significantly.
Sayed Farhad Mousavi, Mohammad Nekoei-Meher, Mohammad Mahdavi,
Volume 2, Issue 2 (7-1998)
Abstract
As unit hydrograph is an important item in flood estimation of the rivers and since flood hydrograph and simultaneous rainfall hyetograph is needed to derive a unit hydrograph, hydrologists recommend synthetic unit hydrographs for areas lacking these hydrometeorological data. A research was conducted in the Zayandehrud-dam watershed (Pelasjan sub-basin) to test the efficiency of synthetic unit hydrographs (Snyder, SCS, and Triangular methods) in hydrological evaluations. For the purposes of this study, natural and synthetic unit hydrographs were determined and compared, using all morphologic, hydrometric and rainfall data. The results showed that Triangular and SCS methods fit natural unit hydrographs better than Snyder method does, but peak instantaneous flow is estimated to be higher than the observed flow. So, the constant 2.083 in peak flow equation is recommended to be changed to 1.74 in this watershed. The Snyder method predicts good peak flows, compared with the other two methods. Generally, it is concluded that Triangular, SCS, and Snyder methods are ranked 1 to 3 for determination of synthetic unit hydrographs in this watershed.
Abolfazl Faraji, Aghafakhr Mirlohi,
Volume 2, Issue 3 (10-1998)
Abstract
In order to study the effects of rate and time of nitrogen application on vegetative characters, i.e., yield and yield components of rice (Zayandeh-rood variety), an experiment was conducted at Isfahan University of Technology research farm during summer 1996. Four N rates including (60, 90, 120 and 150 KgN/ha) and four splitting form (1- all N applied before transplanting 2- 1/3 N applied before transplanting, 1/3 at the beginning of tillering and 1/3 at the emergence of first panicle in 50% hills 3- 1/2 at the beginning of tillering and 1/2 at the emergence of first panicle in 50% hills 4- 1/3 at the beginning of tillering and 2/3 at the emergence of first panicle in 50% hills) were evaluated in a factorial experiment which was arranged in a randomized complete block design with 3 replications. Plant height, number of tillers per unit area and days to heading and maturity increased with an increase in the rate of fertilizer application. Grain yield and number of panicles per square meter increased when the N rate was raised to 120 Kg N/ha, while application of 150 Kg N/ha resulted in the reduction of grain yield and number of panicles. Nitrogen rate increases did not have any significant effect on number of grains per panicle. The grain weight did not follow any particular trend at different application rates, but harvest index and percentage of filled grains were decreased as the N rate increased. The percentage of nitrogen content of plant was increased as a result of higher N - rate at heading and harvest times. Treatments containing base application of nitrogen resulted in an increase in plant height, number of tillers, plant dry matter, grain yield and number of panicles per square meter, although it caused a reduction in harvest index. The number of grains per panicle and grain weight did not follow any particular trend under the influence of time of application, although plant nitrogen content increased with a delay in time of fertilizer application.
Reza Jamshidian, Mohammad Reza Khajehpour,
Volume 2, Issue 3 (10-1998)
Abstract
Methods of seedbed preparation affect establishment, growth and yield of crops via manipulating physical and chemical properties of soil. These effects on wheat-mungbean double-cropping have not been studied in Isfahan. Therefore, the influences of various seedbed preparation methods on soil physical properties and nutrients content and on establishment of mungbean (experimental line 1-61-16) were studied in a wheat-mungbean double-cropping system during 1996 at the Agricultural Research Station, Isfahan University of Technology. Two residue management treatments (burned and unburned) along with four tillage systems (moldboard plow, disk, khishchee and no-till) were laid out in a strip plot design within a randomized complete block design with four replications. Bulk density and penetrability of soil at various depths were not affected by residue management at emergence. However, at the time of flowering, bulk density at 0-15 cm soil depth was lower and soil penetrability at 3-15 cm depth was higher in unburned treatment due to mineralization. Rate and coefficient of emergence of seeds were lower in unburned residue treatment. Soil bulk density at 0-30 cm depths was lower and penetrability at 3-21 cm depth was higher with moldboard plowing at both emergence and flowering time. In addition, lower soil N, P and K content at 0-15 cm depth at emergence and flowering time was obtained with moldboard plowing. Rate and coefficient of emergence were strongly lower in no-till treatment. Based on these results and considering sustainable agricultural goals, incorporating residue with disk tillage might be advantageous under conditions similar to this experiment.
Ali Ashraf Amiri Nejad, Majid Bagher Nejad,
Volume 2, Issue 4 (1-1999)
Abstract
The calcification of soils and the effects of topography on this process were studied in semi-arid regions of Kermanshah. From a toposequence, based on the previous soil surveys of the region, five profiles were selected, and field studies and laboratory analyses were carried out on soils. Alluvial - colluvial fans, piedmont alluvial plains, and old plateaux were three main physiographies on the selected toposequence. Soil moisture and temperature regimes were Xeric and Thermic, respectively. The results indicate that redistribution of carbonates and soil formation processes may be categorized in four specific stages to be described in the text. Accumulation of calcium carbonates in soil profiles showed two basic forms: one in sandy layers of fine - textured soil profiles under the influence of abrupt textural changes and lower permeability, and the second in subsurface horizons of soils with calcareous parent material. The morphological evidences showed that in addition to translocation from upper horizons of carbonates by solution and suspension, physical movements to subsurface layers of fine calcareous materials have also affected the formation of calcic horizons. In other words, CaCO3 may have moved as fine particles through soil cracks and subsequently accumulated in the lower horizons. Soil mineralogy showed considerable amounts of illite, Chlorite, smectite and palygorskite clay minerals. Some pedogenic transformations of illite and chlorite may have caused formation of smectite and palygorskite.
Jahangard Mohammadi,
Volume 2, Issue 4 (1-1999)
Abstract
This study addresses the methodology of studying spatial variability of soil salinity. The information used is based on a semi-detailed soil survey, followed by a free survey, conducted in Ramhormoz, Khuzestan. The study of soil salinity variations was carried out using about 600 sampling points with an average distance of 500 m, at three depths of 0-50, 50-100, and 100-150 cm. To determine the spatial variability of soil salinity at different depths, the variogram which is a statistical function for the spatial variability analysis of the geographical variables was used. The results indicate that all variograms show almost the same range of 12 - 13 km which is closely related to the geographical distribution of the soil parent materials in the area. Ordinary block kriging was used to map salinity at different depths for a block dimension of 500 × 500 m. A comparison between the kriged estimates and the soil salinity map, produced during the soil survey, showed that the overall similarity between the test data and the classified kriging estimates was 40%, while the overall agreement between the test data and the soil survey salinity map was 36%. A detailed similarity calculation showed that the reliability of the classified kriging estimates representing the lowest salinity classes (S0, S1) is larger (75%) than the reliability of the soil survey salinity map representing these classes (50%). Consequently, the results indicate that geostatistical tools can be used to support the present-day procedures of soil salinity mapping.
Mahmood Khoddambashi, Balram Sharma,
Volume 3, Issue 2 (7-1999)
Abstract
In spite of different reports about the inheritance of cotyledon colour in lentil, the precise nature of this phenomenon is unknown. In a comprehensive study, conducted in 1993-96 on inheritance of morphological markers in lentil, two types of green colour, light green and dark-green lentils, were distinguished for the first time. The dark-green showed monogenic and the light-green showed digenic inheritance. To explain this, involvement of three genes, Dg, Y and B in the inheritance of cotyledon colour were considered. At the dominant state of gene Dg, the genes Y and B produce yellow and brown pigments, respectively. At the recessive state (dg dg), no pigment will be produced and the dark-green colour will appear. If gene Dg acts normally (dominant state), but both genes Y and B are at recessive state (Dg-yybb), again no pigment will be produced and cotyledons will be of light-green colour.
Mohammad Shahedi, Payman Goli Khorasgani, Zohreh Hamidi Isfahani,
Volume 3, Issue 2 (7-1999)
Abstract
Stickiness and pastiness after cooking is one of the basic problems of macaroni production technology. Investigation of the factors affecting stickiness and pastiness of Iranian Macaroni is essential. The purpose of this research was to study the effects of percentage of gluten in the flour as well as extruder and drying temperatures on the macaroni quality. The factors studied are as follows:
1- Percentages of flour gluten at levels of 8.5, 10.5, 12.5 and 14.5 prepared by adding gluten to the macaroni flour purchased from the market.
2- Temperature of the dough discharged from the extruder (three levels: 48, 58 and 68 °C) obtained through changing the temperature of the water used in making the dough, circulation and noncirculation water in extruder jacket, and changing the rotational speed of extruder screw and increasing dough retention time.
3- Drying temperature (two levels: 50 and 62 °C) obtained through changing the number of burners in the heating system and using electrical heaters in the drying cabinet.
The results of the e:xperiments and their evaluation are as follows: using flour with a gluten percentage of 12.5 or 14.5 (12.5% gluten is preferred for economic reasons) with an extruder temperature of 48 °C and a drying temperature of 62 °C will improve the macaroni quality. This treatment resulted in the production of macaroni with less stickiness, pastiness and cooking loss.
M. A Hajabbasi, A. F Mirlohi, M. Sadrarhami,
Volume 3, Issue 3 (10-1999)
Abstract
A two-year study (1996-97) was conducted to verify tillage effects on several soil properties and corn yield. The soil (fine loamy, Thermic, typic Haplargids) was treated by conventional (CT) and no-till (NT) systems. Soil organic matter (OM), mean weight diameter (MWD), penetration resistance (Cl), bulk density (BD), total nitrogen (TN) and aggregate size distribution at depths of 0-20 and 20-40 cm were measured.
No-till system caused the OM to be twice as much as that in the conventional tillage system. Total nitrogen in the NT and at depths of 0-20 and 20-40 cm were higher by 30% and 20%, respectively. No differences obtained in bulk density and penetration resistance, but MWD in the NT was 20% and 10% higher than CT in the 0-20 and 20-40 cm depths, respectively. Mean weight diameter of the aggregates in the CT was smaller than that in NT. Aggregates of less than 0.25 mm at 0-20 cm depths were almost 25% higher in CT compared to NT system. The yield in the NT system was significantly lower than CT. Although reduced cultivation could bring a better soil physical condition, low initial organic matter, weak structure and heavy-textured soil produced unsuitable conditions for the crop roots and, consequently, resulted in low yield. Therefore, no-till system in this region would not be recommended.
R. Amiri, A. Rezai, M. Shahedi, S. Dokhani,
Volume 3, Issue 3 (10-1999)
Abstract
This study was conducted to evaluate the capability of reversed-phase high performance liquid chromatography (RP-HPLC) of wheat (Triticum aestivum L.) storage proteins, and their genetic variability in different winter and spring isolines, cultivars and landraces. Gliadin proteins were extracted from the flour of five randomly selected seeds of each genotype. In this method, Nucleosil C18 300 A column (250×4.6 mm ID), equipped with a guard column and acetonitrile containing TFA as mobile phase was used.
All selected conditions for RP-HPLC such as suitable velocity and resolution were sufficient to achieve the objectives of this study. Under these conditions, the number of gliadin components by RP-HPLC analysis was more than electrophoresis subunits. In addition, quantitative results of RP-HPLC facilitated the data analysis. Also gliadin analysis by RP-HPLC had a high potential in detecting rye (Secale cereale L.) genes, so that the presence of ω-secalins in the genome of Falat variety was easily detected. Therefore, it was concluded that RP-HPLC analysis of gliadin proteins is as efficient as electrophoresis, and could even replace it in some cases. The result of cluster analysis for gliadin polypeptides indicated the gradual increase of genetic variation from isolines to landraces. Generally speaking, among the landraces, Ali Abad, Aghda, Sefid Bafghi, Ghermez Bafghi, Shahdas and Sorkheh had greater genetic variations.
B. Bahraini-Nejad, M.r. Khajehpour,
Volume 3, Issue 3 (10-1999)
Abstract
Combining herbicides for controlling broadleaf weeds and grasses in wheat farms has not been studied under Isfahan environmental conditions. Thus, this experiment was conducted in 1995-96 at the Agricultural Research Station, Isfahan University of Technology, in order to investigate the issue. In this study, 2,4-D+MCPA (U46 Combi Fluid 6), bromoxynil, metribuzin, diclofop-methyl and tralkoxydim and their combinations in 11 treatments plus weed-free and weedy checks were evaluated using a randomized complete block design with 4 replications. Goldbachia laevigata and Avena fatua were the dominant weeds. Cirsium arvense and Convolvulus arvensis were of less importance. Efficacy of bromoxynil on annual broadleaf weeds was higher than 2,4-D+MCPA, while 2,4-D+MCPA was more effective on perennial broadleaf weeds. Diclofop-methyl and combination of bromoxynil with tralkoxydim were the most effective on A. fatua, while differences between treatments containing diclofop-methyl or tralkoxydim on decreasing A. fatua numbers were non-significant. The most and the least visual damages to wheat plants were caused by metribuzin and bromoxynil, respectively. Wheat yield was not significantly affected by treatments. However, the highest yield was obtained by tralkoxydim + bromoxynil treatment, which produced the lowest total dry weight of weeds at terminal spikelet and heading stages of wheat. The results obtained here indicate that combination of bromoxynil with tralkoxydim might be the best treatment for the control of all annual weeds under conditions similar to this experiment. But if perennial broadleaf weeds and wild oat are dominant in the field, combination of 2,4-D+MCPAwith diclofop-methyl might be preferred.
M. Alikhani, G.r. Ghorbani,
Volume 3, Issue 3 (10-1999)
Abstract
To determine the best ratios of alfalfa hay to corn silage with similar dietary NDF, cation-anion balance, energy and protein content in the lactating dairy cows, eight mid-lactating Holstein dairy cows with average body weight of 570 kg, and milk yield of 22 kg/d with 3.5% fat, were assigned to each of four experimental diets with alfalfa hay to corn silage ratios of 100:0, 67:33, 33:67 and 0:100., in a 4 × 4 Latin square design with two replicates. Dry matter intake, digestibility, rumen degradability of DM, fat percentage and total solids in milk for diets one to four were 19.09, 19.94, 20.94, 20.90 kg/d 69.07, 65.75, 71.78, 49.82% 52.8, 49.6, 50.4, 46.7% 3.47, 3.53, 3.79, 3.93% 12.17, 12.17, 12.48, 12.60%, respectively. Diets containing 67% silage showed the highest dry matter intake, 3.2% FCM and digestibility. Degradability in rumen were highest and lowest in diets containing 100% alfalfa hay or corn silage, respectively. Increased ratios of silage to alfalfa hay corresponded to increases in milk fat and protein yield, milk protein percentage and total solids in milk.
M. Azimi, S. Massiha, M. Moghaddam, M. Valizadeh,
Volume 3, Issue 4 (1-2000)
Abstract
In order to study the genetic variation among local varieties of onion in Iran, an experiment was conducted in the Research Center, Faculty of Agriculture, Tabriz University. Sixteen populations were evaluated for agronomic characteristics and also total seed proteins via SDS-PAGE. Cluster analysis and principal component analysis were used to group the onion populations under study.
Analysis of variance showed significant differences among varieties for leaf color, leaf length, texture tightness, onion yield per plant, and number of edible layers. No significant differences were observed for the number of twin onions, bulb diameter, and onion dry weight. Hamadan (98-148), Arak (98-95, 98-96, 98-97, 98-103), and Zanjan (98-223) populations acquired the highest onion yield per plant. The significant differences between populations for the majority of characteristics proved the existence of genetic variation in the Iranian onion germplasm. The results from cluster analysis for agronomic characteristics were the same as those from the cluster analysis for the onion yield per plant. The 16 populations were divided into 4 groups. Cluster analysis for the electrophoresis banding pattern resulted in two groups, which was not similar to the dendrogram of agronomic traits. Using principal component analysis, the first principal components determined 97.57% of the total variation. Onion yield per plant was the most important trait in the first principal component and onion dry weight was the second trait in the rank.
G.h. Zamani,
Volume 4, Issue 1 (4-2000)
Abstract
Agricultural colleges have three main objectives: training, research, and offering public services. Transfer and dissemination of agricultural knowledge and technology is the best example of universities’ services. In this regard, agricultural extension has the important role of linking agricultural colleges with agricultural industry. The linkage between extension and agricultural colleges is effective in promoting the two organizations and ultimately enhancing the development of agriculture. Therefore, the significance of this linkage has been emphasized by many program planners as well as researchers.
This descriptive research was conducted to analyze the perception of the faculty members at Agricultural College of Shiraz University and the extension agents and specialists of Fars Province. A theoretical framework was developed based on a “communication model”, and forty-seven factors effective in establishing and promoting the linkage between research and extension were recognized. The results revealed that the most important factor in research-extension linkage is “the degree of contact and knowledge of local agricultural affairs by researchers”. The paper concludes by providing recommendations that could be used to strengthen the interaction between research and extension institutions.
Y. Ebrahim Nejad, J. Pourreza,
Volume 4, Issue 1 (4-2000)
Abstract
This experiment was carried out to study the effect of ionophore drugs (Salinomycin, Lasalocid and their combination) on the performance of broiler chicks. Also their relationship with methionine (three levels) was evaluated. 1215 one-day-old commercial broiler chicks (Arian) were divided into 81 groups, 15 chicks per group, and tested in a completely randomized design with a 3×3×3 factorial experiment and three levels (0/0, recommended and 1.5 times recommended) of drugs and three levels (0.0, 1% and 0.2%) of supplemental methionine.
The results indicated that these drugs reduced body weight gain significantly (p<0.05) at 21 and 56 days of the experiment. Decreasing feed consumption and increasing feed conversion was significant (p<0.05) due to Lasalocid supplementation. Increasing drug level significantly (p<0.05) reduced body weight gain and feed intake and feed conversion was increased at 21 to 42 and 0 to 56 days of the experiment. The effect of supplemental methionine on body weight of 42 days (P<0.05) and feed conversion at 21 to 42 and 0 to 56 days (p<0.01) were significant. The interactions between drug type and drug level on body weight gain, feed consumption and feed conversion were significant (p<0.05). Lasalocid significantly (p<0.05) increased water intake. Drugs did not affect litter moisture and mortality. The results showed that Salinomycin was better than Lasalocid. Also supplemental methionine was not effective in compensating for the growth depression caused by ionophore drugs.
M. Basirat, H. Seyedoleslami,
Volume 4, Issue 1 (4-2000)
Abstract
In 1996 and 1997 pistachio orchards in Isfahan Province were surveyed to determine the presence and damage levels by Eurytoma plotnikovi Nikolskaya and Megastigmus pistacia Walker. In order to investigate seasonal population fluctuation of E. plotnikovi, larval, pupal and adult stages were monitored in three orchards. In each orchard, 200 nuts with more than 50% infestation to overwintering larvae were dissected and examined twice weekly. In 1997 in one orchard, at intervals of one week, 100 randomly selected fresh nuts were examined to determine oviposition trend and damage development. In this field, the biology of the pest was also compared to developmental stages of pistachio trees. In most orchards visited, E. plonikovi was present and was the dominant species in relation to M. pistacia and its damage varied between 0.8-75%. In 1997, start, peak, and end of pupal stage were observed on April 4th, May 7th and May 21st. Start, peak and end of adult emergence occurred on May 4th, May 18th and June 4th. In two other orchards, almost a similar trend was observed. Start, peak and end of oviposition were also observed on May 18th, May 28th and July 2nd. Development of pistachio tree was divided into nine stages and the above mentioned dates were compared to that.
E. plotnikovi had one generation every one or two years. Only one egg was found in each infested fruit and first stage larvae had a long prefeeding period. The use of the information obtained from this study in the management of these pests is discussed.
V. Rameeh, A. Rezai, A. Arzani,
Volume 4, Issue 2 (7-2000)
Abstract
Diallel crosses of six breeding inbred lines of corn (Zea mays L.) were used to estimate combining abilities, heterosis and some other genetic parameters for yield and some of its components. Parents, 15 F1 crosses and 4 filler genotypes, were evaluated in a 5×5 simple lattice design. For all the traits studied, except seed length, the efficiency of lattice design was less than one. Therefore, data were analysed as a randomized complete block and after eliminating the filler genotypes, Grriffing’s method 2 with mixed B model was used in the genetic analyses.
General and specific combining ability (GCA and SCA) mean squares were statistically significant for all traits studied. The ratios of GCA to SCA mean squares were greater than one for all traits, except for the number of seed rows per ear, indicating the importance of non-additive gene effects in their genetic control. Low heritability estimates and degrees of dominance lower than one were further evidence of the presence of non additive gene effects for all the traits studied, except for the number of seed rows per ear. Therefore, production of single cross hybrids in order to take advantage of non-additive gene effects is of prime importance for grain yield, number of seeds per ear row, l00-seed weight, seed length, ear length, and comb percentage. For genetic improvement of number of seed rows per ear, selection methods for parental lines will be more efficient. In the hybrids studied, number of seed per ear row and l00-seed weight played a more important role in the observed variations in yield. In general, hybrids 4×5 and 5×6 with high SCA for number of seed per ear row, l00-seed weight and grain yield were considered favorable for the conditions of this study.
