Year:2007 | Volume:20 | Issue:2 (75 IN AGRONOMY AND HORTICULTURE)|Papers Count:30

To study the effect of sowing date and cultivars on grain yield of maize (Zea mays) in the early Spring sown two experiments were condueted for two seasons (2002-2003) at Agricultural Research Center of Jiroft and Kahnuj. The first, was on early mature cultrvars. Three cultivars, namly Hybrid- 320, Hybrid- 310 and Hybrid- 500 were sown at five sowing date: January 30, 10th, 20th, 30th February and March 11. The design was a split- plot replicated three times with cultivars as main plots and sowing date as sub- plots. In the second experiments, similar to the first one, instead of using early mature corn, delay mature corn has been used. It’s cultivars were (S. C 704, T. W. C 647 and 700 Karaj) The results of 2 years expriements: Showed that the first one in the best condition from cultivar of 320 hybrid with sowing date (January 30) produced 8.8 t/ha and in the second, the highest yield from Karaj 700 with sowing date of (January 30) is 12.8 t/ha, meanwhile products of cultivars are not significant for Jiroft region, delay mature cultivars with sowing date (January 30 – February 30) is recommended.

In order to study the effects of planting time and density on yield and yield componets of sweet corn cultivar ksc404,an experiment was conducted in 1999 at Dasht Nase Sari. In this study the experiment design of split-plot in the form of randomizied complete blocks with four replications was used. The main plots were allocated to 4 dates of sowing(25 Th of April ,15 Th and 25 Th of May, 9 Th of June) ,The sub plots were consisted of 3 plant densities(55,65,75 theousand plant/ha), The result showed, that planting dates and different densities had statistically significant effect at 5% level on the number of total kernel per corn, number of kernel per row, corn hieght, thousand kernel weight, seed weight per ear,corn-stem weight and stem diameter but had no significant effect on the number of corn row, plant height, internode lenght and corn wood diameter. Effects of different planting time on yield were significant and the best planting time with yield of 12.2 ton/ha was 25 th of April. Planting time 15 th and 25 th of May,9 th of June with respect of best planting had %10.2, %37.1, %38 yield reduction respectively. The effect ofdifferent densities on yield were not statistically significant and best yield with 11.2 ton/ha was obtained from 65 thousand plant/ha density. Treatments with(55,75 thousand plant/ha) with respect of best density have %26.9,%16.4 yield reduction. results of this experiment indicated that date of 25 th of April and density of 65 thousand plant/ha have greatest yield.

This experiment was carried out to determine the morphological and qualitative traits and yield stability of 8 rice genotypes in three locations of Guilan province (Rasht, Hashtpar and Rudsar) during 2000-2002. The experimental design was randomized complete block with 4 replications. The size of each plot was 3 m× 6m with hill spacing of 25 cm× 25 cm. In this study 17 traits were measured on 10 random plants from each plot based on standard evaluation system for rice. Simple analysis of variance for yield showed significant differences among the genotypes. Combined analysis of variance showed significant differences among genotypes and locations. The interaction effects of genotype × location and genotype × year were not significant. However, the interactions effects of year × location and year×location× genotype were found significant. The stability of genotypes was evaluated using Lin and Binns method. Results showed genotypes no.830 and 831 were the most stable, respectively, because of having less variance within location and less coefficient of variance. These two genotypes produced the average yield of 5.1 and 5.3 t ha-1 respectively about 1.0 t ha-1 more than the yield of improved check variety (Khazar). Their grain cooking quality characteristics were good with intermediate amylose content, gelatinization temperature and gel consistency. Their milling recovery rates were 68-69% with 57-62% head rice. Their appearance qualities also were suitable with long grain and slender grain shape. They are semi dwarf (115-116cm), lodging resistant and medium in maturity which were one week earlier than Khazar. Consequently, due to higher mean yield compare to Khazar and the desired morphological and grain quality traits, these two lines were selected to release as new rice varieties.

In order to study the effect of corn density and spatial arrangement on growth and physiological indices of redroot pigweed (Amaranthus retroflexus L.) a field experiment was carried out at Esfahan agricultural research station 2003. Treatments were arranged in a factorial split experiment based on RCBD with three replications. Factorial arrangement of corn densities (74000 and 111000 plant ha-1) and planting patterns (single row, rectangular twin row and zigzag twin row) formed the main plots. Split-plots referred to pigweed densities (0, 4, 8 and 12 plant m-1). In addition three experimental plots pigweed pure stand (4, 8 and 12 plant m-1) established in each block. In order to determine pigweed leaf area and dry matter accumulation, destructive sampling of pigweed started at 29 days after corn emergence with 14 days interval. Results indicated that pigweed leaf area index (LAI), total dray matter accumulation (TDM) and weed growth rate (WGR) decreased in corn existence. More corn density, more decrease in weed growth, in such a manner dense corn population, lead to 26.2, 16 and 19.7 percent loss in pigweed LAI, TDM and WGR respectively. These indices influenced more by corn twin row patterns compare to single rows, also effects of zigzag twin row were higher than rectangular twin row, in such a manner in the highest pigweed density, zigzag twin row reduced pigweed LAI, TDM and WGR about 7.9, 4.1 and 6.1 percent more than rectangular twin row pattern. Finally results showed that corn planting pattern effect on pigweed growth indices were lower than corn density. So extending of twin row patterns with increase density of corn can develop its competition ability and suppress the pigweed growth without chemical herbicide application.

Susceptibility to chilling injury in pomegranate fruits is the main limiting factor for storage fruits in low temperatures. Inducing chilling tolerance may make possible to store fruits in low temperature for long time. In this study effect of different concentrations of methyl jasmonate (8, 16 and 24 ml.L) on inducing chilling tolerance of pomegranate fruits (Malas Save) was investigated. Qualitative attributes of treated fruits in different times during low temperature storage and also after transferring were to high emperature was investigated. The results showed that methyl jasmonate suppressed chilling injury and water loss and preserved appearance in pomegranate fruits without any deleterious effect on internal quality. Chilling injury was reduced significantly with increasing methyl jasmonate concentration. fruits chilling injury reduced significantly. The highest chilling injury index was found in control fruits and the lowest one was for 24 ml. L during storage in low temperature and also after keeping at high temperature. Furthermore, no significant difference were found between treated and control fruits all total soluble solids (TSS) and titratable acidity. In general, fruits treated with 24 ml.L methyl jasmonate showed the best appearance with the most controlling effect on  chilling injury.

Information needs of scientific boards in Agricultural Research and Education Organization is measured and evaluated in this research. Study of research interest fields of researchers, determining different kinds of used information, their languages, structures and application of information as wellas the way of access and transfer device of information is among the goals. Survey method is used in this research. Questionnaire is used for information gathering. Due to the large number of population, a sample population is chosen for investigation. Research findings indicate that scientific journals, Internet websites and books are the most important information sources. 97.3 percent of information is used for study and research, 82.8 percent for doing research and 66.8 percent for updating researchers’ information. Direct refer to the office library is the common way for accessing information. According to the results, scientific journals with 245 scores, Internet with 244 scores and books with 201 scores are sequent ranked from one to three. Also, 98 percent of scientific boards used information in English language.

In order to study the effect of plant density on forage yield & quality of forage sorghum 3 year research (2002-2003 and 2004) was conducted at Khoy research station. Experiment was carried out using a split plot design, used on RCBD with 4 replications. The density of 200,250,300 and 350 thousand plant per hectare was considered as main factor levels. the hybrides of speedfeed, sugergraze and Jumbo as sub factor levels. Sowing date was 11 July in even years. investigate charactrestics were plant height T stem diameterT leaf number and tiller number per plant T leaf to stem ratio, fresh fodder and dry matter yield in first cutting, crud protein and ash percent in first cutting and dry matter in second cutting. the harvest was in 10 percent of anthesis. The result of compound analysis of variances showed that an increase in Plant density on the surface unit leads to the reduction stem diameter and tillers. but it could maximing plant height and LAI. The highest fresh fodder, dry matter and leaf to stem ratio obtained in 350000 plant per hectar. plant density had any honestry effect on ash and protein percentage. The maximum dry matter and fresh fodder by 14.99 and 69.69 ton per hectar obtained in speed feed hybride. in this manner the highest dry matter in first and second cutting, fresh fodder, plant height, stem diameter, tiller number and protein percentage were obtained in speedfeed and this hybrid had a superiority to 2 others. sugargraze hybride had the highest rate of %ash. Ultimately, plantation of speed feed forage Sorghum with 350000 plant density as the second cropping was recommended to Khoy farmers.

In order to study the effects of nitrogen fertilizer rates and split application on yield and yield components of different rice cultivars, a field experiment was carried out in the Rice Research Institute of Iran–Deputy of Mazandaran (Amol) – during 2005. A split – split plot experiment in the basis of randomized complete block design with 3 replications and 3 factors including fertilizer rate (100, 150, 200 kg.ha-1), fertilizer split application (in variable ratios in transplanting, tillering and heading stages including S1 (50%, 25% and 25%) S2 (25%, 50% and 25%) and S3 (25%, 25% and 50%) as sub plot and cultivar (Tarom, Shafagh and Hybrid GRH1) as sub sub plot were used. Results showed that the rates of nitrogen fertilizer had significant effect on grain yield, grain number per panicle, filled grain number per panicle, harvest index, fertile tillers number and biomass. Meanwhile cultivars had significant effects in the all mentioned traits. Also, different levels of nitrogen split application have not significant effects except of biomass. In general, among cultivars, Shafagh had the highest grain yield, while hybrid cultivar because of the high unfilled grain per panicle had less grain yield than Shafagh, however traits such as fertile tiller number and grain number per panicle were more in hybrid rice than two other cultivars. The lowest of yield was obtained in Tarom cultivar. Among the mentioned traits, harvest index and grain number per panicle had the highest correlation with grain yield. Interaction effect between split application and cultivar was significant at 1% probability levels for yield, biomass and unfilled grain traits in which the highest yield was belong to the first split application and Shafagh cultivar.

Dates of first fall and last spring frosts on the basis of minimum shelter temperature equal or less than 0oC were determined for 12 synoptic stations for period 1986-2000 in Azerbaijan region. The advection frost was determined based on using of synoptic maps and studying of meteorological elements in different hours. In this work, we found that series of first fall and last spring advection and radiation-advection frosts are random and normally distributed. This study shows that on the average advection frosts start from 6 to 40 days later than radiation-advection frosts in fall and ends 2 to 25 days earlier in spring. Potential growing season that is interval between last spring and first fall advection frost is found to be from 5 to 65 days longer than the growing season defined by the interval from last spring to first fall occurrences of minimum temperature equal or less than 0oC. Crop protection against radiation frosts can bring about too much benefit. To assess whether practical protection of some special crops against radiation frosts is done or not, the number of radiation frosts before first advection frost in fall and after last advection frost in spring, were determined.

To investigate the degradation and persistence of 2,4-D and Atrazin in soil under climatic and soil conditions, during 2002, 2003 field trials were carried out with ifferent amounts of these herbicides at various locations in Nazar Abad (Karaj), Kamiyaran and Dinavar (Kermanshah). Using multi-stage sampling, dispersion and disintegration processes were determined. At application rates of 2 kg/ha, both herbicides were not leached. beyond 10-15cm. At rate of 6 kg/ha, these herbicides could significantly be detected in the 15-20 cm soil layer and herbicide residues were still present in the soil after one year. Within each degradation curve, different velocities of breakdown occured. At the beginning breakdown was slow, then rapid herbicide degradation was found followed by a slower phase at the end. The duration of dispersion was completely different in various soils and conditions.

In Jiroft region, potato tubers keep in store and cold room in summer. During 2001-2002, several stores were surveyed in order to etiological study of potato tuber that exhibited either soft or dry rot symptoms. Infected tubers washed with water and disinfested with 1% sodium hypochlorite and then plated on PDA, WA and CMA edia. Also samples that showed soft rots cultured on NA, NAS and EMB bacteriological media. Pathogenicity tests carried out on health tubers of Primir cultivar by common plant pathological methods. At last, Cylindrocarpon didymum, Fusarium equiseti, Fusarium culmorum, Fusarium solani and Ralstonia solanacearum identified as causal agents of potato tuber rot in Jiroft with 56.4, 17.9, 12.8, 7.7 and 15.4 percent respectively.

To evaluate the intercropping of annual medic (Medicago scutellata cv. Robinson) and barley (Hordeum vulgare cv. Valfajer) effects on quantity and quality of forage yield production, two simultaneous field experiments were conducted in Khoramabad and Kangavar cities in Kermanshah province during 1382-83 growing season at dry farming system. The intercropping treatments comprised of: sole medic (100% medic), 100% medic + 50% barley, 100% medic + 75% barley, 100% medic + 100% barley, 75% medic + 50% barley, 75% medic + 75% barley, 75% medic + 100% barley, 50% medic + 50% barley, 50% medic + 75% barley, 50% medic + 100% barley and sole barley (100% barley). Annual medic and barely were sown at 20 and 140 kg pure living seed per hectare in intercropping system, respectively. The first forage harvest was carried out at early flowering stage of annual medic for both medic and barley above the third growing node of the medic plant. The regrowth was harvested from the soil surface. The compound analysis of the data from two experimental sites showed that intercropping of 100% medic and 100% barley and 75% medic and 100% barley produced the highest yield (1906.8 and 1870.8 kg DM/ha, respectively) and protein (319.1 and 269.7 kg/ha, respectively) among all the cropping combinations. Intercropping system of annual medic and barley was more successful in quantity and quality of forage produced in Khoramabad compared to Kangavar because of more suitable climatic conditions.

Disequilibrium between supply of and demand for agricultural water in pistachio producing regions in most part of Iran, especially in Rafsanjan, is a critical problem. In spite of water scarcity, because of high value, water using in agriculture is enhancing. The results of this strategy are water over drafting and reducing ground water quality. For solving the problem, demand for water must be decreased and supply of water should be increased. In this study, new alternatives for supply of and demand for agricultural water were evaluated economically. The results showed that new methods in supply side such as using desalination plants and water conduction from Karoon River, and micro irrigation systems in demand side have not been accepted by farmers because of high costs. The remedies for this condition are: 1. Using appropriate rules and organizations, the cost of water harvesting in old methods should be increased. 2. Using suitable technology and following appropriate researches, the cost of water use in new methods should be decrease. 3. By introducing proper rules and organizations, decision making horizon and the period in which farmers feel water scarcity should be matched. And so, real water value should be considered as exchange criterion in buying and selling water.

Incorporation of plant residues in soils of semiarid to arid regions is a major principle of sustainable agriculture. Soil N dynamics will be influenced differently following incorporation of various plant residues and it will consequently influence the availability of N for succeeding crop. It is of great importance to understand the effect of soil type on N transformations in plant residue-amended soils. The main objective of this study was to investigate the effects of plant residue and soil types on the N mineralization in plant residue-amended soils. For this purpose, two different soils including Shervedan (clay) and Jouzdan (sandy clay loam) soil were selected and alfalfa, wheat and corn residues were incorporated at the rate of 1% plant residue C kg-1 soil. A control treatment (without addition of plant residues was also considered for both soils). The rate of net N mineralization was measured at the end of 8-week incubation period. Results indicated that among the plant residues, alfalfa residues induced the highest quantities of N mineralization whereas, N immobilization occurred in corn residue-amended soils (based on the average replications of the two soils). Wheat residue-amended soils showed N mineralization to a lower extent compared to alfalfa residue – incorporated soils. The soil type had a significant effect on N mineralization however, the differences between soils were not observed similarly in the three plant residues-amended treatments. The differences in N mineralization of the two soils were much more pronounced in alfalfa residue-treated than those of wheat or corn-residue treated soils. The differences in N mineralization as affected by the soil type were also significant in wheat residue-treated soil but no significant difference was observed between the two soils when treated with corn residues. Overall, we conclude that the results support the hypothesis that, the effects of soil type on N mineralization is heavily affected by the plant residues quality.

To assess and compare the preliminary yield of selected lines of persian clover, an alphalatic design with two replications was carried out, the experiment had five blocks and in each block 30 persian clover lines were planted (sum of 150 lines). The results showed significant difference in 1% level probability for dry matter, protein and digestiable protein yield. The comparison of means showed that the highest dry matter yield, protein and digestiable protein yield beloned to line 37 (Eqlid-e-fars) with 14.82, 3.04 t/ha and 2740.65 kg/ha, respectively. The superior lines beloned to seven populations of persian clover (Eqlid-e-fars, Baladeh-e-Kazeroon, Mahali Zabol, Charmahale-e-bakhtiyari, Dochin-ekordestan, Famoor-e-kazeroon and Hafftehchin-e-Shazand). Mean comparison of quantitive and qualitive forage yield of superior lines compared with total mean showed that were higher 50.66%, 52% and 51.33% from dry matter, protein yield and digestiable protein yield respectively.

In order to investigate of the effects of different levels of drip irrigation and different cultivation pattern on yield and yield components of potato a split plot experiment based on the randomized complete block design with three replications was carried out at Allarog Research Station of Ardebil Province in 2004. Investigated factors included: Different levels of drip irrigation of 60, 80 and 100 percent of evapotranspiration of potato plant as the main plot. Cultivation pattern of the field were: (a) 1 row 75 cm on bed 75 cm (furrow to furrow), (b) 2 rows 35 cm on bed 150 cm (furrow to furrow) and 2rows 45 cm on bed 150 cm (furrow to furrow). It was found that increased irrigation resulted in higher fresh and dry yield of tuber per plant, mean fresh weight of tuber and number of tubers per plant. No significant difference was found in the number of tuber per plant between the treatment of providing 100% and 80% of water requirements. Different irrigation levels also affected the number and fresh weight of marketable tubers, maximum tuber number and tuber weight was obtained at the treatment of providing 100% water requirement. It was concluded that the yield of potato was strongly affected by water stress and there was no significant difference in yield among different cultivation patters.

Drought stress is a major constraint for crop production in arid and semiarid regions, such as Iran. Application of some soil conditioners, like superabsorbent polymers, could be effective for absorbing seasonal rain and suitable source of water for plant growth during dry seasons. The aim of the present study was to evaluate of the effect of four rates of superabsorbent polymer (0, 75, 150 and 225 kg /ha) and three irrigation regimes (6, 8 and 10 days) on growth, yield and yield components of soybean (cult. L11) under field conditions. The results of this study showed that there were significant differences among irrigation regimes on seed yield, 100-grain weight, number of pods per main-branch, number of pods per sub-branch, number of secondary branch per plant, plant height and seed protein content. Moreover, the high rates of superabsorbent polymer (225 kg/ha) increased seed yield, 100-grain weight, number of pod per main branch, oil and protein yield and seed protein content compared to the control (zero polymer) and the lowest rate of polymer (75 kg/ha). These results indicated that high amounts of superabsorbent polymer had positive effects on yield and yield components of soybean even under drought-stress conditions.

Rubisco is the key enzyme in photosynthesis reactions in chloroplast stroma. The small subunit of this enzyme which is encoded by the nuclear genome is targeted into the chloroplast by the activity of its signal peptide. In order to utilize the efficiency of this transit peptides in specific targeting of foreign proteins to chloroplast, the genomic DNA from rapeseed (Brassica napus L.) leaves was isolated. By using the specific primers and PCR methods, the signal sequance (170bp) was isolated and cloned into pUC18 as a cloning and pBI121 as a plant expression vectors. The constract was transfered into tobaccosterile explants via Agrobacterium tumefaciens (strain LBA4404) mediated transformation procedure.The selection of transformed cells were done on kanamycine containing media. PCR with specific primers on the DNA isolated from transgenic plant and GUS staining on leaves of the same samples confirm the presence of the recombinant construct and its activity. Further more, the GUS staining on isolated chloroplast from putative transgenic and control plants show that the product of gus gene targeted to chloroplast succesfully. These results show the general ability of rubisco small subunit transit peptide from Brassica napus in targeting of the heterologus protein (GUS reporter gene) to chloroplast of a heterologus host (tobacco).

The variation of the growing season length during the last decades is one of the important impacts of global warming. It has been intensified by occurrence of early Spring and late Autumn freezing. The length of growing season has been increased in mid and higher latitudes of the northern hemisphere in association with the global warming. For this purpose, there are varieties of indices, but it is necessary to introduce a plant-free definition for applications, such as climate models and it’s changes for interpretation of global warming, appropriate description of forest and farm land. One of the definition is growing season length (GSL) indices was defined by commission for climatology\ climate variability (CLIVAR). It is found by counting the number of days between first span of at least 6 days with daily mean temperature greater than 5oc after July 1st (Jan 1st in southern hemisphere) and first span of 6 days with daily mean temperature less than 5o. igh quality and homogenous daily temperature data sets from 16 Iranian synoptic stations for period of 1951-2003 were used for the study of variation of GSL accompanied by number of frost days and icing days. It was found that these  indices are not appropriate for stations like Bushehr and Abadan where located in southern part of the country. It was determined that there are positive trends for GSL in most of the stations where located in the central and northern parts of the country. The highest values of these trends, 7 to 12 days per decades belongs to Kermanshah, Mashhad and Tehran respectively. The number of frost days has decreased in most of the stations too.

Alfalfa witches’ broom (AWB) is the most important alfalfa disease in Yazd province. To evaluate the status of AWB, the alfalfa growing regions of Yazd province were surveyed in 2001-2004 and geographical distribution, infection rate and severity of AWB disease were assessed. Furthermore, the death rate of infected plants were evaluated during the summer and winter seasons. For sampling, five 1 to 3 years fields were selected randomly and sampling conducted in fifth harvesting. In each field sampling was carried out randomly at five points within a 0.5-m quadrate on a diagonal transect across each of the five fields. Infection of samples was based on characteristic disease symptoms and ELISA test using polyclonal antiserum. The results indicated that AWB is widespread all over the Yazd province except in Taft and Mehriz cities. The highest incidence was found in Chahgeer (up to 100%), Rezwanshahr (up to 100%), Milleshbar (up to 54%), Hassanqaraie (up to 39%), Rezaieae (up to 16%), Eshghabad (up to %10), Amirabad (up to 9%) and Yazd vicinity (up to 3%). About 6% of infected plants in 4th year stands were died during the winter in Esfandabad (Abarkouh, Yazd province). Furthermore, up to 9% death rate of infected plants were found in 3rd year stand in the summer in Rezwanshahr (Sadugh, Yazd province). Based on the results of this study among the cities in the Yazd province AWB is most widespread and severe in Abarkouh and Sadugh regions.