Journal of Agricultural Sciences and Natural Resources
Year:2004 | Volume:11 | Issue:1|Papers Count:21

In order to study growth and grain yield of five rapeseed cultivars (Cerese, Cobra, Global, Rijent and Tower)an experiment was conducted in 1997-1998, under rainfed conditions of Gorgon with average annual rainfall of 500-600 mm. The experimental design was RCBD with four replications. The results showed significant differences in grain yield of cultivars. Ceres showed the highest yield, due to higher leaf area index (LAI), crop growth rate (CGR), and total dry matter (TDM).growth duration didn't significantly differ among four cultivars of Cerese, Global, Rijent and Tower. The susceptible stage of silique development in these cultivars occurred at late winter and early spring. However, in Cobra, this stage occurred at late spring, which resulted in decreasing grain yield, due to water limitation. Therefore, LAI, CGR, TOM, number of siliques and grains per plant are introduced as effective indices on grain yield of rapeseed cultivars.

The objective of this study was to obtain relationships between plant leaf area (cm2 plant-1) with leaf dry weight (g plant-1), total vegetative dry weight (g plant-1 and plant height (cm). For this object, three cotton cultivars (Sahel, Siokra324 and Deltapain25) were used. Sampling was carried out at one month after emergence, squaring, flowering, bolling, boll opening, and second pick from the cultivars under irrigated conditions and four sowing date. At each sampling, leaf area, leaf dry weight, total vegetative dry weight and plant heights were measured. Leaf area range between 170 to 8167 cm2 plant-1 with an average of 3039 cm2 plant-1. Various equations were used to describe relationships between leaf area and mentioned characteristics. Best results were obtained with power equation in linear form {In(y)=a+b*ln(x)}. This equation was used for all combinations of cultivar-sowing date and cultivar-growth stage separately. Results showed that one equation is adequate for all cultivars at all growth stages and sowing dates. Significant relations was found between leaf area and leaf dry weight (R2=0.98), total vegetative dry weight (R2=0.84) and plant height (R2=0.76). It was concluded that equations could be used for estimation of leaf area.

The effects of water stress and different amounts of nitrogen on qualitative and quantitative characteristics of sugar beet were investigated. This experiment was conducted at the farm of Khorasan Agricultural Research Center during growing season of 2001. The experiment was laid out in a completely randomized block design, adopting split plot method. Main factor consists of three water levels; I1: without water stress, I2: continuous water stress and I3: early water stress. Sub plots consist of 3 different nitrogen levels. 80, 160 and 240 kg/ha viz. Root yield, pure sugar content and sugar content, sugar yield, sugar percent of molasses, water use efficiency were registered. The results revealed that the effects of water treatment on above mentioned observations, with the exception of pure sugar content and sugar percent of molasses, were significant. Increasing water consumption resulted in significant root yield increase while sugar percentage was decreased significantly. The effects of N levels on all cases were significant. By increasing the Nitrogen content, root yield increased while sugar percentage decreased. Besides, sugar percentage interaction effects were found significant in all cases. In no water stress treatment, root yield increased due to increasing the fertilizer consumption. But in case of water stress treatments, there was a slight increase in yield. No water stress treatment with 160 kg/ha Nitrogen had the most yield and water stress treatments, especially continuous water stress, had the best water use efficiency.

In order to investigation and determination of vernalization requirement in seedling and soaked seed of two dryland wheat cultivars (Sardary and Sabalan), this experiment was conducted in 2000 at the greenhouse of Agicultural college, Ferdowsi university of Mashhad. Treatments included lenght of vernalization period (in 7 level: 17, 30, 40, 49, 60 and 70 days in 3°C) and vernalization status (soaked seed or seedling) were studied as a factorial experiment in a Randomized complete design with three replications. Results showed that floral induction of Sardary and Sabalan require 17 and 30 days as a vernalization period respectively. After that, increasing of vernalization period to 40 and 49 days (for Sardary and Sabalan respectively) caused completion of vernalization requirement and decrease of days to heading (in main stem and tillers). Vernalization requirement of Sardary not only was less than Sabalan (40 vs. 49 days) but also its response to vernalization was more quantitative in comparison with Sabalan. Increasing of vernalization period also increased tiller number of Sabalan but had no effect on tiller number of Sardary. Results showed that vernalized soaked seed or seedling have a similar developmental rate.

The experiment was condncted at Azad University of Damghan Iran in 1996 by using split plot desigan based on randomized complete bloch with three replication. The main plost were two levels of row spacing (60 and 75 cm) and sub plots were the factorial of two corn hybrids single cross 704 (late maturity) and three way cross 647 (medium maturity) and three levels of plant population (75,90 and 105 thousand plant/he). The differences between hybrids for the plant characters such as, the number of days from planting at pollination and physiological maturity, plant height, dry weight of leaf and stem at pollination and physiological maturity, number of node, corn node and corn sheath at the stage of pollination and dry weight of cob, ear, male inflorescence and whole plant at pollination and physiological maturity were significant. Among characters under study the stem dry weight at physiological maturity, stem and leaf dry weight at pollination and the male inflorescence initiation and the whole plant dry weight at pollination and physiological maturity and also the grain yield were all affected by row spacing. The number of days from planting to pollination and plant height, stem diameter, dry weight of male inflorescence and whole plant dry weight at pollination and physiological maturity, dry weight of stem and corn leaf at pollination, and pollination maturity dry weight of cob at pollination, dry weight of cob, corn sheath and ear, at physiological maturity and also the grain yield were affected by plant population. It could be concluded that the 60 cm row spacing with 90 thousand plants per hectare and also row spacing of 60 cm with 105 thousand plants per hectare are the best combination for single cross 704 and three-way cross 647, respectively

The experimental design was split-split plot, with three wheat cultivars (Atrak, Tajan, and Rasool) in the main plot, three salinity levels of the subsurface water in the first sub-plot, and three depths of water table in the sub- subplots. The experiment was replicated four times. The results show that high subsurface water salinity and water tables have decreased the number of tillers, kernals per spike, fertile spikelets, plant height, 1000-seed weight (TSW), biological yield, and wheat grain yield.However, the harvest index increased significantly by high water table and salinity. Also, the effect of wheat cultivar on the components was statistically significant. Among the measured components, the biological yield, followed by the number of tillers, had the highest correlation with the grain yield. The TSW had the lowest correlation with the grain yield. Also a path analysis has shown that biological yield had the highest direct positive effect on wheat grain yield, through its impact on the number of tillers. The least grain yield was obtained in high levels of salinity and water table. Our results showed that with water table depths of 30, 60, and 90 cm, Tajan had a pronounced priority over the other two cultivars at all salinity levels. Also investigation of the relationship between yield and yield components in the form of a multiple regression equation showed that two components, namely, biological yield and hervest index, accounted most of the variations of wheat grain yield.

In this research Data Envelopment Analysis (DEA) method is used to evaluate the performance of irrigation system and determine their performance standards. In addition, sensitivity analysis is applied to indicate the impact of different alternatives on the performance improvement quantitatively. This technique is applied on eight irrigation system to evaluate the performance from different point of views such as physical system, management system, input, output, monetary view and job creation. Sensitivity analysis is applied on each one of inputs and the impact of their variation on performance improvement is determined. The results of the research could be summarized as Zayandeh rood system has the highest and Minab and Varamin systems have the lowest ranking level from both physical and management point of views. For performance improvement the priority for investment is on both physical and management systems. Sensitivity analysis on Minab system indicates that reducing non of the input indicators individually, down to the corresponding reference level, would not lead to complete improvement of the system. However reducing the input indicators of machinery, network, personnel and costs will improve the performance up to 0.561, 0.548, 0.472 and 0.278 respectively. Using DEA method and sensitivity analysis it is possible to indicate the ranking of system, priority of performance improvement alternatives and impact of the variation of each input on the performance level.

Effect of water quantity and quality on wheat grain yield and yield components were studied in northeast of Golestan province. The treatments included four water levels with 50(W1), 75(W2) 100(W3) and 125(W4) percent of crop water requirement and four water quality with salinity of 1.6(S1.), 7.9(S2), 10.8(S3) and 13.6(S4) ds/m. The experiments were evaluated using a randomized complete block design with split-plot layout which considered water quantity as main plots and water quality as subplots, with three replications. The results revealed that water quantity and quality were significant on wheat yield. Different irrigation depths and salinity levels were not significant on spike. Number per m2 and were significant on 1000-grain weight and grain/spike. The seasonal water consumption by wheat increased when water quantity increased, while it decreased when irrigation water salinity increased. For example, in treatment W4, treatment S4 consumed 88% water as of S1 treatment. Seasonal distribution of water content and salinity in soil profile showed that water content increased when irrigation water salinity was increased. The highest salt concentration occurred in surface soil layer. In all treatments, using saline water accounts for the improvement of water use efficiency (WUE) when fresh water is considered, comparing to total applied water (fresh saline). So that, in W3S4 treatment, WUE for total water use was equal to 9.8 while for fresh water it was 20.9 kg.ha-1.mm-1

In this study the susceptibility of larval instars of Colorado potato beetle to Bacillus thuringiensis subsp. Kurstaki (ber) alone and in combination with henna was investigated. For this reason the larvae were reared on potato leaves in laboratory. Different larval instars were separated by measuring the diameter of head capsules. The experiments were conducted on 1 st, 2 nd, 3 rd, and 4th instar group and LC50 values were 220.384, 465.538, 1283.797 and 3488.562 ppm, respectively. To evaluate the synergistic effect of henna in respectively. To evalute the synergistic effect of henna in combination with B. thuringiensis certain concentration of henna (3000, 4000 and 5000 ppm) was added to the known concentration of B. t. (500 ppm) for 3 rd instar larvae. The results revealed that there is a striking synergistic effect of this material on increasing efficiency of this strain. The larval mortality for mixture of B. t. (500 ppm) with henna (5000 ppm) after six days was 85%, however it was 22.5% and 5% for B. thuringiensis and henna alone, respectively.

Aspects of the biological parameters of local populations of the sweet potato whitefly, B. tabaci (Genn.) (Hom: Aleyrodidae) as an important pest of cotton were compared during 2001. The infested cotton leaves containing nymphs and pupae were collected from Darab, Qom, Saveh, Gonbad, Gorgan, College of Agriculture campus, Varamin, Garmsar, Orsoiieh (Kerman), Rafsanjan and Shooshtar fields. Experiments were conducted in a growth chamber under 24±20C, 55±3% RH and 16:8 (L:D) photoperiod on cotton, Gossypium hirsutum L. (Varamin 76 variety). The newly emerged populations of each locality were released into a large cage (40x50x70 centimeter) set on cotton plants separately. Emergence of adults, and crawlers and percentages of females emerged from 100-200 eggs at four replications were also calculated. Total fecundity, oviposition period, adult's longevity, sex ratios and daily fertility rates of 50 mated females were calculated for each local population. The grouping results indicated that total eggs/female for B. tabaci populations were ranked highest in Saveh, Collage of Agriculture and Qom (113.25, 102.63 and 92.88) respectively, medium in Garmsar, Shooshtar, Orsoiieh, Gorgan, Rafsanjan and Gonbad (89.75, 82.63, 73.63, 63.88, 63.5 and 61.38) respectively and lowest at Darab (57.88). There were significant differences between parameters of total fecundity and oviposition period at 5% level and between sex ratios and developmental time at 1%. Level. However, no significant difference was found between maximum adults longevity at 5% level.

In order to study the virulence of Pyrenophora graminea isolates from 19 barley fields of Azarbaijan Provinces, a research program was conducted in the Plant Protection Department, Faculty of Agriculture, University of Tabriz, Iran, in 2000, using the susceptible variety of Zarjo. After isolation, 26 isolates were purified via hyphal-tip culture. The Sandwich method was used to inoculate the seeds. Isolates were rated according to the method of Mathur and Bhatangar. Results showed that 8 isolates Marand 3, Bostonabad, Khasseban- Tirre, Ajabshir 2, Ahar 2, Osku 1 Ghahveie, Marand 2/1 and Azarshahr with more than 50% (50-100%) infected plants were very virulent, 7 isolates Khoy, Osku 2- Sefeed, Mianeh 1, Marand 2/2 and Ajabshir 1 with 25-50% infected plants were virulent, the others were classified as intermediate, weak and very weak. Since many isolates were highly virulent and could cause substantial yield loss in each growing season, it is necessary to conduct studies to evaluate barley varieties and landraces in order to select genotypes resistant to leaf stripe of barley.

Karyotype and C-banding pattern in two populations of Aegilops umbellulata from two geographical locations of north- west of Iran were studied. Aceto-iron-hematoxilin and Giemsa C-banding techniques were used to chromosome staining and banding patterns analysis, respectively. Chromosome characteristics were measured using Micro measure software. The results of this study revealed that the genome of this species consisted of two pairs of metacentric (1U and 4U), three pairs of submetacentric (3U, 5U and 7U) and two pairs of acrocentric (2U and 6U) chromosomes. Each chromosome, having a distinctive banding pattern, was recognizable easily. Karyological characteristics and banding patterns of the two populations were similar not only to each other but also to those of the standard karyotype of this species. There were, however, some minor variations between these two populations. Meanwhile, some minor differences were observed in karyological characteristics and banding patterns of 1U, 2U, 5U and 6U chromosomes between the two populations and the standard karyotype. Although the standard karyotype of Aegilops umbellulata can be used as a general model for karyo type of this species, but care must be made in identifying C-bands when considering transfer of desired chromatin from this species into wheat.

European honey bee (Apis mellifera L.) colonies infested with varroa mites (Varroa destructor A.&T.) were used to determine the correlation between temperature, relative humidity and their effects on miticide properties of formic acid 65% (1998-2000). Sixteen colonies were selected with sister queens. The colonies were divided to 4 treatments and 4 replications. The formic acid 65% applied in 80, 120, 160 and 200 ml/colony during 16 day. The percentage of dead mites was measured by sticky board's method. During study, daily temperature and relative humidity were recorded. Results showed that mean mites mortality hadn't significant different in the first year (2.3-13 C, 42-100 Rh%) and the second year (5.7-18.1 QC, 49-100 Rh%). But treatments had significant different in the third year (9.523.5°C, 38-100 Rh %). The correlation between mortality with temperature and relative humidity were found significant (r=0.181) and not significant (r=-0.05) respectively (P<0.05). In during the three years averages of mites mortality were increased any year and end of treatments

Many of the small and mid-size watersheds in Alborz south ranges are un-gagged for estimation of the sediment yield, and therefore, having a suitable empirical model to estimate the sediment yield is essential for any soil conservation and watershed management in this part of the country. However these types of models should be calibrated through some gagged watersheds in the similar environmental setting to validate the empirical models to be able to use them in the un-gagged watersheds. In this study, MPSIAC (Modified Pacific South-West Inter-Agency Committee) model is used for estimation of six gagged sub-watersheds in the Alborz south ranges to validate the model. Six gagged small to mid- size watersheds of Emameh, Roodak, Afgeh, Siara, Bilagan and Gozledareh with the range of 1800-6000 hectares are used for this validation study. The comparison of the observed sediment yield in the gagged station at 1 present level in the Emameh, Roodak, Afgeh and Gozledareh watersheds with the estimation made by the model have no significance differences. However in the. other two watersheds, Siara and Bilegan, the difference were significant at the same significant level, therefore, this model is not recommended to be used to estimate the sediment yield of the similar watersheds in this area. The poor estimation of the topography and land use factors and the low number of the sediment data collection years in these two watersheds were the main reason for the failure test. The difference between the observed sediment yield and the estimation by the model were 27.8, 43.2, 46.46, 80.9, 64.4 and 13.5 in Emameh, Roodak, Afgeh, Siara, Bilegan and Gozledareh, respectively.

Most of the experts have a similar idea about debris flow and flash flood and usually make mistake in management, controlling, estimation of sediment load and reconstruction of peak flow and precipitation data. After occurrence of a harmful flash flood in August 1999, samples of sediments have been taken randomly from the undisturbed cross section of river. Then granulometery and hydrometery tests have been done and four sedimentologic indices have been calculated and interpreted. From the study it concluded that the selected flow was a type of debris flows and classified as a high sediment flow. A severely decrease in cross section of flow has been seen from upstream to downstream, which indicates the action of debris flow in the river. To study the case of debris flow, the Atterberg Limits test has been conducted that the Liquidity Limit of samples was 50%. These types of sediments, by absorbing a low percentage of water, forms landslids and mud flows.

Soil erosin is a complex process and pervasive geomorphologic hazard (earth cancer) and its rate is counted as a comprehensive index for assessing degree of development and sustainability of land management programs of the countries. Due to the strong dependence of pedogenesis on geomorphic systems, there is a close relationship between geomorphic units and erosion at different spatial level. In this research the potential erosion rate of watershed was estimated by MPSIAC model within geomorphologic facies (as work unit) that differentiated on the homogeneity of topography. Litho logy and erosion reaction at semi-detailed level and 1:50000 scale. Based on obtained results, this watershed contains three from II to IV sediment yield and five from II to VI erosion intensity classes. Their mean specific sediment and erosion rates are 322 and 1105 m3/km2/y respectively. A regression equation with R=0.981 was established between specific erosion rate and effective factors of model in each geomorphic facies that significant at 5% level. Also, in multiple regression analysis (backward) all of the nine effective factors remained in the equation with R2=0.95478 at significant level. Differences of erosion rate inter geomorphologic unit (unit., type, sub-type and facies (76 polygons with repeat) and also differences in number and area of polygons of unit maps and sediment and erosion intensity map was compared by Chi-square test. In 17 tests, beside differences in polygon number of unit, sub-type, erosion and sediment maps, the other differences are significant at 0.01 to 0.05 (0.01<P<0.05) body ><level. different at watersheds in management hazard erosion and sediment of estimation for units work suitable as used be can other each to relation genetic close hierarchy spatial with geomorphologic Therefore watershed. Kashidar rate type diversity indicate relationships These>

Amirkelayeh Protected Area is situated in the north of Lahijan and 28 km to the northwest of Langerud, it covers an area of 1230 hectars. A contribution to the flora, life form and geographical features of the lagoon is given. In this lagoon a total of 85 species and subspecific taxa including 3 charophyta, 5 pteridophyta, 41 dicotyledonae and 36 monocotyledonae were identified. They belong to 45 families and 70 genera. The following families have the highest number of species: Cyperaceae, Poaceae, Ranunculaceae, Lemnaceae and Potamogetonaceae. 53 species (63.1%) are cosmopolitan; it means that they are distributed in the some different regions. The distribution of 22 species is limited to north of Iran. Also, 5 species are mainly distributed in the north and sparsely in the northwest of Iran. Geophyte with 40 species (48.8%) is the most frequent life form of the Protected Area.

The range lands depletion of production on potentials and deterioration of vegetation have negative effects on the income of live stock producers and family economy in Dashli Brune area, north of Golestan Province. In a field experiment during 2001 the effect of education, social structure, ownership and family income on live stock producers participation in range lands reclamination and Development projects have been studied by using Likert Method and statistical analysis, such as T -test and F-Regression in 127 samples among 190 live stock producers families. The results indicated that income resource of 95% of agricultural is live stock products are based on 308 heads of animals, 6 hec of irrigated land and 22 hec of rain fed land. The multi variables regression experiment (Back -ward method) and the tests conducted also indicated that ownership and rain fed land are two most important factors in live stock producers participation.