Year:2003 | Volume:16 | Issue:58 (in Agronomy and Horticulture)|Papers Count:22

Determination of forage quality of available species is one of the fundamental factors for the management rangelands. NDF, ADF, CF, Cp and digestibility are some of the important factors in evaluation of forage quality. The present research was conducted in Javaher Deh of Ramsar range having an elevation of 2500 m above sea level and annual precipitation of 700 mm. During the study, samples were collected from Trifolium pretense and Coronilla varia species with eight replication from exclosured area. NDF, ADF, CF, Cp and total energy were then measured for the analysis of flowering and seeding stages. Soil samples of root zone were also collected for EC, pH, K, P and N. ANOVA and regression test were applied using SPSS to investigate the forage quality changes during phonological stages and the relationship between soil characteristics and phonological stages with forage quality indices. The results showed that forage quality of both species was higher in flowering stage than that of seeding stage. Which is because of high value of CP and also low degree of ADF, NDF and CF. Forage quality changes of T. pretense in phonological stages was more than C. varia species. However, the forage quality of T. pratense in flowering stage was higher than of C. varia while it is reverse in seeding stage. In present study significant correlation was no found between forage quality and soil characteristics except in case of the relationship between soil nitrogen, crude protein and total energy of C. varia.

A cytological study of 14 cultivars of barley was performed. The seeds of these cultivars were obtained from the center of Agricultural Researal of Isfahan. These seeds were cultivated, at the experimental field of the Isfahan's university by the end of November 1999. After surveying their morphological features, by using standard method of chromosome study; the meristematics cells of the root tip were stained and squashed. Karyotypes of at least 10 meristemtic cells were studied. Karyological studies including measurement of chromosomes length and determination of arm ratio for each chromosome were done. The data were analysed by wards method of and Euclidian distance coefficient by using Statistical software. The related phenogram on the basis of similarity of cultivars based on the chromosomes arm ratios was drawn. In this phenogram two main phenomenon's were observed. which separate the cultivars of Hordeum distichon from the cultivars of H. vulgare species. The results of this research were compared and analyzed with the results of other studies.

Morphological and cytological characters are used in classification of plants, may improve the existing systems of plant classification. There fore, we decided to investigate the above aspect in some genera and population of Zira in Iran. Materials were collected from their natural habits. Herbarium specimens were also examined to check lidentity of the collected material. Fifty four morphologic and seven karyotypic characteristics of plants were measured. Bumium, Cminum and Carum. Based on morphological chracters, 4 species have been recognized by cluster analysis in Bunium genous which confirms the Rechinger classification (1987). Bunium persicum and Bunium cylindricum were placed in one cluster. Unknown Bunium and Bunium wolffii were nearest and furthest species of this cluster respectively. Cluster analysis of morphologic and karyotypic data showed dissimilarity between some of the populations in Bunium and Cuminum which may be to local adaptation. However such morphological and genomic difference may by used to further plant systematic and breeding purposes.

The corn armyworm (Spodoptera exigua Hb.) is one of the main pests of summer as well as winter corn crop in the Khuzestan province. The pest has a wide host range, and damage to sugar beet and corn crops is economically important in Khuzestan province.The biological characteristics including, life cycle, number of generation, kind of damage, host preference, egg laying and population fluctuation of the pest were examined during this investigation.Egg clusters could be deposited on upper or lower side of corn leaves as well as on stems. Each larval stage had special feeding behavior. Damage caused by the thirtd and forth Corn plants with 3-4 leaves were preferred for egg lagging by female insects compare to older and yoounger plants. As diapouse is facultative in this insect, in an experiment conducted in optimal 17± 1 laboratorial conditions (300.), 10L/14RH and 60-70% generation were reared in one year.In the field condition of Khouzestan, the insect produced eight generations per year. Braconidae) and: Habrobracon sp. (Hym. Braconidae): Apanteles glomeratus (Hym. Were collected in the larval stages of the: pest. Chrysopa earn ea L. (Neur. Chrysopidae) and Vespa sp. (Hym. Vespidae) were among the most active predators which seemed to have an important role in the lowering pest population.

Growth and P and N assimilation of pistacia plants in response to infection by a vesicular - arbuscular fungus (Glomus dimorphicum Boyetchko & Tewari) were characterized. Infection by this VAM fungus significantly increased the plant growth of non - mycorrhizal planets in no – P treatment. The VAM-enhanced growth was similar to that induced by increases in P nutrition. Root growth was less influenced by P deficiency than shoot growth moreover P deficient plants accumulated a lower proportion on total P than high P Plants. P uptake by roots was enhanced by VAM fungus. Infection by this VAM fungus decreased as P nutrition increased. Moreover VAM colonization enhanced shoot concentration of N and through a general improvement of overall plant mineral nutrition promoted plant growth.

The effects of nonsaline, & saline soils with low, medium or high salinity (EC =1.7, 10, and 18 decisiemens per meter, respectively) on catalase, peroxidase, and nitrate reductase activity of different parts of colza (Brassica napus L.), cultivars PF 7045.91 and Hyola 401 and also the efficiency of comparing these activities as a tool for estimating the tolerance of these cultivars in saline conditions has been studied. Plants were grown in plastic pots filled with soils with different electrical currencies mentioned above, collected from different areas of the Golestan province, Iran. After 4 months, randomly selected plants were used for determining peroxides and nitrate reductase activities of root and rosette leaves, and after 5 months such an experiment was also prepared but for determining catalase activity of rosette and inflorescence leaves. Results indicated that catalase activity in both cultivars increases by increasing salinity. Such an increase is more sever in the Hyola than in PF cultivar. By increasing salinity from nonsaline to medium slain 10 dS/m), nitrate reductase and peroxidase activity of roots increases more severely in the Hyola than in the PF cultivar, and also the decrease in nitrate reductase activity in rosette leaves of the Hyolais slower than PF cultivar. Reversely in high salinity, and by comparing with control, the rate of increase in nitrate reductase and peroxidase activity of root in PF is more sever than in Hyola cultivar. By regarding the whole results of this study, it seems that the tolerance of Hyola to saline conditions is more than PF cultivar from nonsaline to medium saline conditions, but in high salinity PF is the more tolerant cultivar. It also may be concluded that comparing the rate of increase in nitrate reductase and peroxides activity of roots, probably is a suitable device for comparing tolerance of these cultivars.

Water stress considers as most important I environmental stresses. The effect of water stress in secondary metabolite fluctuation of Hypericum perforatum (hypericin) evaluated with performance of well water, mild and severs water stress treatments in Karaj research station. In this experiment a CRBD with 3 replications in 3 years was used. Well water (-0.3 bar), mild water stress (-3 bar) and sever water stress (-15bar) treatments according 17.4, 11.5 and 8.5 water weight percent relative to dry soil were performed respectively. Hypericin extracted in two stages by soxhelt (using CHCL3 and MeOH) and measured by UV spectrophotometer in 590 nm. The results showed that top yield, hypericin percentage and hypericin yield increased with well water. Mild and sever water stress caused to decreasing hypericin and yield of Hypericum perforatum. Top yield and hypericin amount in the first harvest was 2-3 folds to the second harvest. Correlation between hypericin amount and flowers per plant was significant and positive. In spite of Hypericum perforatum resistance to water stress, it produced lower tops and hypericin under water stress. Adequate and on time irrigation causes to completely growth and more flower which increases quality in H.perforatum.

This study was conducted to investigate of the effects of rhyzobium strains on seed germination traits of three alfalfa varieties. This study was carried out as two factorial experiments using completely randomized design with three replications in Alborz research center, Karaj, Iran, 2002. Three varieties of alfalfa (Ghareh yonjeh, FAO and Australia) constituted the main plots and 2 levels of rhizobium and control were the sub plots. The experiments were carried out under laboratory and glasshouse conditions. In laboratory, each experiment unit was a petry dish containing 25 seeds. In glasshouse it was a plot of 15 seeds. In both conditions the percent of germination, speed of germination, length of seedlings and seed vigor were recorded. The results showed that rhyzobium bacteria had a significant effect on percent and speed of germination, but it was not significant. The interaction effects between varieties and rhyzobium were significant for seedling length and vigor in both experiments. These results indicate that rhyzobium strains have varied effects no germination characteristics for different varieties and conditions.

This research was performed in order to evaluate four cultivars of cotton (Cooker312, Sahel, Saiokra, Jokuroa) for studying the percent of callus induction from hypocotyle, leaf and root segments. After production of sterile seedlings, different parts of seedlings (hypocotyle, leaf and root) were cultured on MS medium without any hormons. After production of sterile seedlings, different parts of seedlings (hypocotyle, leaf and root) were cultured on MS medium with different proportion of 2.4-0 and kin [(0.1, 0.1), (0.5, 0.5), (0.5-1), (1.1).(2.1) and (5.1) mg/lit)]. The explants incubated under light at 25±2°c for callus induction in all of cultivars, MS medium supplemented with 2.4-0 and kin (0.1, 0.1), (0.5,0.5) mg/lit containing was the best medium for callus induction in hypocotyle explants. But in media (mg/lit) 2.4-0 and kin (0.5, 0.5) mg/lit] leaf was more responsive. The most effecting medium for callus induction in root segments was MS supplemented with 2.4-0 and kin (0.5, 0.5), only in cooker cultivar and other cultivars did not response. In summary results of variance analysis showed that the factors under investigating had significant effect on callus induction, only jointed effects of variety part did not have any significant effect.

Agricultural ecosystems are related to economical and society condition widely, that there are in the world. The major target of agricultural ecosystems management is maximum energy flow and human service materials. Energy cycle is a subject of agricultural ecology and in different locations of world, input and output energy are calculated in different agricultural ecosystems. A way of estimation agriculture development and product stability in agricultural location in using of energy flow method. In this consideration, energy flow at agricultural ecosystem of wheat under rainfed farming was evaluated with using of statistics and information related province agricultural organization (Preparation of questionnaire from province farmers). The related data of inputs and outputs are become equivalent values of input and output energy, and then was calculated energy efficiency. Energy value of used factors and inputs of this type cultivation was 5359510.08 kcal/ha-1 and output (production) energy value of wheat grain yield 7062898 and 5684204 respectively. Also, energy efficiency value (output: input ration) was 0.42 that energy efficiency value of grain and straw was 0.76 and 0.94, respectively. Data showed the most of using energy of wheat cultivation of Mazandaran province were nitrogen fertilizer using and machinery using energy probably, due to climatical condition of Mazandaran province.

Powdery mildew is one of the most important disease on saxaoul plants (Haloxylon spp) in Khorassan province and other areas of Iran. The causal agent of disease is Leveil/ula saxaouli (Sorok) Golovin. In this study effectiveness of different temperature (5-30c) on germination of ascospores on surface of glass slides after 24 hours and conidia after 24, 48 and 72 hours were evaluated. The results indicated that minimum germination of conidia were occured after 24 hs. in 5°c and maximum after the same time in 25°c With rate of %3.17 and %24.09 respectively.Maximum and minimum ascospores germination were %45 in 20°c and %8 in 5°c respectively.

Polygonum and rumex are genera of polygonaceae family, and widely distributed in Kerman province. There are some doubtful points in taxonomy of both genera. We attempted to investigate morphological and chemical characters by statistical analysis. Specimens were collected form their natural habitats in Kerman province. Thirty six morphological characters were studied by cluster analysis. The results support recognition of two sections, Polygonum and persicaria, in genus polygonum. Polygonum minus is placed in sect. Persicaria and isolated from other species of section polygonum. Mean while the existence of two subgenera, Acetosa and Rumex, in genus Rumex was confirmed. Flavonoides were studied by two dimensional paper chromatography and data was analysed by cluster analysis. Herbaceous and woody species showed different flavonoid patterns. Again Polygounm minus is isolated from other species and existence of two sub genera, Acetosa and Rumex in genus Rumex is supported by flavonoides. Therefore, the results obtained by chemical studies are mostly in accordance with morphological studies and confirm the existing classification.

In the lack of forage production, (specially at drought conditions), sometimes farmers use gramineae species to be grazed by animals addition to produce seeds. In order to provide food for animals, the effects of different treatments of two cultivars of rye and two cultivars of triticale were studied using a field experiment conducting a split plot design with 4 replications in Bu-Ali-Sina medicine plant garden in Hamedan, Iran, from 1998-1999 Two factors including cultivars and different stages of harvesting were studied. The main plots were allocated to the cultivars of rye and triticale. Forage harvesting at the end of tillering stage and at the beginning of jointing stage, and a control (no harvesting) were used as subplots. In addition to the yield of seed and forage, the number of tillers and plant height were evaluated. The results showed that other than forage yield, there was highly significant difference between cultivars. Different effects of harvesting stages were found only in the case of plant height and seed yield. The interaction between cultivars and forage harvesting were significant on seed and forage yield. In general, in Hamedan conditions, the rye Stratuskaya with a high yield of forage harvesting in both tillering and jointing stages is recommended but cultivar Juvenilla-22 must be harvested only in tillering stages. However, replication of this experiment in several locations for at least three years is strongly recommended.

Alfalfa (Medicago sativa L.) is one of the important forage crops in arid and semi-arid region. Drought as environmental stress reduce plant growth specially alfalfa. In order to study of alfalfa (Medicago sativa L.) calli and in vitro selection for drought tolerance a factorial trial as completely randomized design with 9 treatments and 10 replications was done. The comparison was made on variety CUF 101 and soma clones 7R1 and 7R2 in the stage of callus initiation, from view of wet weight, dry weight, dry to wet weight ratio and accumulation of proline in the callus and finally evaluation of regeneration in the presence of different mannitol concentrations (0, 0.4 and 0.7 molar). Results showed that there is a significant difference between alfalfa genotypes in terms of wet weight, dry weight, dry to wet weight ratio, praline accumulation and regeneration percentage in different mannitol concentrations. By increasing drought stress (mannitol concentrations) amounts of dry weight, dry to wet weight ratio and accumulation of proline were increased while the callus wet weight and regeneration percentage were decreased. Shoot formed on high concentrations of mannitol (0.4 molar) were transferred to root induction medium for root induction and shoot elongation. The resulting plantlets were potted into a soil-sand-peat moss mixture for adaptation then transferred to soil to set seed.

The com armyworm (Spodoptera exigua Hub. Zimm.) is one of the most important pests of corn crop in Khuzestan province of Iran. Young corn plants are more susceptible to this insect defoliator. Microbial control of S. exigua specially by Bacillus thuringiensis Ber. is one of the most effective methods and is recommended by workers. This research was conducted to evaluate B. thuringiensis pathogenicity both in laboratory and field trials, in Khuzestan province. In prime step, different serotypes were evaluated by bioassay in the laboratory conditions. The results demonstrated that serotypes 1 and 3a3b were more virulent compare to third strain. In other bioassay, it was shown that second larval instars was more susceptible and along with larval growth and development, virulence of spores and crystal bodies lowered, significantly. Also, it was shown that in a few hours, affected larvae restrained significantly to feeding from corn leaves, compared with control. Application of surfactant agents such as triton x-100 in bacterial suspension increased virulence of the pathogen on associated host. In the field studies, virulence of B. thuringiensis was the same as the laboratory studies. Based on our results, B. thuringiensis can be accounted as an effective biological control agent for S. exigua in Khuzestan province.

Powdery mildew is one of the most important disease in Saxaoul (Haloxylon spp). The aim of this study was comparison of different Saxaoul genotypes in response to powdery mildew fungus (Leveillula saxaouli). This study was carried out from 1998-2002 at Bajestan Desert Plants Reseach Station. The data showed there is very significant difference between genotypes for powdery mildew fungus (α=%1). There is also significant difference between genotypes for powdery mildew fungus in each year and all of years (except between 2001 and 2002). But there was no significant difference among blocks in the experiment. Means of powdery mildew intensity in 1999, 2002, 2001 and 2002 were 45.19, 33.59, 11.30 and 13.52% respectively. Mean comparison among genotypes showed that the lowest powdery mildew intensity was on 25 (Kerman), 37 (Khorasan), 19 (Ghom), 24 (Kerman), 10 (Kerman), 10 (Yazd) and 38 (Khorasn) genotypes. Vigority reduced from 1999-2002 but there was no correlation between vigority and powdery mildew intensity.