Year:2006 | Volume:19 | Issue:1 (70 IN AGRONOMY AND HORTICULTURE)|Papers Count:13

In the present research seeds of red cabbage (Brassica oleracea L. cv. saccata) were genninated in sterile conditions and then grown in plastic pots for I month. Unique plants in their vegetative growth phase were selected and divided to the control and treatment groups, randomly. The treatment plant groups were exposed to a 30 mT static magnetic field for 10 days, each 5 hours and then both the treated plants and the control ones were harvested, frozen with liquid N2, and kept at -80°cuntil used for biochemical measurements. Exposure of seeds of red cabbage to the aforesaid static magnetic field during germination also induced further growth of the plants. Compared with the non-treated plants, increase in the contents of anthocyanins, and wall-bound phenolic compounds of shoot were observed in those plants which were treated with static magnetic field. The later also had reduced activity of PAL and reduced amounts of lignin and total sugar contents in both roots and shoots, compared with those of the control plants.

Bacterial wilt is the most important disease of potato in Southern Kerman. The results of phenotypical, biochemical, nutritional and pathogenicity tests on 48 strains isolated from wilted potato in Southern Kerman (Jiroft, Kahnouj, Barn, Baft and Bardsir cities) showed that Ralstonia solanacearum is the causal agent of the disease in these areas. All strains of R. solanacearum examined were very similar in all but 25 phenotypic features and belonged to race 3, phenotype B of biovar 2 (biotype 2-A). Strains appeared very similar to almost identical in whole-cell protein patterns in SDS-PAGE and also in agar-gel diffusion tests, when a polyclonal antiserum prepared in rabbit against a representative strain was used.

Rubia tinctourum is a valuable medicinal plant that it is from iran and it has been used in pharmaceutical industries and staining industrial. seeds of this species have germination problems. In order to breaking seed dormancy, this experiment has been conducted in Tehran University on the base of Completely Randomized Design in four replications. The treatments of this experiment were as: Continued light, gibberellic acid (500 ppm), stratification (4°C inthree duration of 2, 4 and 6 weeks) and scarification by sulfuric acid 98% (10,15 and 20 min), sand paper and hot water. The highest germination was obtained for.15 min scarification by sulfuric acid (90%). However the effect of scarification with hot water and sand paper were the same as acid sulfuric effect. The results showed that exposing the seeds under continued light and gibberlic acid had no significant effect on seed germination. Exept generation percent, Root length, shoot length, time of germination and seedling fresh weight were studded. Seed scarification by acid sulfuric at 20 min decreased root length, shoot length and seedling fresh weight. Seed scarification by hot water (90°C) in 10 min only decrease root length and seedling fresh weight. It was concluded using sand paper was the best using for breaking seed dormancy of madder.

In order to evaluate effects of limited irrigation and root harvesting dates on yield and some of quality characteristics of sugar beet, an experiment was conducted during 2002 in Miandoab Agriculture Research Station using a factorial split plot design arranged in randomized complete block design with three replication. Three irrigation levels 40, 70 and %100 of crop water requirement and four genotypes (Rasoul, Shirin, Dorothea and BRl) were allocated as factorial design to main plots and five harvesting dates placed in sub plots. Results showed that Dorothea cultivar in full irrigation had maximum amount of root yield and white sugar yield. Increasing of harvesting dates was resulted to enhancing of the traits. The traits had minimum amount at last harvest. The cultivar effect was significant on root yield and sodium and the effect of harvesting date on the potassium, sodium and sugar content. An interactive effect, was observed between irrigation levels and harvesting date on the amount of root yield and white sugar yield and between the kind of cultivar and harvesting date on nitrogen and a locality. This study showed that Dorothea cultivar had least impurity and the most root yield. In the other hand we concluded that if environmental conditions allows, delay in harvesting date will cause improvement of root quality.

Application of biofertilizers, especially plant growth promoting rhizobacteria (PGPR) through integrating use by chemichal fertilizers is most important strategy for integrated plant nutrition in sustainable management of agroecosystems and their production increase by Adequate Input Sustainable Agriculture (AISA) system. In order to study the effect of Azotobacter chroococcum, Azospirillum brasilense As. lipoferum and Pseudomonas fluorescens application on late maturity maize (Zea mays L.) single cross hybrids (SC700, SC 704 & a promising single cross B73xK18) silage fodder yield a factorial field experiment was conducted. Hybrids seeds single inoculated with one by one bacteria and coinoculated by two and four bacterial combined inoculants and no inoculation as control treatment. In grain milky stage, Plants harvested and then silage fodder yield per hectare, plant fresh weight, dry weight (biomass) per hectare and per plant, plant leaf number and top of ear leaf number, plat height and stem diameter were determined. Results revealed that all studied traites affected by experimental treatments. Interactions of maize hybrids and plant growth promoting rhizobacteria for plant fresh weight and top of ear leaf number were significant (p<0.05) and other studied traits highly significant (p<0/01). Also this results cleared that silage fodder yield per hectare and other studied traits of SC704 when the seeds coinoculated by four bacteria were better than other hybrieds.

To locate QTLs controlling morphological characters of Arabidopsis thaliana under water stress condition, 93 recombinant inbred lines resulted from the cross between two ecotypes of Colombia and Niederzenz were tested using factorial experiment in a randomized complete block design with five replications. The characters: number of leaves, size of rosette, plant height, number of branches, number of silique and flowering time were measured during the experiment. The results of analysis of variance showed significant differences between ecotypes for all the characters measured indicating the presence of genetic variation. The results of QTL analysis using marker regression indicated that under water stress condition flowering time is controlled by 3 QTLs located on the chromosomes 1 and 4. Plant height is controlled by one QTL located on chromosome 1.Number of leaf and the size of rosett are controlled by two QTLs located on chromosome 1.Number of branch and silique are also controlled by one QTL located on chromosome 1. The contribution of QTLs controlling flowering time, plant heigh number of leaf, size of rosett, number of branch and number of silique in the total genetic variance was almost 90%, 72%, 89% and 47%, respectively.

In this experiment the effect of natural and artificial factors on dormancy and acceleration of sprouting of potato was studied, according to Iran potato cultivation continuation project It was carried out in Hamedan Agricultural Research center, in factorialling (4x7) completely randomized design with 3 replications and 2 factor, during 1998.The first factor was four potato cultivars: Agria, Morfona, Draga and Moren, and the second factor was six methods of breaking dormancy, containing: temperature, heat-cold shoking, gibberllic acid, carbon disulphide (CS2) and carbon dioxcide (CO2) and one check treatment The results showed that in all steps of sprouting the differences between the cultivars and treatments and their interaction were significant at %1. The cold-heat treatment had the least effect and the carbon dioxide and gibberllic acid and carbon disulphide had the highest effect and carbon dioxide in order to break tuber dormancy.

There has been an attempt to identify factors, which influence natural resource preservation towards achieving sustainable development. Because of complexity and vast areas of rangelands, it seems logical to empower local people in order to participate in preservation and renovation of these resources. One of the mechanisms in social mobilization in rural areas is through the cooperative systems. This study is sought to investigate the factors influencing the participation of rangers in Kurdistan province in North-west Iran. A survey research method was used. A questionary was used as a research instrument. A total of 26 cooperatives with at least 3 years of experience throughout 8 districts in Kurdistan were surveyed. A random sample of 15% - 20% members of each cooperative was selected. The findings indicated that Nine factor were significantly related with individual participation in cooperatives: Relationships between rangers and natural resource personnel, fatalism, achievement orientation, technical knowledge, level of education, cost- benefit, social impact of participation, contact with extension service and input supply. Contact with extension service and educational level were the two factors which entered in the regression model and explained 39 percent of variability in participation by rangers.

To study the effects of sowing depth along with sowing seeds with and without husk on soil seed bank as well as natural regeneration of annual medics, this experiment was conducted during 2001 and 2002 growing seasons. The experimental treatments were arranged in factorial-split plots based on a complete randomized block design with 3 replications. Six annual medic cultivars were assigned to the main plots were the sowing depths of 2, 4, and 6cm along with sowing seeds with and without husk were randomly assigned to the sub plots. Sowing plants at 2cm depth without husk not only caused a better germination and a uniform establishment, but also resulted in a higher biological yield as well as a richer seed bank. Medicago rigidula cv. Rigidula produced the highest biological yield overall sowing treatments among annual medic cultivars. In the same conditions the highest seed production as well as the richest seed bank belonged to Medicago truncatula cv. Caliph. As the seeds were sown deeper, plant density decreased due to a week germination and pasture establishment which led to a lower dry matter and seed production. When the seeds were sown with pods in the same situation the decrements of dry matter and seed were enhanced. Based on the results of this experiment it is suggested to achieve a good pasture establishment in the first year of ley-farming system, all the medic seeds must be scarified before sowing.

In order to evaluate 19 advanced lines of bread wheat, an experiment was carried out in a randomized complete block design with three replications at Gorgan Agricultural Research Station for three years, from 2000 to 2003. Each plot consisted of six rows of 6.6 meter with 18cm between the rows. Simple and combined analyses of variance was done and results showed significant difference (p<0.01) for grain yield among genotypes and genotype year interaction. To determine the stable genotypes, stability analysis was done using of parametric methods (environmental variance and coefficient variation) and non-parametric methods Rank. Path coefficient analysis was done in order to investigation of correlation between characteristics with grain yield and determination of their portion with all characteristics according to simple analysis of variance. The results of this study showed significant (p<0.01) difference among genotypes for evaluated traits. Phenotypic and genetic correlation coefficient between grain yield and traits (1000 KW, plant height, and length of spike, number of spike let, and number of grain per spike, grain weight per spike, grain yield and biomass) were close to each other. This indicated that covariance and environmental variance were minor. The genetic correlation was used for path analysis. Correlation coefficient of grain yield with grain weight per spike, number of grain per spike and 1000KW was significant (p<0.01). The results of path analysis showed that direct effect of grain weight per spike was minor. But direct effect of grain number per spike was high. In addition indirect effects of grain number per spike and grain weight per spike by 1000 KW were high. The results of path analysis revealed that using trait number of grain per spike selection for high yield in Golstan province conditions is very important and this may depend on climate and disease conditions in Golestan province. Result of environmental variance showed that genotypes number 10,8,12 and 20 with lowed value for environmental variance had the highest stability. Based on coefficient of variance, genotypes number 10,8,12 and 20 had the highest stability, respectively. Based on non-parametric method of rank, genotypes number 12 andlO with R of 1.3 and 4 respectively lowest variances and standard deviation (Sd) of rank had the highest stability. Results based on analyses of variance and different stability methods, genotype number 12 with good stability and highest yield of 1140Kgha-l (22.4%) than the check cultivar (Tajan) can be recommended for cultivation in Gorgan region. Results suggest that this line suitable for Gorgan.

Alfalfa is usually cultivated in the Spring but there are problems about the time of cultivation in cold and semi-cold regions. In the Fall cultivation this species will die because of Winter cold. In Spring cultivation also pastures are not ready for entering human and machinery to cultivate seeds. In this study' by using of some allelopathic compounds were delayed germination starts until temperature become suitable and exist enough moisture. In first stage the effect of some allelochemicals (Caffeine' Ephedrine' Vanillin' ABA' Eucalyptus and Walnut leaf extracts and Onobrychis seed extract was considered on percentage germination', germination start' coefficient of velocity and coefficient of allometry. Compounds that don't have negative effect on percentage germination and seedlings growth and also delayed germination start for long time were selected as suitable inhibitors (Vanillin' Eucalyptus leaf extract and ABA). In second stage' selected compounds were coated around seeds by seed pelleting method. Indicator of percentage germination' germination start and coefficient of velocity were calculated. Allelopathic compounds of ABA and Eucalyptus leaf that coated around seeds delayed germination start for longer time.

In the present research, we studied the effects of ascorbic acid (AsA) to act as a highly effective antioxidant in soybean (Glycine max L. cv. Union x Elf) plants undergoing oxidantive stress caused by nickel (Ni). One-week-old hydroponically-grown seedlings were exposed to variable concentrations of NiCl2, 6H2O (0, 0.5, 1mM) and AsA (0.1 mM). Ni was more accumulated in roots than in shoots. Surprisingly, root-to-shoot translocation of Ni depressed by ASA. In the absence of ASA, excess Ni suppressed biomass production of both roots and shoots and reduced chlorophyll content in leaves, while ASA removed these effects. The existence of Ni induced oxidative stress can be demonstrated by an increasing in malondialdehyde (MDA) production. This rise could be explained by activation of the enzyme lipoxygenase (LOX, EC.1.13.11.12). Addition of ASA together with Ni ions, almost completely restored LOX activity and reduced MDA production. In the other hand, ascorbate peroxidase (APX, EC 1.11.1.11) and catalase (CAT, EC 1.11.1.6) activities in both roots and leaves were strongly reduced by Ni stress. While ASA highly increased APX and CAT activities in Ni-stressed plants. Consequently, ascorbic acid by sequestration of Ni in roots and with an altogether increases in the activities of antioxidant enzymes reduces Ni induced oxidative damage in a certain extent.

This experiment was conducted in incubator in orther to study the effects of water potential on seed germination, rate of germination and seedlings growth of four sugar beet genotypes named Madison, 7233-P29, 7233-P21 and le. Four water potential including distilled water as control, -0.37, -0.59 and -0.81 Mpa which made by NaCl and NaCl+CaCl2 in 5 to 1 molar ratio. The experiment was carried out based on completely randomized design with four replications. Results of variance analysis showed that effects of water potential, type of salt composition and cultivar on germination percentage, rate of germination, root and shoot length were significant. With decreasing water potential, germination percentage and rate of germination declined but the response of germination persentage was greater than rate of germination. Cultivars Madison and IC had the highest and the lowest percentage and rate of germination respectively. The effect of salt composition was significant on rate and percentage germination. The percentage of germination at water potential -0.37 which made by NaCl + CaCl2 significantly was higher than the same water potential made by only NaCl. However, at lower water potential (-0.59 and -0.81 Mpa) the rate and percentage of germination significantly were higher at NaCl solution rather than NaCl + CaCl2 solution. When seeds were transferred to unstressed condition, after 20 days of salinity treatment, there was some recovery. Recovery ranged from 27% to 79% germination. This shows that the inhibitory influence of salinity on sugar beet seed germination was mostly due to osmotic effect and a small portion of the inhibition could be attributd specific ionic effect.