AGRICULTURAL RESEARCH
Year:2006 | Volume:5 | Issue:3|Papers Count:7

RAPD analysis offers a quick and comparatively cheap approach for the detection of genetic differences, since it has extensively been used in studying genetic diversity in different plants. This technique was employed to assess genetic diversity of 28 local populations of Tareh Irani (Allium ampeloprasum) and to examine their relationship with kurrat (Allium ampeloprasum Kurrat Group) and leek (Allium ampeloprasum Leek Group). Nine of 320 random 10-mer primers revealed scorable polymorphism between populations of Tareh Irani and it would be further evaluated for use in genetic mapping. Genetic distances between each of these plants were calculated and cluster analysis was used to generate a dendrogram showing phylogenetic relationship between them. Leek and Kurrat felt in two distinct groups, separated from Tareh Irani populations. Tareh Irani populations also were separated from each other in 6 groups. Most of them were belonged to 6thgroup indicating the low genetic distance between them. Ahvaz19, Zabo126 and Arak58 populations were located individually in three distinct groups, having higher genetic distances with other populations. The results were in agreement with previous studies.

This study was carried out to evaluate antagonistic properties of Trichoderma harzianum on soilborn pathogenic fungi of potato including Rhizoctonia solani, Fusarium solani, Colletotrichum coccodes, Fusarium oxysporum, in laboratory, controlled miniplot and field experiments in four years. T harzianum isolates and pathogenic fungi were isolated and identified at the first year. Experiments were done in Miniplot containing sterilized soil with 12 treatments and four replications including non-infested control, infested controls and treated with T harzianum using RCB design. Results showed that the disease percentage in infested treatments by R. solani, F.solani, C. coccodes, F. oxysporum were 37.22%, 29.13%, 26.34% and 24.26% respectively, whereas in each above mentioned treatments, treated with T. harzianum disease percentage reduced to 18.14%, 15.36%, 14.5% and 15.24% respectively. The results were significantly different at the level 1%. In field experiment, effect of T. harzianum on the natural infested soil (to all pathogenic fungi) was studied using two treatments including Agria and Marfona cultivars and the means were compared. Results. showed that T. harzianum reduced the disease incidence from 17 and 15 percent to 9.5 and 8.5 in Agria and Marfona cultivars respectively. Means of yield were increased from 32 and 36 to 45 and 41 ton per hectare, in Agria and Marfona cultivars, respectively. Therefore according to the obtained results in control of fungal diseases of potato the application of T. harzianum in root and crown is recommended in integrated soil-born disease management.

Gene expression patterns at early stages of somatic embryogenesis in chick pea was studied using 2,4-D and 2,4,5-T (3 mg/L each) in MS medium. Emberyogenic callus was produced in media containing 2,4,5-T followed by forming globular shape embryos while this did not occur in the media containing 2,4-D. In order to study the effect of these treatments on the embryogenesis patterns, differential display (RAP-PCR) was used. Extraction of mRNA from callus tissue was carried out 7, 14, 21, 28, 35 and 42 days after zygotic embryo culture. Reverse transcript reaction of cDNA first strand was made using three oligo dt primers anchored with; dTA, dTG, dTC and amplification step was performed by the use of 8 arbitrary primers of 12 nucleotides. Separation of bands was done on the denaturing polyacrilamide gel and vertical electrophoresis. The bands were shown by using silver nitrate (AgN03) staining method and resulted bands were pictured by scanner and saved in computer memory. The number of dT bands was used as an indicator of gene expression. The results showed that dTC oligo primer produced maximum number of bands. All primers showed the same gene expression pattern. The gene expression was high at first and the second weeks of culture, but from the third to fourth weeks the rate of gene expression ceased while a considerable increase in gene expression was observed in the fourth to sixth weeks of culture. Although there was differences between the treatments all during the stages of the experiment, but the difference was more obvious at late stages of embryogenesis. The results showed the same gene expression pattern in chick pea was however different in terms of comparing with the studied model plants, but it was similar from the point of view of its pattern.

The effect of water deficit on growth and development, yield and yield components of maize at vegetative (V8) and grain filling stages (R3) was investigated. Six hybrids including three commercial hybrids (SC301, SC647, SC704) and three leafy hybrids (Leafy 1, Leafy2, Leafy3) were evaluated. A split plot laid out a complete block design with three replications was used. Water deficit at vegetative stage caused delay in phenological stages, but stress in grain filling stage and both of two stages reduced the duration of reproductive stage. Biological yield was reduced, significantly, by stress at evaluated growth stages. In stress and control treatments, leafy hybrids had high potential in total and leaf dry matter production. Water stress during the both of vegetative and grain filling stages reduced the yield of all hybrids. SC704 and SC301 hybrids had highest and lowest reduction in grain yield with 43% and 32% losses, respectively. Furthermore, stress in grain filling stage had more destructive effect than vegetative stage on grain yield. Water deficit at both of two stages had most reductive effect on growth and development, stress at grain filling stage and water deficit at vegetative stage have less reductive effect, respectively.

Fusarium root rot of bean caused by Fusarium solani f.sp. phaseoli is an important disease of this crop worldwide. In this study, biological control of the disease was examined using rhizosphere bacteria. One hundered and twenty two bacterial isolates from bean rhizophere were evaluated by dual culture on PDA media on antagonistic activity against Fusarium solani f.sp. phaseoli five isolates showing higher antifungal activity were selected for fm1:her investigation. Based on the biochemical, physiological and morphological characteristics, isolates B99 and B23 were identified as Bacillus cereus, and isolates B12, B80 and B83 as Bacillus subtilis. The ability of bacteria to produce liquid and volatile antifungal compounds, siderophores, cellulase and poisonous compounds such as hydrogen cyanide were stuqied in vitro. Volatile compounds and extracellular liquid metabolits of all tested isolates affected the pathogen and decreased its colony growth rate compared to the control. In cellulase test all of the isolates but B'12, B99 and B83 were able to produce cellulase. None of the isolates produced hydrogen cyanide. The effects of selected bacteria isolates on disease severity, percentage of disease incidence and plant growth indexes using sterilized and nonsterilized soils by two methods comprising soil treatment and seed dressing treatment with bacteria were studied in vivo. In this study the isolates B83 and B12 decreased the disease severity to the levels of 1.7 and 2.1 respectively. The isolates B12, B80 and B83 decreased the disease incidence percentage to 17,37 and 21 percent respectively. The isolates B12, B83-and' B23 increased bean dry weight in seed dressing treatment method in sterile. soil to 5.9, 5.5 and 4.5 gram respectively.

In this study, a part of the floods water volumes of Ghara-Chay basin located in Hamadan province was investigated using excess rainfall determination. In this regard, digital elevation model, rainfall gradient and isohyetal map of the basin were prepared using the maximum daily rainfall of the meteorological stations of the region for different return periods. Then, based on the soil infiltrations and satellite images, the soil hydrological groups and land use maps were produced. Finally, by overlaying the prepared maps, the curve number maps were developed. The depths of direct runoff from the storm generations were computed using the SCS method. The overland flow plan of each storm was developed by conversion and combination of all the information maps in the GIS. A classification consisting 7 runoffs category which was included the runoff depth less than 20 mm to higher than 120 mm was considered. The difference between the classes was 20 mm. Frequency of each class was calculated from 25 to 200 year return periods. The results confirmed a high relationship between the digital elevation model and the runoff depth maps. They showed that the overland tlow decreases from high lands toward plain of the basin that is exactly coherent with the long term t10w coefficient of the basin. An exponential decreasing trend was identified between the runoff depth and the area of each class. In exception of the class which was less than 20 mm, the area of each class was directly related to return periods from 200 to 25 years. In the class less than 20 mm, the inverse relationship between the surface and return periods showed that the runoffs with an area about 50% of the total area of basin, are the normal runoffs that occur frequently, but in the rest of the classes, which flow depth increase, non-flooding flows play a major role.