فصلنامه گیاه و زیست بوم
پیاپی 11 (پاییز 1386)

In order to investigate genetic potential and genetic variation in various Haloxylonpopulations, an experiment was conducted on genotypes collected from different areas ofthe country in 2007 at an experimental station located nearby Ghom called Hossein Abad.The experiment was based on randomized complete block design with three replications.Several morphological characteristics were evaluated on 15 progenies of each 27 genotypes of Haloxylon aphyllum. Analysis of variance were performed on the recordedcharacteristics that indicated the a great deal of genetic variation and differences between the characteristics studied during the 7year of experiment. Therefore, in breeding and selection programmers interrelationship between the characters must be used to achieve the breeding objectives. Most of the studied characters such as plant height, trunk diameter, crown diameters at two different directions, showed positive significant correlation of investigation. Plant height showed a positive significant correlation to trunk diameter and crown diameters for the 7th year of study. Based on the 7th results, the genotype number 18 originated from Sistan and Baluchestan is determined as the best genotypes. It is recommended to use this genotype during next phase of the study to estimate required genetic parameter in next generations.

Soybean is one of the major crop in our country specially in Mazandaran and Gorgan Province. Due to the very important nutrition value as wel as significant role of soybean in food industry, doing no research about the effect of micro elements on soybean, and regard to Zn-role in soybean, this experiment was conducted to evaluate the effect of different rate and methods of Fe- fertilizers on soybean yield. The test conducted in field experiment by 0, 30, 60, 120 kg/ha Zinc Sulfate treatment. The methods of application were banding and brodcasting, with and without foliar (3/1000 Zinc Sulfate) application. After farming and management practices, the crop yield and the weight of thousand seeds were determind at harvest for every plot. The results indicated that the maximum yield was in three treatments: one, '' 30 kg/ha zinc sulfate with band method and use of foliar application'' treatment 2580 kg/ha). Other treatments were ''60 kg/ha Zinc Sulfate with band, brodcast and use offoliar application with 2490 kg/ha, 2420 kg/ha yield. The effect of Zn-fertilizers and the method of application werent significant on height of plant and thousand seed weight (1% and 5% level).

In order to evaluate the Allelopatic effects of barley biomass (derived from differentphonological stages) on thin leaves weed suppressing in mung bean (Vigna radiate L.)production a field experiment was carried out in Shahr-e Rey the Islamic Azad Universitytraining-research field (2005-2006) using factorial experiment based on Randomizedcomplete blocks design with four replications. Experimental treatments obtained fromfactorials of barley biomass rates (2, 4, 6, and 8 t/ha) and their age (biomass derived fromtillering, stem elongation, heading, soft dough stages and straw after barley harvest). Barley biomass incorporated to the soil before seed bed preparation procedures for mung bean.Results showed that biomass age factor had significant effect on thin leaves weed control.Also all levels of barley biomass decreased weed fresh and dry weight. Mung bean seedyield significantly affected by biomass age. The highest amount of seed yield (87.10 g/m2)obtained under the use of heading biomass barley to mung 4 t/h effect. So regarding toenvironmental pollution of the south of Tehran which created by over the use of chemicalfertilizers and pesticides, the application of barley biomass to decrease weed growth ishighly recommended.

The effects of climate change on snowmelt runoff timing and changes in irrigation waterprogaramming in agriculture is very important in the rivers with snowmelt runoff regime.Inthis study, The peak time index of snowmelt runoff is calculated and Mankendal Test isapplied to study the trend index and climate change GCM models (ECHAM4 model) isapplied to study the effects of climate change on the peak time of snowmelt runoff with two scenarioes for next 100 years in karoon and Dez basins in the southwest of Iran. The main purpose of this research is determine the changes in the peak time of snowmelt runoff in karoon and dez rivers, for suitable progaramming in future. Research results showed that a shift is observed in the peak time of snowmelt runoff from spring to winter and this trend amount is 3 days in every decade.

Leaf-derived calli from Solanum hybrids were treated under different thermal regimes toinduce chromosome instability. DNA extracted from callus-derived regenerants had verylow yield. The chromosomes were tracked by chromosome-specific microsatellites. Markerloss was observed at a high frequency, so the possibility of technical artefacts was examined by repeating PCR for individuals with apparently lost alleles. Repeated PCRs revealed that the marker loss in initial reactions were not genuine. Marker loss was stimulated by using a manually-diluted DNA template, postulating that the tissue quality can influence the reliability of the DNA profile. Possible mechanisms of this situation are discussed.

To study the effect of the application of different levels of macro and micro elements onqualitative and quantitative characteristics of the wheat genotypes (Triticum aestivum) aSplit plot exferiment arranged in randomized complete block design with three replicationswas conducted. The research field of the Ghaleh-sin located at Varamin branch in 2006-2007.The main plot consisted of appling fertilizer at 5 levels (1-N,P 2-N,P +K 3-N,P,K+Zn 4-N,P,K,Zn+Fe 5-N, P, K, Zn+Cu)and sub plots, consisted of the 3 genotypes (Shiraz,Pishtaz, M72). Analysis of data indicated that the best results were obtained in the Shirazgenotype with 4443.2 kg/h grain yield. The effects of Application of fertilizer weresignificant. The highest grain yield achieved from N,P,K, Zn, Fe, Cu with 4941.5 kg/h, thelowest grain yield and another characteristic was obtained from appling only N, P. Analysisof variance showed a significant effect of Ratio Fitik Acid/Zn at Applying fertilizer. Thelowest ratio was obtained from applying N, P, K, Zn and Fe (A4).

The Compressing of soil due to traffic of agricultural machines and tillage tools whichaffect on the soil physical features and performance of agriculture production is going tobecome worst by mechanization of agriculture and vast application of tools.In this research, as a split plot experiment based on a completely randomized blok desing has been used and the effect of three types of tillage (moldboard plow-without moldboard plow and chisel plow)on two levels with and without subsoiling on selected plant and soil parameters was studied. Soil parameters under study included:1-moisture content 2-Bulk density of soil, before and two months after planting in two depth of (0-10cm) and (10-20cm)and plant parameters included:1-The percentage of germination 2-plant dry matter. analysis of variance and Duncans multiple range test for comparision of means has been used. It was determined that in plots with subsoiler, the treatment of bz(subsoiler + moldboard plow)had a significant difference with az(subsoiler + chisel) and cz(subsoiler + without moldboard).On the other hand in plots without subsoiler a chisel showed a siginificant difference with b(moldboard plow) and c(without moldboard plow)

This research is about the reaction of two rape seed (Brassica napus L.) cultivars towarddrought on, primary vegetative period, the percentage of germination, the length ofhypocotyle and the length of seedlings root. Brassica cultivars were PF (spring type) and SLM (winter type). Dry stress was made by different concentrations of PEG. Applied treatments are as follows: Distilled water, PEG 0/1 gr/ml (pressure -2 bar), 0/14 gr/ml (pressure -4 bar), 0/19 gr/ml (pressure -8 bar), 0/23 gr/ml (pressure -12 bar). Treatments were irrigated every three days in the same conditions and after six days, related characteristics considered. The result showed that percentage of germination length of hypocotyle, the length of seedlings root in both cultivars decreased with the increase of PEG concentration and SLM cultivar in high concentration of PEG in comparison with PF had more resistance toward stress.