مهدی مین باشی

Mycorrhizal fungi play a crucial role in promoting the growth and yield of agricultural plants, including sugarcane. To evaluate optimal conditions for these fungi and enhance sugarcane yields in Khuzestan Province (Iran), the species and spore density of mycorrhizal fungi were investigated in a research project across eight sugarcane cultivation and industry companies. Combined soil samples were collected from 25 sub-samples of each 64 selected farms and analyzed in the laboratory. The spores were isolated using wet sieving and decanting method followed by sucrose centrifugation used for determination of fungal species and spore density. Meanwhile, factors such as the physicochemical properties of the soil, crop rotation and ratoon age were measured and recorded, and their impact on spore density and sugarcane yield was calculated statistically. A direct and intimate correlation was also discovered between the density of spores in the soil and the yield of sugarcane, with the best outcomes found in well-drained fields (adequate sand), a neutral to slightly alkaline pH, sufficient moisture, and controlled levels of nitrogen, phosphorus, and potassium. On the other hand, crop rotation with plants like alfalfa or wheat which are mycorrhizal dependent as well as allowing fields to go fallow, and using fresh ratoon also led to an increase in the density of mycorrhizal fungi spores and sugarcane yield.

Wheat, as a strategic crop, has a special place in agricultural production of Iran and it has the highest cultivation area in the country. One of the most important limiting factors of wheat production in the world and in the country is weeds. Having comprehensive knowledge of the flora and species diversity of weeds is one of great importance for wheat management and it perceived as a primary need for production management and effective method of weed control in wheat farming program. In order to study of weed flora and evaluation of species, functional and structural diversity of weeds in wheat field of Golestan province, weeds population were surveyed at different cities during 2015 and the results were compared with the findings of last decade surveys. Randomized sampling method as W shape was conducted systematically using 0.5×0.5 m quadrate. All weeds in each quadrate were identified, counted and recorded for subsequent data entry and analysis. Mean density, frequency and uniformity percentage and relative abundance were calculated based on Thomas, 1985. Species Similarity index between different cities and Shannon and Simpson species diversity indices in each city were calculated based on available formula. Then cluster analysis based on average linkage method is carried out by SAS 9.2 for clustering different cities on basis of calculated traits that mentioned above. In this study, 51 plant species from 20 families were recorded. The most number of weeds were recorded in Poaceae, Fabaceae and Asteraceae families with 14, 7 and 6 weed species, respectively, but Poaceae, Polygonaceae and Brassicaceae were the most important weed families in wheat fields of Golestan provice, based on their relative abundance, respectively. The results showed that 78.43 % of recorded weeds were annual and the rest were perennial, 29.41 % of weeds were monocotyledons and 70.48% were dicotyledones. Avena ludoviciana and Phlaris minor with 40.21 and 37.11% relative abundance were the most important weed from narrow-leaved weeds and Sinapis arvensis with 32.42% relative abundance was the most important weed from broad-leaved weeds. P. minor, A. ludoviciana ،Veronica persica poir. and Stellaria media (L.) Vill. had the highest mean density in wheat fields of provice, respectively. The result of this study showed that the density of Avena ludoviciana, Sinapis arvensis, Phalaris minor, Lolium rigidum, Polygonum aviculare, Fumaria officinalis and Veronica persica has increased while the density of Polygonum convolvulus and Melilotus officinalis decreased over time gradually. Increase of narrow-leaved weeds than last decade may be related to continuous application of aryloxy phenoxy propionate herbicides for the years and resistance of weeds to this group of herbicides. Decrease of P. convolvulus density than last decade can be contributed to successful control of this weed by available herbicides such as tribenuron methyl, bromicid M.A. (bromoxinil+MCPA) and 2, 4, D. The most uniformity index was observed in A. ludoviciana (29.15), S. arvensis (26.57), P. minor (21.90) and V. persica (18.03), respectively. S. arvensis, A. ludoviciana, P. minor and V. persica with 42.55, 41.49, 41.49 and 30.85 % had the most frequency, respectively. The highest richness (the number of species) was observed in Khan Bebin (26 species) and the lowest (8 species) was in Kord Koy. Low richness in Kord Koy may be contributed to poor drainage of soil in this city that many of weed species cannnot adapt with this condition. The highest and Shannon diversity index was observed in Gonbad (2.48) and Khan Bebin (2.44) and the lowest value was observed in Kord Koy (1.18). The highest Simpson diversity index was observed in Kalaleh (0.43) and Minoo Dasht (0.4) and the lowest value was observed in Gonbad (0.11) and Khan Bebin (0.11). Different cities of Golestan Provience were grouped in 7 clusters for weed uniformity and weed abundance but for weed density they were grouped in 8 clusters. The most important weed in Aq qala, Bandargaz, Khan Bebin, Kord Koy, Kalaleh and Gorgan cities were Melilotus officinalis, P. minor, S. arvensis, Phalaris paradoxa, P.convolvulus, V. persica. A. ludoviciana was the most important weed in Ali Abad, Gonbad and Minoo Dasht cities. In general A. ludoviciana (40.21), P. minor (37.11), S. arvensis (32.42), and V. persica (27.96) had the most relative abundance in wheat fields and study of their control methods must be considered as research priorities in Golestan provice.

In order to the effectiveness of tank mix application of dual and broadleaf herbicides to control weeds, a field experiment was conducted at the Islamabad research station, Kermanshah, Iran, during 2014-2015. Treatments consisted of the application of (Mesosulfuron - methyl + Idosulfuron – methyl + Mefenpyr diethyl), (2,4D + MCPA), (Bromoxynil + MCPA) and (Mesosulfuron -methyl + Idosulfuron – methyl + Diflufenican + Mefenpyr diethyl) at different rates and tank mixing together.Treatments were arranged in a randomized complete block design with four replications.Results indicated that tank mix application of (Mesosulfuron - methyl + Idosulfuron – methyl + Mefenpyr diethyl) in combination with(Bromoxynil + MCPA)desirable controlled C. pycnocephalus, G. tricornutum, C. oxycanta and S. arvensisand reduced their density between 74% to 100% compared to control without spraying, while the single treatments controlled these weeds between 40% to 73%.Application of tank mix (Mesosulfuron - methyl + Idosulfuron – methyl + Mefenpyr diethyl) in combination with (Bromoxynil + MCPA)at rates 0.5 + 1.25 and 0.25 + 1.25 increased wheat grain yield at rates1927 (155%) and 2031 (158%)kg/ha respectively, compared to control without spraying, as well as weight of 1000 grain above herbicides increased at rates 44 (198%) and 45 (198%) gr respectively

A survey was conducted to study the effects of soil and climatic factors on distribution of weeds in 48 parks in 22 districts of Tehranin 2014. 52 weed species from 21 plant families were identified. Multivariate analyses with canonical correspondence analysis (CCA) showed that changes in the weed species distribution were due to soil traits (pH, Phosphorus, Nitrogen, Potassium, %Carbon, %Organic matter, EC) and environmental conditions during previous years. Green foxtail (Setaria viridis), hairy crabgrass (Digitaria sanguinalis), ragweed (Kochia scoparia) and knotweed (Polygonum patulum) had a wide distribution in the areas with high temperature. Where the soil nitrogen were high, Green foxtail (Setaria viridis), Ragweed (Kochia scoparia), Ladino clover (Trifolium repense), Knotweed (Polygonum patulum) and Sow thistle (Sonchus oleraceus ) density was found frequently. Besides, there was a correlation between soil potassium and the density of Broad leaf plantain (Plantago major L.), Little hogweed (Portulaca oleracea), Watter grass (Echinochloa crus-galli), Procumbent yellow-sorrel (Oxalis corniculata) and Common dandelion (Taraxacum officinale) in turfgrasses. Based on the results of this study, it would be possible to overcome these problems to some extent by predicting future problems of weeds and changing management plans.

A study was conducted to assess the weed flora changes in the irrigated wheat fields during the last decade in 52 fields located in seven cities at Tehran province in 2015. The frequency, Unifromaty and dominance index of species were calculated and they were compared with the mentioned indices from 2005. In 2015, 66 species of weedsfrom 26 families were identified, of which, 55 species were broad-leaf and the others were grasss. 10 species that had been observed in 2005 had been omitted from the fields and 15 new species from 11 families were identified. Amaranthaceae, Dipsacaceae, Plantaginaceae, and Solanaceae were the four families that were for the first times observed in the fields of the province for the first times. Brassicaceae, Poaceae and Asteraceae families were dominant families in the fields. The broadleaf species of flixweed, knotweed, bindweed and fumitory with dominance indices of 117/94, 97/82, 81/09 and 46/11 and the grasss of wild oat,wild barley,annual ryegrassferalrye with dominance indices of 86/59, 50/94, 27/64 and 15/41 had the greatest dominance indices respectively. The differences of dominance index of the most species were negative. The results of study indicated the dominance reduction of the most weeds and their control improvementy although in a few number of weeds such as wild mustard and catchweed, an increase in the dominance index was observed.

In order to investigate the efficacy of sulfosulfuron (Apyros® WG75%) on the control of broomrape (Phelipanche aegyptiaca (Pers.) Pomel) and the tomato yield (sunseed cultivar), an experiment was carried out in a randomized complete block design with 4 treatments and 4 replications on tomato in three separate fields (Khamir, Minab and Roodan regions) in Hormozgan province in 2015. Treatments were sulfosulfuron at 20, 30 and 40 g/ha and control (weed check with broomrape). All herbicide treatments were used at 30, 40, 50 days after tomato transplanting in fields. The results of multivariate analysis of variance show significant differences on density and dry weight of broomrape and so on dry weight and yield of tomato due to the location and treatment effects and their interactions at 1% level. Mean comparison of data show that with increase in the concentration of sulfosulfuron there is a decrease in broomrape density and dry weight and an increase in tomato dry weight and yield. Accordingly, the sulfosulfuron at 30 g/ha was shown to be the best treatment because this value of sulfosulfuron had suitable controlling effects on P. aegyptiaca and had no side-effects on tomato plants. According to the results, with 30 g/ha of sulfosulfuron the broomrape density in Khamir, Minab and Roodan regionswere counted to be 4.25, 2.60 and 3.73 broomrape/m2 respectively. The dry weight of broomrape in three regions was registered as 43.75, 32.75 and 53.04 g/ m2, the tomato dry weight was registered as 79.212, 64.73 and 65.605 ton/ha and the tomato yield was registered as 92.977, 78.468 and 79.375 ton/ha, respectively.

Kermanshah province, Iran, comprises an area, of 24640 km2 and is located between 33°37′-35°17′N and 45°20′-48°1′E. The average annual precipitation is 450 mm. Most of the fields surveyed in this study lie between 542 and 1554 m a.s.l. Among the factors decreasing the wheat yields, weeds have an important role. The results of some researches show that the weeds flora depends on climatic conditions, temperature and amount of rainfall in spring and in summer. Environmental factor splay a key role in the weed cover. These differences affected by climatic conditions, latitude and longitude. Multivariate statistical methods that have been addressed in this study area powerful tool to study the relationship between environmental factors and ecological weed community composition (Hassannejad & Pourhaydar Ghafarbi, 2013; Lososova et al., 2004). Correlation and regression of data floristic and environmental factors were used in the CCA (Canonical Correspondence Analysis) technique (Legendre & Legendre, 1998).
A survey was conducted to study the effects of soil and climatic factors on distribution of weeds in 85 irrigated wheat fields in 11 counties based on its area under irrigated wheat. An Experiment was conducted in Kermanshah province during 2011-2012. After choosing the field to be surveyed, the surveyor followed a “w”-designated set pattern to enumerate the weeds in each type of field. The pattern and number of 0.25 m2 quadrats varied according to the size of the fields. The field surveys were made during the wheat tillering to stem elongation stages. Frequency, density and mean density index of species in each county were calculated. After weed species were collected in the fields, we arranged the samples into the first matrix where weed species are represented by columns and fields of different districts by rows. Also, in the second matrix, environmental factors are represented by columns and fields of different districts by rows. Data on weed communities and environmental factors of all districts were analyzed through with ordination methods like canonical correspondence analysis (CCA) and weed species distribution and environmental factors displayed in ordination diagrams. These ordination methods were done with mean density of 29 abundant weed species for CCA using CANOCO (Version 4.5). Ordination plots were produced for both sampling sites and weed species associated with environmental factors. For CCA, we used site elevation, humidity for 10 years period, daily raining for a 10 years period. Soil characteristic included calcium, phosphor, potassium, nitrogen, sodium, magnesium, pH were determined. Sand, clay and silt in soils were measured and elevation of each field was gained by GPS.
162 weed species belonging to 33 plant families were identified in these fields. Multivariate analyses with canonical correspondence analysis (CCA) showed that changes in the weed species distribution were due to soil characters (pH, Calcium, Magnesium, Phosphorus, Nitrogen, Sodium, Potassium, silt percent, clay and loam in soil tissue, cation exchange capacity, EC) and environmental conditions during former years. The first and second RDA axes described 64% of variations in the weed populations affected by climatic factors. Winter wild oat (Avena ludoviciana L.), ryegrass (Lolium rigidum Gaud.), wild mustard (Sinapis arvensis L.) and canary seed (Phalaris brachystacys Link.) in areas of high temperature and low altitude, had a wide distribution. High evaporation increased wild barely (Hordeum spontaneum C. Koch.), Corn cleavers (Galium tricornutum Dandy.) and Vetch (Vicia assyriaca Boiss.) density during last decade. Where the soil nitrogen and phosphorus rates were high, Wild barely (Hordeum spontaneum C. Koch.) density was found frequently in wheat fields of Kermanshah. In the wheat fields of Kermanshah, Bindweed (Convolvulus arvensis L.) and wild safflower (Carthamus oxyacantha M. B.) were more abundant in clay soils. High Corn cleaver (Galium tricornutum Dandy.) density was found in alkaloid and sandy soils.
Generally predict that if the temperature rise over the next few years, weed density and abundance of wild oat, ryegrass and wild mustard will be increased in irrigated wheat fields.
Acknowledgments
The authors acknowledge the financial support of the project by agricultural Research education and extension organization and College of Agriculture and Natural Resources, Tehran University.

To evaluate weed management problems in wheat fields during 2011 and 2012, 1300 farms were visited, in 13 provinces with different climatic conditions. 1300 Farms (each province 100 farms) were visited, and information on weed management methods was collected according to a questionnaire form. These forms were later evaluated and analyzed. Changes of the most dominant weed species in the last decade indicate that management actions during this period were not appropriate. The usual method for managing weeds in wheat fields were chemical control and the use of non-chemical methods was not used very common. In more than 20% of cases herbicides were not used at the right time. Most farmers (over 50%) used herbicides clodinafop-propargyl and tribenuron-methyl herbicides and the ability to mix with each other due to their low price, easy accessibility. About 30% of farmers used standard equipment o spray herbicides (tractor air assisted boom and micron air sprayer) but the rest used unconventional equipment (tractor air assisted lance, turbo liner, atomizer and wheelbarrow lance sprayer). The major weak points in wheat management practices included: Unawareness of the extent of damages caused by weeds, delayed weed control, incorrect spraying practices, lack of access to necessary instructions and failure to comply with the proper cropping pattern.

In order to investigating theeffects of crop rotation and applying of herbicides on weed distribution in irrigated wheat fields of Kermanshah province، this study was performed during 2011-2012. Multivariate analysis (RDA) revealed the significant relationship between composition and species frequency and exerted management techniques. The first and second features of RDA indicated 57%، 74. 9% and 58. 3% distribution variance under the effect of crop rotation، grass herbicides and rotation، and broadleaf herbicides and rotation respectively. The highest effect was for the continuously wheat cultivation which had a positive correlation with the frequency of the weeds including Lolium rigidum، Hordeum spontaneum، Avena ludoviciana، Lithospermum arvense and phalaris brachystachys. Application of the herbicide clodinafop propargyl and rotation between wheat-barley and wheat-sugar beet had a low correlation with grass weeds. The weeds including Sinapis arvensis، Carthamus oxycantha، Vicia assyriaca and Galium tricurnutum in the rotation wheat- barely were not controlled by applying 2،4-D، tribenuron methyl and Sulfosulfurun and had a high density.

In order to determine changes in weed flora in wheat fields of Savojbolagh and Shirvan counties, the results of studies in 2000 and 2010 were compared. Based on the first study (2000) in Savojbolagh County, 57 species belong to 19 families and in Shirvan county 28 species belong to 13 families were detected. In second study (2010) in Savojbolagh County, 53 species belong to 19 families and in Shirvan county 53 species belong to 18 families were detected.Some species of flora were removed and some new species were added to the flora. Abundance index of some species were changed, some species lost their dominance and others became dominant. Any change in the dominance index due to changes in frequency, density, or both, can be related to many factors. In Savojbolagh dominance of many species including knotweed (Polygonum aviculare), bedstraw (Galium aparine), lepyrodiclis (Lepyrodiclis holosteoides). speedwell (Veronica camplypoda) and fumitory(Fumaria vaillantii) were due to increase in density but in Shirvan dominance of many species including common lambsquarters(Chenopodium album), hairy vetch(Vicia villosa), (Goldbachia laevigata) and Canada thistle (Circium arvense) were due to increase in density, except for knotweed (Polygonum aviculare) was due to increase in frequency. Any change in the abundance of grass weed species in wheat fields of Savojbolagh indicate that the management methods applied for these species have failed after a decade and winter wild oat (Avena ludviciana) and feral rye (Secale cereale) remain as the dominant grass weed species. Change in abundance index of broadleaf weed species in Savojbolagh and dominance of some species such as knotweed, lepyrodiclis and speedwell showed that change flora of broadleaf weeds was in response to weed management methods. Introduction of new species to the wheat fields of Shirvan was considerable. The management methods applied were clearly the reasons for the floral changes, we should now adopt new strategies to manage the new species.

A survey was carried out in irrigated wheat fields to assess the flora changes in the weed communities structures and flora change in Kermanshah province in 2002 and 2012. 85 fields from 11 counties were evaluated. Some population indices such as plant species frequency، density and species dominance were calculated for 2012 and were compared to the values for 2002. Results showed that in 2012، 112 weed species were distributed throughout wheat fields consisting of 18 grass weed species and 94 broadleaves. Convolvulus arvensis، Avena ludoviciana، Sinapis arvensis and Hordeum spontaneum were dominant weed species in 2002. In 2012، the respective species not only were found dominant but also showed 128. 3، 29. 14، 51. 46 and 36. 31 percent increase in dominance index، respectively. In contrast، the weed species Galium tricornutum، Glycyrrhizia glabra، and Phalaris brachystachys، respectively showed 10. 45، 52. 27، and 27. 16 percent decrease in dominance index compared to values calculated for 2002. Forty four new weed species were identified in 2012 that were not observed in 2002. In addition، our observations from the areas out of random quadrates sampling resulted in identifying forty eight new weed species. Shannon diversity index showed no difference from 2002 to 2012 for Kermanshah and Kangavar. Simpson dominance index indicated an increase in weed species evenness in Kermanshah county in 2012.

Weed identification is considered the most fundamental task in weed management. It would be possible to decide on specific methods of weed control through availability of weed information in a particular location, otherwise applying different methods of control will not show satisfactory effects. Wheat is the most important crop in West Azerbaijan province so that more than 2000000 hectares are under wheat farming, based on Jihad Organization information. In order to identify dominance weeds and their density 48 fields were selected in 7 cities of West Azerbaijan province during 2004-2007. Based on Thomas method, a W pattern was selected considering the area of each field, and then 1m×1m quadrate was thrown accordingly. The genus and species within each quadrate were determined. By using specific formulas, the density, frequency and uniformity of each weed species were calculated. Geographic coordinate’s of each field (Latitude, Altitude and Elevation) were determined by using GPS. In irrigated wheat fields 52 weed species from 20 families were recognized from which. Sinapis arvensis L., Vicia sp; Conringia orientalis(L.) Andrz., and Fumaria parviflora Lam. had the highest density in irrigated wheat fields in West Azarbayjan province. The most dominant narrow leaf weeds were Secale cereale L., and Avena ludoviciana Dun.

An audit was made for weed science in Iran by Iranian Society of Weed Science for the years 2009 and 2010. All the information was collected by filling special forms. Other information was collected by media search. All collected data was processed and analyzed according to the requirements of this report. Results indicated that the number of MSc candidates accepted for weed science in six state universities was 86 and ten Islamic Azad university branches، 443، during the two years of this survey. At the same period، 18 PhD candidates were accepted in the two state universities (Tehran and Mashhad). The number of scientific body of weed science specialists at the above mentioned universities was 18 in state and 10 in Islamic Azad university branches. In the research sector، there were 97 researchers active in weed research at the Ministry of Agriculture research units of whom 41 were members of the scientific body. A total of 356 scientific articles were published during this study period، of which 30 were ISI grade and 9 extension category. Amongst the 30 ISI articles، 21 were from state universities، 6 Islamic Azad university branches and 3 from agricultural research units. It was also shown that 62. 02% of all the published articles were of basic nature and 37. 92%، applied. The above data also revealed that، on the average، for every member of the scientific body of universities and research units، 2. 56 articles have been published (3. 81 for state universities، 1. 67 for Islamic Azad university branches and 1. 76 for agricultural research units). As for articles presented at Iranian and foreign conferences، a total of 620 articles were recorded. The subject of 194 were chemical، 168 non-chemical، 180 basic and 78 biological studies. During This period، 15 weed science books (12 authored، 3 translations) were published، four of which belonged to state universities، one from Islamic Azad university branches and 10 from agricultural research units. During the period of this survey، 240 theses were presented، of which 71 belonged to state universities and 169 came from Islamic Azad university branches.

In order to identify and determine weeds distribution in rainfed wheat fields of Kermanshah province, 58 fields in 7 counties were investgated during 2001 and 2009. After weed survey the charsterictics of weed species were evaluated. Then density, frequency, uniformity, mean density, abundance index, Shannon- Weaver diversity index and Simpson index were determined. In rainfed wheat fields of Kermakshah province 91 weed species were identified out of which 15 species belong to grass weed and 53 species belong to broadleaf weed. Poaceae, Fabaceae, Asteraceae and Rubiaceae were the most important families with, 57, 35.5, 34.6 and 18 percent of FIV, respectively. Based on the result of this study Galium tricornatum, Vicia hyrcanica, Vaccaria pyramidata and Anthemis cotula were the dominant broadleaved weeds. Avena ludoviciana, Hordeum spontaneum and Bromus tectorum were the most important grass weeds. In addition the most important troubeling preharvest weeds were Convolvulus arvensis, Carthamus oxyacanthus and Glycyrrhiza glabra in rainfed wheat fields. Shannon-Weaver diversity index showed the highest species diversity were in Kermanshah with 2.67 and the lowest species diversity in Songhor and Sarpolezohab were with 1.8 and 1.9, respectively.

Surveying weeds of irrigated barley fields is one of the most important practices in weed management. Based on cultivated areas irrigated barley in all counties of Ardabil province during six years (2000-2005), 46 sample barley fields were selected and weed species were counted in each sampling point and population indices were calculated with Thomas method. By using specific furmula the density, frequency and uniformity of each weed species in fields were calculated. In each field longitude, latitude and altitude were recorded by using GPS. These data were used for producing weed maps using GIS. Results showed that Galium tricurnatum, Fumaria vaillantiand Raphanus raphanistrum were dominante broadleaf species in irrigated barley fields of Ardabil province. The dominant grassy weed species in these fields were Avena fatua and Secale cereal. Convolvulus arvensis and Cirsium arvense were the most important troublesome plants prior to harvesting in irrigated barley fields of this province.

In order to identify and determine the distribution of weeds in irrigated wheat fields of Kermanshah province, 142 fields in 11 counties were investgated during 2000 to 2008. After weed survey the charsterictics of weed species were evaluated. Then density, frequency, uniformity, mean density, abundance index, Shannon- Wiener diversity index, Simpson index were determined. In irrigated wheat fields of Kermakshah province 91 weed species were identified that 15 species belonged to grass weed and 76 species were belonged to broadleaf weed. Asteraceae, Fabaceae, Poaceae and Brassicaceae were the most important families with 59. 7, 26. 5, 23 and 18. 4 percent of FIV, respectively, were most important plant families. Based on the result of this study Galium tricornatum، Centaurea depressa and Sinapis arvensis were the dominant broadleaved weeds. Hordeum spontaneum and Avena ludoviciana were the important grass weeds. In addition, the most important troubleome preharvest weeds were Glycyrrhiza glabra, Sophora alopecuroides and Convolvulus arvensis in irrigated wheat fields. Shannon- Wiener diversity index showed the highest species diversity were in Kermanshah with 3. 27 and the lowest species diversity in Javanrood and Sarpolezohab were respectively 1. 15 and 2. 28.

This study was done to evaluate different nonlinear regression models to describe response of germination rate to temperature in Brassica napus L. (canola), Sinapis arvensis L. (wild mustard), Raphanus raphanistrum L. (wild radish), Descurania sophia L., Phalaris minor L. (phalaris). This experiment based on completely block randomized design with 3 replications at Plant Research Institute (Dep. of Weed Research) laboratory in 2011. The seeds treated with different temperatures (0, 5, 10, 15, 20, 25, 30, 35, 40 and 45 oC) and the germination rate were calculated. The result showed that temperature had significant effect on germination rate of all plants. Tree regression models (Dent-like, Segmented and Beta) used to predict germination rate and cardinal temperature. Root mean square of error (RMSE), coefficient of determination and corrected AKAIKE index (AICc) were used to find the appropriate model(s). Therefore segmented model were superior compared to other models in canola and all weeds. It was concluded that this model can be used to quantify response of common weeds of canola field germination to temperature and to obtain cardinal temperature of germination. Base (Tb), optimum (To) and ceiling (Tc) temperature were predicted with appropriate models. Tb, To, Tc were for canola 1.8, 25, 40.9; wild mustard 2.01, 15, 30.6, wild radish 1.9, 15, 30.1, D. sophia 1.2, 26.9, 35 and phalaris 1.9, 15.5, 30.3 respectively. These parameters are required to predict common weeds of canola field germination and emergence.

This experiment was conducted to study the effects of some environmental factors on dispersal and density of five dominant grass weeds including of Avena ludoviciana، Avena fatua، Phalaris minor، Lolium rigidum، Secale cereal in irrigated wheat fields of Iran. Altitude، annual mean of soil temperature، rainfall and evaporation were got from topography and climatic maps، was used as environmental factors in this experiment. Also، abundance percentage of mentioned weeds was determined in different kinds of climate (based on cilianinov method) and 10 types of soil in Iran. According to the results، among studied environmental factors، altitude and annual mean of soil temperature on density of Phalaris minor، altitude and annual mean of soil temperature and rainfall on density of Lolium rigidum and Avena fatua، annual mean of soil temperature، rainfall and evaporation on density of Avena ludoviciana and annual mean of soil temperature on density of Secale cereal had the highest effect. Study of these weeds dispersal in different climates showed that Avena fatua and Avena ludoviciana had the highest and lowest dispersal in different climates، respectively. Also، Avena ludoviciana and Lolium rigidum had the highest and lowest consistency in different soil types، respectively.

In order to study the effect of environment temperature and GR60 concentration on seed germination and growth of Orobanche aegyptiaca and Orobanche cernua, two experiments were conducted under controlled conditions in Weed Research department of Iranian Research Institute of Plant Protection in 2008. The first experiment was established as a completely randomized design with factorial arrangement of treatments and five replications. The first factor was GR60 concentration (zero, one, two and five ppm), the second factor was broomrape species (O. aegyptiaca and O. cernua), and the third factor was temperature (10, 20 and 30?C). The second experiment was also conducted with the same statistical design and species, temperature at three levels (15, 20 and 30?C) and host plants at two levels (tomato and tobacco). Results indicated that GR60 stimulated seed germination of both broomrape species. Broomrape germination increased up to 20?C. O. cernua needed less GR60 for maximum germination compared to that of O. aegyptiaca. Stem weight of broomrape species increased by moderate increase in temperature.

To evaluate the distribution of clodinafoppropargyl resistant wild oat to in south western Iran (Khuzestan province), 50 fields which were sprayed with aryloxyphenoxypropionate herbicides were sampled. Those fields at which wild oat had been controlled efficiently by these herbicides were selected for the experiment. Populations (50 suspicious to resistance and 1 susceptible) were studied in a randomized complete block design with four replications in 2005. Populations of wild oat were sprayed during two- to four- leaves stage using the recommended dose of herbicide. Shoot biomass, survived plant and EWRC visual rating, were recorded four weeks after herbicides application. Longitude and latitude of different sampling locations were registered using GPS. Grouping populations using cluster analysis showed that 52% of populations were resistant, 28% were suspicious to resistance and only 18% of populations were susceptible and semi susceptible. Furthermore resistant populations were detected in all of parts of khouzestan province.

In order to identify ecotyps of field binweed (Convolvulus arvensis L.), seeds from eight proviences, including 125 populations were gathered and sent to Weed Research Department of Plant Pests & Diseases Research Institute, Tehran, Iran. These seeds planted in a uniform environment condition in Tehran. On the base of 24 morphological and physiological characteristics of seedling that derived from rhizomes, 21ecotypes recognized. Consistent variation in leaf morphology, floral characteristics and degree of leaf and flower pubescence, when ecotypes grown in an uniform conditions were found. Mature blades of the different field binweed varied in length from 2 to 4.5 cm and in width from 1.2 to 3.1 cm. Leaf shape greatly varied among the different field binweeds (Fig. 2). Leaf angle varied from 32 to 69 degree for the different ecotypes. Flower diameter varied from 1.7 to 3.3 cm for the different ecotypes. In majority of ecotypes, stigma lobes raised above the anthers. The ecotypes also differed in their flowering capacity. The earliest flowering ecotype formed flower 50 days before the latest and produced 6 times more flower per plant, which indicated further differences in seed production potential between ecotypes. The variability in growth and reproduction observed between these field binweed ecotypes may explain the survival and adaptability of a population of this weed as environmental condition and control practices change.