فصلنامه مطالعات حفاظت گیاهان
سال سی و پنجم شماره 1 (بهار 1400)

Endophytic microorganisms are present inside plant tissues without evident disease symptoms, but they have different interactions with their host. These microorganisms have revealed a great potential to be exploited as a biological control agent of troublesome weeds. Endophytic microorganisms in association with weed roots can act as a soil application herbicide through toxin secretion. These agents in most cases do not kill target weed but instead, have an ability to suppress them noticeably, so the crop can compete with companion weeds very successfully. Unfortunately, the endophytic microorganisms of weeds are less studied and such studies is very limited. So, this experiment was conducted to study root endophytic Fusarium species of Hordeum spontaneum and Rapistrum rugosum as serious weeds of winter cereals of our country. Fusarium species are one of the most important host-specific microorganisms in the biological control program of weeds.

The weeds planted in pots filled with the soil of wheat farms sampled from Alborz, Tehran, Khorasan shomali, Khuzestan, Fars, Qazvin, Kermanshah and Golestan provinces (Iran), under greenhouse condition. The plant harvested at 5–6 leaf stage, roots were cut from the crown and sliced into small pieces. Then the pieces of root were cultured on specific Fusarium medium, Penta chloro Nitro Benzene Peptone Agar (PPA). Fusarium spp. grown on the medium, sub-cultured onto the Water Agar (WA) medium. After 24-72 h hyphae tip of the isolates translocated onto the Potato Dextrose Agar (PDA) medium and let them to fully grow and pure isolates obtained.  Some morphological details of the species e.g. chlamydospore formation and physical characteristics of it, color and diameter of the colony (after 72 h) were assessed according to their growth habit on PDA medium. Each species translocated onto Carnation Leaf Agar (CLA) and Synthetic Nutrient Poor Agar (SNA) mediums to evaluate other necessary morphological characteristics. Sporodochium formation and physical characteristics of macroconidia on CLA, and microconidia formation and physical characteristics of microconidia on SNA, also assessed. Isolates were identified based on molecular data that were generated for TEF 1-α gene, following PCR amplification as well.  Pro Chromas (1.7.6 version) and Editseq (5.01 version) softwares were used to edit the sequences before further processing. Edited sequences were blasted in NCBI (http://www.ncbi.nlm.nih.gov/blast/) and compared to those sequences that already existed in the database to find similarities and molecularly identification of species. Selected sequences of the study and those isolates from the database were alignment using Clustal X (version 2.1) software and finally phylogenic tree was drawn using MEGA6 (molecular evolutionary genetics analysis). And appropriate outgroup was exploited to sequences analysis. Finally, maximum composite likelihood method was used to analyze and assessment of nucleotide sequence of gene regions of different isolates. With taking into account of all these information together, we were able to identify all isolated Fusarium species with confidence.

Fusarium equiseti was the dominant species recovered in several regions, while the other Fusarium species were site and species-specific. F. equiseti was recovered from the root of H. spontaneum and R. rugosum plants cultured in the soil of Fars and Golestan. This species also recovered from the root of H. spontaneum and R. rugosum cultured in the soil of Khouzestan and Qazvin provinces respectively. In addition, F. redolens and F. acutatum were recovered from H. spontaneum root cultured in the soil of Khorasan Shomali and Qazvin provinces respectively. On the other side, F. torulosum and F. oxysporum were recovered from R. rugosum root cultured in the soil of Kermanshah and Tehran respectively. Totally 10 isolates of five different species of Fusarium recovered from the root of H. spontaneum and R. rugosum. It shows probably a lot of Fusarium species (and maybe other microorganisms) are in contact with weeds root which can be utilized as their potential biological agent, but the potential is not studied to a great extent. There are many reports that show many species of Fusarium are exploited as biological agents of different weed species. This is because of the host specificity of the fungus Fusarium which turns it to a suitable and efficient agent in the biological control program of serious hard to chemical control weeds.

Many grass weeds are very hard to manage with conventional methods especially chemical means. We have to look for other alternative solutions to overcome them. Biological control of weeds is a promising approach to wisely control of weeds, especially those that are very resistance prone or hardly controlled with available herbicides. Exploiting this approach needs proper and diverse control means. Microorganisms are a rich source of biological agents of weeds that less attention has been paid to them. Endophytic microorganisms of weeds are a new generation of biological agents that studies have been focused on them recently. The first step to choose an efficient agent is having a deep knowledge about what kind of species are living with them. In fact, detailed knowledge about endophytic microorganism of weeds can aid in better understanding of the nature of interactions between weed-microbe and how to exploit these as agents in weed biological control programs.

The potato is one of the most dicotyledonous human nutrition, and this product is in fifth grade under the cultivation area. Isfahan province is one of the most strategically located areas for the production of potato. Potato suffered by several diseases that directly or indirectly caused by number of pest, including plant parasitic nematodes. The most important damage and parasitic nematodes in potato fields are cyst forming nematode Globodera rostochiensis and G. pallida , root-knot nematodes Meloidogyne spp, tuber and stem rot nematodes Ditylenchus destructor and  D.dipsaci and root lesion nematodes Pratylenchus spp, respectively. However, many other species are found associated with potato, such as Belonolaimus longicaudatus, Xiphinema spp., Rotylenchulus spp., Radopholus similis, Logidorus spp. Most of these have not been property assessed. There are no specific above ground symptoms of diagnostic value associated with potato nematode infections. However, root injury causes stress and reduces uptake of water and nutrients which in turn causes stunting, yellowing and other discoloration and wilting of the foliage under drought conditions. Karimipoor (2012) identified and determined the density population internal parasitic nematodes in the potato fields of Isfahan. Also, Erfani Porghasemi et al. (2011) identified plant parasitic nematodes in potato fields in Khorasan Razavi province. Giti and et al. (1390) try to identify and report golden potato cyst nematode occurrence (Globodera rostochiensis) and its distribution in Hamadan province. The aim of this study was to identify plant parasitic nematodes of potato fields in Friedan region in Isfahan province.

Soil sampling: In order to identify plant parasitic nematodes of potato fields in Friedan region in Isfahan province, 115 soil samples and root samples were collected during spring and summer of 2013 and 2014. Soil samples were taken from the depth of 30 cm put in polyethylene bags with necessary labeled and brought to the laboratory and processed. Processing of samples: Nematodes were extracted from soil samples by sieving and centrifugal flotation technique and from root samples by using blender and centrifuge and  were then transferred to glycerin according to the modified De Grisse method (1969). Genera and species were identified based on morphological and morphometric characters. Species were heat- killed by adding boiling 4% formalin solution and were then transferred to anhydrous glycerin according to De Grisse (1969). The permanent slides were prepared from the extracted nematodes. Measurements and drawing were performed using a drawing tube attached to an "Olympus BH2" light microscope (LM).  .
Measurements and drawing: Measurements were taken with an ocular micrometer of "Olympus BH2" model microscope. Drawing were prepared with drawing tube attached to the compound microscope. The nematodes were identified by light microscope based on morphological and morphometric characters.

In this study, 12 species belonging to 4 genera of the family Tylenchidae, related to infra order Tylenchomorpha were identified as follows: Boleodorus thylactus and B. hyderi , Discotylenchus brevicaudatus, D. attenuatus and D. discretus,  Filenchus afghanicus, F. balcarceanus, F. qurtus, F. vulgaris, F. thornei and F. pratensis and Tylenchus naranensis. In which, four species Bolodorus hyderi, Discotylenchus attenuatus, Filenchus balcarceanus and Tylenchus naranensis are described and two species Boledorus hyderi and Filenchus balcarceanus are reported as new records for fauna nematodes of Iran. Species were identified by valid key (Geraert, 2008). Morphological and morphometric measurements of B. hyderi specimens have been in close agreement to the measurements given by Geraert (2008). This species was compared with the close species Boleodorus volutus. Studied species was similar to the close species tail shape but differ in stylet length and vulva slit situation so that the length of stylet in studied species was more than B. volutus (The length of the style in discussed species is 9-11um and in the similar species is 8-9 um). In addition, vulva slit situation differ in studied these species. V factor is 59 -65 in studied species and 76-79 in the close species. Therefore, population under study was identified as B. hyderi.  This species was collected from soil around roots of potato fields (Abasabad-Chadgan) in Friedan region of Isfahan province as a new record from Iran. In this study, the specimens of F. balcarceanus were collected from soil around roots of potato fields (Geshnizjan-Chadgan) in Friedan region of Isfahan province showed a close resemblance in the morphometric measurements to the original description given by Geraert (2008) with slight variation. This species was compared with close species Filenchus butteus, Filenchus teres and Filenhus retusus. In the species F. butteus, lateral filed marked by four incisures, not areolated delimiting three bands of equal width but in similar species, body has two lateral fields. The length of stylet in studied species was more than F. teres and F. retusus (Stylet length in discussed species is 9 um and in two other species is 7 um).  This species was reported for the first time in Iran.

In this study, 12 species from 4 genera of the family of Tylenchidae were identified. Among these genera and species, four species including Bleodorus hyderi, Discotylenchus attenuatus, Filenchus balcarceanus and Tylenchus naranensis are described and two species Bleodorus hyderi and Filenchus balcarceanus are reported as new records for Iran nematode fauna.

Pistachio is one of the most important export products of the country and root knot nematode is one of the threatening factors in its production. The most prevalent species in pistachio orchards are those of Meloidogyne javanica and M. incognita. Plants have a wide range of defense mechanisms effective against the invasion of various pathogens and pests. These mechanisms include pre-existing physical barriers, chemical barriers, and induced defense responses. Beneficial soil microorganisms such as Trichoderma spp. and arbuscular mycorrhizal fungi (AMF) can protect plants from infection by direct mechanisms such as production of toxins, enzymes, and other metabolites or by inducing systemic resistance. Induce resistance to the root knot nematode occurs following an increased accumulation of different antagonistic compounds such as peroxidase and polyphenol oxidase. Increased levels of these enzymes has been observed in different plants that are responsible for the induced protection against Meloidogyne.

In this study potential of antagonistic fungi, vesicular-arbuscular mycorrhiza (Funneliformis mosseae, Rhizophagus intraradices, Funneliformis caledonius) and Trichoderma (Tricoderma aureoviride,Tricoderma harzianum) and mixed of both fungi against Meloidogyne javanica under greenhouse conditions was investigated. In order to investigate the effect of antagonistic fungi on the induction of defense enzymes in pistachio seedlings of Badami Riz Zarand cultivar, the study was performed as a factorial experiment based on completely randomized design with twelve treatments in three replications in the greenhouse. Pistachio seedlings were inoculated at the stage of 8-10 leaf with 60 g of mycorrhizal mixture and three months later, these plants were sampled for examination. In order to ensure the purity of the fungi and the colonization of the roots, staining of the plant roots was performed and microscopic examination was performed to observe different organs of the fungus. After confirming the mycorrhiza treatment, Trichoderma treatment was applied. For Trichoderma treatment, 10 g of mixture of isolates T1, T2, T3, T4 and T5 per kg of soil was used. Pure nematode populations were prepared from a single egg mass on Early Urbana tomatoes. Pistachioseedlings were inoculated with 5000 second-stage juveniles of nematode 21 days after Trichoderma treatment.Nematode indices including the number of galls, egg masses and second juveniles per gram of root, the number of eggs in each egg mass and reproductive factor after 75 days for each treatment were measured.The second experiment was performed to investigate the effect of biological treatments on nematode indices in a completely randomized design with six treatments and three replications. Defense enzymes level of Peroxidase (POX), Polyphenol oxidase (PPO) and phenylalanine ammonia lyase (PAL) determined at four times of one and a half, three, five and a half and twelve days after nematode inoculation.

Disease indices showed a significant decrease in fungi treatments compared to the nematode control. Trichoderma treatment showed a significant difference in all indicators compared to the other treatments. Reproductive index in Trichoderma treatment and its combination with mycorrhizal treatment decreased by 72 and 33.3 and nematode population decreased by 73.4% and 36.2% compared to the control, respectively. Extracellular hydrolytic enzymes play important role in the infection process of Tichoderma species against plant-parasitic nematodes. In mycorrhiza treatment, although there was no significant difference in gall index and egg mass with the control, but the number of second juveniles and nematode reproductive factor showed a significant decrease compared to the control. This may be due to the small size of the egg mass and the effect on the number of eggs. Previous results on mycorrhizal species of Rizophagus irregularis in tomato plant showed that egg masses and number of eggs in treated roots have a significant reduction. The maximum enzymatic activity for POX, and PPO was obtained in different treatments on the twelfth day. The maximum amount for PAL activity in seedlings treated with mycorrhizal and Tricoderma fungi was observed after five and a half days. The level of different enzymes increases after treatment with mycorrhiza and Trichoderma in plants, each of which plays a role in limiting the development of nematodes.

Due to the high proliferation of nematodes in pistachio orchards and due to the environmental hazards of nematicides, the use of biocontrol agents is recommended. The studied fungal strains in the present study could be used as components in an integrated approach to manage M. incognita on pistachio plants. The use of plant growth promoting fungi such as mycorrhiza and Trichoderma while improving plant growth, can reduce the use of fertilizers and chemical pesticides and are effective for better plant growth and development and disease control. However, further studies on the use of combinations of these fungi with other bacterial antagonists and even animal manures as well as garden studies are necessary.

Today, the control of Rhynchophorus ferrugineus Olivier (Coleoptera: Curculionidae) as quarantine and destructive pest of date plantation due to the inner parts of the tree trunk is limited to chemical control that indiscriminate application of different types of pesticides such as imidacloprid has caused the resistance of this insect. In this study, the lethal effect of botanical compounds including garlic essential oil and its secondary metabolites (diallyl disulfide, diallyl trisulfide) and eucalyptus essential oil and its secondary metabolites (1,8-cineole, aromadendrene) on enzymatic activity (general esterases, glutathione S-transferase, acetylcholinesterase in red palm weevil were studied and compared with imidacloprid (commercial form and technical substance).

Adults (Male and female) of R. ferrugineus (red palm weevil) were collected from infected date palm plantations in Saravan (Iran) and transferred to the laboratory for propagation (25±3°C, 60±5% relative humidity, 12:12-h light: dark cycle). Bioassay tests were performed on larvae of the same age (2nd instar). The toxic effects of all compounds were investigated separately and in binary mixtures. The bioassay experiment was performed using a topical-fumigant method in three replications (10 larvae per replicate) in a completely randomized design. Two μl of different lethal concentrations (LCs) of chemicals were poured on the anterior part of the 2nd instar larval thorax and they were transferred to 8 cm Petri dishes. The mortalities were recorded 24 hours after treatment. Lethal concentrations of LC25 and LC50 were calculated using SPSS software version 21. Then, binary mixtures of LC25 and LC50 concentrations (LC25+LC25, LC50+LC25, LC50+LC50) of the studied compounds were performed to investigate the additive, synergistic, and antagonistic effects with a similar bioassay method. Enzymatic assays were performed using conventional methods. The effect of these binary mixtures, as well as LC25 and LC50 values of the individual status of each toxic compound on the activity of the mentioned enzymes, were evaluated 24 hours after treatment. Lethal concentrations (25 and 50%) and inhibition concentration of 50% of acetylcholinesterase (IC50) activity were calculated using the probit model and SPSS (v. 21). Scatter diagrams and regression lines between different concentrations of chemicals for inhibition of acetylcholinesterase were calculated with Sigma Plot software version 12.3. Also, the comparison between lethal concentrations was performed using the ratio of lethal concentrations and 95% confidence interval. In addition, the mean comparison between the data obtained from biochemical experiments with SPSS software (v. 21) and the Tukey test was performed at a 5% level.

The LC25 and LC50 values of garlic essential oil, diallyl disulfide, diallyl trisulfide were calculated as "9.23 and 23.61", "2.33 and 4.64 ","2.75 and 5.01 "µL mL-1; for eucalyptus essential oil, 1,8-cineole, aromadendrene were as "12.46 and 33.41", "4.26 and 7.83", "3.68 and 7.84 " µL mL-1 and for commercial form and technical substance imidacloprid were as" 0.012 and 0.025 "and" 0.009 and 0.004 µL mL-1, respectively. Results showed that the binary mixtures of LC50+LC50 including "diallyl trisulfide+imidaclopride technical substance", "diallyl trisulfide+aromadendrene","diallyl trisulfide+1,8-cineole","diallyl disulfide+technical substance imidacloprid","diallyl disulfide+aromadendrene","diallyl disulfide+1,8-cineole" had synergistic effects. The results showed a significant increase in general esterases and glutathione S-transferase activity in the larvae treated with the individual status and binary mixtures. A significant decrease in acetylcholinesterase activity was observed in all treatments. Results showed that the lowest and highest concentrations of the studied toxic compounds for 50% inhibition of acetylcholinesterase activity were obtained by 0.328 mg ml-1 of "diallyl trisulfide+1,8-cineole" and 4.485 mg ml-1 of garlic essential oil, respectively. In addition, the results showed that the highest (80.30%) and lowest (6.50%) levels of acetylcholinesterase inhibition were obtained by 2 μl ml-1 of "diallyl trisulfide+1,8-cineole" and 0.1 μl ml-1 of the commercial form of imidacloprid.

Despite the better control of red palm weevil after treatment with imidacloprid compare to botanical insecticides (essential oils and secondary metabolites), however, the resistance to this pesticide has been demonstrated because of long-term exposure. Therefore, according to the results of the synergistic effects of secondary metabolites together or even with imidacloprid, a decrease in the activity of detoxifying enzymes, as well as acetylcholinesterase, was observed, which may indicate the key point that these enzymes have not been able to eliminate these binary mixtures from the hemolymph of red palm weevil, so they could play an effective role in the management of this pest. Therefore, it can be hoped that plant essential oils can control red palm weevil in palm plantation alone or in binary mixture together or with other conventional pesticides. Further studies are needed to make a more confident decision in this regard. One of the problems of plant essential oils as well as their secondary metabolites is the low stability of these compounds in the environment, so one of the issues that can be paid more attention to is increasing their stability in the environment and how to release them in the environment, which can be done with various formulations such as nanoformulations, in particular, assume to solve this problem. Therefore, the study of the stability and formulation of plant essential oils and their secondary metabolites in the environment is a topic that should be considered in future research to be able to implement the potential ability of these compounds in agricultural pest management in practice.

Increasing beekeeping activities, it is important to identify the main sources of pollen in a region and their value for bee colonies and pollen production. The latter may have a significant impact on the morphology, behavior, and physiology of all individuals and on the quality of pollination services as well. Therefore, pollen has a great impact on colony health. Several researches have shown that pollen quality varies in terms of the type and quality of amino acids and the amount of total protein, depending on the origin of the flower. For this reason, the palynological diversity of pollen is a good measure of the quality of bees' lives. Pollen and nectar of plants used by bees in some regions of Iran have been investigated in the literature However, there are no data about the status of bee pollen sources in Semnan province. The present work aims to consider changes in the plant composition and pollen concentrations of honey samples during the investigation period. Especially, to determine honey bee forager’s pollen preferences in the study area, and to prepare a guide of a year round floral calendar for beekeepers and farmers for better understanding the blooming periods of bee pollinated plants.

This research was conducted in 2017 in different regions of Semnan province. Semnan province with an area of 97491 square kilometers occupies 5.8 percent of the country's area. This province located between 34º, 13´ to 37 º, 20´ N latitude and from 51 º, 51´to 57 º, 3´ E longitude. In this study, for quantitative analysis of pollen grains, the amount of one kilogram of honey was prepared from 25 beekeepers in Semnan province at the end of summer and the geographical coordinates of the hive locations were recorded using a GPS device. All samples were analysed using the standard pollen analysis a hemocytometer was used to count the number of pollens in a certain volume of solution. Pollen grains were counted using a light microscope with a magnification of 100. These steps were repeated ten times for each sample of honey. To identify pollen grains, one drop of the well-homogenised pollen grain suspension was applied to a microscope slide, covered with a 22 mm × 22 mm cover glass and sealed with nail varnish. For each sample, several microscopic slides were prepared and were observed using light and polarised light microscopy. Pollen grains were identified to species level where possible by comparison to the reference pollen collection prepared from hand-collected pollens from known flowering plants in the study area. The frequency of occurrence was calculated as the percentage of samples, in which one pollen type was observed. Honey samples were classified using the method of Liux et al. (16).

In this research, 505 types of pollen grains were identified in honey samples collected from the study areas, which belonged to 83 plant families. Among these grains, pollen grains of 474 plant species were identified in honey of Abrsaj, Abar, Shahkooh paeen, Bastam, Dibaj Damghan and Rameh Garmsar regions and 31 species of honey from other regions of the province and from the honey supplied by beekeepers migrated to Semnan province. Based on the comparison of the means between the number of pollen grains in standard samples, the highest number of pollen grains was recorded in Qatari and Folad mahalle regions (respectively with an average of 1174 000 and 169000).The lowest number of pollen grains was observed in Comercial sample and Abrsaj2 (with the mean of 17000 and 140000, respectively) (Figure 3). The results of comparing the means as well as the classification table of pollen grains showed that 72% of the studied areas (18 areas) placed in class 3 (100000 to 500000 grains in the standard sample), 16% (4 regions) in class 4 (500000 to 1000000 pollen grains), 8% (2 regions) in class 5 (above 1000000) and 4% (1 region) in class 1 (less than 20000), in terms of the number of pollen grains per 10 grams of honey. In this study, no sample was included in class 2. The results of identifying pollen grains and their abundance in honey samples showed that the most important plant species used by foraging bees were related to Asteraceae, Leguminosae, Lamiaceae, rosaceae, Apiaceae, and Brassicaceae, Liliaceae and Ranunculaceae families, respectively. The results also showed that the range and diversity of plants in the composition of the honey spectrum of each region are of particular importance. The higher density of a plant species and the wider level of its distribution, the more dramatic use of bees. These results help to prove the complexity and heterogeneity of environmental and ecological phenomena in feeding and grazing bees’ process.

The present study complements previous melissopalynological studies from other provinces of Iran and provides additional and new information on regional plant resources for pollen in honey. In this study all honey samples were obtained directly from local beekeepers and the melissopalynological analysis was completed with direct observations of the search behavior of worker bees. Therefore, we were able to determine the origin of the pollen in the honey using the location of the hive, the season and the available flower source. However, more studies are needed to fully understand the preferential behavior of grazing bees and the pollen of honey produced in the area.

Weeds on dryland chickpea fields are the main yield loss factor. Therefore, weed identification is the most important operation for weed management. Chickpea is one of the most important crops in Kurdistan province of Iran. Kurdistan province ranked forth and first in area under cultivation of chickpea and its production in Iran, respectively. This study was carried out in order to identify weed species, determine the dominant weeds, and develop the distribution maps of dryland chickpea fields in Kurdistan province.

Based on cultivation area of chickpea and the topographic condition of Kurdistan province, 33 fields were randomly selected in 2013 and weed species were determined in 5 counties, e.i., Dehgolan, Kamyaran, Divandareh and Saqez. The selection of the fields in each county was done based on acreage of chickpea in the county. Weed identification were done at each region, during three leaf and podding stages of chickpea. These periods were chosen because of easiness identification of weed species at these stages and the possible recording of weed control practices applied on fields. Demographic indices of weed species were calculated, and then the dominant weeds were determined. Also the latitude, longitude and altitude of each sampling point using GPS were recorded. By using these data, the distribution maps of the dominant weed species in ArcGIS area were produced.

The number of weeds observed in this study during period of three leaf stage of chickpea were 52 species mostly from Astraceae, Poaceae, Apiaceae and Caryophyllaceae families and the most important weeds in surveyed area based on abundance index were catchweed bedstraw (Galium aparine L.), field bindweed (Convolvulus arvensis L.), shepherd,s needle (Scandix pecten veneris L.), salsify (Tragopogon graminifolius DC.), volunteer winter wheat (Triticum aestivum L.), dove-foot geranium (Geranium molle L.) and great bur parsley (Turgenia latifolia (L.) Hoffm). The number of weeds observed at podding stage were 58 species with most abundant families of Astraceae, Poaceae, Brasicaceae, Apiaceae and Caryophyllaceae and the most important weeds based on abundance index were field bindweed, salsify, sun spurge (Euphorbia helioscopia L.), shepherd’s needle, catchweed bedstraw, dyer’s croton (Chrozophora tinctoria (L.) Juss.) and smell melon (Citrolus colocynthis L.). The most dominant grass weed species was volunteer winter wheat (Triticum aestivum L.) because of the common crop rotation (Chickpea-Winter wheat). The distribution map of the dominant weeds showed that field bindweed, salsify, sun spurge, shepherd’s needle and catchweed bedstraw were seen in all surveyed counties but great bur parsley in Sanandaj, volunteer wheat and sun spurge in Kamyaran and smell melon in Divandareh and Dehgolan were not seen. The time of tillage for preparing of chickpea seedbed is spring in Kurdistan province and narrow leaf weeds emerge often in fall but they produce numerous seeds. The annual weeds had the highest population on chickpea fields because of the annual soil disturbance, having similar requirements with the annual crop and abundant seed production. Although, perennial weeds, i.e., field bindweed and salsify caused more problem for the farmers because of herbicides limitation for this crop and tremendous energy required for hand weeding of this crop for weed control in this province. It is not easy to control weeds with rhizome and thorn. To determine the abundance index, frequency and uniformity had a higher values than the mean field density. Higher values for these three parameters for a particular species indicated that these species were well-suited with the soil and climate conditions in which it was growing, while higher rates of the mean field density for certain species indicated that they had a higher competitive or reproductive ability than other species.

The management of weeds on dryland chickpea fields in Kurdistan province is not satisfactory. The results showed that field bindweed and salsify were dominant weeds in this study area with high density due to particular weed management approaches. Therefore, farmers should change their weed management strategies in these regions. We will be able to make decision based on previously developed weed distribution maps. Better knowledge of the past and present is a key component for the improvement of the planning that will effect Iran’s agricultural division in the years ahead. Findings from this study and similar studies are helpful to establish new ways for the sustainable economic development in Iran’s agriculture.

Barley is known to be an allelopathic plant and its allelopathic potential on weeds, and some other crops has been proven. Increasing use of herbicides has an adverse environmental impact and increases the weed resistance to herbicides. Eco-friendly methods for controlling weeds reduce the amount of herbicide use and reduce the damage caused by it. Some plants have alternate properties (allelopathies) that can be used to reduce or stop the growth of other plants, especially weeds. Allelopathy is an interference mechanism based on any direct or indirect effect (primarily inhibitory) by one plant on another through the release of chemicals that escape into the environment. Barley (Hordeum vulgare L. ssp. vulgare) is well known for its allelopathic compounds. The decomposition of barley plant residues in the soil, release numerous allelochemical compounds such as phenolic compounds, flavonoids, synoglycosides, alkaloids and polyamines. Till now 44 chemicals have been identified as potential allelochemicals that contribute to its allelopathic activity in Hordeum vulgare. The present work aimed to study the allelopathy potentials expressed by residues as straw among two barley genotypes on rhizome growth and physiological attribute of bindweed (Convolvulus arvensis L.).

This experiment was conducted in 2013 at Islamic Azad University, Shoushtar Branch. The experiment was factorial based on completely randomized design (CRD) with four replications. Four different amounts (10, 20, 30 and 40 g per one kg soil) of two barley cultivars (local ecotype and Sarasary 10) residual were prepared. Rhizomes were harvested from a depth of 30 cm soil and cultivated in the pot. The culture medium included plastic pots of 30 cm in diameter. The traits included seedling weight and length, malondialdehyde concentration, fatty acid percent, α-amylase activity, catalase activity, peroxidase activity, glutathione reductase activity, GA and ABA concentration of bindweed rhizome. The concentration of GA and ABA hormones was investigated based on the Kamal method. Statistical analysis was made using the SPSS Ver.13 statistical program. Significantly different means were separated at the 0.05 probability level (p = 0.05) by the least significant difference (LSD) test. Pearson’s correlation analysis was also conducted among different variables.

Results indicated the effect of genotype, residual amount and their interaction on rhizome malondialdehyde concentration, fatty acid percent, α-amylase activity, catalase activity, peroxidase activity, Glutathione reductase activity, GA and ABA concentration. Increasing the amount of residues for the local genotype caused a significant decrease in seedling fresh weight. The lowest fresh weight of bindweed was 40 g residues of local genotypes, in which was 73.6% lower than the control without residues. Increasing the amount of local and Sarasary 10 residues in the soil caused a significant reduction in the length of the bindweed seedlings. The negative effect of local ecotype residual on α-amylase activity was more than modern genotype. The mixing of 40 g residues of local ecotype and Sarasary10 genotype with soil decreased this enzyme by 38% and 79.5%, respectively, compared to the control without residues. Increasing the amount of residuals, reduces gibberellin hormone and increased rhizome the ABA content. The slope of the changes in gibberellin hormone and the increase of ABA in the local ecotype was higher than the modern genotype. Antioxidant enzymes increased in response to an increase in the amount of residues up to about 20 grams in the pot and then decreased significantly. Reducing antioxidant enzymes at high levels of barley residues led to an increase in the amount of fatty acids and Malondialdehyde, indicating the peroxidation of the cell membrane. In general, the residuals of local genotype compared to cultivar Sarasary 10 had a more harmful effect on all studied traits of bindweed rhizome and seedling. It seems that in areas where bindweed is dominant, it is possible to use local barley residuals to reduce the damages.

Soybean is one the strategic crops which contributes to provide a part of food in 43 countries. Soybean planting area and production in the world are 102 million hectare and 261 million tonnes respectively. Its planting area was 764000 ha in Iran in 2013. Mazandaran, Guilan and Golestan are the most soybean producing province in Iran. Golestan with 53405 ha and 90000 tonnes production is the first soybean producer in Iran. Weed competition is considered one of the most important inhibitor factors, which not only causes yield losses but also, reduction in quality by interference in soybean growth and development. Yield reduction by weeds was reported by 28% under the Caspian Sea climate. Mean yield loss for one plant/square meter, has been reported up to 30% and it may reach to 80% in higher weed density. Therefore study of soybean weed control is avoidable.

In order to control weeds in soybean fields, an experiment was conducted as Randomized Complete Block Design (RCBD) with three replications in Gorgan agricultural research stations in a field that had enough weed infection. The treatments were triflutalin (treflan 48% EC) 2.5 l/ha, metribuzin (sencor 70 % wp) 0.5 l/ha, metribuzin 0.5 l/ha+ trifluralin 2.5 l/ha, imazethapyr (persuite 10% SL) 0.6 l/ha, imazethapyr 0.8 l/ha as pre plant, oxyfluorfen (goal 24% EC)0.75 l/ha, pendimethalin (stomp 33% EC) 3 l/ha,  imazethapyr 0.6 l/ha, imazethapyr 0.8 l/ha,  metribuzin 0.3+ imazethapyr 0.6 l/ha, pendimethalin 2.5 l/ha + imazethapyr 0.6 l/ha as pre-emergence, oxyfluorfen 0.5 l/ha, bentazon (basagran 48% SL) 1.5 l/ha,  imazethapyr 0.6 l/ha, imazethapyr 0.8 l/ha,  bentazon+ imazethapyr 0.6 l/ha, cletodim (select super 12% EC) 1l/ha + imazethapyr 0.6 l/ha as post-emergence at 4-6 leaf stage and weed free treatment as a control. Plot size was 1.4m×10m. Seed rate, row spacing, cultivar and other cultivation method was done by conventional method. Each plot was divided to two parts, which one part was treated by herbicides and the other part was held untreated and considered as control treatment. In weed free check treatments, weeding was done with 10 days interval but in weedy check no weeding and no chemical weed control was done.  To investigate the effect of treatments on weed number, weed fresh and dry weight, a quadrate of 0.5 × 0.5 m was fixed in each plot (so that it represents the weeds of whole plot). Before harvesting, all of the emerged weed species in fixed quadrates were identified, counted and their dry weight was measured after drying in 75 celcius degree oven for 72 hours. At harvest 5 plants per plot were randomly selected and yield components were measured. For yield, two 0.5 m2 quadrates were harvested in each plot and grain yield and biomass were determined. Qualitative evaluation of soybean, which includes chlorosis and necrosis in leaves, was done based on EWRC standard method. Data analysis of variance was performed using SAS software version 9.1 and the means were compared using LSD test at 5% level. Since field data were not normal, a logarithmic and root square ( ) transformation was used to normalize data.

The results showed that all treatments caused reduction in weed number percentage than control treatment. The highest reduction was observed in imazethapyr 0.8 l/ha (pre plant) at par with hand weeding treatment. Pendimethalin 2.5 l/ha + imazethapyr 0.6 l/ha, metribuzin 0.3+ imazethapyr 0.6 l/ha as pre emergence had the next rank. The highest yield after hand weeding was obtained in imazethapyr 0.8 l/ha (pre plant) followed by pendimethalin 2.5 l/ha + imazethapyr 0.6 l/ha and imazethapyr 0.8 l/ha as pre emergence. Therefore based on the results of this study using of imazethapyr 0.8 l/ha as pre plant or pre emergence are recommended for weed control in soybean fields and mixing of this herbicide with pendimethalin is also conducive to increasing the herbicide spectrum. Application of this herbicide (imazethapyr 0.8 l/ha) at 4-6 leaf stage of weeds, to obtain higher yield is possible too. The results of this experiment showed that some of post-emergence herbicides caused a little phytotoxicity on soybean (oxifluorfen 0.5 liters / ha (20%), Bazagaran + Persoite (15%), Coltodium + Persoite (10%), Bazagaran (5 to 10%), Persuite 0.8 liters per hectare (lower than 5%)). It should be noted that the phytotoxicity of all treatments was eliminated in the later stages of growth.

Sunflower (Helianthus annuus L.) is a major worldwide oilseed crop that develops slowly during the initial weeks after planting. Weed competition with sunflower during the first four weeks after crop emergence can reduce sunflower yield significantly. Promoting seed germination is the most direct way to improve sunflower growth and competition with weeds. Per-treatment of seed by cold plasma through accelerating seed germination can increase competitive ability of plant with weeds. Cold plasma treatment significantly increased wheat growth and yields. Thus, increasing plant growth can improve competitive ability of it with weeds. The aim of this study was to investigate the effect of cold plasma treatment on growth and yield of sunflower in competition with weeds.

This experiment was carried out as factorial based on randomized complete block design with three replications at Shahrood University of Technology (latitude of 36° 25 'N and longitude of 54° 57' E with an elevation of 1345 m) in 2016. Experimental factors were including cold plasma at six levels: control, hydro-priming of seeds for 10 hours, pretreatment of seeds with cold plasma radiation for 15 and 30 seconds, hydro-priming of seeds for 10 hours + cold plasma radiation for 15 and 30 seconds and weed control at three levels: control (no weeding), weeding all season and application of trifluralin (1200 g. a.i. ha-1). Dielectric barrier discharge plasma jet was operated in ambient air under sterile conditions in the laboratory of Faculty of Physics, Shahrood University of Technology. After seed priming in distilled water for 10 hours, sunflower seeds were taken in petri plates and treated with the plasma for determined times. Seeds were planted in the field immediately after cold plasma treatment. Seed number per head, 100 seeds weight, harvest index, biological, grain and oil yield of sunflower and weed dry weight were recorded. Statistical analyses of data were performed with statistical software MSTATC. Significant differences between means refer to the probability level of 0.05 by LSD test.

The results showed that seed number per head, biological and grain yield, harvest index, oil yield and weed dry weight significantly affected by interaction effects of treatments. Results showed that biological, oil and seed yield of sunflower decreased by 62.76, 56.11 and 55.86% in weed-infest than weed-free treatments respectively. Seed number per head and biological yield of sunflower significantly increased by using different pretreatments methods than control in the weed-infest conditions. Also, pretreatment of seeds with cold plasma for 30 seconds increased oil and seed yield of sunflower by 68.8 and 58.5 percent respectively in the weed infest treatment than control. The plasma treatment of soybean seeds up to 2 min showed positive effects on their germination rate and seedling growth. Cold plasma has essential roles in a broad spectrum of developmental and physiological processes in plants, including reducing the bacterial bearing rate of seeds, changing seed coat structures, increasing the permeability of seed coats, and stimulating seed germination and seedling growth. In addition, plasma treatment also could improve the physiological metabolism of the plant, such as de-hydrogenase activity, superoxide dismutase and peroxidase activities, photosynthetic pigments, photosynthetic efficiency and nitrate reductase activity. It seems that hydro-priming technique and cold plasma irradiation with improving seed germination and seedling early growth can led to more and faster germination and better competition of sunflower plants with weeds. 

Based on our results, pre-treatment of seeds by cold plasma and hydro-priming in addition to reducing weed biomass, could significantly improve the growth characteristics and yield of sunflower through increasing crop competitive ability with weeds.

The light received by plants is composed of different types of wavelengths (sanged from ultraviolet to infrared). The region among 400 nm to 700 nm is what plants use to drive photosynthesis, typically referred as Photosynthetically Active Radiation (PAR). Plants are so proper light filters. Leaf chlorophylls and carotenoids absorb and use most of the R light available for photosynthesis, but reflect or transmit most of the FR light, those parts of light which transmitted through vegetation, depleted in red and strongly enriched in far-red even before direct shading takes place. The natural R:FR ratio varies from 1 to 1.2 in sunlight above a canopy, gradually decreasing to lower to 0.2 under a dense canopy. Red to Far Red ratio (R:FR) is considered as an indicator of the light quality. Plants are able to detect changing in light quality via their phytochromes. Understanding the decrease of light quality create a series of reactions in the plant such as stem elongation, reduction in stem diameter, and reduction in shoot and root biomass and so forth that are known as shade avoidance syndrome (SAS). In this research, a pot experiment established to evaluate the effects of neighboring on shade avoidance mechanism in red bean (Phaseolus vulgaris).

Pot experiment was conducted based completely randomized designs with four replications at the Research Greenhouse of Ferdowsi University of Mashhad, 2016 and 2017. The treatments included the red bean (Phaseolus vulgaris) growth without neighboring and 1, 2 and 3 red bean plants as neighbors. In each pots (23 cm diameter and 21.5 cm height), 3 to 4 red bean seeds (Straight, Derakhshan) were planted and finally one plant was selected and kept for 45 days. The distance between each treatment was one meter for keeping plants away from mutual shading. In each treatment, 25 cm distant was considered between pots. After 45 days, R:FR ratio was measured beneath the canopy using a quantum sensor (SKR 200 model) subsequently, the main plant were harvested and some traits were measured. Shoot height, petiole length, and area of canopy, first leaf and plant symmetry. Then plants separated into leaves and stems. After measuring the total leaf area using LI-3000 area meter, plant parts were oven-dried at 80°C and weighed. The analysis of variance (ANOVA) for completely randomized design was performed for all responses using PROC GLM in SAS 9.3. Treatment means were compared using either the LSD test or single degree of freedom contrasts.

Result of this experiment showed that by increasing the number of neighboring plants to 3 plants,  the light quality (R to FR ratio) decreased down to 0.5 in 3 plants neighbored treatment. Accordingly, changing the light quality influenced the traits reactions. By increasing the adjacent plants number, shoot and plant height were increased. The highest plant (28 cm) and shortest (4.55 cm) petiole length was recorded in the non-neighbor treatment. To measure the leaf biomass, plants were separated into the left (that part of plant with growth opposite the neighbor) and right (toward neighbor plant growth). Result showed that in the trait with 1 plant in neighborhood, symmetry of plant was impaired (0.23 percent). In the trait with 3 neighbors, the first leaf angle was 1/35 that indicates plants attempt to reach towards high light quality. In this experiment, plant symmetry and plant angle was proposed as a shade avoidance syndrome. One main result in this experiment was reduce in area of canopy and reduction in lateral growth and production of branches in plant. In some crops such as legumes, lateral expansion to making pods is the main part of yield. Reaching out for light and increase in plant height would suppress the lateral growth which impact the productivity of plant. Moreover, diminish in leaf aria index reduce the leaf dry matter, as the main photosynthetic organs decreased. Finally, result of this experiment and those study on shade avoidance effect on crop destiny, should be considered in yield gap estimation. In these sort of experiments, total icons involve in yield diminish is considered except shade avoidance. Role of light quality also should be noted in future studies.