نشریه دانش علفهای هرز
سال هفدهم شماره 1 (بهار و تابستان 1400)

The main purpose of this research was to investigate the effect of sulfosulfuron, as a chemical herbicide, on different populations of wild barley in Iran. A factorial experiment was conducted under outdoor condition based on randomized complete block design (RCBD) with three replications at Fars Agricultural and Natural Resources Research and Education Center during 2014-2015. The main factors were 29 different populations of wild barley, application of sulfosulfuron WG 75% at 5 doses (0, 9.97, 9.97+9.97 (as a split dose at two stages), 19.95 and 29.92 g ai h-1) and different application times of sulfosulfuron (one- to three-leaf of Zadoks growth stage (ZGS11-13), at an early stage of tillering (ZGS21-23), and stage of stem elongation (ZGS31-33)). The growth traits of wild barley were evaluated 45 days after herbicide treatments. The results showed that sulfosulfuron decreased the growth of all wild barley populations, and the lowest fresh weight was obtained by the highest level of herbicide (29.92 g aih-1). Application a split dose (i.e. 9.97+9.97 g ai h-1) showed to slightly retard the growth of wild barely. Using sulfosulfuron at ZGS11-13 was found to have better effect on controlling wild barley. Populations of wild barley displayed various responses to different times and doses of herbicide application. Overall, the response of wild barley to the applied herbicide could probably be attributed to their inter-population variability and their ability to tolerate the herbicide.

To evaluate the effectiveness of trifluralin tolerance of in different varieties of wheat, barley and oats crops, greenhouse and field experiments were conducted in the College of Agriculture and Natural Resources, Razi University, Kermanshah, Iran, in 2015 and 2016. In greenhouse study, 64, 12, and 38 varieties of wheat, barley and oats were tested, respectively. In field study 11 oat varieties (Ugf775456, Wallaroo, Euro, Wintaroo, Gamitchell, Potoroo, Brusher, Quall, Swan and Mortlock) two barley (Nosrat and Ryhan), and two wheat (Psrsi and Pishtaz) varieties were examined. Trifluralin dose of 2. 5 liters per hectare of its commercial form was used in both study. A factorial experiment in a randomized complete block design (greenhouse) and a randomized complete block design (field) with three replications were used. Traits measured in greenhouse study were, germination percentage and dry weight; in field study grain yield, emergence percentage and length of coleoptile were recorded. In percentage yield better crops of barley, oats and wheat, but barley and wheat were better in other traits. Oat crops in grain yield and germination percentage is higher than bread wheat. The oat crop yield and germination percentage than barley Tolerant varieties of wheat, the first year the percentage of germination percentage was the leading figure, but the second year the Community had a higher percentage of the vanguard

In order to evaluate the effects of planting density of bean cultivars on competitive ability with weeds, this field experiment was arranged as a split plot in a randomized complete block design with three replications in Tobacco Research Institute of Rasht, Iran, in 2017. Treatments included five cultivars of bean (Akhtar, Derakhshan, Yaghout, Dorsa and Shokoufa) and three planting densities (15, 25 and 35 plant.m-2 in weedy conditions). The results showed that all evaluated characteristics were affected by cultivar, density or interaction of two factors except for plant height. Dorsa and Shokofa cultivars resulted in the highest and lowest secondary branch number per plant and pod number per plant respectively. The highest nod number per plant was showed at densities of 25 and 35 for Yaghout cultivar, and at 25 plants.m-2 for Dorsa cultivar. Also these cultivars showed the highest grain number per pod. Derakhshan among other varieties, produced the highest pod length and plant dry weight. Derakhshan and Dorsa cultivars had the highest plant fresh weight at densities of 15 and 25 plants.m-2. Maximum 100-grain weight observed in the Derakhshan cultivar. Among all cultivars, Yaghout cultivar (averaged on three densities) produced the highest grain yields. Secondary branch number per plant and Grain number per pod of bean cultivars were higher in densities of 25 and 35 than 15 plants.m-2. In general, it seems that suitable red and white bean cultivars for planting in this region based on yield, are Yaghout and Dorsa.

In order to evaluate the effect of planting density and application of reduced herbicide doses in optimizing weed control and management in intercropping of red bean cultivars, an experiment was conducted in 2016 at the University of Tehran Research Farm using reduced doses of Imaztapir herbicide at five levels (0, 25, 50, 75). And 100% of the recommended dose of herbicide with manual weeding (as the main plot and different bean planting densities (40, 50 and 60 plants per square meter) as a sub-plot and pure and mixed cultivation system of standing and climbing cultivar was performed as a sub-plot. The results showed that the interaction effects of herbicide application on cultivation system and herbicide application on planting density, dry weight and bean yield were significant and also with increasing herbicide dose and plant density bean dry weight and bean seed yield increased and weed dry weight and Weed density decreased. At low herbicide doses, the use of a mixed culture system was more involved in reducing weed density and increasing bean biomass than increasing density; However, in high doses of herbicides, the role of increasing density was superior to intercropping, so to preserve the environment and reduce the economic costs of spraying, reduced doses of herbicides can be used to reduce biomass and weed density, which reduces its competitiveness with the crop. Density and mixed culture system used.

In order to investigate the effect of weeds on lentil, an experiment was conducted on a farm located in the Razi university, Kermanshah. The levels of weed infestation in different parts of the farm were classified into six classes from low to high. Sampling was performed using a 1m2 quadrat during the lentil growth season. The results showed that at the weed infestation level of greater than 50% (highest infestation level), the rate of reduction in the seed number, seed weight, pod number, pod weight, thousand seed weight were 79.5%, 81.7%, 80.1%, 85.4% and 13.5% respectively in comparison with the weed infestation level of less than 10% (minimum infestation level). The results of stepwise regression models showed that the presence of weeds during the first (30 days after emergence) and fourth sampling stage (60 days after emergence) had a significant effect on different traits of lentil. In the first sampling stage, Convolvulus arvensis and Galium aparine were detected as the most important weeds with a significant negative coefficient on the number of pods (-12.3 and -11.4, respectively), pod weight (-0.21 and -0.19, respectively), seed number (-12.25 and -12.20, respectively) and seed weight (-0.62 and -0.59, respectively). In the fourth stage of sampling, G. aparine and Lactuca serriola with a significant negative coefficient; number of pods (-11.65 and -2.23, respectively), the seed number (-12.74 and -2.23, respectively) and seed weight (-0.62 and -0.11) were the most important weeds of the field.

Echinochloa oryzoides is a new specific weed of paddy fields that was first reported in Guilan in 2006 and now has infested tens of thousands of hectares of paddy fields. Characteristics of new and common species of barnyardgrass and their response to some selective rice herbicides were studied to provide a solution for their management. Results showed that panicle emergence time of new species was 11 and 21 days earlier than Hashemi rice and barnyardgrass, respectively. In addition, new one had lighter color and shorter panicle length (12.8 cm) than the common one (23 cm) and rice (27.6 cm). Seed shattering was less than 1% in new species and rice and was about 99% in barnyardgrass. Weight of 1000-seed in new species (4.5 g) was more than common species (2.5 g) and less than rice (25 g). Germination rate of one year old seeds of barnyardgrass and new barnyardgrass were 9 and 6% and it was 30 and 73% for three years seeds, respectively. The results of dose-response experiments showed that two species susceptibility to Thiobencab and Pertilachlor herbicides was similar, but the new species was more susceptible to bensulfuron-methyl. Therefore, according to the results of this study, due to the bright color and early panicle initiation, which enable easy identification of new barnyardgrass, as well as lack of seed shattering and greater susceptibility to herbicides, to manage new species, physical removing before rice harvest and also herbicide rotation especially in the fields that planted for seed production is recommended.

Broadleaf weeds cause serious damages in the new established alfalfa fields.In order to evaluate the efficacy of some herbicides in controlling broadleaf weeds in newly planted alfalfa fields,an experiment was conducted in a randomized complete block design with 8 treatments and 4 replications in Chahar takhteh station of Research and Education Center of Agriculture and Natural Resources Chaharmahal and Bakhtiari Province (Shahr-e-kord) during the summer of 2013-2014. Treatments were Eptam (Eradicane EC 82%) dose 5 Lha-1, Metribuzin (Sencor WP 70%) dose 750 gha-1, 2,4-DB (Butress EC 42.3%) doses 3 and 3.5 Lha-1, Bentazon (Bazagran SL 48%) dose 3 Lha-1, Imazethapyr (Pursuit SL 10%) doses 0.5 and 1 Lha-1 (with 200 ml citogit), and control (weed infested).The results showed that the highest efficiency was observed in 1 L Imazethapyr ha-1 that on average, in all three harvesting, the density and biomass of shepherd needle, nettle and bogloss was decreased 83 to 89.5% and 82.5.to 97.6%, respectively. Also 1 L imazethapyr ha-1 resulted the highest alfalfa biomass in the first and third harvesting of  (53.9 to 87.1%),and in the second harvesting, 3.5 L 2,4-DB (Butress EC 42.3%) ha-1 resulted in the highest alfalfa biomass (90.4%). Overall, imazethapyr controlled weeds well and it was a suitable herbicide for alfalfa fields due to low dose and reduction of adverse environmental effects.

To determine the cardinal temperatures and variation of ground cherry′s germination, an experimentwas conducted based on a completely randomized design with 4replications in the weed laboratory at Kurdistan University in 2018. Treatments were 5, 10, 15, 20, 25, 30, 35, 40 and 42.5 ºC. Also, the effect of seed burial (20 cm) duration on germination variations, another experiment was conducted based on completely randomized design with 8 levels of seed burial time (1 and 2 weeks, 1, 2, 3, 4, 5 and 6 months) with 4replications. Furthermore, to investigate the germination, the cumulative germination and germination speed were measured in both tests. Results showed that 5 and 10 ºC have no effect on ground cherry′s germination but others temperatures significantly (p= 0.05) changed germination speed and cumulative germination. The best temperatures for cumulative germination parameter were 40 and 42.5 ºC and the worst was the 20 ºC. Additionally, both parameters were significantly (p= 0.05) affected by the seed burial duration in all treatments, so that the maximum cumulative germination (a), slope of germination variation (b), and time to 50% of germination (t0) parameters were minimized in all seed burial duration treatments but there was a significant difference between seed burial duration, especially between short periods and longer periods. Finally, it can be said that in infested area with ground cherry′s, using deep tillage and burying seeds deep in the soil and after that using minimum or no tillage, the rate of contamination may be significantly reduced.

The spread of weed resistance to herbicides is expanding in Iran; therefore, monitoring of resistance to the most commonly used herbicides and evaluation of cross-resistance to the herbicides were carried out on 38 canarygrass accessions collected from wheat fields in five provinces (Golestan, Fars, Khuzestan, Ardabil and Tehran provinces) of Iran. The whole plant screening test was conducted with four replications in the greenhouse of Iranian Research Institute of Plant Protection in 2019. Plants at the two- to -three leaves stage were exposed to the recommended field dose of herbicides. Four weeks after spraying, the percentage of fresh and dry weights and plants survival were measured. Of the 38 accessions, 13 (34%), eight (21%), two (5%) and one (about 2.5%) accessions were classified to being high resistant and suspected resistant to mesosulfuron+iodosulfuron+mefenpyr-diethyl (Atlantis), clodinafop-propargyl (Topik), pinoxaden (Axial), and mesosulfuron+iodosulfuron+difloficane+mefenpyr- diethyl (Othello), respectively. Overall, mesosulfuron+iodosulfuron+diflufenican+mefenpyr- diethyl and pinoxaden showed higher efficiency on the accessions than the other two herbicides. Cross-resistance to clodinafop-propargyl and pinoxaden herbicides was observed in two accessions (GM1 from Golestan, PA1 from Ardabil). One accession (AL1) from Golestan province showed resistance to mesosulfuron+iodosulfuron+mefenpyr-diethyl and mesosulfuron+iodosulfuron+diflufenican+mefenpyr- diethyl. Resistance to ACCase inhibitors in the accessions collected from Khuzestan province and the cross-resistance in the accessions collected from Golestan and Ardabil provinces showed the rapid development of herbicide resistance problem in Iran, especially in the mentioned provinces. Therefore, it is necessary to pay more attention to the prevention, delay and management of canarygrass herbicide-resistant accessions.

The present study was conducted to investigate the effect of different water hardness levels on the efficacy of clodinafop-propargyl and mesosulfuron+iodosulfuron+mefenpyr-diethyl with and without adjuvants in control of winter wild oat (Avena ludoviciana). The experiment was conducted as a randomized complete block design in factorial arrangement with three replications at the research greenhouse of Iranian Research Institute of Plant Protection during 2017-2019. The experiment factors included herbicides doses at four levels of 25, 50, 75% and 100% of the recommended field rate of each herbicide (the recommended dose for Topik and Atlantis were 64 and 18 g a.i ha-1 , respectively), concentrations of hardness at five levels (0, 250, 500, 750 and 1000 ppm of Calcium bicarbonate) and different levels of ammonium sulfate and urea ammonium nitrate adjuvants at three levels (0, 1 and 2% v/v). The results indicated that the water hardness higher than 500 ppm led to a reduction in the efficacy of clodinafop-propargyl in control of winter wild oat. However, the efficacy of mesosulfuron+iodosulfuron+mefenpyr-diethyl was not influenced by any level of water hardness. According to the results of this experiment, the use of ammonium sulfate 2% or ammonium urea nitrate 1 to 2% reduced the negative effects of hard water containing calcium carbonate with a concentration of more than 500 ppm on the effectiveness of the herbicide clodinafop-propargyl, and reduced the recommended dose of this herbicide by 25 to 50%. Furthermore, the use of ammonium sulfate 2% or urea ammonium nitrate 1% increased the efficacy of mesosulfuron+iodosulfuron+mefenpyr-diethyl.

Genus Orobanche is one of the most important parasitic weeds worldwide in several crops such as mushroom, rapeseed, bean, potato, tobacco, tomato, carrot, and other products belonging to Solanaceae, Apiaceae, and Asteraceae families. These weeds are considered as a serious threat to rapeseeds and other crops of the genus Brassica. They cause 5-100 percent yield loss in rapeseed in semi-tropical regions. There are 39 species of Orobanche in Iran. So far, there was no report of parasitic broomrape species in the Iranian rapeseed farms. As a result of a study conducted during the 2017-2019 cropping seasons, five parasite species, O. aegyptiaca, O. nana, O. oxyloba, O. hirtiflora and O. mutelii are reported for the first time on rapeseed farms from, , Ilam (Dehloran Township, Musian, Dasht-e-Abbas), Golestan (Gorgan Township, Galikesh Mountain), Golestan, Ilam (Dehloran Township), and Golestan (Gonbad Township, Simin Shahr, Gamishli Nazar, Ghareh Tappeh, Bandar Torkman, Ghareh Tappeh) Provinces, respectively, in Iran.

 The experiment was conducted to evaluate soil applicant herbicides effects on controlling growth of Orobanche among 3 Sunflower cultivars (Prograss, Farrokhi & Confectionary (Ajili)) The location of the experiment was Khayraj village, Buin Zahra city, Qazvin province, which was conducted in the year 2017. The experiment was conducted in a completely randomized block design with 18 treatments, one waterlogging treatment and 17 other herbicide treatments with three concentrations (0%, 75% and 100% recommended) with three replications. The measured traits included density, Fresh weight, dry weight of Orobanche and biological indicators of sunflower. The results of the experiment showed that the best control of Orobanche was in the treatment of trifloxysulfuron (Envoke) WG 75%) 20g/ha (92.2%), Flooding method (90.1%), Butacchlor (Machete) 3L/ha (88.1%), cycloate (Ro-Neet EC 72%) 1.5L/ha (88%) and etal-fluoraline (Sonalan EC33. 3%) 4L/ha (87%). In this study, among the three sunflower cultivars, respectively Ajili, Farokhi and Progres were sensitive to Orobanche. The effect of herbicide on sunflower cultivars was not significant.