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Knowledge about the fitness cost imposed by herbicide resistance in weeds is instrumental in devising integrated management methods. The present study investigated the germination response of ACCase-resistant (R) and susceptible (S) winter wild oat under different environmental conditions. The DNA of the plants was sequenced after being extracted and purified. The segregated F 2 seeds were subjected to various temperatures, water potentials, NaCl concentrations, different pHs, darkness conditions, and burial depths. The results of the sequencing indicated that Ile-2041-Asn mutation is responsible for the evolution of resistance in the studied winter wild oat plants. The seeds were able to germinate over a wide range of temperatures, osmotic potentials, NaCl concentrations, and pHs. Germination percentage of R and S seeds under dark and light conditions was similar and ranged from 86.3 to 88.3%. The highest emergence percentage for both R and S plants was obtained in 0, 1, and 2 cm depths and ranged from 66.6 to 70.3%. In overall, no differences were observed in the germination response between the R and S winter wild oat plants under all studied conditions. No fitness cost at seed level indicates that control of R winter wild oats is more difficult, and it is essential to adopt crop and herbicide rotation to delay the further evolution of resistance.

Assessing the impacts of alien plant species is scientifically important and critical for supporting invasion-related policies. Generic Impact Scoring System (GISS) and Environmental Impact Classification for Alien Taxa (EICAT) are standardized schemes to evaluate, compare, and eventually predict the magnitudes of the variety of impacts invasive species can have. Here, we apply these two systems to classify alien plants of Iran according to the magnitude of their environmental and socioeconomic impacts. A review of published literature and online resources was undertaken to collate information on the reported environmental and socioeconomics impacts of 27 alien plants in Iran. The resulting data ranked species by their total sum of impact scores and by their highest scores. According to total impact scores from GISS Eichhornia crassipes, Ailanthus altissima, Imperata cylindrica, Amsinckia menziesii, and Paulownia sp. had the highest impacts. About 60% of alien plants assessed had higher environmental impacts than socioeconomic impacts, 18% had higher scores for socioeconomic impacts, and 22% scored the same in both categories. According to EICAT, Ulex europaeus, Ambrosia psilostachya, E. crassipes, A. altissima, and A. menziesii were the five species with major impacts; other 16 species (59%) were classified as with moderate impacts, five with minor and two of minimal concern. Seven species had similar rankings by both GISS and EICAT. The deficit of scientific literature to quantify impacts on complex ecosystem services in Iran or emphasis on the reversibility of impacts in the EICAT protocol could explain differences in ranking of species by the two schemes. GISS and EICAT could be used to link impact magnitudes and type (environmental or socioeconomic) to biological traits to understand and forecast species with different types of impact.

Invasive alien plants (IAPs) disrupt biodiversity, ecosystem functions, rural livelihoods, and human health/well-being. Hence, the negative impact of Cenchrus setaceus (syn. Pennisetum setaceum) as an invasive weed poses many concerns in terms of environmental and socio-economic impact. The abundance in previous research on invasion ecology, weed biology, and the management of C. setaceus establishes the chance to carry out an in-depth evaluation of this invasive alien species for a cohesive understanding, closely linked to policy development. This systematic review aims to provide a comprehensive evaluation of previous research, identify knowledge gaps, and incorporate recent practical research findings on C. setaceus to elucidate management options. Standard methods were used to collect the literary evidence on multiple thematic aspects linked with its traits and management. Results revealed the substantial negative impacts of C. setaceus on ecosystems, ascribed to multiple physiological, biochemical, and ecological features. Further, a multitude of plant traits such as rapid seed distribution and efficient reproductive strategies imposed serious challenges in the control of C. setaceus. Deployment of integrated control methods for at least three years in depleting seed bank conjunction by planting native grass may help in its confinement. In conclusion, policy measures like strict biosecurity/legal regulations, explicit elucidation of weed biology, early detection and response, ecological modeling, and long-term monitoring with community participation can expand the horizon of C. setaceus control and help achieve its sustainable management.

Glyphosate has been used for roadside weed control in southern Spain for over 40 years, and most populations of goldentop (Lamarckia aurea L.) Moench have putatively developed resistance to this active ingredient. The physiological and biochemical basis for glyphosate resistance in this weed has been investigated. Dose–response studies indicated that the resistant biotype (R) was almost 13 times more resistant to glyphosate compared to a known susceptible biotype (S). Studies of foliar glyphosate retention and 14C-glyphosate uptake/translocation showed no significant differences between both L. aurea biotypes. Basal 5-enolpyruvylshikimate-3-phosphate synthase (EPSPS) activity (µmol µg−1TSP min−1) showed similar values between R (0.82 ± 0.04) and S (0.75 ± 0.05) biotypes. On the other hand, the resistance factor (I50R/I50S) did not show a difference between the two biotypes. Therefore, it was concluded that target-site (TSR) resistance mechanisms are not involved in glyphosate resistance in this weed species. The metabolism of glyphosate to form the non-toxic metabolites aminomethylphosphonic acid (AMPA), glyoxylate, and sarcosine was greater and faster in the R compared to the S biotype; thus, glyphosate resistance is due to non-target-site resistance (NTSR) mechanisms. This paper is the first report of glyphosate resistance in L. aurea in the world.

Glyphosate has been used for more than 15 years for weed management in citrus groves in the Gulf of Mexico, at up to 3–4 applications per year. Goosegrass ( Eleusine indica (L.) Gaertn.) control has sometimes failed. In this research, the mechanisms governing three goosegrass biotypes (Ein-Or from an orange grove, and Ein-Pl1 and Ein-Pl2 from Persian lime groves) with suspected resistance to glyphosate were characterized and compared to a susceptible biotype (Ein-S). Dose-response and shikimate accumulation assays confirmed resistance of the resistant (R) biotypes. There were no differences in glyphosate absorption, but the R biotypes retained up to 62–78% of the herbicide in the treated leaf at 96 h after treatment (HAT), in comparison to the Ein-S biotype (36%). The 5-enolpyruvylshikimate-3-phosphate synthase (EPSPS) activity in the Ein-Or and Ein-S biotypes was over 100-fold lower than the Ein-Pl1 and Ein-Pl2 ones. The latter showed a high EPSPS-basal activity, a mutation at Pro-106-Ser position in the EPSPS gene, and EPSPS overexpression. The EPSPS basal and EPSPS overexpression were positively correlated. The R goosegrass biotypes displayed poor glyphosate translocation. Furthermore, this grassweed showed, for the first time, two mechanisms at the target-site level (Pro-106-Ser mutation + EPSPS overexpression) acting together simultaneously against glyphosate.

Parapholis incurva (curved parapholis) is an annual grass that is widely increasing its distribution in areas of barley production in northern Iran. Laboratory experiments were conducted to evaluate the type of dormancy and the effect of different methods of dormancy breaking, to determine cardinal temperatures using nonlinear regression models, and to test the effects of other ecological factors such as drought, salinity, heat shock and pH on germination of curved parapholis seeds. The results showed that the best method for dormancy breaking is applying 75 ppm gibberellic acid + 30 s of sulfuric acid, with highest germination percentage (84 %). It was also demonstrated that temperature significantly affects the germination rate and germination percentage of curved parapholis. The highest germination percentage was obtained between 18 and 25°C, while the lowest germination percentage occurred at below 5°C and above 30°C. Using a segmented model, the base, optimum and ceiling temperatures were estimated to be 1.25°C, 23.29°C and 35°C, respectively. Seed germination declined as the osmotic potential increased from -0.6 to -1.2 MPa. With increasing drought stress and salinity stress, the germination percentage reached less than 50% at -0.88 and -0.84 MPa, respectively. The maximum germination percentage was observed at a pH of 6 and 7. According to this result regulating the soil microclimate (temperature) through field preparations, soil amendments and cultural practices can be employed to better long-term management of curved parapholis.

The establishment and spread of plants in their native or alien geographical ranges are determined by their germination. This study investigated the impact of different factors on variations in cardinal temperatures. We used the lm procedure and measured the effect size by the Eta-square approach to find the association of different factors (species, ecotypes, origin (native/alien), year, and life cycle) with the cardinal temperatures of 31 species. Our results showed that the base, optimum, and maximum temperatures responded differently to these factors. The base temperature was less impacted by ecotypes compared with the optimum and maximum temperatures, whereas the species had a higher impact on the variation in the base temperature. The effect of the origin of weedy plants on the base temperature was higher than the optimum and maximum temperatures. The effect of the year on the optimum temperature was more prominent than that on the base and maximum temperatures. The results confirmed that weedy alien plants preferred high and narrow ranges of base, optimum, and maximum temperatures and probably will be more problematic in summer crops. The results indicate that alien plants can benefit from warmer conditions in invaded areas at the germination stage. These findings lay the foundation for further studies to elucidate which factors are more important.

New introductions of alien Ipomoea species and their negative impacts have increased in Greece, Türkiye, and Iran. However, little is known about their current status, distribution, impacts, and management. Here, we provide a detailed overview of Ipomoea species in these countries and discuss the current and proposed management options for restoring invaded plant communities. We report on four alien Ipomoea species in Greece (three naturalized and one casual), 10 in Türkiye (eight naturalized and two casual), and 11 in Iran (eight naturalized of which two are invasive and three casual). Their most significant negative impact was detected in agricultural areas, especially in spring crops like soybean, cotton, and maize, with I. hederacea , I. purpurea , and I. triloba being the most troublesome weeds. Native plants are mainly threatened by I. indica , I. leucantha , and I. triloba . The management of Ipomoea species differs according to the habitats invaded; in agricultural areas, the management is more dependent on the host crop and the available registered herbicides, whereas in areas with natural habitats, other management options such as mechanical and biological measures are more appropriate. The information from this work will be useful for the early detection of Ipomoea species in countries neighboring the already invaded ones.

Cutleaf geranium is a weed infesting crop fields in various parts of the world. The present study was conducted to determine the cardinal temperatures of germination for its seeds to have a better understanding about temperature needs of this species. Since the seeds were dormant after being harvested, they underwent different dormancy breaking methods. Then, cardinal temperatures were estimated. Among dormancy breaking methods including constant and alternating temperatures, gibberellic acid, H2SO4 and gibberellic acid+ H2SO4 treatments, pre-chilling and after-ripening, after-ripening was the most successful one. Dent and segmented models were the most suitable models for determination of cardinal temperatures. Base, optimum, and ceiling temperatures for dent model were estimated 0.02, 18.97 to 25.32, and 27.00 °C, respectively. These values for segmented model were 0.01, 24.3 and 27.08 °C. The seeds showed high germination uniformity at 15 and 20 °C, but they entered into a state of thermo-dormancy as temperature reached about 27 °C. According to the temperature conditions of the studied region, early sowing of canola will result in the weed being faced with higher than ceiling temperatures. Thus, generalizing, the proper sowing date may be regarded as a feasible management practice in controlling this weed in any given area. This was the first report on estimation of cardinal temperatures in cutleaf geranium.

Weeds, such as Phalaris spp., can drastically reduce the yield of crops, and the evolution of resistance to herbicides has further exacerbated this issue. Thus far, 23 cases of herbicide resistance in 11 countries have been reported in Phalaris spp., including Phalaris minor Retz., Phalaris paradoxa L., and Phalaris brachystachys L., for photosystem II (PS-II), acetyl-CoA carboxylase (ACCase), and acetolactate synthase (ALS)-inhibiting herbicides. This paper will first review the cases of herbicide resistance reported in P. minor, P. paradoxa, and P. brachystachys. Then, the mechanisms of resistance in Phalaris spp. are discussed in detail. Finally, the fitness cost of herbicide resistance and the literature on the management of herbicide-resistant weeds from these species are reviewed.