مدل سازی الگوی جوانه زنی دو توده تاج خروس در واکنش به دما

In order to investigate the germination characteristics and cardinal temperatures of Thymus transcaspicus, a laboratory experiment was conducted with two different cultivated and natural seedlots at constant temperatures including 2, 5, 10, 15, 20, 25, 30, 35, 40 and 45 °C in a completely randomized design with four replications. Two seedlots were monitored for variability in germination criteria based on three regression models namely: Five-parameters Beta (FPB), Intersected-lines (ISL) and Quadratic Polynomial (QPN) models. The effect of temperature on rate and percentage of seed germination in both seedlots was significant. For both seedlots the highest germination percentage (GP) was within the range of 10-30 °C while the highest germination rate (GR) occurred in 30 °C. Although means of GP and GR for the field seedlot were higher than the natural seedlot, variability of GP and GR in response to temperature was higher for natural seedlot. Best model fit over the entire temperature range was obtained by the FPB and ISL models for both seedlots. However, FPB model showed most suitable fitness particularly in the case of natural seedlot. Based on the regression between germination rate and temperature in both seedlots, the cardinal temperatures (Tbase, Topt and Tmax) were: (1.2-3.84), (29.1-25.8) and (45-47) °C for field seedlot and (1.0-3.3), (24.9-29) and (45-46) °C for natural seedlot, respectively.

Weed management is one of the major constraints in the Zimbabwe smallholder farming sector contributing to smallholder poor yields, hence there is need to identify cropping systems that have potential to reduce weed pressure while improving crop yields. Conservation agriculture has been suggested as one of these farming systems. The implementation of CA three key principles reduces weed pressure even when the use of herbicides is minimised. Crops included in crop rotations, intercropping or relay cropping may have faster growth rate than weeds hence, have a comparative advantage over weeds. Maintenance of permanent soil cover through crop residues impedes weed germination thereby reducing weed population. Elimination of ploughing also reduces the chances of bringing buried weed seeds to the surface where their chances for germination are high. Hence, some seeds lose viability thus reducing weed density. Weed seeds accumulate at the surface, when allowed to set seed, increasing their exposure to predation resulting in reduction of weed density over time. The use of herbicides ensures that the fields are weed free as the season’s progress thus ensuring better yields at the end of each growing season. Hence, weeds are reduced in CA systems over time despite the weeding option used.

Chemicals end up in the environment in many different ways, intentional and unintentional. Plant protection products, hereinafter referred to interchangeably as pesticides, make up the quantitatively largest share of harmful substances which are used deliberately. Chemical pesticides are used to protect crops and plant products from harmful organisms and the diseases they cause, and contain one or more chemical and usually synthetically manufactured active substances. Pesticides combat animals acting as pests, e.g. insects (insecticides) or rodents (rodenticides), offer protection from diseases such as fungal infestations (fungicides) or simplify production methods and decrease the related costs through reducing the number of hours worked. Pesticides also include herbicides which are used to control weeds. Other applications include plant growth regulation and the conservation of plant products. Alongside climate change, major changes to global nutrient cycles, the destruction of habitats and other factors, pesticide contamination plays a significant role in the concept of planetary boundaries, which suggests that crossing critical thresholds leads to profound disturbances in the Earth system processes.

In order to determine cardinal temperatures and some germination characteristics for type one seed (upper segment) and type two seed (lower segment) of Rapistrum rugosum, an experiment was conducted on two type seed and10 levels of temperatures (3, 5, 10, 15, 20, 25, 30, 35, 40 and 45 °C) in completely randomized design with four replications in factorial experimental arrangement in Weeds Research Laboratory, Faculty of Agriculture, Ferdowsi University of Mashhad in 2012. Results indicated that the cardinal temperatures for type one seed (Min, Opt and Max) were 0.7, 35.8 and 45.4C° and for type two seed were 1.3, 31.7 and 48.5, respectively. The highest germination percentage for type one seed (upper segment) was in temperature range 10-35°C and for type two (lower segment) was in 5-35°C. Germination percentage in type two seed (81%) was more than type one (41%). There was significant different between length of plumule and radical of type one and two seed in 10°C (P≤0.05). As length of plumule and radical of type one was more than type two seed.

A soja transgênica apresenta mecanismo de resistência ao Glifosato, mas existem estudos que demonstram efeitos negativos desse herbicida sobre a fase inicial de desenvolvimento da semente. Também há relatos que o uso do bioestimulante evitam a perda de vigor da semente na fase inicial quando em contato com o Glifosato. Este trabalho teve como objetivo avaliar o efeito de subdoses de glifosato e bioestimulante em sementes de soja. Foi utilizado o delineamento inteiramente casualizado em esquema fatorial 2x5, com quatro repetições. As sementes foram submetidas a cinco subdoses de Glifosato zapp 620 (0; 3,5; 7,0; 10,5 e 14 mL-1 L) e ao tratamento de sementes com Stimulate® à 0 e 7,5 mL L-1. Em laboratório, as unidades experimentais constituíram-se de rolos de papel de germinação com as sementes de soja, para avaliar testes de primeira contagem da germinação, envelhecimento acelerado, teste frio, comprimento de raízes e parte aérea, condutividade elétrica, massa seca de raiz e parte aérea e germinação total. Os tratamentos com bioestimulante na semente sob subdoses de Glifosato aumentam a germinação total das plântulas e apresentam maior vigor para os testes de resistências, porém reduz o vigor e diminui a taxa de crescimento e acúmulo de matéria seca da parte aérea e raiz.

پیزور علفهرزی چند ساله و مقاوم به غرقاب از خانواده اویارسلام است که در سالهای اخیر جمعیت آن در مزارع برنج شمال کشور رو به افزایش است. بهمنظور کنترل شیمیایی پیزور در برنج، آزمایش مزرعهای طی دو سال متوالی در مؤسسه تحقیقات برنج کشور واقع در رشت اجرا شد. در سال اول، کارایی علف‌کش‌های رایج مزارع برنج شامل پرتیلاکلر، بوتاکلر، بنسولفورونمتیل، اکسادیارژیل و تیوبنکارب در کنترل پیزور مطالعه شد. بر مبنای نتایج سال اول، کارایی برخی علف‌کش‌های انتخابی و جدید از گروه سولفونیل اوره ها ( ALSها) مزارع برنج از جمله فلوستوسولفورون، پنوکسولام، مت‌سولفورونمتیل و نیز علف‌کش پیرازولیت از خانواده پیرازول‌ها در مقایسه با بنسولفورونمتیل در سال دوم مورد بررسی قرار گرفت. نتایج سال اول نشان داد که حداقل زیست‌توده پیزور در کرت‌های تیمار شده با بنسولفورونمتیل (5/1 گرم بر متر مربع) و پرتیلاکلر (6/10 گرم بر متر مربع) در شش هفته پس از نشاکاری مشاهده شد، درحالی‌که سایر علف‌کش‌ها کارایی مطلوبی در کنترل پیزور نداشتند. نتایج آزمایش سال دوم مشابه نتایج آزمایش اول، یعنی کارایی بسیار خوب بنسولفورونمتیل (97%≤) در کنترل پیزور بود. بعلاوه، نتایج نشان داد که کاربرد فلوستوسولفورون و پیرازولیت سبب کاهش معنی‌دار زیستتوده پیزور (91%≤) در مقایسه با شاهد عدم کنترل گردید، درحالی‌که علف‌کش‌های پنوکسولام و مت‌سولفورون تأثیر بسیار کمی در کاهش زیستتوده پیزور (49%≥) داشتند. با توجه به مکانیزم عمل متفاوت علف‌کش‌های جدید و سازگاری آنها با برنج، کاربرد آنها در تناوب با علف‌کش‌های موجود برای کنترل شیمیایی پیزور و اجتناب از مقاومت در صورت ثبت در کشور توصیه میشود.

In 1984-1986, a survey was carried out to determine weed species, density and widespread in second crop soybean fields in Adana, Antalya, Hatay, Icel, Kahramanmaras provinces. The possibilities of the most effective control measures were also studied with various chemical and mechanical control methods; and then studied on soybean yield and rotation crop wheat. According to the results of survey; in the second crop soybean fields in desity in Adana, nudsedge species ( Cyperus rotundus L.) common purslane ( Portulaca oleracea L), Johnson grass [ Sorghum halepense (L.) Pers.], in Icel common purslane, nudsedge species, tumble pigweed ( Amaranthus albus L.); in Antalya nudsedge species, common purslane, johnson grass; in Kahramanmaras, awnless barnyard grass ( Echinochloa colonum (L.) Link.), common purslane, johnson grass; in Hatay tumble pigweed, nudsedge species, awnless barnyard grass were determined weed species which are the most important, and their density were above 10 plant/m2. In widespread nudsedge species was the most important weed in all provinces; at the same time the other species were also important weeds which are widespread in second crop soybean field. In 1984-1985, control experiments were carried out in Cukurova Agricultural Research Institute, metolachlor, prometryn, terbutrin, linuron, trifluralin, metribuzin, vernolate, fluazifop-butyl, bentazon and mechanical control were tested against all weeds. Metolachlor (500 ml/da prep.) was found effective against purple nudsedge, and fluazifop-butyl (100 ml/da prep.) gave sufficient effect against johnson grass. It was not found different among chemical and mechanical control to effect and yield. For that purpose, mechanical control could be recommended against weeds in soybean fields. I has been found that the herbicides were not phytotoxicity to germination of rotation wheat seeds.

A split plot experiment based on randomized complete block design with three replications was carried out in 2015 to determine the best stage for harvest of three dill (Anethum graveolens) ecotypes (Varamin, Isfahan, Malayer) under different irrigation conditions (irrigation after 70, 100, 130 and 160 mm evaporation from class A pan), in order to produce high quality seeds.Results clearly showed that seed quality of all ecotypes under different irrigation intervals was increased with improving seed development on the mother plants. Maximum seed quality on the basis of electrical conductivity of seed leachates, germination percentage and rate and seedling dry weight was obtained at about 2-12 days after mass maturity, depending on ecotypes and irrigation intervals. Earlier harvests due to immaturity and later harvests because of aging reduced seed germination and vigor.Seed vigor of all dill ecotypes gradually diminished with declining water availability to the mother plants. It was, therefore, concluded that irrigation of dill plants particularly during seed filling could improve the quality of seeds. Nevertheless, the best seed moisture content for harvesting dill plants and producing high-quality seeds was about 15-20%. The most vigorous seeds on the basis of germination rate and seedling dry weight were produced by Varamin, followed by Malayer ecotypes.

In order to investigate the effects of different exogenous hormones on the dormancy and germination of lettuce seeds, this paper soaks the lettuce seeds in ACC, GA, CaCl2 and SNP solutions with different concentrations, respectively, observes the quantity of lettuce seeds germinated, calculates the germination rate, and analyzes the optimum concentrations to break the period of dormancy and promote the germination of seeds to increase the germination rate of seeds. Through the observation of lettuce seeds soaked with ACC, GA, calcium chloride and SNP in different time periods, it is found that ACC, GA, calcium chloride and SNP solutions can all promote the germination of lettuce seeds. Lettuce falls within the Lactuca genus, the Asteraceae family. It likes cold climate and the suitable temperature for growth is 15-20°C. If the temperature exceeds 25°C, the high temperature in the leafy head will cause the necrosis and rot and poor growth of interior leaves (Song et al., 2013). The temperature for germination of seeds ranges between 15-20°C. If the temperature is higher than 25°C, the seed coat will not be able to absorb water, affecting the germination (Li et al., 2012). When lettuce is sowed in summer, it needs to be treated at a low temperature. After being soaked, it should be placed in the refrigerator freezer to accelerate germination and should not be sowed until the sprout turns white. Lettuce is rich in protein, sugar, vitamins, minerals and other nutrients. It is popular among consumers due to its crisp texture, fresh taste and fragrance and rich nutrition (Hu and Zhan, 2014). Few research has been conducted on the effects of exogenous hormones on the germination rate of lettuce seeds. This study takes lettuce seeds from the same source as the test material and conducts tests on the germination rate of lettuce seeds, trying to explore the effects of ACC, GA, CaCl2 and SNP solutions with different concentrations on the germination rate of lettuce seeds so as to improve the germination rate.

پتانسیل آللوپاتیک غلظت‌های مختلف (0، 5، 10، 20 و 40 درصد) عصاره آبی اندامهای هوایی یونجه بر جوانه زنی و رشد ریشه چه چهار گونه علف هرز (تاج خروس سفید Amaranthus albus، تاج خروس هیبرید hybridus.Amaranthus، تاجریزی سیاه Solanum nigrum و سلمه تره ‍Chenopodium album) در شرایط آزمایشگاهی به صورت فاکتوریل در قالب طرح کاملاً تصادفی با 3 تکرار مورد ارزیابی قرار گرفت. نتایج نشان داد که درصد جوانه زنی نهایی، متوسط زمان جوانه زنی، یکنواختی جوانه زنی، مدت زمان رسیدن تا 10، 50 و 90 درصد جوانه زنی و طول ریشه چه چهار گونه علف هرز تحت تأثیر غلظت‌های عصاره، گونه‌های علف هرز و اثر متقابل آنها قرار گرفتند. با افزایش غلظت عصاره آبی یونجه درصد جوانه زنی نهایی به صورت خطی کاهش یافته و متوسط زمان جوانه زنی و مدت زمان رسیدن تا 10 و 50 درصد جوانه زنی نیز افزایش یافت. طول ریشه چه، یکنواختی جوانه زنی و مدت زمان رسیدن تا 90 درصد جوانه زنی از یک رگرسیون درجه دو پیروی می‌کردند و با افزایش غلظت عصاره، طول ریشه چه کاهش و مدت زمان رسیدن تا 90 درصد جوانه زنی افزایش و یکنواختی جوانه زنی تا عصاره با غلظت 20 درصد افزایش و بعد از آن کاهش یافت. تاجریزی سیاه بیشترین درصد جوانه زنی، طول ریشه چه و یکنواختی جوانه زنی و سلمه تره طولانی ترین متوسط زمان جوانه زنی و مدت زمان رسیدن تا 10، 50 و 90 درصد جوانه زنی را داشتند. تاج خروس هیبرید کمترین درصد جوانه زنی، متوسط زمان جوانه زنی، طول ریشه چه، مدت زمان رسیدن تا 10، 50 و90 درصد جوانه زنی و تاج خروس سفید کمترین یکنواختی جوانه زنی را داشتند. به طور کلی گونه تاجریزی سیاه مقاوم ترین و تاج خروس هیبرید حساس ترین گونه به عصاره آبی یونجه بودند.

Humic acid is an organic acid without environmental destructive effects that is applied for increasing germination rate and wheat establishment. In order to evaluate effects of different levels of humic acid on germination of four wheat cultivars; an experiment was conducted in 2008 at Research Laboratory of Faculty of Agriculture, Ferdowsi University of Mashhad. A randomized completely block design with four replications used with factorial combination of humic acid concentration (0, 36, 54, and 72 mg/l) and wheat cultivars (Sayons, Chamran, Pishtaz and Sabalan). Results showed that all traits except germination rate were significantly different (p

The germination requirements of Talinum triangulare were studied under control conditions in the laboratory. Treatments included 7 temperature regimes (fluctuating day: night temperature regimes of 50℃: 45℃, 45℃: 40℃, 40℃: 35℃, 35℃: 30℃, 30℃: 25℃, 25℃: 20℃ and 20℃: 15℃), 6 water potential levels (0 MPa、-0.05 MPa、-0.1 MPa、-0.2 MPa、-0.3 MPa and -0.4 MPa), and 9 salinity concentrations (0%、0.05%、0.1%、0.2%、0.3%、0.4%、0.6%、0.8% and 1.0% NaCl), using a completely randomized design with 3 replications. The seeds germinated at temperatures between 25 and 45℃ with the optimum. The best germinate temperatures was 35/30℃ of alternate temperatures. If the alternate temperatures was 50/45℃ (light/dark) and 20/15℃, the seed can't germinate. The best germinate temperatures was 35℃ of constant temperatures. If the constant temperatures was 50℃ and 20℃, the seed can't germinate. The seeds germinated at water potentials between 0 MPa and -0.2 MPa with the optimum. The best water potentials was 0 MPa. The seeds germinated at salt stress between 0% and 0.8% with the optimum. If the salt stress higher with 0.8%, the seed wasn't germinate. When the alternate temperatures were 25/20℃ and salt stress was 0.6%, the seeds germination only was 0.7%. When the alternate temperatures were 35/30℃ and salt stress was 0.8%, the seeds germination was 56.7%. When the alternate temperatures were 40/35℃ and salt stress was 0.6%, the seeds germination was 42.7%. The optimum temperatures can enhance the Talinum triangulare Willd.'s salt stress level.

نماتدهای ریشه گرهی (Meloidogyne spp) از جمله عوامل بیماریزای بسیار مهمی هستند که خسارت زیادی به محصولات کشاورزی وارد می‌سازند. روش‌های متعددی (تناوب زراعی، ارقام مقاوم و ترکیبات شیمیایی) برای کنترل آنها به کار گرفته شده است. هزینه بالا و مشکلات زیست‌محیطی (ترکیبات شیمیایی)، توجه محققان را به استفاده از روش های غیر‌شیمیایی همچون استفاده از گیاهان و فرآورده های گیاهی برای مدیریت این نماتدها معطوف کرده است. جهت بررسی تأثیر حضور تعدادی از گیاهان خانواده نعناع روی نماتد ریشه‌گرهی، از سه گیاه دارویی آویشن باغی (Thymus vulgaris)، مرزه (Saturea hortensis) و زوفا (Hyssopus officinalis) استفاده شد. این آزمایش در گلخانه ای بصورت فاکتوریل و در قالب طرح کاملا تصادفی با چهار تکرار با کشت تنها و مخلوط گوجه‌فرنگی با گیاهان دارویی زوفا، آویشن و مرزه، در حضور و بدون حضور نماتد انجام شد. ارزیابی نتایج سه ماه بعد از تلقیح نماتد و بر اساس شاخص های رشدی گوجه فرنگی و پارامترهای بیماری زایی نماتد صورت گرفت. تجزیه و تحلیل آماری داده های حاصل ‌‌نشان دهنده اثر معنی‌دار حضور سه گیاه دارویی مذکور روی کاهش خسارت نماتد بود. مؤثرترین گیاه در کاهش خسارت و بیماری زایی نماتد مرزه بود و آویشن باغی، و زوفا در درجات بعدی قرار گرفتند. در مجموع بررسی‌های گلخانه‌ای گیاهان دارویی مورد آزمایش، اثرات کنترلی مطلوبی علیه نماتد ریشه گرهی از خود نشان دادند و می‌توان استفاده از آنها را در برنامه‌های مدیریت نماتد ریشه‌گرهی مورد توجه قرار داد.

در اصلاح و احیاء مراتع توجه به مرحله جوانه زنی و استقرارگراس های پایا که حساس به تنشهای محیطی می باشد ضروری به نظر می رسد. بدین منظور تکنیک پرایمینگ بذر جهت بهبود سرعت جوانه زنی و بنیه گیاهچه پنج گراس چند ساله فصل سرد مرتعی شامل Bromus confinis، Elymus elongatum، Agropyron pectiniform، Festuca ovinaو Festuca arundinaceae با استفاده از ماده اسمتیک پلی اتیلن گلایکول (PEG 8000) در غلظتهای 0، 5/0 ، 1، 5/1 ، 2 و 5/2 مگاپاسکال (MP) برای دوره­های نگهداری صفر، 2، 4، 6 و 8 روز (D) مورد ارزیابی قرار گرفت. این آزمایش به صورت فاکتوریل در قالب طرح کاملا تصادفی در 4 تکرار اجرا شد. نتایج تجزیه واریانس نشان داد که تفاوت بین تمامی عوامل مورد مطالعه و اثرات متقابل آنها برای سرعت جوانه زنی و اجزاء گیاهچه بسیار معنی داربود (P

Weeds and Their Management: Rationale and Approaches, R.K. Kohli, D.R. Batish, and H.P. Singh Weed Management: A Basic Component of Modern Crop Production, R. Labrada Contributions to Weed Suppression from Cover Crops, M.L. Hoffman and E.E. Regnier Utilizing Brassica Cover Crops for Weed Suppression in Annual Cropping Systems, R.A. Boydston and K. Al-Khatib Grass-Legume Mixed Cover Crops for Weed Management N.R. Burgos, R.E. Talbert, and Y.I. Kuk Rye As a Weed Management Tool in Vegetable Cropping Systems, J.B. Masiunas A Rotation Design That Aids Annual Weed Management in a Semiarid Region, R.L. Anderson Examining Tillage and Crop Rotation Effects on Weed Populations in the Canadian Prairies, R.E. Blackshaw, A.G. Thomas, D.A. Derksen, J.R. Moyer, P.R. Watson, A. Legere, and G.C. Turnbull Potential of Allelopathy and Allelochemicals for Weed Management, D.R. Batish, H.P. Singh, R.K. Kohli, and G.P. Dawra Progress in Developing Weed-Suppressive Rice Cultivars for the Southern United States, D.R. Gealy and K.A. Moldenhauer The Ecology of Weed Seed Predation in Herbaceous Crop Systems, F.D. Menalled, M. Liebman, and K.A. Renner Mowing for Weed Management, W.W. Donald Herbicide Fate Under Conservation Tillage, Cover Crop, and Edge-of-Field Management Practices, M.A. Locke, R.M. Zablotowicz, and M.A. Weaver Strategies for Developing Bioherbicides for Sustainable Weed Management, S.M. Boyetchko and E.N. Rosskopf Developing Microbial Weed Control Products: Commercial, Biological, and Technological Considerations, K.L. Bailey and E.K. Mupondwa Implementation of Weed Biocontrol in Forest Vegetation Management for Conifer Production, S.F. Shamoun Characterization of Phytotoxins from Phytopathogenic Fungi and Their Potential Use As Herbicides in Integrated Crop Management, A. Evidente and M.A. Abouzeid Applications of Soil and Rhizosphere Microorganisms in Sustainable Weed Management, R.J. Kremer Herbicide-Resistant Crops and Weed Management, K.N. Reddy and C.H. Koger Strategies for Managing Herbicide-Resistant Weeds, H.J. Beckie and G.S. Gill Recent Advances in Parasitic Weed Research: An Overview, J.R. Qasem Management of Weeds in Pasture Systems, B.M. Sindel Integrated Turfgrass Weed Management, R.S. Chandran Approaches to Integrated Weed Management, D.D. Buhler Learning Groups for Implementation of Integrated Weed Management: Principles and Practical Guidelines, N. Jordan, H. Niemi, S. Simmons, R. Becker, J. Gunsolus, and S. White Index Reference Notes Included