Novel Use of Trinexapac-Ethyl to Study Weed Seed Germination

Understanding seed biology and onset of germination requirements is a key point for designing effective weed management programs. Gibberellins (GAs) are known to play a role in onset of germination of several species. Onset of germination often requires an increase in de novo GA content or an increase in sensitivity to GAs. Reduced germination of seeds incubated in solutions containing compounds that inhibit GA synthesis provide evidence that GAs are required to trigger germination. Trinexapac-ethyl (TE), a GA synthesis inhibitor, is frequently used as a plant growth regulator in crop production. However, to the best of our knowledge, TE has not been used to study the requirement of GAs in onset of germination. Germination studies were conducted using seeds of artichoke thistle and common teasel under a range of TE concentrations (0 to 500 μM TE), a combined solution of 125 μM TE + 100 μM GA3for artichoke, and 250 μM TE + 100 μM GA3for common teasel. Germination tests were conducted at 20/10 C (12-h thermoperiod) in darkness for artichoke and at constant 15 C with 12 h of light for common teasel. Germination of artichoke in 125 μM TE was reduced to 47% when compared with the check (95%), but the combined TE + GA3solution maintained germination at 84%. Germination of common teasel in 250 μM TE was reduced to 10% when compared with the check (91%), and the combined TE + GA3solution increased germination to 63%. These results demonstrate the utility of TE to study the role of GAs in onset of germination. This novel use of TE is a valuable option to study germination requirements of weed species, and therefore contributes to the design of weed management programs.

Download Full-text

Weeds and Their Effect on the Performance of Maize and Finger Millet in Mid-Hills of Nepal

International Journal of Applied Sciences and Biotechnology ◽

10.3126/ijasbt.v2i3.10790 ◽

2014 ◽

Vol 2 (3) ◽

pp. 275-278 ◽

Cited By ~ 1

Author(s):

Tika Bahadur Karki ◽

Shrawan K. Sah ◽

Resam B. Thapa ◽

Andrew J. McDonald ◽

Adam S. Davis ◽

...

Keyword(s):

Weed Management ◽

Crop Production ◽

Finger Millet ◽

Crop Yields ◽

Management Strategies ◽

Cropping System ◽

Weed Species ◽

Ageratum Conyzoides ◽

Alternative Crop ◽

Weed Infestation

Relay cropping of maize with fingermillet (maize/fingermillet) is the predominant cropping system for sustaining food security situation in the hilly regions of Nepal. In this region weed pressure severely reduces crop yields. Basic information on weed species composition, biomass production and their effect on crop yields and economics are lacking for this region. This information will be necessary to develop effective weed management strategies for the future. In light of this an empirical study was carried out in two representatives mid hill districts of Parbat and Baglung during summer season of 2010/2011 in Nepal. A total of 10 major weed species with densities of 172 in Parbat and 311 per 0.25m2 area in Baglung were observed. The highest percentage of both relative and absolute densities were recorded for Ageratum conyzoides in Parbat and Polygonum chinensis in Baglung. Weed infestation under farmers practice of crop management reduced the grain yield of maize by 1.985 Mt ha-1 (117%) in Baglung and 1.760 Mt ha-1 (108%) in Parbat. Similarly, in finger millet it was 0.489 Mt ha-1 (63%) in Baglung and 0.403 Mt ha-1 in Parbat. Similarly, the combined yield of both the crops was also significantly reduced by 79.3% and 61.7% in Baglung and Parbat respectively. Hence, weeds are directly affecting the crop performance in the region. Therefore, there is an urgent need to develop an alternative crop production system in the hills. DOI: http://dx.doi.org/10.3126/ijasbt.v2i3.10790Int J Appl Sci Biotechnol, Vol. 2(3): 275-278

Download Full-text

Diverse Approaches to Herbicide-Resistant Weed Management

Weed Science ◽

10.1614/ws-d-15-00117.1 ◽

2016 ◽

Vol 64 (SP1) ◽

pp. 570-584 ◽

Cited By ~ 44

Author(s):

Micheal D. K. Owen

Keyword(s):

Weed Management ◽

Crop Production ◽

Production Systems ◽

Cost Effective ◽

Developed Countries ◽

Weed Species ◽

Herbicide Resistant ◽

Cost Effective Method ◽

Evolution Of Resistance ◽

Complexity Cost

Herbicides have been the principal means of weed control in developed countries for approximately 50 yr because they are the most cost-effective method. Such general use of herbicides has resulted in weed resistance to herbicides, which continues to be a growing problem. Within the past decade, the evolution of resistance to the once-dominant herbicide glyphosate has resulted in major concerns about the future ability to control weeds in many crop systems. Moreover, many weed species have evolved resistance to multiple mechanisms of herbicide action. Given the dearth of new herbicides with novel mechanisms of action, it appears inevitable that weed management programs will need to be supplemented by the use of tactics other than herbicides. However, the inclusion of more diversity for weed management also introduces complexity, cost, and time constraints to current crop production systems. This paper describes broadly the considerations, opportunities, and constraints of diverse weed management tactics to address the burgeoning problems with herbicide resistance.

Download Full-text

WEED MANAGEMENT IN AEROBIC RICE: ROLE OF ESTABLISHMENT METHODS AND HERBICIDES

Experimental Agriculture ◽

10.1017/s0014479717000576 ◽

2017 ◽

Vol 55 (1) ◽

pp. 88-104

Author(s):

SUSHMITA MUNDA ◽

SANJOY SAHA ◽

TOTAN ADAK ◽

NITIPRASAD JAMBHULKAR

Keyword(s):

Grain Yield ◽

Weed Management ◽

Aerobic Rice ◽

Weed Species ◽

Weed Density ◽

Establishment Method ◽

Dry Seasons ◽

Grass Weed ◽

Selection Of

SUMMARYWeed management in rice depends on establishment method and proper selection of herbicide. A field experiment was conducted during dry seasons of 2013 and 2014 to develop a robust strategy for effective weed management in aerobic rice system for tropical rice belts. The efficacy of post-emergent herbicides bispyribac-sodium, azimsulfuron and flucetosulfuron were evaluated under different rice establishment methods (row sowing, spot seeding and broadcasting). Grass weed species constituted 58–68% of the total weed density across the establishment methods in the weedy check treatment. The total weed density and weed biomass were lowest in spot seeding with azimsulfuron (35 g active ingredient (a.i.) ha−1) 30 and 60 days after sowing. Among herbicides, use of azimsulfuron caused the highest grain yield (5.2 Mg ha−1), realizing 72% increase in grain yield over the weedy check. Yields in row sowing and spot seeding were similar and the same was verified when comparing yields in plots treated with bispyribac-sodium and azimsulfuron. Based on our findings and considering both weed presence and grain yield, azimsulfuron in spot seeding can be recommended in aerobic rice.

Download Full-text

Selected Pacific Northwest Rangeland and Weed Plants as Hosts of Pratylenchus neglectus and P. thornei

Plant Disease ◽

10.1094/pdis-12-13-1295-re ◽

2014 ◽

Vol 98 (10) ◽

pp. 1333-1340 ◽

Cited By ~ 3

Author(s):

Richard W. Smiley ◽

Guiping Yan ◽

Jennifer A. Gourlie

Keyword(s):

Pacific Northwest ◽

Crop Production ◽

Production Systems ◽

Downy Brome ◽

Weed Species ◽

Nematode Density ◽

Pratylenchus Neglectus ◽

Jointed Goatgrass ◽

Green Foxtail

Eighteen rangeland plants and 16 weed species were assayed in the greenhouse for efficiency as hosts of Pratylenchus neglectus and P. thornei. Hosting ability ratings were assigned using the ratio of final versus initial nematode density and by comparing the final nematode density to that of susceptible wheat controls. Good hosts of both Pratylenchus spp. included thickspike bluegrass ‘Critana’, smooth brome ‘Manchar’, seven wheatgrasses, and jointed goatgrass. Good hosts of P. neglectus but not P. thornei included two hairy vetches, western wheatgrass ‘Rosana’, big bluegrass ‘Sherman’, tall wheatgrass ‘Alkar’, green foxtail, kochia, large crabgrass, palmer amaranth, redroot pigweed, tumble mustard, and wild oat. Good hosts of P. thornei but not P. neglectus included hard fescue ‘Durar’, sheep fescue ‘Blacksheep’, downy brome, and rattail fescue. Poor or minor hosts of both Pratylenchus spp. included two alfalfas, dandelion, horseweed, lambsquarters, prostrate spurge, and Russian thistle. These assays will provide guidance for transitioning rangeland into crop production and for understanding the role of weeds on densities of Pratylenchus spp. in wheat-production systems.

Download Full-text

Weed Management Strategies in Organic Rice Production System- A Review

International Journal of Environment and Climate Change ◽

10.9734/ijecc/2020/v10i1230334 ◽

2020 ◽

pp. 519-528

Author(s):

Abhinandan Singh ◽

S. Pazhanisamy ◽

Rodda Chandana Devi ◽

Amit Kumar Singh ◽

Chandra Mohan Mehta

Keyword(s):

Weed Management ◽

Crop Production ◽

Crop Yields ◽

Management Strategies ◽

Rice Production ◽

Weed Species ◽

Organic System ◽

Pests And Diseases ◽

Organic Rice ◽

Environment And Health

Farmers view weeds as the number one barrier to organic rice production. Also, organic rice-growing farmers feel weed management is their number one priority, so they need more research about weed management under organic conditions from the researchers. Weeds can be considered a significant problem because they have a tendency to decrease crop yields by increasing competition for moisture, sunlight and nutrients also serving as host plants for pests and diseases. Since the development of herbicides, farmers have been used these chemicals to eradicate weeds from their fields. Using herbicides not only increased crop yields as well as reduced the labour required to remove weeds. Today, some farmers have a renewed interest in organic methods of managing weeds since the widespread use of agrochemicals has affected the environment and health. It has also been found that in some cases herbicides use can cause some weed species to dominate fields because the weeds develop resistance to herbicides. Moreover, some herbicides are destroying weeds that are harmless to crops, resulting in a potential decrease biodiversity. It is important to understand that under an organic system of seed control, weeds will never be eliminated but only managed. Consistent methods of weed management can reduce the costs and contribute to economical crop production without endangers the environment.

Download Full-text

Oximes and nitric oxide signalling in Medicago truncatula root system architecture

10.48035/tesis/2454/41092 ◽

2020 ◽

Author(s):

◽

Javier Buezo Bravo ◽

José Fernando Morán Juez ◽

Raquel Esteban Terradillos

Keyword(s):

Nitric Oxide ◽

Crop Production ◽

De Novo ◽

Nitrogen Nutrition ◽

Plant Root ◽

Molecular Configuration ◽

Model Legume ◽

Oxidative Pathway ◽

Cruciferous Plants

Nitric oxide (NO) is a widely recognized signalling molecule in plants. It affects almost every developmental step during the whole plant’s lifespan. Among all of its already described functions, NO is recognised to act synergistically with Indole-3-acetic acid (IAA), promoting the development of the secondary roots. Until now, only a few reductive NO synthesis pathways have been confirmed, whereas no oxidative pathway has been yet described. Experiments of our research group measured de novo synthesis of NO3- and NO2- in Pisum sativum and M. truncatula grown with NH4+ as the sole N source (unpublished data). This fact suggests the existence of an oxidative pathway for NH4+ in the Fabaceae family, which is proposed to be part of the signalling of the NH4+ toxicity and to participate in the alleviation mechanism. Due to their molecular configuration, oximes are very strong candidates for being the precursors of NO, and thus the first step into this nitrogen oxidation pathway. Among these oximes, Indole-3-acetaldoxime (IAOx) is particularly relevant since it is placed in the crossroad between IAA and indole glucosinolates. The role of IAOx in growth-signalling and root phenotype is poorly studied in cruciferous plants and mostly unknown in non-cruciferous plants. In this PhD thesis, we aim to demonstrate that IAOx is present in M. truncatula playing an important role of signalling during plant root development and also that this signalling is mediated by NO. For that purpose, we synthesized a set of pure IAOx and other indolic and non-indolic oximes and performed pharmacological approaches with the model legume M. truncatula. We analysed the root phenotype, quantified the indolic compounds in tissue (shoots and roots) and measured the Indole-3- acetaldehyde oxidase and IAOx dehydratase genes expression. Our data showed that all the oximes promoted the ‘superoot’ phenotype. All this matches with the hypothesis that IAOx exerts its signalling by liberating NO. This new knowledge is a step forward towards the discovery of an oxidative NO synthesis pathway in plants and throws light into the interplay between IAOx, IAA and nitrogen nutrition, which will be paramount for further field research in crop production.

Download Full-text

Weed management practices in Argentina crops

Weed Technology ◽

10.1017/wet.2019.26 ◽

2019 ◽

Vol 33 (03) ◽

pp. 459-463 ◽

Cited By ~ 5

Author(s):

Julio Alejandro Scursoni ◽

Alejandra Carolina Duarte Vera ◽

Fernando Hugo Oreja ◽

Betina Claudia Kruk ◽

Elba Beatriz de la Fuente

Keyword(s):

Weed Management ◽

Crop Production ◽

Management Practices ◽

Integrated Weed Management ◽

Weed Species ◽

Chemical Application ◽

Modes Of Action ◽

The People ◽

Herbicide Timing ◽

Narrow Row

AbstractData from surveys are used to help quantitatively diagnose the relative importance of chemical and nonchemical management practices, identify weed problems, and provide potential solutions. However, to our knowledge, such surveys have not been conducted in Argentina. In 2016, advisors and crop producers from cropping areas across Argentina were surveyed through email with the objectives to identify the main weed species problems and assess the use of chemical and nonchemical weed management practices in different crop production areas in Argentina. Fleabane, pigweed, johnsongrass, fingergrass, goosegrass, barnyardgrass, and ryegrass were considered the most important weeds. More than 53% of the producers used only chemical options; 86% used chemical fallow (i.e., keeping weed free with chemical application); 62% used full herbicide rates; 46% used proper herbicide timing; 41% used multiple modes of action; and 32% used rotation of herbicide modes of action. The main nonchemical practices used were crop rotation (45%); avoiding seed production during (31%) and after (25%) the crop cycle; narrow row spacing (19%); and cultivars with greater competitive ability (18%). Less than 15% of the people surveyed used increased crop densities or altered date of sowing. There is a high dependence on chemical control in the main crops grown in Argentina. Extension efforts are needed to emphasize the importance of integrated weed management.

Download Full-text

A Statewide Survey of Stakeholders to Assess the Problem Weeds and Weed Management Practices in Nebraska

Weed Technology ◽

10.1017/wet.2018.35 ◽

2018 ◽

Vol 32 (5) ◽

pp. 642-655 ◽

Cited By ~ 15

Author(s):

Debalin Sarangi ◽

Amit J. Jhala

Keyword(s):

Weed Management ◽

Crop Production ◽

Management Practices ◽

Acetolactate Synthase ◽

Grain Sorghum ◽

Primary Concern ◽

Weed Species ◽

Common Waterhemp ◽

Herbicide Resistant ◽

Crop Area

AbstractStakeholders were surveyed across Nebraska to identify the problem weeds and assess common weed management practices. A total of 425 responses were returned across four Nebraska extension districts (Northeast, Panhandle, Southeast, and West Central). Collectively, 61.2% of total farmed or scouted areas in Nebraska were under no-till production, and corn and soybean were the major crops (82.3% of total farmed or scouted area). Common waterhemp, horseweed, and kochia were the most problematic weeds statewide. Widespread occurrence of glyphosate-resistant (GR) weeds such as common waterhemp, horseweed, kochia, and Palmer amaranth were a serious problem in GR crop production. Additionally, 60% of growers in Nebraska reported the presence of at least one GR weed species on their farms. The most commonly used preplant burndown herbicides were 2,4-D and glyphosate, followed by saflufenacil and dicamba. In Nebraska, 74% and 59% of corn and soybean growers, respectively, were using PRE herbicides; however, more than 80% of growers were using POST herbicides for in-crop weed management. Atrazine alone or in premix or tank mix with mesotrione,S-metolachlor, or acetochlor were the most widely applied PRE herbicides in corn and grain sorghum, whereas the most commonly used PRE herbicides in soybean were the inhibitors of acetolactate synthase (ALS) and protoporphyrinogen oxidase (PPO). Glyphosate was the most frequent choice of the survey respondents as a POST herbicide in GR corn and soybean; 2,4-D was the most commonly used POST herbicide in grain sorghum and wheat. In Nebraska, only 5.2% of total crop area was planted with glufosinate-resistant crops. Most of the respondents (89%) were aware of the new multiple herbicide–resistant crops, and 80% of them listed physical drift and volatility of the auxinic herbicides as their primary concern. Forty-eight percent of survey respondents identified herbicide-resistant weed management as their primary research and extension priority.

Download Full-text

Determination of optimal doses of glyphosate for controlling weeds at several stages in southwestern Buenos Aires province (Argentina)

Journal of Plant Protection Research ◽

10.1515/jppr-2017-0047 ◽

2018 ◽

Vol 0 (0) ◽

Cited By ~ 1

Author(s):

Diego Javier Bentivegna ◽

Gisela Lorena Moyano ◽

Juan Facundo Fabián Daddario ◽

Guillermo Tucat

Keyword(s):

Weed Management ◽

Buenos Aires ◽

Growth Stages ◽

Buenos Aires Province ◽

Weed Species ◽

Application Rates ◽

Median Diameter ◽

Artichoke Thistle ◽

Nutrient Resources

AbstractEfficient weed management is essential for avoiding competition for water, light, and nutrient resources in semiarid zones. Chemical weed control with glyphosate was evaluated on perennial wall-rocket (Diplotaxis tenuifolia), artichoke thistle (Cynara cardunculus), slender wild oat (Avena barbata), and perennial ryegrass (Lolium perenne). Plants at early, middle and advanced vegetative stages were used in this study. Glyphosate potassium salt was applied at rates of 0.0675 (1/16x), 0.135 (1/8x), 0.27 (1/4x), 0.54 (1/2x), 1.08 (x) and 2.16 (2x) kg acid equivalent (ae) · ha−1. Glyphosate combined with 2,4-D amine salt was evaluated at rates of 1.08 kg ae · ha−1and 0.53 kg active ingredient (ai) · ha−1, respectively. The volume of the spray was 100 l · ha−1with 86 droplets · cm−2and a Volume Median Diameter (VMD) of 421.19 μm. In general, all the tested weeds were controlled with a quarter of the label rate. Three sizes of tested plants were controlled in a similar way at the same glyphosate dose rate. Moreover, the addition of 2,4-D to glyphosate did not produce an increase in the control of broadleaf weeds. The results showed that glyphosate was effective in controlling the tested weed species, including low application rates for all the growth stages in the southwestern Buenos Aires province.

Download Full-text

Qualitative and Quantitative Assessment of Common Weed Species in West Gondar Sesame Growing Area, Ethiopia

ABC Journal of Advanced Research ◽

10.18034/abcjar.v9i2.507 ◽

2020 ◽

Vol 9 (2) ◽

pp. 53-62

Author(s):

Asfaw Ambaw ◽

Yohannes Ebabuye ◽

Yimer Abeje

Keyword(s):

Weed Management ◽

Crop Production ◽

Similarity Index ◽

Control Measures ◽

Growth Stages ◽

Practical Training ◽

Weed Species ◽

Management Options ◽

Qualitative And Quantitative ◽

Weed Survey

Weeds compete with crops grown for resource limits such as water, nutrients, and light. Weed infestation is one of the major factors limiting sesame production, as its seedlings grow slowly during the first few weeks making it a weak competitor at earlier crop growth stages. Weed induced sesame yield reductions of up to 65 percent, and a need for a crucial weed-free duration of up to 50 days following planting. Weed surveys are useful for determining the occurrence and relative importance of weed species in crop production systems. Weed survey on a farm basis is needed to establish efficient weed management and decision making mechanisms and to evaluate weed control measures. Therefore this survey was conducted to assess qualitative and quantitative weed species in sesame growing areas of west Gondar, Ethiopia. Weed survey was conducted in 2012 at Metema and 2013 main cropping season at Metema, Tach Armachiho, and Mirab Armachiho district. data on weed species type and count were taken along the diagonal with 50cm x 50cm quadrate at a 15-meter interval at three points. Visual identification, manuals, photographs, leaflets, and books were used for identifying weed species. They conducted interviews with farmers, development agents, and district experts working in the region. Weed species compositions were analyzed by frequency, abundance, dominance, and similarity index. In the districts, 31common weed species or groups of species from 17 families were recorded. Ipomea cordofana Br., Grass spp’, Commelina benghalensis L. Andropogon abyssinicus (Fresen) R.Br., Boerhaavia erecta L., Corchorus olitorius L.kudra, Corchorus trilocularis L., Leucas martinicensis (Jacq) ait.f. and Ipomea triloba are the most prevalent, abundant, and important weeds in sesame fields in north Gondar. As to this on-farm and practical training on identification and demonstration management options should be given on the low land of north Gondar farmers.

Download Full-text