scholarly journals Genetic variation associated with PPO-inhibiting herbicide tolerance in sorghum

2020 ◽  
Author(s):  
Pragya Adhikari ◽  
Emma Goodrich ◽  
Samuel B. Fernandes ◽  
Alexander E. Lipka ◽  
Patrick Tranel ◽  
...  
Keyword(s):  
Weed Management ◽  
Crop Production ◽  
Production Systems ◽  
Herbicide Tolerance ◽  
Significant Snps ◽  
Underlying Mechanism ◽  
A Genome ◽  
Sorghum Production ◽  
Association Mapping Study ◽  
Greenhouse Assay

AbstractHerbicide application is crucial for weed management in most crop production systems, but for sorghum herbicide options are limited. Sorghum is sensitive to residual protoporphyrinogen oxidase (PPO)- inhibiting herbicides, such as fomesafen, and a long re-entry period is required before sorghum can be planted after its application. Improving sorghum for tolerance to such residual herbicides would allow for increased sorghum production and the expansion of herbicide options for growers. To investigate the underlying mechanism of tolerance to residual fomesafen, a genome-wide association mapping study was conducted using the sorghum biomass panel (SBP) and field-collected data, and a greenhouse assay was developed to confirm the field phenotypes. A total of 26 significant SNPs (FDR<0.05), spanning a 215.3 kb region, were detected on chromosome 3. The ten most significant SNPs included two in genic regions (Sobic.003G136800, and Sobic.003G136900) and eight SNPs in the intergenic region encompassing the genes Sobic.003G136700, Sobic.003G136800, Sobic.003G137000, Sobic.003G136900, and Sobic.003G137100. The gene Sobic.003G137100 (PPXI), which encodes the PPO1 enzyme, one of the targets of PPO-inhibiting herbicides, was located 12kb downstream of the significant SNP S03_13152838. We found that PPXI is highly conserved in sorghum and expression does not significantly differ between tolerant and sensitive sorghum lines. Our results suggest that PPXI most likely does not underlie the observed herbicide tolerance. Instead, the mechanism underlying herbicide tolerance in the SBP is likely metabolism-based resistance, possibly regulated by the action of multiple genes. Further research is necessary to confirm candidate genes and their functions.

scholarly journals Exploiting Olive Mill Byproducts and Other Waste for Organic Weed Management

Horticulturae ◽  
2019 ◽  
Vol 5 (3) ◽  
pp. 59 ◽  
Author(s):  
Tubeileh ◽  
Schnorf ◽  
Mondragon ◽  
Gray
Keyword(s):  
Weed Management ◽  
Crop Production ◽  
Production Systems ◽  
Agricultural Waste ◽  
Petri Dish ◽  
Bell Pepper ◽  
Loam Soil ◽  
Vegetation Water ◽  
Organic Weed Management ◽  
Olive Mill

Weed management represents one of the most serious and costly challenges in organic crop production systems. Agricultural waste/byproducts might present phytotoxicity that can be exploited to control weeds. Two experiments were designed to study the effects of four concentrations of olive vegetation water (OVW) and a control water treatment (with no OVW) on cheeseweed (Malva parviflora L.) seed germination in petri dishes and pots. In a third experiment, two rates of four composts (crop residue mix (CR), olive pomace (OP), dairy/horse manure (DM), and an OP/DM mix) were mixed into a clay‒loam soil at 0.10 or 0.20 L L−1, to assess their effects on weed number and biomass, in addition to bell pepper (Capsicum annuum L.) growth. In the petri dish experiment, the three highest OVW concentrations completely prohibited germination during the five-week duration of the study. For the pot experiment, 25 mL application of OVW significantly delayed and reduced cheeseweed germination, with the reduction being proportional to the concentration of OVW. In the third experiment, composts reduced weed dry matter (composed mostly of purslane (Portulaca oleracea L.)), with the CR compost being the most effective, reducing total weed biomass by 67% compared to the control. CR10 and DM10 tended to increase bell pepper yields, although none of the plant parameters was significantly affected by the compost treatments.

scholarly journals Diverse Approaches to Herbicide-Resistant Weed Management

Weed Science ◽  
2016 ◽  
Vol 64 (SP1) ◽  
pp. 570-584 ◽  
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.

Weed management: fact or fable?

1981 ◽  
Vol 295 (1076) ◽  
pp. 185-197 ◽  
Keyword(s):  
Weed Control ◽  
Growth Regulators ◽  
Weed Management ◽  
Crop Production ◽  
Management Practices ◽  
Production Systems ◽  
Cropping System ◽  
Ground Cover ◽  
Management Approach ◽  
Leguminous Crops

Weed management is a new term for the age-old practice of employing all available means, in a planned way, to keep weed populations under control. It seeks to distinguish the systematic approach to weed control, based on scientific knowledge and rational strategies, from the pragmatic destruction of weeds. The remarkable efficiency of herbicides has in recent years emphasized the latter and allowed revolutionary methods of crop production to be practised. These have, however, led to serious new weed problems which in turn require more intensive herbicide use. The need for a weed management approach is increasingly recognized. New opportunities for this are provided by the availability of numerous herbicides and plant growth regulators and a growing understanding of the biology, ecology and population dynamics of weeds in relation to crop production systems. Examples discussed include: systematic control of grass weeds in intensive cereals in Britain, weed control in rice and in soybeans, the control of aquatic weeds by biological and chemical methods and an experimental zero-tillage cropping system for the humid tropics based on herbicides, growth regulators and ground-cover leguminous crops. In such management systems, interference of weed behaviour by exogenous growth regulators is likely to be of increasing significance. Constraints on the adoption of weed management practices include lack of support for weed science as a discipline, limited appeal to the agrochemical industry and inadequate extension services in many countries.

New Technologies and Approaches for Weed Management in Sustainable Agriculture Systems

1994 ◽  
Vol 8 (2) ◽  
pp. 403-407 ◽  
Author(s):  
Donald L. Wyse
Keyword(s):  
Sustainable Agriculture ◽  
Weed Management ◽  
Crop Production ◽  
New Technologies ◽  
Production Systems ◽  
Farming Systems ◽  
The United States ◽  
Alternative Methods ◽  
Systems Research ◽  
Agriculture Systems

Weed science has a long history of solving weed management problems for farmers. Over the last four decades most of the solutions to weed problems have been based on herbicide technology. Thus, most crop production systems in the United States rely heavily on herbicides as the primary method of weed management. During the last decade environmentalists, farmers, agricultural scientists, policy makers, and the general public have begun to question the long-term sustainability of conventional farming systems. The sustainability of these systems is being questioned because of environmental, social, and economic concerns caused by global competition, cost of production, soil erosion, water pollution, and concern over the quality of rural life. Weeds are the major deterrent to the development of more sustainable agriculture systems. Since weeds dictate most of the crop production practices (e.g., tillage, herbicides, cultivation, row spacing) weed scientists must become the leaders of collaborative integrated approaches to agriculture systems research. New crop production systems must be developed that are less destructive to the environment, are profitable, conserve energy, and support rural community development. The goal is to facilitate the development of ecologically based alternative methods of weed management that will support crop production systems that require less tillage and herbicide inputs. To accomplish this goal, research efforts must be radically expanded in weed/crop ecology and in the development of ecologically based technologies for weed management.

scholarly journals Reducing the Risks of Herbicide Resistance: Best Management Practices and Recommendations

Weed Science ◽  
2012 ◽  
Vol 60 (SP1) ◽  
pp. 31-62 ◽  
Author(s):  
Jason K. Norsworthy ◽  
Sarah M. Ward ◽  
David R. Shaw ◽  
Rick S. Llewellyn ◽  
Robert L. Nichols ◽  
...  
Keyword(s):  
Weed Control ◽  
Herbicide Resistance ◽  
Best Management Practices ◽  
Weed Management ◽  
Crop Production ◽  
Management Practices ◽  
Production Systems ◽  
Herbicide Resistant ◽  
Economic Thresholds ◽  
Soil Seedbank

Herbicides are the foundation of weed control in commercial crop-production systems. However, herbicide-resistant (HR) weed populations are evolving rapidly as a natural response to selection pressure imposed by modern agricultural management activities. Mitigating the evolution of herbicide resistance depends on reducing selection through diversification of weed control techniques, minimizing the spread of resistance genes and genotypes via pollen or propagule dispersal, and eliminating additions of weed seed to the soil seedbank. Effective deployment of such a multifaceted approach will require shifting from the current concept of basing weed management on single-year economic thresholds.

Influence of fluctuating temperatures on emergence of shattercane (Sorghum bicolor) and giant foxtail (Setaria faberi)

Weed Science ◽  
1998 ◽  
Vol 46 (3) ◽  
pp. 330-335 ◽  
Author(s):  
George O. Kegode ◽  
R. Brent Pearce ◽  
Ted B. Bailey
Keyword(s):  
Soil Temperature ◽  
Environmental Conditions ◽  
Weed Management ◽  
Crop Production ◽  
Production Systems ◽  
Soil Surface ◽  
Temperature Fluctuations ◽  
Primary Objective ◽  
Giant Foxtail ◽  
Emergence Patterns

Understanding patterns of shattercane and giant foxtail field emergence during the spring and summer in the Midwest is important to determine the best weed management programs for crop production systems. The primary objective of this study was to determine percentage emergence of shattercane and giant foxtail under field conditions as influenced by soil temperature fluctuations, in 1992 and 1993. A secondary objective was to determine the difference in emergence percentage based on shattercane and giant foxtail seed lots harvested in different years (1985, 1991, and 1992). Soil temperature fluctuations were manipulated by artificially shading the soil surface with plastic netting that provided 30, 60, and 90% of incident sunlight in addition to the full sunlight control (0% shade). Giant foxtail and shattercane seed was planted at depths of 1.25, 2.5, 5, and 10 cm under each shade, and emergence was monitored for 45 d. Soil temperature fluctuations were reduced by increasing depth and amount of shade. Increasing depth of seed significantly reduced percentage emergence by 63 and 54% for shattercane, and 71 and 73% for giant foxtail in 1992 and 1993, respectively. Decreasing light intensity significantly reduced percentage emergence of shattercane by 72 and 73% in 1992 and 1993, respectively, but did not decrease giant foxtail emergence. Seed lots of both species were different from one another both years. These results were consistent over years, even though 1993 precipitation was three times that for 1992. Therefore, shattercane seed uses diurnal fluctuations in temperature to sense proximity to the soil surface and covering vegetation to avoid germination when conditions are unfavorable for growth. In contrast, giant foxtail seed can germinate readily and grow when environmental conditions are within an acceptable range and when seed is not buried too deeply. Differences in percentage emergence between seed lots could play a major role in emergence patterns of shattercane and giant foxtail observed in the field and may be influenced by environmental conditions during seed development on parent plants.

scholarly journals Crop Diversification for Improved Weed Management: A Review

Agriculture ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 461
Author(s):  
Gourav Sharma ◽  
Swati Shrestha ◽  
Sudip Kunwar ◽  
Te-Ming Tseng
Keyword(s):  
Climate Change ◽  
Weed Management ◽  
Crop Production ◽  
Production Systems ◽  
Cropping System ◽  
Farming Systems ◽  
Crop Diversification ◽  
Herbicide Resistant ◽  
Technology Innovations ◽  
Diversified Farming Systems

Weeds are among the major constraints to any crop production system, reducing productivity and profitability. Herbicides are among the most effective methods to control weeds, and reliance on herbicides for weed control has increased significantly with the advent of herbicide-resistant crops. Unfortunately, over-reliance on herbicides leads to environmental-health issues and herbicide-resistant weeds, causing human health and ecological concerns. Crop diversification can help manage weeds sustainably in major crop production systems. It acts as an organizing principle under which technological innovations and ecological insights can be combined to manage weeds sustainably. Diversified cropping can be defined as the conscious inclusion of functional biodiversity at temporal and/or spatial levels to improve the productivity and stability of ecosystem services. Crop diversification helps to reduce weed density by negatively impacting weed seed germination and weed growth. Additionally, diversified farming systems are more resilient to climate change than monoculture systems and provide better crop yield. However, there are a few challenges to adopting a diversified cropping system, ranging from technology innovations, government policies, farm-level decisions, climate change, and market conditions. In this review, we discuss how crop diversification supports sustainable weed management, the challenges associated with it, and the future of weed management with respect to the diversification concept.

Banded Herbicide Applications and Cultivation in a Modified No-till Corn (Zea mays) System

1992 ◽  
Vol 6 (3) ◽  
pp. 535-542 ◽  
Author(s):  
Allan G. Eadie ◽  
Clarence J. Swanton ◽  
James E. Shaw ◽  
Glen W. Anderson
Keyword(s):  
Weed Control ◽  
Weed Management ◽  
Soil Conservation ◽  
Crop Production ◽  
Field Experiments ◽  
Production Systems ◽  
Corn Production ◽  
No Till ◽  
Annual Weeds ◽  
Corn Grain

The acceptance of no-till crop production systems has been limited due to expected problems with weed management. Field experiments were established at two locations in Ontario in 1988 and one location in 1989. Band or broadcast applications of preemergence (PRE) combinations of high or low label rates of atrazine with or without metolachlor or inter-row cultivation, were evaluated for their effectiveness in controlling annual weeds in no-till corn. At each location, different herbicide and cultivation combinations were required to achieve adequate weed control. Corn grain yield was equivalent regardless of whether herbicides were applied as a band or broadcast treatment at all three sites. At two of the three sites, one cultivation combined with herbicides applied as a band was adequate to maintain weed control and corn grain yields. Selective application of herbicides in bands represented an approximate 60% reduction in total herbicide applied into the environment. The integration of a shallow post-plant inter-row cultivation combined with the soil conservation attributes of no-till, would enhance the sustainability of a modified no-till corn production system.

Weed management in conservation crop production systems

2002 ◽  
Vol 2 (3) ◽  
pp. 123-132 ◽  
Author(s):  
MARTIN A. LOCKE ◽  
KRISHNA N. REDDY ◽  
ROBERT M. ZABLOTOWICZ
Keyword(s):  
Weed Management ◽  
Crop Production ◽  
Production Systems

scholarly journals Weed management practices in natural ecosystems: a critical overview

Koedoe ◽  
2000 ◽  
Vol 43 (1) ◽  
Author(s):  
C.F. Reinhardt
Keyword(s):  
Biological Control ◽  
Weed Management ◽  
Crop Production ◽  
Management Practices ◽  
Production Systems ◽  
Management Practice ◽  
Management Tool ◽  
Natural Ecosystems ◽  
Basic Biology ◽  
Herbicide Use

Increasing public pressure against the use of pesticides and other agricultural inputs has placed increased emphasis on the development of ecologically based pest management. One distinct reaction of the Weed Science discipline has been the swing away from herbicide research to increased research on the basic biology and ecology of weeds in hopes of reduced reliance on "technological crutches" such as herbicides and other practices that are potentially harmful to the environment. Biological control is the long-standing alternative to the use of herbicides and interest in the former practice has been boosted by the realization that the use of herbicides may lead to the development of herbicide resistance in weed populations, and that herbicide residues occur in surface and groundwater. Supporters of herbicide use would point out that biological control is generally not effective in crop production systems, and is basically slow-acting. Debates between protagonists for the exclusive use of one or the other weed management practice tend to obscure the benefits that integration of different techniques are likely to have. For natural ecosystems it is proposed that integration of the more subtle practice of biological control with the use of herbicides, which relatively quickly overwhelm a biological system with mortality, is likely to be the most effective weed management tool. Different weed management practices that could be considered in natural ecosystems are discussed in terms of three key performance rating criteria, viz. activity, selec- tivity and persistence In this concise review, general discussion is focussed on the fundamentals of weed management practices, with the view to promote concept-based approaches that are critical for the development of effective weed management strate- gies.

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