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Agronomy
Special Issues
Weed Management and Herbicide Resistance
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Weed Management and Herbicide Resistance

A special issue of Agronomy (ISSN 2073-4395).

Deadline for manuscript submissions: closed (1 May 2013) | Viewed by 90849

Special Issue Editor

Prof. Dr. David R. Shaw

E-Mail Website
Guest Editor
Department of Plant and Soil Science, Mississippi State University, Box 9722, Mississippi State, MS 39762, USA
Interests: herbicide resistance management; herbicide resistance education; spatial technologies in agriculture

Special Issue Information

Dear Colleagues,

The evolution of herbicide resistance in plants is one of the most pressing issues facing managed landscapes today. While the development and widespread distribution of glyphosate-resistant weeds has brought prominence to the issue, resistance to herbicides dates back more than 50 years, and has been reported for nearly every class of herbicides. Fundamentally, managing herbicide resistance requires a reduction in the selection pressure through a diversified and proactive program of weed management, coupled with an intimate understanding of the biology and ecology of species with the potential for developing resistance. Management must take into account cultural, mechanical, and chemical options, all brought together into a long-term, sustainable weed management strategy. This special issue brings together the latest research findings dealing with all aspects of herbicide resistance, including biology, ecology, physiology, and practical management strategies. Effective educational strategies for land managers and policy-makers will also be addressed.

Dr. David R. Shaw
Guest Editor

Manuscript Submission Information

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Keywords

  • resistance
  • herbicides
  • glyphosate
  • weed management
  • physiology of resistance
  • resistance evolution
  • gene flow
  • biology of resistance
  • management strategies

Published Papers (12 papers)

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Research

473 KiB  
Article
Implications of Environmental Stress during Seed Development on Reproductive and Seed Bank Persistence Traits in Wild Oat (Avena fatua L.)
by Robert S. Gallagher, Kristen L. Granger, Amanda M. Snyder, Dennis Pittmann and E. Patrick Fuerst
Agronomy 2013, 3(3), 537-549; https://doi.org/10.3390/agronomy3030537 - 30 Jul 2013
Cited by 10 | Viewed by 6576
Abstract
Weeds produce seed under a wide range of conditions, depending on timing of emergence, prevailing crop, soil microsites, and climatic conditions, among other factors. We hypothesized that the maturation environment during weed seed development will influence reproductive allocation and seed persistence traits, such [...] Read more.
Weeds produce seed under a wide range of conditions, depending on timing of emergence, prevailing crop, soil microsites, and climatic conditions, among other factors. We hypothesized that the maturation environment during weed seed development will influence reproductive allocation and seed persistence traits, such as seed dormancy and vigor, and needs to be considered when formulating weed management strategies. This research evaluated the effects of shade and drought stress on reproductive allocation, seed dormancy and seed vigor in select lines of wild oat (Avena fatua L.). Plants were grown in the greenhouse under drought stress and shade. Harvested seed were subjected to controlled after-ripening and aging regimes. Drought and shade reduced reproductive allocation and resulted in seed with less intense primary dormancy compared to the plants grown under resource-rich conditions, but had no apparent effect on seed vigor. Our data provide additional support to the hypothesis that seed dormancy within a species is a highly plastic trait that can be strongly influenced by the growth conditions of the mother plant. Such plasticity may have important implications for establishing ecologically-based weed control criteria on which threshold-based weed management systems are implemented. Full article
(This article belongs to the Special Issue Weed Management and Herbicide Resistance)
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1004 KiB  
Article
Large Genetic Variability in Chickpea for Tolerance to Herbicides Imazethapyr and Metribuzin
by Pooran M. Gaur, Aravind K. Jukanti, Srinivasan Samineni, Sushil K. Chaturvedi, Sarvjeet Singh, Shailesh Tripathi, Inderjit Singh, Guriqbal Singh, Tapas K. Das, Muraleedhar Aski, Neelu Mishra, Nagasamy Nadarajan and C. L. Laxmipathi Gowda
Agronomy 2013, 3(3), 524-536; https://doi.org/10.3390/agronomy3030524 - 22 Jul 2013
Cited by 26 | Viewed by 9345
Abstract
Chickpea (Cicer arietinum L.) is known to be sensitive to many herbicides and, therefore, choices for using post-emergence herbicides for weed control are limited. The present study was aimed at identifying sources of tolerance to two herbicides with different modes of action [...] Read more.
Chickpea (Cicer arietinum L.) is known to be sensitive to many herbicides and, therefore, choices for using post-emergence herbicides for weed control are limited. The present study was aimed at identifying sources of tolerance to two herbicides with different modes of action (imazethapyr—amino acid synthesis inhibitor; and metribuzin—photosynthesis inhibitor) for use in breeding herbicide tolerant cultivars. Screening of 300 diverse chickpea genotypes (278 accessions from the reference set and 22 breeding lines) revealed large genetic variations for tolerance to herbicides imazethapyr and metribuzin. In general, the sensitivity of the genotypes to metribuzin was higher compared to that for imazethapyr. Several genotypes tolerant to metribuzin (ICC 1205, ICC 1164, ICC 1161, ICC 8195, ICC 11498, ICC 9586, ICC 14402 ICC 283) and imazethapyr (ICC 3239, ICC 7867, ICC 1710, ICC 13441, ICC 13461, ICC 13357, ICC 7668, ICC 13187) were identified, based on average herbicide tolerance scores from two experimental locations each. The herbicide tolerant lines identified in this study will be useful resources for development of herbicide tolerant cultivars and for undertaking genetic and physiological studies on herbicide tolerance in chickpea. Full article
(This article belongs to the Special Issue Weed Management and Herbicide Resistance)
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292 KiB  
Article
The Impact of Volunteer Corn on Crop Yields and Insect Resistance Management Strategies
by Paul T. Marquardt, Ryan M. Terry and William G. Johnson
Agronomy 2013, 3(2), 488-496; https://doi.org/10.3390/agronomy3020488 - 14 Jun 2013
Cited by 12 | Viewed by 6380
Abstract
Volunteer corn (VC) has reemerged as a problematic weed in corn/soybean rotational cropping systems. This reemergence and increasing prevalence of volunteer corn has been correlated to an increased adoption of herbicide-resistant (HR) corn hybrids and the adoption of conservation tillage. Since the introduction [...] Read more.
Volunteer corn (VC) has reemerged as a problematic weed in corn/soybean rotational cropping systems. This reemergence and increasing prevalence of volunteer corn has been correlated to an increased adoption of herbicide-resistant (HR) corn hybrids and the adoption of conservation tillage. Since the introduction of HR crops, control options, weed/crop competition, and other concerns (i.e., insect resistance management of Bt traits) have increased the amount of attention that volunteer corn is receiving. The objective of this review is to discuss what is known about VC prior to and after the introduction of HR crops, and to discuss new information about this important weed. Full article
(This article belongs to the Special Issue Weed Management and Herbicide Resistance)
516 KiB  
Article
Glyphosate-Resistant Goosegrass from Mississippi
by William T. Molin, Alice A. Wright and Vijay K. Nandula
Agronomy 2013, 3(2), 474-487; https://doi.org/10.3390/agronomy3020474 - 29 May 2013
Cited by 17 | Viewed by 6504
Abstract
A suspected glyphosate-resistant goosegrass [Eleusine indica (L.) Gaertn.] population, found in Washington County, Mississippi, was studied to determine the level of resistance and whether the resistance was due to a point mutation, as was previously identified in a Malaysian population. Whole plant [...] Read more.
A suspected glyphosate-resistant goosegrass [Eleusine indica (L.) Gaertn.] population, found in Washington County, Mississippi, was studied to determine the level of resistance and whether the resistance was due to a point mutation, as was previously identified in a Malaysian population. Whole plant dose response assays indicated a two- to four-fold increase in resistance to glyphosate. Leaf disc bioassays based on a glyphosate-dependent increase in shikimate levels indicated a five- to eight-fold increase in resistance. Sequence comparisons of messenger RNA for epsps, the gene encoding the enzyme 5-enolpyruvylshikimate-3-phosphate synthase, from resistant and sensitive goosegrass, revealed a cytosine to thymine nucleotide change at position 319 in the resistant accessions. This single nucleotide polymorphism causes a proline to serine amino acid substitution at position 106 in 5-enolpyruvylshikimate-3-phosphate synthase. A real-time polymerase chain reaction assay using DNA probes specific for the nucleotide change at position 319 was developed to detect this polymorphism. Goosegrass from 42 locations were screened, and the results indicated that glyphosate-resistant goosegrass remained localized to where it was discovered. Pendimethalin, s-metolachlor, clethodim, paraquat and fluazifop controlled resistant goosegrass 93% to 100%, indicating that several control options for glyphosate-resistant goosegrass are available. Full article
(This article belongs to the Special Issue Weed Management and Herbicide Resistance)
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170 KiB  
Article
Downy Brome (Bromus tectorum L.) and Broadleaf Weed Control in Winter Wheat with Acetolactate Synthase-Inhibiting Herbicides
by Seshadri S. Reddy, Phillip W. Stahlman and Patrick W. Geier
Agronomy 2013, 3(2), 340-348; https://doi.org/10.3390/agronomy3020340 - 18 Apr 2013
Cited by 10 | Viewed by 6227
Abstract
A study was conducted for three seasons in northwest Kansas, USA to evaluate acetolactate synthase (ALS)-inhibiting herbicides for downy brome (Bromus tectorum L.) and winter annual broadleaf weed control in winter wheat. Herbicides included pyroxsulam at 18.4 g ai ha−1, [...] Read more.
A study was conducted for three seasons in northwest Kansas, USA to evaluate acetolactate synthase (ALS)-inhibiting herbicides for downy brome (Bromus tectorum L.) and winter annual broadleaf weed control in winter wheat. Herbicides included pyroxsulam at 18.4 g ai ha−1, propoxycarbazone-Na at 44 g ai ha−1, premixed propoxycarbazone-Na & mesosulfuron-methyl at 27 g ai ha−1, and sulfosulfuron at 35 g ai ha−1. The herbicides were applied postemergence in fall and spring seasons. Averaged over time of application, no herbicide controlled downy brome more than 78% in any year. When downy brome densities were high, control was less than 60%. Pyroxsulam controlled downy brome greater than or similar to other herbicides tested. Flixweed (Descurainia sophia L.), blue mustard [Chorispora tenella (Pallas) DC.], and henbit (Lamium amplexicaule L.) control did not differ among herbicide treatments. All herbicides tested controlled flixweed and blue mustard at least 87% and 94%, respectively. However, none of the herbicides controlled henbit more than 73%. Fall herbicide applications improved weed control compared to early spring applications; improvement ranged from 3% to 31% depending on the weed species. Henbit control was greatly decreased by delaying herbicide applications until spring compared to fall applications (49% vs. 80% control). Herbicide injury was observed in only two instances. The injury was ≤13% with no difference between herbicides and the injury did not impact final plant height or grain yield. Full article
(This article belongs to the Special Issue Weed Management and Herbicide Resistance)
217 KiB  
Article
Integrated Palmer Amaranth Management in Glufosinate-Resistant Cotton: II. Primary, Secondary and Conservation Tillage
by Jatinder S. Aulakh, Andrew J. Price, Stephen F. Enloe, Glenn Wehtje and Michael G. Patterson
Agronomy 2013, 3(1), 28-42; https://doi.org/10.3390/agronomy3010028 - 15 Jan 2013
Cited by 23 | Viewed by 6399
Abstract
A three year field experiment was conducted to evaluate the role of soil inversion, cover crops and spring tillage methods for Palmer amaranth between-row (BR) and within-row (WR) management in glufosinate-resistant cotton. Main plots were two soil inversion treatments: fall inversion tillage (IT) [...] Read more.
A three year field experiment was conducted to evaluate the role of soil inversion, cover crops and spring tillage methods for Palmer amaranth between-row (BR) and within-row (WR) management in glufosinate-resistant cotton. Main plots were two soil inversion treatments: fall inversion tillage (IT) and non-inversion tillage (NIT). Subplots were three cover treatments: crimson clover, cereal rye or none (i.e., winter fallow); and the sub subplots were four secondary spring tillage methods: disking followed by (fb) cultivator (DCU), disking fb chisel plow (DCH), disking fb disking (DD) and no tillage (NT). Averaged over years and soil inversion, the crimson clover produced maximum cover biomass (4390 kg ha−1) fb cereal rye (3698 kg ha−1) and winter fallow (777 kg ha−1). Two weeks after planting (WAP) and before the postemergence (POST) application, Palmer amaranth WR and BR density were two- and four-times less, respectively, in IT than NIT. Further, Palmer amaranth WR and BR density were reduced two-fold following crimson clover and cereal rye than following winter fallow at 2 WAP. Without IT, early season Palmer amaranth densities were 40% less following DCU, DCH and DD, when compared with IT. Following IT, no spring tillage method improved Palmer amaranth control. The timely application of glufosinate + S-metolachlor POST tank mixture greatly improved Palmer amaranth control in both IT and NIT systems. The highest cotton yields were obtained with DD following cereal rye (2251 kg ha−1), DD following crimson clover (2213 kg ha−1) and DD following winter fallow (2153 kg ha−1). On average, IT cotton yields (2133 kg ha−1) were 21% higher than NIT (1766 kg ha−1). Therefore, from an integrated weed management standpoint, an occasional fall IT could greatly reduce Palmer amaranth emergence on farms highly infested with glyphosate-resistant Palmer amaranth. In addition, a cereal rye or crimson clover cover crop can effectively reduce early season Palmer amaranth emergence in both IT and NIT systems. For effective and season-long control of Palmer amaranth, one or more POST applications of glufosinate + residual herbicide as tank mixture may be needed in a glufosinate-based cotton production system. Full article
(This article belongs to the Special Issue Weed Management and Herbicide Resistance)
1013 KiB  
Article
Development of a Geo-Referenced Database for Weed Mapping and Analysis of Agronomic Factors Affecting Herbicide Resistance in Apera spica-venti L. Beauv. (Silky Windgrass)
by Dario Massa, Yasmin I. Kaiser, Dionisio Andújar-Sánchez, Rocío Carmona-Alférez, Jörg Mehrtens and Roland Gerhards
Agronomy 2013, 3(1), 13-27; https://doi.org/10.3390/agronomy3010013 - 04 Jan 2013
Cited by 17 | Viewed by 8291
Abstract
In this work, we evaluate the role of agronomic factors in the selection for herbicide resistance in Apera spica-venti L. Beauv. (silky windgrass). During a period of three years, populations were collected in more than 250 conventional fields across Europe and tested for [...] Read more.
In this work, we evaluate the role of agronomic factors in the selection for herbicide resistance in Apera spica-venti L. Beauv. (silky windgrass). During a period of three years, populations were collected in more than 250 conventional fields across Europe and tested for resistance in the greenhouse. After recording the field history of locations, a geo-referenced database has been developed to map the distribution of herbicide-resistant A. spica-venti populations in Europe. A Logistic Regression Model was used to assess whether and to what extent agricultural and biological factors (crop rotation, soil tillage, sowing date, soil texture and weed density) affect the probability of resistance selection apart from the selection pressure due to herbicide application. Our results revealed that rotation management and soil tillage are the factors that have the greatest influence on the model. In addition, first order interactions between these two variables were highly significant. Under conventional tillage, a percentage of winter crops in the rotation exceeding 75% resulted in a 1280-times higher risk of resistance selection compared to rotations with less than 50% of winter crops. Under conservation tillage, the adoption of >75% of winter crops increased the risk of resistance 13-times compared to rotations with less than 50% of winter crops. Finally, early sowing and high weed density significantly increased the risk of resistance compared to the reference categories (later sowing and low weed density, respectively). Soil texture had no significant influence. The developed model can find application in management programs aimed at preventing the evolution and spread of herbicide resistance in weed populations. Full article
(This article belongs to the Special Issue Weed Management and Herbicide Resistance)
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242 KiB  
Article
Monitoring and Management of Imidazolinone-Resistant Red Rice (Oryza sativa L., var. sylvatica) in Clearfield® Italian Paddy Rice
by Laura Scarabel, Cesare Cenghialta, Dario Manuello and Maurizio Sattin
Agronomy 2012, 2(4), 371-383; https://doi.org/10.3390/agronomy2040371 - 19 Dec 2012
Cited by 35 | Viewed by 8229
Abstract
The introduction in Italy of Clearfield® rice cultivars carrying imidazolinone-resistant traits provides an efficient option to control red rice, a conspecific weed of cultivated rice. However, despite the promulgation of specific guidelines for Clearfield® technology management, imazamox red rice survivors have [...] Read more.
The introduction in Italy of Clearfield® rice cultivars carrying imidazolinone-resistant traits provides an efficient option to control red rice, a conspecific weed of cultivated rice. However, despite the promulgation of specific guidelines for Clearfield® technology management, imazamox red rice survivors have been reported by farmers. Forty-two fields were monitored in 2010 and 2011 throughout the Piedmont and Lombardy regions and field cases were recorded of herbicides use and agronomic practices. Whole-plant sensitivity to imazamox was assessed and the resistance mechanism was determined by molecular analysis. Twenty-six red rice populations out of 42 were imazamox-resistant and plants of all the resistant populations possess a Ser to Asn substitution at locus 653 of the ALS gene determining the target-site resistance. Farmers frequently grow Clearfield® varieties for more than two consecutive years so increasing the selection pressure exerted by imazamox and favoring the evolution of resistant red rice. To maintain the sustainability of this new technology, a proper management based on crop rotation, utilization of certified seeds and strict control of red rice escapes has to be implemented. More generally, all stakeholders must increase their awareness that the selection pressure exerted by ALS inhibitors in rice cropping system should be reduced. Full article
(This article belongs to the Special Issue Weed Management and Herbicide Resistance)
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215 KiB  
Article
Multiple Resistance of Horseweed to Glyphosate and Paraquat and Its Control with Paraquat and Metribuzin Combinations
by Thomas W. Eubank, Vijay K. Nandula, Daniel H. Poston and David R. Shaw
Agronomy 2012, 2(4), 358-370; https://doi.org/10.3390/agronomy2040358 - 19 Dec 2012
Cited by 11 | Viewed by 7119
Abstract
Greenhouse and field studies were conducted in 2007 and 2008 to investigate possible multiple-resistance of horseweed to paraquat and glyphosate, and to evaluate the effect of the addition of metribuzin to paraquat on control of paraquat-resistant horseweed. Results indicated that the GR50 [...] Read more.
Greenhouse and field studies were conducted in 2007 and 2008 to investigate possible multiple-resistance of horseweed to paraquat and glyphosate, and to evaluate the effect of the addition of metribuzin to paraquat on control of paraquat-resistant horseweed. Results indicated that the GR50 (herbicide dose required to cause a 50% reduction in plant growth) value for the susceptible population S102 was 0.066 kg ae/ha glyphosate, and for the resistant population MDOT was 0.78 kg/ha glyphosate. The level of glyphosate resistance for MDOT was 12-fold compared with S102. The GR50 value for the susceptible population S102 was 0.078 kg ai/ha paraquat, and for the resistant population MDOT was 0.67 kg/ha paraquat. The level of paraquat resistance for MDOT was 9-fold compared to S102, suggesting multiple-resistance to glyphosate and paraquat in the MDOT population. In field studies the addition of metribuzin to paraquat improved horseweed control. Full article
(This article belongs to the Special Issue Weed Management and Herbicide Resistance)
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238 KiB  
Article
Integrated Palmer Amaranth Management in Glufosinate-Resistant Cotton: I. Soil-Inversion, High-Residue Cover Crops and Herbicide Regimes
by Jatinder S. Aulakh, Andrew J. Price, Stephen F. Enloe, Edzard Van Santen, Glenn Wehtje and Michael G. Patterson
Agronomy 2012, 2(4), 295-311; https://doi.org/10.3390/agronomy2040295 - 05 Nov 2012
Cited by 23 | Viewed by 6708
Abstract
A three year field experiment was conducted to evaluate the role of soil-inversion, cover crops and herbicide regimes for Palmer amaranth between-row (BR) and within-row (WR) management in glufosinate-resistant cotton. The main plots were two soil-inversion treatments: fall inversion tillage (IT) and non-inversion [...] Read more.
A three year field experiment was conducted to evaluate the role of soil-inversion, cover crops and herbicide regimes for Palmer amaranth between-row (BR) and within-row (WR) management in glufosinate-resistant cotton. The main plots were two soil-inversion treatments: fall inversion tillage (IT) and non-inversion tillage (NIT). The subplots were three cover crop treatments: crimson clover, cereal rye and winter fallow; and sub subplots were four herbicide regimes: preemergence (PRE) alone, postemergence (POST) alone, PRE + POST and a no herbicide check (None). The PRE herbicide regime consisted of a single application of pendimethalin at 0.84 kg ae ha−1 plus fomesafen at 0.28 kg ai ha−1. The POST herbicide regime consisted of a single application of glufosinate at 0.60 kg ai ha−1 plus S-metolachlor at 0.54 kg ai ha−1 and the PRE + POST regime combined the prior two components. At 2 weeks after planting (WAP) cotton, Palmer amaranth densities, both BR and WR, were reduced ≥90% following all cover crop treatments in the IT. In the NIT, crimson clover reduced Palmer amaranth densities >65% and 50% compared to winter fallow and cereal rye covers, respectively. At 6 WAP, the PRE and PRE + POST herbicide regimes in both IT and NIT reduced BR and WR Palmer amaranth densities >96% over the three years. Additionally, the BR density was reduced ≥59% in no-herbicide (None) following either cereal rye or crimson clover when compared to no-herbicide in the winter fallow. In IT, PRE, POST and PRE + POST herbicide regimes controlled Palmer amaranth >95% 6 WAP. In NIT, Palmer amaranth was controlled ≥79% in PRE and ≥95% in PRE + POST herbicide regimes over three years. POST herbicide regime following NIT was not very consistent. Averaged across three years, Palmer amaranth controlled ≥94% in PRE and PRE + POST herbicide regimes regardless of cover crop. Herbicide regime effect on cotton yield was highly significant; the maximum cotton yield was produced by the PRE + POST herbicide regime. Averaged over three years, the PRE, POST and PRE + POST cotton yields were about three times higher than no herbicide regime. In a conservation tillage production system, a PRE + glufosinate POST herbicide based regime coupled with a cereal rye cover crop may effectively control Palmer amaranth and maximize cotton yields. Full article
(This article belongs to the Special Issue Weed Management and Herbicide Resistance)
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1610 KiB  
Article
Allelopathy—A Tool to Improve the Weed Competitive Ability of Wheat with Herbicide-Resistant Black-Grass (Alopecurus myosuroides Huds.)
by Nils-Ove Bertholdsson
Agronomy 2012, 2(4), 284-294; https://doi.org/10.3390/agronomy2040284 - 18 Oct 2012
Cited by 20 | Viewed by 8694
Abstract
Controlling black-grass in winter wheat production in northern Europe is an increasing problem because of more frequent winter crops and development of herbicide resistance in weeds. Alternative weed management strategies are needed, e.g., use of more competitive cultivars. Factors that increase cultivar competitiveness [...] Read more.
Controlling black-grass in winter wheat production in northern Europe is an increasing problem because of more frequent winter crops and development of herbicide resistance in weeds. Alternative weed management strategies are needed, e.g., use of more competitive cultivars. Factors that increase cultivar competitiveness include early vigor and straw length, but also allelopathy. Therefore, the allelopathic properties of wheat cultivars included in the Swedish national list or in the release pipeline were investigated using a bioassay with herbicide-resistant and herbicide-sensitive black-grass as receiver plants. Wheat-rye translocation lines were also included in this screening to identify possible sources of high allelopathic activity. The bioassay results were followed up in two-year field trials. The results revealed large variations in allelopathic activity between cultivars. Most cultivars showed interference with both herbicide-sensitive and herbicide-resistant black-grass, although the allelopathic effect was lower on the herbicide-resistant biotype. Cultivars with high allelopathic activity gave only half the black-grass biomass of low allelopathic cultivars. Dinaro, a triticale (wheat-rye hybrid) cultivar and the new wheat cultivar Nimbus showed the highest allelopathy and inhibition of black-grass growth. Only a few wheat lines with rye chromatin, all or part of a rye chromosome, showed high allelopathy. Use of cultivars with high allelopathic activity can thus be important in integrated weed management of black-grass. Full article
(This article belongs to the Special Issue Weed Management and Herbicide Resistance)
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249 KiB  
Article
Understanding Lolium rigidum Seeds: The Key to Managing a Problem Weed?
by Danica E. Goggin, Stephen B. Powles and Kathryn J. Steadman
Agronomy 2012, 2(3), 222-239; https://doi.org/10.3390/agronomy2030222 - 24 Sep 2012
Cited by 31 | Viewed by 9253
Abstract
The 40 million hectare southern Australian winter cropping region suffers from widespread infestation by Lolium rigidum (commonly known as annual or rigid ryegrass), a Mediterranean species initially introduced as a pasture plant. Along with its high competitiveness within crops, rapid adaptability and widespread [...] Read more.
The 40 million hectare southern Australian winter cropping region suffers from widespread infestation by Lolium rigidum (commonly known as annual or rigid ryegrass), a Mediterranean species initially introduced as a pasture plant. Along with its high competitiveness within crops, rapid adaptability and widespread resistance to herbicides, the dormancy of its seeds means that L. rigidum is the primary weed in southern Australian agriculture. With the individuals within a L. rigidum population exhibiting varying levels of seed dormancy, germination can be staggered across the crop-growing season, making complete weed removal virtually impossible, and ensuring that the weed seed bank is constantly replenished. By understanding the processes involved in induction and release of dormancy in L. rigidum seeds, it may be possible to develop strategies to more effectively manage this pest without further stretching herbicide resources. This review examines L. rigidum seed dormancy and germination from a weed-management perspective and explains how the seed bank can be depleted by control strategies encompassing all stages in the lifecycle of a seed, from development to germination. Full article
(This article belongs to the Special Issue Weed Management and Herbicide Resistance)
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