Phenotypic Trait Variation in Populations of a Global Invader Mayweed Chamomile (Anthemis cotula): Implications for Weed Management

Mayweed chamomile (Anthemis cotula L.) is an annual crop weed that has become a substantial impediment to diversify traditional wheat-based cropping systems such as in the Pacific Northwest (PNW), USA. Some of the broadleaf rotational crops are vulnerable to the weed as they are less competitive or lack compatible herbicides for A. cotula management. Although A. cotula has been present in the PNW for more than a century, traits that contribute to invasiveness and how these vary among the weed populations have not been investigated. We assessed trait variation with a common garden greenhouse experiment by comparing 19 A. cotula populations from the PNW and Kashmir Valley, India. Seeds from individual plants from each population were used to grow plants through their senescence. We measured phenological (e.g., flowering duration), morphological (e.g., plant biomass), reproductive fitness (e.g., number of flower heads), and physiological (floral scent VOCs: volatile organic compounds) traits on individual plants and analyzed the data using mixed-effects models. We found high inter-population variation in most of the traits measured, but the variation was not associated with the geographical distance. Seedling emergence within 30 days of planting ranged from 2 to 49% for PNW populations to 55 to 72% for Indian populations. Flowering duration ranged from 2 to 3 months among populations. Other traits such as initial and final flowering dates, the total number of flower heads, and floral scent VOCs also differed among populations. These trait patterns may indicate a localized adaptation of A. cotula populations to environmental or management regimes, variation arising from anthropogenic or natural dispersal, multiple introductions, genetic drift, or combinations of these. Regardless of the processes, the trait variation suggests that weed management plan for A. cotula may need to be tailored to specific locations instead of a uniformly adopted plan across the region.

Download Full-text

Within-Population Trait Variation in a Globally Invasive Plant Species Mayweed Chamomile (Anthemis cotula): Implications for Future Invasion and Management

Frontiers in Agronomy ◽

10.3389/fagro.2021.640208 ◽

2021 ◽

Vol 3 ◽

Author(s):

Subodh Adhikari ◽

Ian C. Burke ◽

Samuel R. Revolinski ◽

Julia Piaskowski ◽

Sanford D. Eigenbrode

Keyword(s):

Cover Crops ◽

Management Practices ◽

Invasive Plant ◽

Floral Scent ◽

Seedling Emergence ◽

Phenotypic Trait ◽

Phenotypic Traits ◽

Trait Variation ◽

Invasion Mechanisms ◽

Sib Families

Quantification of variation for phenotypic traits within and among weed populations facilitate understanding of invasion mechanisms and management tactics. In the Pacific Northwest (PNW), USA, in response to climate change and to improve sustainability, producers are increasingly adopting broadleaf crops and cover crops, but Mayweed chamomile (Anthemis cotula L.) is a significant barrier to diversifying cropping systems because of its abundance and lack of herbicide options for its control. To quantify within-population phenotypic trait variation and heritability, plants (n = 300) from six half-sib families (i.e., seed source plants or mother plants) from each of 10 A. cotula populations (infested farms or sites) in the PNW were grown from seed through the flowering stage in the greenhouse common garden experiment. We measured percent seedling emergence, the initial date of flowering, flowering duration, plant biomass, number of flower heads, floral scent profiles, and other traits on individual plants. Trait variation was high among half-sib families within each population. For example, in two of the populations, percent seedling emergence within 30 days of planting ranged from 5 to 41% and 3 to 53%, respectively. As another example, initial date of flowering in two other populations ranged from 61 to 93 days and 58 to 92 days, respectively. Differences among half-sib families were greatest for flowering period, which differed by a month in most populations, and floral scent profiles. Heritability estimates were higher than 1.0 for most phenotypic traits, indicating that the study plants were more closely related than half-sibs (i.e., included full-sibs or products of selfing). These patterns of phenotypic trait variation are potentially caused by local edaphoclimatic factors and within-field farm management practices, suggesting that management of A. cotula might be challenging and differ within and across farms.

Download Full-text

Effect of Crop Residues on Weed Emergence

Agronomy ◽

10.3390/agronomy11010163 ◽

2021 ◽

Vol 11 (1) ◽

pp. 163

Author(s):

Nebojša Nikolić ◽

Donato Loddo ◽

Roberta Masin

Keyword(s):

Weed Management ◽

Crop Residues ◽

Cropping Systems ◽

Chenopodium Album ◽

Seedling Emergence ◽

Amaranthus Retroflexus ◽

Weed Species ◽

Field Quantity ◽

Crop Fields ◽

No Till

Weed behaviour in crop fields has been extensively studied; nevertheless, limited knowledge is available for particular cropping systems, such as no-till systems. Improving weed management under no-till conditions requires an understanding of the interaction between crop residues and the seedling emergence process. This study aimed to evaluate the influence of maize and wheat residues, applied in three different quantities (1, the field quantity, 0.5, and 1.5-fold amounts of the field quantity), on the emergence of eight weed species: Abutilon theophrasti, Amaranthus retroflexus, Chenopodium album, Digitaria sanguinalis, Echinochloa crus-galli, Setaria pumila, Sonchus oleraceus, and Sorghum halepense. The experiment was conducted over two consecutive years. The results showed that the quantities 1 and 1.5 could suppress seedling emergence by 20 and 44%, respectively, while the quantity 0.5 seems to promote emergence by 22% compared with the control without residues. Weed species showed different responses to crop residues, from C. album showing 56% less emergence to S. halepense showing a 44% higher emergence than the control without residues. Different meteorological conditions in the two-year experiment also exhibited a significant influence on weed species emergence.

Download Full-text

Reproductive allometry in four annual weeds

Australian Journal of Botany ◽

10.1071/bt18087 ◽

2019 ◽

Vol 67 (2) ◽

pp. 99

Author(s):

A. C. Guglielmini ◽

A. M. C. Verdú ◽

E. H. Satorre

Keyword(s):

Seed Production ◽

Weed Management ◽

Plant Biomass ◽

Cropping Systems ◽

Quantitative Relationship ◽

Linear Functions ◽

Seed Number ◽

Weed Species ◽

Plant Seed ◽

Biomass Plant

Differences in plant biomass/plant seed production relationship imply that plants suppressed by competition to the same extent, may not suffer the same reduction in seed number setting. This size-dependent process evidenced by the quantitative relationship between plant growth and allocation to reproductive structures can be considered from an allometric perspective. The aim of this study was to describe the reproductive allometry of four annual weed species of the Pampas cropping systems by modelling the plant biomass/plant seed production relationship in Digitaria sanguinalis, Amaranthus hybridus, Setaria verticillata and Chenopodium album. To achieve this goal, two experiments developed during two consecutive growing periods (Experiments 1 and 2) were set up under greenhouse conditions. Weed species were grown in monocultures and in binary mixtures, with each other and with soybean crop, to obtain plants of different size after the effect of intra and interspecific competition. Data per plant regarding biomass versus seed number production considering monocultures and mixtures from Experiments 1 and 2 were analysed for each species using linear regression. Parameters of the linear functions fitted for C. album, S. verticillata and D. sanguinalis did not differ between experiments and data were pooled. Thus, three single specific models were obtained with the same intercept of zero (y-axis intercept when x = 0 was zero) and different slopes, 1122, 69 and 130 seeds g plant biomass–1 respectively. In the case of A. hybridus, the slopes were different in Experiments 1 (123 seeds g plant biomass–1) and 2 (74 seeds g plant biomass–1). Moreover, reproductive allocation changed allometrically under highly competitive stress since small plants failed to set seeds, unless a plant biomass threshold was attained (x-axis intercept when y = 0 was positive). Besides the ecological interpretation in reproductive output, implications in weed management are considered.

Download Full-text

Germination Ecology of Brachiaria eruciformis in Australia and Its Implications for Weed Management

Agronomy ◽

10.3390/agronomy10010030 ◽

2019 ◽

Vol 10 (1) ◽

pp. 30

Author(s):

Ahmadreza Mobli ◽

Mahboobeh Mollaee ◽

Sudheesh Manalil ◽

Bhagirath Singh Chauhan

Keyword(s):

Sodium Chloride ◽

Seed Germination ◽

Weed Management ◽

Cropping Systems ◽

Germination Rate ◽

Seedling Emergence ◽

Soil Surface ◽

Burial Depth ◽

The World ◽

Noxious Weed

Brachiaria eruciformis (Sm.) Griseb. is a noxious weed of Australia and other parts of the world. The effects of different environmental conditions on the seed germination and seedling emergence of three biotypes sourced from different cropping systems (mungbean field, sorghum field, and fenceline) of this weed were evaluated. There were no differences in the response of biotypes to the evaluated factors; therefore, the data was pooled across the biotypes. The highest germination rate was observed at 30/20 °C, and seeds germinated both in light and dark conditions. Seed germination was influenced by different sodium chloride (NaCl) concentrations and water potentials, and no seeds germinated at 200 mM NaCl and −0.8 MPa water potential. Seeds germinated (>70%) at a broad range of pH, from 4 to 10. Compared with seeds sown on the soil surface, a burial depth of 4 cm reduced the seedling emergence by 84%. Similarly, a sorghum residue amount of 4 t ha−1 on the soil surface reduced the seedling emergence by 65%, compared with no sorghum residue cover. No seedlings emerged from seeds buried at 8 cm depth and >4 t ha−1 sorghum residue. This study suggests that burying seeds deep into the soil through tillage or employing a residue cover on the soil surface can reduce B. eruciformis emergence.

Download Full-text

Competitive attributes ofA. sativa, T. aestivum, andH. vulgareare conserved in no-till cropping systems

Weed Science ◽

10.1017/s0043174500091384 ◽

1999 ◽

Vol 47 (6) ◽

pp. 712-719 ◽

Cited By ~ 3

Author(s):

Anne Légère ◽

Yuguang Bai

Keyword(s):

Hordeum Vulgare ◽

Avena Sativa ◽

Growth Parameters ◽

Cropping Systems ◽

Seedling Emergence ◽

Biomass Accumulation ◽

Tillage Systems ◽

Area Index ◽

No Till ◽

Lower Test

The robustness of competitive attributes of cereals such as rapid and uniform seedling emergence, tillering, early biomass accumulation and canopy closure, and height advantage over weeds have not yet been tested under environmental conditions typical of no-till (NT) cropping systems. Our objective was to evaluate the effects or NT practices on growth and productivity ofAvena sativa, Triticum aestivum, Hordeum vulgare, and associated weeds. The experiment was conducted on a Kamouraska clay at La Pocatière, QC, in 1994, 1995, and 1996.Avena sativa, T. aestivum, andH. vulgarewere grown under tilled and NT practices. Cereal growth parameters were measured six (1994) or seven (1995) times between planting and the 11th week after planting but only once in 1996. Grain yields and yield components were determined at crop maturity.Avena sativaandH. vulgarepopulations were little affected by tillage, whereasT. aestivumpopulations were reduced by 16 to 20% in NT systems. Growth in height in NT systems was either similar or greater than in tilled systems in all three cereals. Cereal leaf area index (LAI) and biomass accumulation was also comparable between tillage systems, except forT. aestivumLAI in 1994, which was greater in tilled plots on two sampling dates. Response of annual dicots to tillage was inconsistent in all crops. Annual monocots dominated in some but not all NT systems. Perennial dicots dominated in NT systems, whereas perennial monocots were more abundant in tilled systems in all three cereals.Avena sativaandT. aestivumyields in NT plots were comparable or greater than in tilled plots, in spite of having either lower test weights (A. sativa) or lower 1,000-grain weights (T. aestivum). NTT. aestivumproductivity was maintained in spite of reduced plant establishment.Hordeum vulgareyields were also similar across tillage systems, except in 1995, when yields in tilled plots were greater than in NT plots. The height advantage observed for NTH. vulgaredid not result in improved yields. All three cereals, and particularlyA. sativa, appeared well suited to NT systems, despite the pressure provided by different weed groups, compared to tilled systems. However, results suggest that NT production of cereals could benefit from improved attention to perennial dicot control and crop seedling establishment, particularly forT. aestivum.

Download Full-text

Deciphering Substrate-Specific Methane Yields of Perennial Herbaceous Wild Plant Species

Agronomy ◽

10.3390/agronomy11030451 ◽

2021 ◽

Vol 11 (3) ◽

pp. 451

Author(s):

Moritz von Cossel ◽

Lorena Agra Pereira ◽

Iris Lewandowski

Keyword(s):

Plant Species ◽

Dry Matter ◽

Plant Biomass ◽

Cropping Systems ◽

Wild Plant ◽

Small Scale ◽

Social Ecological ◽

Wild Plant Species ◽

Global Demand ◽

Bioenergy Cropping Systems

The global demand for plant biomass to provide bioenergy and heat is continuously increasing because of a growing interest among many industrialized and developing countries towards climate sound and renewable energy supply. The exacerbation of land-use conflicts proliferates social-ecological demands on future bioenergy cropping systems. Perennial herbaceous wild plant mixtures (WPMs) represent an approach to providing social-ecologically more sustainably produced biogas substrate that has gained increasing public and political interest only in recent years. The focus of this study lies on three perennial wild plant species (WPS) that usually dominate the biomass yield performance of WPM cultivation. These WPS were compared with established biogas crops in terms of their substrate-specific methane yield (SMY) and lignocellulosic composition. The plant samples were investigated in a small-scale mesophilic discontinuous biogas batch test for determining the SMY. All WPS were found to have significantly lower SMY (241.5–248.5 lN kgVS−1) than maize (337.5 lN kgVS−1). This was attributed to higher contents of lignin (9.7–12.8% of dry matter) as well as lower contents of hemicellulose (9.9–11.5% of dry matter) in the WPS. Only minor, non-significant differences to cup plant and Virginia mallow were observed. Thus, when planning WPS as a diversification measure in biogas cropping systems, their lower SMY should be considered.

Download Full-text

Influence of chaff and chaff lines on weed seed survival and seedling emergence in Australian cropping systems

Weed Technology ◽

10.1017/wet.2020.142 ◽

2020 ◽

pp. 1-22

Author(s):

Michael J. Walsh ◽

Annie E. Rayner ◽

Annie Rutledge ◽

John C. Broster

Keyword(s):

Cropping Systems ◽

Seedling Emergence ◽

Field Studies ◽

Wild Oat ◽

Weed Seed ◽

Weed Species ◽

Environment Effect ◽

Seed Survival ◽

Cropping Seasons ◽

Rigid Ryegrass

Abstract Chaff lining and chaff tramlining are harvest weed seed control (HWSC) systems that involve the concentration of weed seed containing chaff material into narrow (20 to 30 cm) rows between or on the harvester wheel tracks during harvest. These lines of chaff are left intact in the fields through subsequent cropping seasons in the assumption that the chaff environment is unfavourable for weed seed survival. The chaff row environment effect on weed seed survival was examined in field studies, while chaff response studies determined the influence of increasing amounts of chaff on weed seedling emergence. The objectives of these studies were to determine 1) the influence of chaff lines on the summer-autumn seed survival of selected weed species; and 2) the influence of chaff type and amount on rigid ryegrass seedling emergence. There was frequently no difference (P>0.05) in survival of seed of four weed species (rigid ryegrass, wild oat, annual sowthistle and turnip weed) when these seed were placed beneath or beside chaff lines. There was one instance where wild oat seed survival was increased (P<0.05) when seed were placed beneath compared to beside a chaff line. The pot studies determined that increasing amounts of chaff consistently resulted in decreasing numbers of rigid ryegrass seedlings emerging through chaff material. The suppression of emergence broadly followed a linear relationship where there was approximately a 2.0% reduction in emergence with every 1.0 t ha-1 increase in chaff material. This relationship was consistent across wheat, barley, canola and lupin chaff types, indicating that the physical presence of the chaff was more important than chaff type. These studies indicated that chaff lines may not affect the over summer-autumn survival of the contained weed seeds but the subsequent emergence of weed seedlings will be restricted by high amounts of chaff (>40 t ha-1).

Download Full-text

Weeds as Pathogen Hosts and Disease Risk for Crops in the Wake of a Reduced Use of Herbicides: Evidence from Yam (Dioscorea alata) Fields and Colletotrichum Pathogens in the Tropics

Journal of Fungi ◽

10.3390/jof7040283 ◽

2021 ◽

Vol 7 (4) ◽

pp. 283

Author(s):

Pauline Dentika ◽

Harry Ozier-Lafontaine ◽

Laurent Penet

Keyword(s):

Weed Management ◽

Natural Experiment ◽

Disease Risk ◽

Cropping Systems ◽

Correlation Effect ◽

Local Scale ◽

Potential Control ◽

Weed Host ◽

Species Characteristics ◽

The Tropics

The transition toward sustainable agriculture requires rethinking cropping systems in the light of less intensive and chemically reliant practices. Weed management is one of the target practices to evolve cropping systems with decreased impact on the environment. While softened management will lead to increased weeds/crops coexistence, it is of importance to assess the relative benefits and drawbacks of new practices. Among the potential drawbacks of weeds/crops coexistence, disease risk may increase if weeds are hosting pathogens. In this study, we assessed the potential of weeds for hosting pathogenic generalist fungi known to translate into disease in crops. We first describe prevalence in fields after harvest and relate prevalence to species characteristics and communities. Then, we directly test the idea that weeds serve as inoculums sources during cropping with a natural experiment. This study highlights variation in host skill among feral weeds for Colletotrichum species, including potential congeneric sub-specialization on different weeds within communities. Last, prevalence within fields was more correlated to focal crop inoculation rates compared to local weed load, but there was a significant correlation effect with prevalence on weeds in the vicinity of fields, suggesting that weeds are mediating disease levels at the local scale, too. Results pointed to the importance of weed host skill in disease risk yet open the door to the potential control of pathogens via targeted weed management.

Download Full-text

The Pitfalls of Relating Weeds, Herbicide Use, and Crop Yield: Don't Fall Into the Trap! A Critical Review

Frontiers in Agronomy ◽

10.3389/fagro.2020.615470 ◽

2020 ◽

Vol 2 ◽

Author(s):

Nathalie Colbach ◽

Sandrine Petit ◽

Bruno Chauvel ◽

Violaine Deytieux ◽

Martin Lechenet ◽

...

Keyword(s):

Crop Yield ◽

Weed Management ◽

Crop Production ◽

Yield Loss ◽

Crop Yields ◽

Cropping Systems ◽

Crop Productivity ◽

Arable Farming ◽

Herbicide Use ◽

The Impact

The growing recognition of the environmental and health issues associated to pesticide use requires to investigate how to manage weeds with less or no herbicides in arable farming while maintaining crop productivity. The questions of weed harmfulness, herbicide efficacy, the effects of herbicide use on crop yields, and the effect of reducing herbicides on crop production have been addressed over the years but results and interpretations often appear contradictory. In this paper, we critically analyze studies that have focused on the herbicide use, weeds and crop yield nexus. We identified many inconsistencies in the published results and demonstrate that these often stem from differences in the methodologies used and in the choice of the conceptual model that links the three items. Our main findings are: (1) although our review confirms that herbicide reduction increases weed infestation if not compensated by other cultural techniques, there are many shortcomings in the different methods used to assess the impact of weeds on crop production; (2) Reducing herbicide use rarely results in increased crop yield loss due to weeds if farmers compensate low herbicide use by other efficient cultural practices; (3) There is a need for comprehensive studies describing the effect of cropping systems on crop production that explicitly include weeds and disentangle the impact of herbicides from the effect of other practices on weeds and on crop production. We propose a framework that presents all the links and feed-backs that must be considered when analyzing the herbicide-weed-crop yield nexus. We then provide a number of methodological recommendations for future studies. We conclude that, since weeds are causing yield loss, reduced herbicide use and maintained crop productivity necessarily requires a redesign of cropping systems. These new systems should include both agronomic and biodiversity-based levers acting in concert to deliver sustainable weed management.

Download Full-text

Seasonal cycles in germination and seedling emergence of summer and winter populations of catchweed bedstraw (Galium aparine) and wild mustard (Brassica kaber)

Weed Science ◽

10.1614/ws-05-107r1.1 ◽

2006 ◽

Vol 54 (1) ◽

pp. 114-120 ◽

Cited By ~ 50

Author(s):

Husrev Mennan ◽

Mathieu Ngouajio

Keyword(s):

Soil Depth ◽

Cropping Systems ◽

Seedling Emergence ◽

Seed Mass ◽

Soil Surface ◽

Burial Depth ◽

Galium Aparine ◽

Wild Mustard ◽

Seed Population ◽

Brassica Kaber

Catchweed bedstraw and wild mustard each produce two populations per year: a winter population (WP) in June, and a summer population (SP) in September. Experiments were conducted to determine whether the WP and SP differ in seed mass and seasonal germination. Seeds of both weeds were buried at 0, 5, 10, and 20 cm in cultivated fields, and retrieved at monthly intervals for 24 mo for germination tests in the laboratory. Additionally, seedling emergence from seeds buried at 0, 5, and 10 cm in the field was evaluated for 1 yr. Seeds from the WP were heavier than those from the SP for both species. Germination of exhumed seeds was affected by burial depth and by seed population. It was highest for seeds that remained on the soil surface and declined with increasing depth of burial. The WP of catchweed bedstraw produced two germination peaks per year, whereas the SP and all populations of wild mustard had only one peak. The WP of both weeds germinated earlier than the SP. Seedling emergence for both species in the field was greater for the WP than for the SP. Increasing soil depth reduced seedling emergence of both the WP and SP of wild mustard and affected only the WP of catchweed bedstraw. We conclude that the WP and SP of catchweed bedstraw and wild mustard seeds used in this study differed in seed mass, seasonal germination, and seedling emergence. The ability of a WP to produce large seeds that germinate early and have two germination peaks per year could make these populations a serious problem in cropping systems.

Download Full-text