scholarly journals Reducing shade avoidance can improve Arabidopsis canopy performance against competitors

2019 ◽  
Author(s):  
Chrysoula K. Pantazopoulou ◽  
Franca J. Bongers ◽  
Ronald Pierik
Keyword(s):  
Weed Management ◽  
Canopy Closure ◽  
Shade Avoidance ◽  
Leaf Movement ◽  
Light Penetration ◽  
Sustainable Solutions ◽  
Individual Fitness ◽  
Weed Growth ◽  
Petiole Elongation ◽  
Light Capture

AbstractThe loss of crop yield due to weeds is an urgent agricultural problem. Although herbicides are an effective way to control weeds, more sustainable solutions for weed management are desirable. It has been proposed that crop plants can communally suppress weeds by shading them out. Shade avoidance responses, such as upward leaf movement (hyponasty) and stem or petiole elongation, enhance light capture of individual plants, increasing their individual fitness. The shading capacity of the entire crop community might, however, be more effective if aspects of shade avoidance are suppressed. Testing this hypothesis in crops is hampered by the lack of well-characterized mutants. We therefore investigated if Arabidopsis competitive performance at the community level against invading competitors is affected by the ability to display shade avoidance. We tested two mutants: pif4pif5 that has mildly reduced petiole elongation and hyponasty and pif7 with normal elongation but absent hyponasty in response to shade. Although pif4pif5 performed similar to wildtype, we found that pif7 showed significantly increased canopy biomass and suppression of invading competitors as compared to its wildtype. Our data thus show that modifying specific shade avoidance aspects has potential for plant community performance. This may help to suppress weeds in crop stands.HighlightHyponastic response in canopies facilitates light penetration and weed growth. Inhibition of this response to neighbors increased canopy biomass, canopy closure and suppression of competitors.

scholarly journals Weed Management and Fertility Levels Influence on Weed Growth and Performance of Wheat (Triticum aestivum L.)

2019 ◽  
Vol 8 (04) ◽  
pp. 2038-2044
Author(s):  
Anshul Gupta ◽  
S.S. Yadav ◽  
L.R. Yadav ◽  
A.K. Gupta
Keyword(s):  
Triticum Aestivum ◽  
Weed Management ◽  
Triticum Aestivum L ◽  
Weed Growth ◽  
And Performance

Volunteer potato interference in carrot

Weed Science ◽  
2006 ◽  
Vol 54 (1) ◽  
pp. 94-99 ◽  
Author(s):  
Martin M. Williams ◽  
Rick A. Boydston
Keyword(s):  
Weed Management ◽  
Yield Loss ◽  
Management Strategies ◽  
Field Studies ◽  
Functional Relationships ◽  
Weed Growth ◽  
Volunteer Potato ◽  
Tuber Production ◽  
Hand Weeding ◽  
Management Recommendations

Weed management systems in carrot are limited in part by a lack of fundamental understanding of crop–weed interactions. Irrigated field studies were conducted to quantify the effect of volunteer potato density and duration of interference on carrot yield and to determine relationships among weed density, duration of weed growth, and volunteer potato tuber production. A season-long volunteer potato density of 0.06 plants m−2produced from 150 to 230 g tubers m−2and resulted in an estimated 5% crop yield loss. At two volunteer potato plants m−2, the same level of crop loss was estimated with a duration of interference of 430 growing degree days (GDD), a time at which the weed had already produced 130 g tubers m−2. Volunteer potato height at the time of weed removal predicted carrot yield loss (R2= 0.77) and may be useful for timing of management strategies such as hand weeding. Functional relationships describing carrot–volunteer potato interactions provide simple information that is useful for developing weed management recommendations for carrot, a crop that relies on multiple tactics for managing weeds, and rotational crops that are negatively affected by persistence of volunteer potato.

scholarly journals Morphological Response of Soybean (Glycine max (L.) Merr.) Cultivars to Light Intensity and Red to Far-Red Ratio

Agronomy ◽  
2019 ◽  
Vol 9 (8) ◽  
pp. 428 ◽  
Author(s):  
Tina Hitz ◽  
Jens Hartung ◽  
Simone Graeff-Hönninger ◽  
Sebastian Munz
Keyword(s):  
Cropping Systems ◽  
Light Emitting Diode ◽  
Red Light ◽  
Photosynthetic Photon Flux Density ◽  
Photon Flux ◽  
Photon Flux Density ◽  
Shade Avoidance ◽  
Internode Elongation ◽  
Morphological Response ◽  
Petiole Elongation

In soybean production, the shade avoidance response can affect yield negatively in both mono- and inter-cropping systems due to increased heterogeneity of the crop and lodging. This is mainly regulated by photoreceptors responding to the ratio between red and far-red light (R:FR) and photosynthetic photon flux density (PPFD). In this study, three soybean cultivars were grown under different R:FR and PPFD in a light emitting diode (LED) climate chamber to disentangle the effect of each on morphology and dry matter. Results showed that plant organs were influenced differently and indicated an interaction with the increase in assimilates at high PPFD. Internode elongation was mainly influenced by low PPFD with an additive effect from low R:FR, whereas petiole elongation responded strongly under low R:FR. Hence, petiole elongation can be seen as the main response to the threat of shade (high PPFD and low R:FR) and both petiole and internode elongation as a response to true shade (low PPFD and low R:FR). Interactions between cultivar and light treatment were found for internode length and diameter and leaf mass ratio, which may be unique properties for specific cropping systems.

Effects of Photoperiod on Reproductive Development in Velvetleaf (Abutilon theophrasti)

Weed Science ◽  
1995 ◽  
Vol 43 (4) ◽  
pp. 627-633 ◽  
Author(s):  
David T. Patterson
Keyword(s):  
Weed Management ◽  
Vegetative Growth ◽  
Competitive Ability ◽  
Simulation Models ◽  
Reproductive Development ◽  
Fruit Weight ◽  
Weed Growth ◽  
Growth Differences ◽  
Shoot Weight ◽  
Reciprocal Transfer

When velvetleaf plants from Mississippi and Minnesota populations were maintained in growth chambers with day/night temperatures of 29/23 C and photoperiods of 11, 12, 13, 14, and 15 h, flower buds and open flowers appeared first in the 12 h photoperiod. Buds and flowers appeared 2 to 4 d later at photoperiods of 11, 13, or 14 h. Increasing the photoperiod beyond 14 h to 15 h delayed bud appearance an additional 7 d in the MN plants and 12 d in the MS plants. Open flowers appeared four to five nodes higher, 10 d later at 15 than at 14 h in the MN plants and 20 d later in the MS plants. Vegetative shoot weight and fruit weight 73 d after emergence were greater in 13 h or longer photoperiods than at 11 or 12 h. In shorter photoperiods, MN plants produced more vegetative growth than MS plants, but the reverse occurred at longer photoperiods where MS plants were taller than MN plants. These growth differences occurred because earlier shifts in allocation to reproductive growth in MN plants limited their vegetative growth, particularly in the longest photoperiods. Differences in rate of reproductive development between populations were not evident until photoperiod exceeded 13 h. Reciprocal transfer of plants of the MS population between short and long photoperiods revealed the durations of the juvenile (pre-inductive), inductive, and post-inductive phases to be 3 to 5, 7 to 8 (short day) or 30 (long day), and 10 to 11 d, respectively. Differences in competitive ability among latitudinal biotypes of photoperiodically-sensitive weeds may depend on time of emergence in the field and consequent photoperiod exposure. Weed growth simulation models to be used in development of expert systems for weed management should take photoperiodic sensitivity into account.

Effect of Vineyard Row Orientation on Growth and Phenology of Glyphosate-Resistant and Glyphosate-Susceptible Horseweed (Conyza canadensis)

Weed Science ◽  
2011 ◽  
Vol 59 (1) ◽  
pp. 55-60 ◽  
Author(s):  
Marisa Alcorta ◽  
Matthew W. Fidelibus ◽  
Kerri L. Steenwerth ◽  
Anil Shrestha
Keyword(s):  
Leaf Area ◽  
Growth And Development ◽  
Dry Weight ◽  
Conyza Canadensis ◽  
Light Penetration ◽  
Low Light ◽  
Weed Growth ◽  
Light Levels ◽  
East West ◽  
Number Of Seeds

Horseweed has become increasingly common and difficult to control in San Joaquin Valley vineyards, due in part, to the evolution of glyphosate resistance. The development of weed-suppressive vineyard designs in which the trellis design, spacing, and row orientation combine to cast dense shade on the weed canopy zone (WCZ) may reduce weed growth. The relevance of such a system to horseweed, which can grow to be as tall, or taller, than a typical grapevine trellis, is uncertain. Also unknown is whether a glyphosate-resistant (GR) biotype and glyphosate-susceptible (GS) biotype would perform similarly under such conditions. Therefore, we compared the growth and development of two potted horseweed biotypes (GR and GS) in vinerows oriented east–west (EW) and north–south (NS). Rows oriented EW allowed less light penetration to the WCZ than NS rows throughout the study, and horseweed biotypes responded to low light levels by producing leaves with larger specific leaf area and leaf area ratios than those in the NS rows. Also, the leaf, stem, and root dry weight of the horseweed plants in the EW rows was reduced by 30% compared to the horseweed plants in NS rows. Leaf number was also reduced in the horseweed plants in the EW rows, but only for the GS biotype. Row orientation did not affect phenological development or the number of seeds produced by the GR or GS biotypes, but the GR biotype budded, flowered, and set seed approximately 1 wk earlier than the GS biotype. Thus, shade associated with the EW vinerows reduced horseweed growth, but not fecundity, and the GR biotype reached reproductive maturity earlier than the GS biotype.

Investigating the Human Dimension of Weed Management: New Tools of the Trade

Weed Science ◽  
2010 ◽  
Vol 58 (4) ◽  
pp. 503-510 ◽  
Author(s):  
Doug Doohan ◽  
Robyn Wilson ◽  
Elizabeth Canales ◽  
Jason Parker
Keyword(s):  
Mental Models ◽  
Weed Management ◽  
Mental Model ◽  
Perceived Risk ◽  
Belief Systems ◽  
Human Dimension ◽  
Weed Species ◽  
Management Decisions ◽  
Weed Growth ◽  
Farmer Decision Making

The human dimension of weed management is most evident when farmers make decisions contrary to science-based recommendations. Why do farmers resist adopting practices that will delay herbicide resistance, or seem to ignore new weed species or biotypes until it is too late? Weed scientists for the most part have ignored such questions or considered them beyond their domain and expertise, continuing to focus instead on fundamental weed science and technology. Recent pressing concerns about widespread failure of herbicide-based weed management and acceptability of emerging technologies necessitates a closer look at farmer decision making and the role of weed scientists in that process. Here we present a circular risk-analysis framework characterized by regular interaction with and input from farmers to inform both research and on-farm risk-management decisions. The framework utilizes mental models to probe the deeply held beliefs of farmers regarding weeds and weed management. A mental model is a complex, often hidden web of perceptions and attitudes that govern how we understand and respond to the world. One's mental model may limit ability to develop new insights and adopt new ways of management, and is best assessed through structured, open-ended interviews that enable the investigator to exhaust the subjects inherent to a particular risk. Our assessment of farmer mental models demonstrated the fundamental attribution error whereby farmers attributed problems with weed management primarily to factors outside of their control, such as uncontrolled weed growth on neighboring properties and environmental factors. Farmers also identified specific processes that contribute to weed problems that were not identified by experts; specifically, the importance of floods and faulty herbicide applications in the spread of weeds. Conventional farmers expressed an overwhelming preference for controlling weeds with herbicides, a preference that was reinforced by their extreme dislike for weeds. These preferences reflect a typical inverse relationship between perceived risk and benefit, where an activity or entity we perceive as beneficial is by default perceived as low risk. This preference diminishes the ability of farmers to appreciate the risks associated with overreliance on herbicides. Likewise, conventional farmers saw great risk and little benefit in preventive measures for weed control. We expect that thorough two-way communication and a deeper understanding of farmer belief systems will facilitate the development of audience-specific outreach programs with an enhanced probability of affecting better weed management decisions.

Weed management options in transgenic stacked and non transgenic maize (Zea mays) hybrids-A review

2017 ◽  
Vol 38 (04) ◽  
Author(s):  
K. Sivagamy ◽  
C. Chinnusamy ◽  
P. Parasuraman
Keyword(s):  
Weed Control ◽  
Weed Management ◽  
Crop Growth ◽  
Control Programme ◽  
Growth And Yield ◽  
Growth Stages ◽  
Management Options ◽  
Maize Crop ◽  
Weed Growth ◽  
Vigorous Growth

Weeds are generally hardy species having fast growth, deep root system and capable of competing very efficiently with cultivated crops for the available resources and adversely affect the crop growth and yield. Weed management systems that rely on post emergence control assume that crops can tolerate competition for certain periods of time without suffering yield losses. Initial slow growth particularly at early crop growth stages and wider plant spacing of maize crop encourages fast and vigorous growth of weeds. It is of paramount importance that, competition from weeds must be minimized to achieve optimum yield. Among the different weed control methods, chemical method bears many advantages in suppressing weed growth and to get healthy and vigorous crop stand. Non-selective herbicide molecules with a variety of mode of action were discovered, developed and marketed for successful weed control programme.

Ecological weed management by cover cropping: effects on weed growth in autumn and weed establishment in spring

Weed Research ◽  
2008 ◽  
Vol 48 (6) ◽  
pp. 492-502 ◽  
Author(s):  
H M KRUIDHOF ◽  
L BASTIAANS ◽  
M J KROPFF
Keyword(s):  
Weed Management ◽  
Cover Cropping ◽  
Weed Growth ◽  
Ecological Weed Management

An Evaluation of Two Novel Cultivation Tools

2012 ◽  
Vol 26 (2) ◽  
pp. 316-325 ◽  
Author(s):  
Glenn J. Evans ◽  
Robin R. Bellinder ◽  
Russell R. Hahn
Keyword(s):  
Weed Control ◽  
Weed Management ◽  
Environmental Data ◽  
Yield Response ◽  
Growth Stages ◽  
Operational Parameters ◽  
Crop Response ◽  
Weed Growth ◽  
Operational Variables ◽  
Organic Weed Management

Cultivation is a critical component of organic weed management and has relevance in conventional farming. Limitations with current cultivation tools include high costs, limited efficacy, and marginal applicability across a range of crops, soil types, soil moisture conditions, and weed growth stages. The objectives of this research were to compare the weed control potential of two novel tools, a block cultivator and a stirrup cultivator, with that of a conventional S-tine cultivator, and to evaluate crop response when each tool was used in pepper and broccoli. Block and stirrup cultivators were mounted on a toolbar with an S-tine sweep. In 2008, the tripart cultivator was tested in 20 independently replicated noncrop field events. Weed survival and reemergence data were collected from the cultivated area of each of the three tools. Environmental data were also collected. A multivariable model was created to assess the importance of cultivator design and environmental and operational variables on postcultivation weed survival. Additional trials in 2009 evaluated the yield response of pepper and broccoli to interrow cultivations with each tool. Cultivator design significantly influenced postcultivation weed survival (P < 0.0001). When weed survival was viewed collectively across all 20 cultivations, both novel cultivators significantly increased control. Relative to the S-tine sweep, the stirrup cultivator reduced weed survival by about one-third and the block cultivator reduced weed survival by greater than two-thirds. Of the 11 individually assessed environmental and operational parameters, 7 had significant implications for weed control with the sweep; 5 impacted control with the stirrup cultivator, and only 1 (surface weed cover at the time of cultivation) influenced control with the block cultivator. Crop response to each cultivator was identical. The block cultivator, because of its increased effectiveness and operational flexibility, has the potential to improve interrow mechanical weed management.

scholarly journals YUCCAauxin biosynthetic genes are required for Arabidopsis shade avoidance

PeerJ ◽  
2016 ◽  
Vol 4 ◽  
pp. e2574 ◽  
Author(s):  
Patricia Müller-Moulé ◽  
Kazunari Nozue ◽  
Melissa L. Pytlak ◽  
Christine M. Palmer ◽  
Michael F. Covington ◽  
...  
Keyword(s):  
Light Treatment ◽  
Auxin Signaling ◽  
Shade Avoidance ◽  
Biosynthetic Genes ◽  
Petiole Elongation ◽  
Quadruple Mutant ◽  
Avoidance Responses

Plants respond to neighbor shade by increasing stem and petiole elongation. Shade, sensed by phytochrome photoreceptors, causes stabilization ofPHYTOCHROME INTERACTING FACTORproteins and subsequent induction ofYUCCAauxin biosynthetic genes. To investigate the role ofYUCCAgenes in phytochrome-mediated elongation, we examined auxin signaling kinetics after an end-of-day far-red (EOD-FR) light treatment, and found that an auxin responsive reporter is rapidly induced within 2 hours of far-red exposure.YUCCA2, 5, 8,and9are all induced with similar kinetics suggesting that theycould act redundantly to control shade-mediated elongation. To test this hypothesis we constructed ayucca2, 5, 8, 9quadruple mutant and found that the hypocotyl and petiole EOD-FR and shade avoidance responses are completely disrupted. This work shows thatYUCCAauxin biosynthetic genes are essential for detectable shade avoidance and thatYUCCAgenes are important for petiole shade avoidance.

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