Incorporating environmental factors to describe wild radish (Raphanus raphanistrum) seedling emergence and plant phenology

Weed Science ◽  
2020 ◽  
Vol 68 (6) ◽  
pp. 627-638
Author(s):  
Theresa Reinhardt Piskackova ◽  
S. Chris Reberg-Horton ◽  
Robert J. Richardson ◽  
Katie M. Jennings ◽  
Ramon G. Leon
Keyword(s):  
Seedling Emergence ◽  
Environmental Variable ◽  
Wild Radish ◽  
Raphanus Raphanistrum ◽  
Phenological Stages ◽  
Validation Data ◽  
Biphasic Model ◽  
Winter Annual ◽  
Best Fit ◽  
Best Parameters

AbstractWild radish (Raphanus raphanistrum L.) is a weed found globally in agricultural systems. The facultative winter annual nature of this plant and high genetic variability makes modeling its growth and phenology difficult. In the present study, R. raphanistrum natural seedbanks exhibited a biphasic pattern of emergence, with emergence peaks occurring in both fall and spring. Traditional sigmoidal models were inadequate to fit this pattern, regardless of the predictive environmental variable, and a corresponding biphasic model (sigmoidal + Weibull) was used to describe emergence based on the best parameters. Each best-fit chronological, thermal, and hydrothermal model accounted for at least 85% of the variation of the validation data. Observations on phenology progression from four cohorts were used to create a common model that described all cohorts adequately. Different phenological stages were described using chronological, thermal, hydrothermal, daylength-dependent thermal time, and daylength-dependent hydrothermal time. Integrating daylength and temperature into the models was important for predicting reproductive stages of R. raphanistrum.

Time of Emergence Affects Survival and Development of Wild Radish (Raphanus raphanistrum) in South Carolina

Weed Science ◽  
2010 ◽  
Vol 58 (4) ◽  
pp. 402-407 ◽  
Author(s):  
Jason K. Norsworthy ◽  
Mayank S. Malik ◽  
Melissa B. Riley ◽  
William Bridges
Keyword(s):  
South Carolina ◽  
Life Cycle ◽  
Biomass Production ◽  
Field Experiments ◽  
Seedling Emergence ◽  
Wild Radish ◽  
Raphanus Raphanistrum ◽  
Minimal Growth ◽  
Survival And Development ◽  
Developmental Phases

Field experiments were conducted from 2004 through 2006 at Pendleton and Clemson, SC, to determine the influence of seasonal emergence of wild radish on phenological development, survival, and seed and biomass production in a noncompetitive environment. The duration of four developmental phases, emergence to bolting, bolting to flowering, flowering to silique production, and silique production to maturity, were recorded following wild radish sowing at monthly intervals from October 2004 through September 2006. Seedling emergence occurred 2 to 4 wk after sowing. Mortality of seedlings that emerged from December through March was greater than that of seedlings that emerged in all other months. Wild radish that emerged from April through August completed its life cycle by summer or early autumn. Wild radish that emerged from September through November was able to survive the winter and complete its life cycle the following spring. The developmental phases most affected by time of emergence were emergence to bolting and bolting to flowering. The duration of emergence to bolting ranged from 249 to 479 growing degree days (GDD), and bolting to flowering from 270 to 373 GDD, depending on the month of emergence. The total life cycle of wild radish varied from a low of 1,267 GDD following June emergence to 1,503 GDD following November emergence. Multiple regression analysis revealed that emergence to bolting and silique production to maturity phases were dependent on accumulated heat units and photoperiod. Seed and biomass production were influenced by month of emergence. An average of 1,470 seeds plant−1was produced when emergence occurred in July and 10,170 seeds plant−1when emergence occurred in November. Plants that emerged in autumn exhibited minimal growth during the winter months, but conditions were conducive for growth in mid-March and April, with biomass production of 809 g plant−1at silique production.

Survival and fecundity of wild radish (Raphanus raphanistrum L.) plants in relation to cropping, time of emergence and chemical control

1988 ◽  
Vol 39 (3) ◽  
pp. 385 ◽  
Author(s):  
FD Panetta ◽  
DJ Gilbey ◽  
MF D'Antuono
Keyword(s):  
Chemical Control ◽  
Seedling Emergence ◽  
Sowing Date ◽  
Wild Radish ◽  
Raphanus Raphanistrum ◽  
Large Numbers ◽  
Negative Effect ◽  
Grain Contamination ◽  
Survival Of Seedlings

During consecutive seasons, wild radish (Raphanus raphanistrum L.) seedling emergence decreased exponentially with increasing time after the emergence of lupin crops. Initial survival of seedlings was markedly reduced by pre-emergence applications of simazine at 0.75 kg a.i. ha-1. In the absence of herbicide, however, the presence of a lupin crop did not have a negative effect upon early survival. Probabilities of reproduction of wild radish plants decreased with later emergence within treatments; no plants which emerged later than 21 days after crop emergence produced seeds. Seed production by wild radish was considerably higher when lupins were sown late. Regardless of sowing date, the application of triazine herbicides reduced the amount of seeds produced to the point where grain contamination was insignificant. However, the few plants which escaped herbicide treatment produced large numbers of seeds. Virtually no seeds were produced when additional post-emergence applications of simazine (0.375 kg a.i. ha-1) were made. It is argued that the major role of post-emergence application in this crop-weed system is to prevent reproduction by plants which escape the pre-emergence application, rather than to control late-emerging plants.

Henbit (Lamium amplexicaule), Common Chickweed (Stellaria media), Shepherd's-Purse (Capsella bursa-pastoris), and Field Pennycress (Thlaspi arvense): Fecundity, Seed Dispersal, Dormancy, and Emergence

Weed Science ◽  
2014 ◽  
Vol 62 (1) ◽  
pp. 97-106 ◽  
Author(s):  
Erin C. Hill ◽  
Karen A. Renner ◽  
Christy L. Sprague
Keyword(s):  
Seed Production ◽  
Seedling Emergence ◽  
Crop Productivity ◽  
Seed Fate ◽  
Stellaria Media ◽  
Thlaspi Arvense ◽  
Emergence Patterns ◽  
Field Pennycress ◽  
Winter Annuals ◽  
Winter Annual

Winter annual weeds protect the soil from erosion and retain nutrients during the winter; however, they can also act as a host for crop pests and pathogens and impede planting. Increased knowledge of the reproductive biology and the seed fate of winter annuals would be useful to improve management and crop productivity. The objectives of this research were to determine the recruitment biology of shepherd's-purse, henbit, common chickweed, and field pennycress, including seed production, dispersal, dormancy, and seedling emergence, based on growing degree days (GDD). Henbit was the least prolific of the four weeds studied, producing 800 to 40,000 seeds m−2at naturally occurring densities; shepherd's-purse was the most prolific, producing 11,000 to 400,000 seeds m−2with 40 to 230 plants m−2. Fifty percent seed rain occurred for henbit, common chickweed, shepherd's-purse, and field pennycress at 620, 790, 880, and 1300 GDDBase,0C, respectively. Overall, seeds were dormant for all species at the time of dispersal. In 2 of 3 yr, dormancy of later-dispersed common chickweed decreased after 6 mo of storage at natural, fluctuating temperatures in the absence of water. The emergence patterns of the four species followed the Gompertz equation and were indicative of facultative winter annuals. The emergence patterns by rate were similar between henbit and common chickweed and between shepherd's-purse and field pennycress. Seed production, dispersal, dormancy, and seedling emergence were influenced by moisture; therefore, including a precipitation or soil moisture component into a GDD model (such as the use of hydrothermal time) would improve the accuracy of predicting winter annual reproduction, seed fate, and emergence.

Identity and Activity of 2,4-Dichlorophenoxyacetic Acid Metabolites in Wild Radish (Raphanus raphanistrum)

2018 ◽  
Vol 66 (51) ◽  
pp. 13378-13385 ◽  
Author(s):  
Danica E. Goggin ◽  
Gareth L. Nealon ◽  
Gregory R. Cawthray ◽  
Adrian Scaffidi ◽  
Mark J. Howard ◽  
...  
Keyword(s):  
Dichlorophenoxyacetic Acid ◽  
Wild Radish ◽  
Raphanus Raphanistrum ◽  
Acid Metabolites ◽  
2,4 Dichlorophenoxyacetic Acid

Mesotrione: a new preemergence herbicide option for wild radish (Raphanus raphanistrum) control in wheat

2021 ◽  
pp. 1-23
Author(s):  
Michael J. Walsh ◽  
Peter Newman ◽  
Paul Chatfield
Keyword(s):  
Dose Response ◽  
Field Trials ◽  
Grain Production ◽  
Wild Radish ◽  
Raphanus Raphanistrum ◽  
Wheat Growth ◽  
Ps Ii ◽  
High Frequencies ◽  
Herbicide Resistant ◽  
Pot Trials

Abstract Wild radish is the most problematic broadleaf weed of Australian grain production. The propensity of wild radish to evolve resistance to herbicides has led to high frequencies of multiple herbicide resistant populations present in these grain production regions. The objective of this study was to evaluate the potential of mesotrione to selectively control wild radish in wheat. The initial dose response pot trials determined that at the highest mesotrione rate of 50 g ha−1, PRE application was 30% more effective than POST on wild radish. This same rate of mesotrione POST resulted in a 30% reduction in wheat biomass compared to 0% for the PRE application. Subsequent, mesotrione PRE dose response trials identified a wheat selective rate range of >100 and < 300 g ai ha−1 that provided greater than 85% wild radish control with less than 15% reduction in wheat growth. Field evaluations confirmed the efficacy of mesotrione at 100 to 150 g ai ha−1 in reducing wild radish populations by greater than 85% following PRE application and incorporation by wheat planting. Additionally, these field trials demonstrated the opportunity for season-long control of wild radish when mesotrione PRE was followed by bromoxynil POST. The sequential application of mesotrione, an HPPD-inhibiting herbicide, PRE followed by bromoxynil, a PS II-inhibiting herbicide POST has the potential to provide 100% wild radish control with no effect on wheat growth.

Predicting OSS Development Success

2013 ◽  
pp. 315-336
Author(s):  
Uzma Raja ◽  
Marietta J. Tretter
Keyword(s):  
User Involvement ◽  
Data Sets ◽  
Validation Data ◽  
Multiple Data ◽  
Competing Models ◽  
New Variables ◽  
End User Involvement ◽  
The Relationship ◽  
Communication Methods ◽  
Best Fit

Open Source Software (OSS) has reached new levels of sophistication and acceptance by users and commercial software vendors. This research creates tests and validates a model for predicting successful development of OSS projects. Widely available archival data was used for OSS projects from Sourceforge.net. The data is analyzed with multiple Data Mining techniques. Initially three competing models are created using Logistic Regression, Decision Trees and Neural Networks. These models are compared for precision and are refined in several phases. Text Mining is used to create new variables that improve the predictive power of the models. The final model is chosen based on best fit to separate training and validation data sets and the ability to explain the relationship among variables. Model robustness is determined by testing it on a new dataset extracted from the SF repository. The results indicate that end-user involvement, project age, functionality, usage, project management techniques, project type and team communication methods have a significant impact on the development of OSS projects.

The Effects of Depth and Duration of Seed Burial on Viability, Dormancy, Germination, and Emergence of Ivyleaf Speedwell (Veronica hederifolia)

2006 ◽  
Vol 20 (2) ◽  
pp. 438-444 ◽  
Author(s):  
Husrev Mennan ◽  
Bernard H. Zandstra
Keyword(s):  
Seedling Emergence ◽  
Soil Surface ◽  
Burial Depth ◽  
Triphenyltetrazolium Chloride ◽  
Primary Dormancy ◽  
Dry Storage ◽  
Winter Annual ◽  
High Level ◽  
Depth Of Burial ◽  
Over Time

Experiments were conducted to investigate the effects of depth and duration of burial on seasonal germination, primary and secondary dormancy, viability, and seedling emergence of ivyleaf speedwell (Veronica hederifoliaL.) seeds. The seeds were buried at 0, 5, 10, or 20 cm and retrieved from the field at monthly intervals. The exhumed seeds were germinated at 5 C. In the second experiment, seeds were stored in the laboratory after harvest and tested for germination at monthly intervals. In each experiment, nongerminated seeds were treated with triphenyltetrazolium chloride at monthly intervals to test their viability. The effects of stratification and burial depth on seedling emergence were observed for 1 yr. The seeds exhumed from the soil were dormant at the beginning of the experiment and exhibited dormancy/nondormancy/conditional dormancy cycling throughout the experiment. Depth of burial and time affected seed germination. Seeds retrieved from the soil surface germinated well initially, but germination decreased as depth of burial increased. In the dry storage experiment, seeds had a high level of primary dormancy, and viability decreased over time. Seedling emergence decreased when depth of burial increased. Seedlings emerged nonuniformly throughout the year and demonstrated typical winter annual characteristics.

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