Crop and stubble effects on seedling emergence of sourgrass, palmer amaranth, wild radish and fleabane

2021 ◽  
Author(s):  
Fernando H. Oreja ◽  
Adriana E. Lenardis ◽  
Elba B. de la Fuente
Weed Science ◽  
2010 ◽  
Vol 58 (4) ◽  
pp. 402-407 ◽  
Author(s):  
Jason K. Norsworthy ◽  
Mayank S. Malik ◽  
Melissa B. Riley ◽  
William Bridges

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.


2013 ◽  
Vol 2013 ◽  
pp. 1-8 ◽  
Author(s):  
Aman Chandi ◽  
David L. Jordan ◽  
Alan C. York ◽  
Jim Burton ◽  
Susana R. Milla-Lewis ◽  
...  

Palmer amaranth is a very problematic weed in several crops in the southern USA due to its competitive ability and resistance to herbicides representing different mechanisms of action. Variation in growth and subsequent interference of North Carolina Palmer amaranth accessions has not been examined. A greenhouse experiment determined response of 15 North Carolina Palmer amaranth accessions to drought stress beginning 15 days after seedling emergence (DAE) for a duration of 3, 5, 7, and 9 days. Following exposure to drought, plants were grown under optimal moisture conditions until harvest at 30 DAE. Five accessions each of glyphosate-resistant (GR), acetolactate synthase inhibitor-resistant (ALSR), and acetolactate synthase inhibitor-susceptible and glyphosate-susceptible (ALSS/GS) were compared. Variation in response to drought stress, based on height and dry weight reduction relative to nonstressed controls, was noted among accessions. Stress for 3 or more days affected height and dry weight. Height and dry weight of GR and ALSR accession groups were reduced less by drought than the ALSS/GS accession group. Results suggest a possible relationship between herbicide resistance and ability of Palmer amaranth to withstand drought stress and thus a possible competitive advantage for resistant accessions under limited moisture availability.


1988 ◽  
Vol 39 (3) ◽  
pp. 385 ◽  
Author(s):  
FD Panetta ◽  
DJ Gilbey ◽  
MF D'Antuono

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.


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

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.


2012 ◽  
Vol 26 (4) ◽  
pp. 807-812 ◽  
Author(s):  
Prashant Jha ◽  
Jason K. Norsworthy

Experiments were conducted in 2008 and 2009 in Fayetteville, AR, to determine the influence of late-season herbicide applications on control, seed reduction, seed viability, and seedling fitness of two glyphosate-resistant (GR) Palmer amaranth biotypes, one from Mississippi County (MC) and the other from Lincoln County (LC) in Arkansas. Glyphosate (870 g ae ha−1), glufosinate (820 g ai ha−1), 2,4-D amine (1,060 g ae ha−1), dicamba (280 g ae ha−1), and pyrithiobac (70 g ai ha−1) were each applied at the first visible sign of inflorescence of GR Palmer amaranth plants. Glufosinate, 2,4-D, and dicamba provided 52 to 74% control of MC GR Palmer amaranth plants 28 d after treatment (DAT). The LC biotype was larger (94 cm tall) than the MC biotype was (64 cm tall) at application and was more difficult to control. Although control of GR Palmer amaranth was inadequate, late-season applications of glufosinate, 2,4-D, and dicamba reduced seed production of the LC biotype by 75 to 87% and production of the MC biotype by 94 to 95% compared with nontreated plants. Irrespective of biotypes, glufosinate, 2,4-D, and glyphosate reduced 100-seed weight by 22% compared with the nontreated control, and viability of seeds produced by treated plants was only 45 to 61% compared with 97% seed viability in nontreated plants. Glyphosate, glufosinate, 2,4-D, or dicamba reduced cumulative seedling emergence by an average of 84% compared with the nontreated check. Seedling biomass was four times greater for the LC than for the MC biotype, suggesting greater vigor and fitness for the LC progeny. This research demonstrates that a single, late-season (early inflorescence stage) application of glufosinate, 2,4-D, or dicamba could potentially reduce seedbank replenishment of GR Palmer amaranth. Additionally, reduction in seed weight, viability, and seedling recruitment would impair the success of GR Palmer amaranth progeny in the following season.


2014 ◽  
Vol 28 (3) ◽  
pp. 552-559 ◽  
Author(s):  
Timothy L. Grey ◽  
Fred S. Turpin ◽  
Lenny Wells ◽  
Theodore M. Webster

A survey was conducted in 2012 in Georgia to determine the most troublesome weeds in pecan orchards and document common herbicide weed control practices. Weed control practices and infestations in pecan were divided between winter and summer seasons. The most troublesome pecan winter weed species were wild radish and Italian ryegrass, whereas the most troublesome summer season weeds were Palmer amaranth and bermudagrass. Other weeds included crabgrass species, bahiagrass, Florida pusley, purslane species, morningglory species, curly dock, and cutleaf evening-primrose. The most widely used POST herbicide in both the winter and summer season was glyphosate. The most commonly used year-round herbicides with soil persistence were pendimethalin, diuron, flumioxazin, halosulfuron, simazine, indaziflam, and oryzalin. Use of multiple herbicides, PRE- and POST-contact and soil-persistent, with various herbicide mechanisms of action, have benefited pecan producers by providing year-round weed control, despite herbicide-resistant weeds being widely established in this region.


Author(s):  
K.H. Widdup ◽  
T.L. Knight ◽  
C.J. Waters

Slow establishment of caucasian clover (Trifolium ambiguum L.) is hindering the use of this legume in pasture mixtures. Improved genetic material is one strategy of correcting the problem. Newly harvested seed of hexaploid caucasian clover germplasm covering a range of origins, together with white and red clover and lucerne, were sown in 1 m rows in a Wakanui soil at Lincoln in November 1995. After 21 days, the caucasian clover material as a group had similar numbers of emerged seedlings as white clover and lucerne, but was inferior to red clover. There was wide variation among caucasian clover lines (48-70% seedling emergence), with the cool-season selection from cv. Monaro ranked the highest. Recurrent selection at low temperatures could be used to select material with improved rates of seedling emergence. Red clover and lucerne seedlings produced significantly greater shoot and root dry weight than caucasian and white clover seedlings. Initially, caucasian clover seedlings partitioned 1:1 shoot to root dry weight compared with 3:1 for white clover. After 2 months, caucasian clover seedlings had similar shoot growth but 3 times the root growth of white clover. Between 2 and 5 months, caucasian clover partitioned more to root and rhizome growth, resulting in a 0.3:1 shoot:root ratio compared with 2:1 for white clover. Both clover species had similar total dry weight after 5 months. Unhindered root/ rhizome devel-opment is very important to hasten the establishment phase of caucasian clover. The caucasian clover lines KZ3 and cool-season, both selections from Monaro, developed seedlings with greater shoot and root growth than cv. Monaro. KZ3 continued to produce greater root growth after 5 months, indicating the genetic potential for improvement in seedling growth rate. Different pasture estab-lishment techniques are proposed that take account of the seedling growth characteristics of caucasian clover. Keywords: establishment, genetic variation, growth, seedling emergence, Trifolium ambiguum


2019 ◽  
Vol 20 (1) ◽  
pp. 14-24
Author(s):  
Gabriel Campbell-Martínez ◽  
Mack Thetford ◽  
Deborah L Miller ◽  
Héctor E Pérez
Keyword(s):  

2017 ◽  
Vol 45 (2) ◽  
pp. 282-295
Author(s):  
R. Vihotogbé ◽  
C. Watson ◽  
R. Glèlè Kakaï ◽  
F. Wichern ◽  
B. Sinsin ◽  
...  

2016 ◽  
Vol 6 (1) ◽  
pp. 905-913
Author(s):  
Bahram Majd Nassiry ◽  
Neda Mohammadi

    One of the effects of reducing water content on soil is reduction of growth and development of seedlings and variation of field development. Seed priming technique has been known as a challenge to improve germination and seedling emergence under different environmental stresses. The objectives of this research were to evaluate the effects of osmo-priming on germination characteristics and changes of proline, protein and catalase activity of Ocimum basilicum seeds. Results showed that drought stress reduced the germination characteristics and drought stress in -8 bar was the critical stress.  Priming treatments were include KNO3, PEG and NaCl by 0, -4 and -8 bar concentrations. The seeds were primed with those materials for 8 and 16 hours. The highest germination characteristics were obtained from nitrate potassium in -8 bar for 16 hours priming. Therefore the best seed treatment under drought stress during germination was obtained from the osmo-primed with -8 bar nitrate potassium for 16 hours. The drought stress increased proline and catalase activity but reduced total protein. Priming treatment increases proline, total protein and catalase activity under drought and control conditions. It is concluded that priming results in improvement in germination components of Ocimum basilicum in drought stress conditions and increases the resistance to drought stress with improvement of proline, protein and catalase activity in germination phase.


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