A5041879832- Weed Control and Herbicide Applications
- Pesticide and Herbicide Environmental Studies
- Plant tissue culture and regeneration
- Legume Nitrogen Fixing Symbiosis
- Allelopathy and phytotoxic interactions
- Plant and animal studies
- Plant Parasitism and Resistance
- Agronomic Practices and Intercropping Systems
- Nematode management and characterization studies
- Plant and fungal interactions
- Banana Cultivation and Research
- Soybean genetics and cultivation
- Biological Control of Invasive Species
- Plant Disease Management Techniques
- Chromosomal and Genetic Variations
- Composting and Vermicomposting Techniques
- Plant Stress Responses and Tolerance
- Seed and Plant Biochemistry
- Botany, Ecology, and Taxonomy Studies
- Fungal Plant Pathogen Control
- Plant Virus Research Studies
- Plant nutrient uptake and metabolism
- Genetically Modified Organisms Research
- Seedling growth and survival studies
- Botanical Research and Chemistry
National Institute of Food and Agriculture
2022-2023
Agricultural Research Service
2012-2023
United States Department of Agriculture
2013-2023
Cropping Systems Research Laboratory
2023
Mississippi Delta Community College
2007-2010
Mississippi State University
2006-2010
John Wiley & Sons (United States)
2010
Delta Air Lines (United States)
2006-2007
North Dakota State University
2000-2006
Virginia Tech
1999-2001
The influence of environmental factors on germination and emergence horseweed was examined in growth chamber experiments. Germination highest (61%) under 24/20 C day/night temperature light. Horseweed seed observed both light (13 h photoperiod) complete darkness (24 h), but continuous only 0 to 15% compared with 61% All other experiments were conducted 13-h conditions. 19 36% over a pH range from 4 10, trend toward higher neutral-to-alkaline > 20% at < 40 mM NaCl concentration lowest...
A tall waterhemp population from Missisippi was suspected to be resistant glyphosate. Glyphosate dose response experiments resulted in GR 50 (dose required reduce plant growth by 50%) values of 1.28 and 0.28 kg ae ha −1 glyphosate for the glyphosate-resistant (GR) -susceptible (GS) populations, respectively, indicating a five-fold resistance. The absorption pattern 14 C-glyphosate between GS populations similar up 24 h after treatment (HAT). Thereafter, susceptible absorbed more (55 49%...
Amaranthus spinosus, a common weed of pastures, is close relative palmeri, problematic agricultural with widespread glyphosate resistance. These two species have been known to hybridize, allowing for transfer Glyphosate-resistant A. spinosus was recently suspected in cotton field Mississippi.Glyphosate-resistant biotypes exhibited fivefold increase resistance compared glyphosate-susceptible biotype. EPSPS amplified 33-37 times and expressed 37 more glyphosate-resistant than susceptible The...
Abstract Several grass and broadleaf weed species around the world have evolved multiple-herbicide resistance at alarmingly increasing rates. Research on biochemical molecular mechanisms of multiple-resistant populations indicate a prevalence herbicide metabolism catalyzed by enzyme systems such as cytochrome P450 monooxygenases glutathione S -transferases and, to lesser extent, glucosyl transferases. A symposium was conducted gain an understanding current state research metabolic in that...
Aminomethylphosphonic acid (AMPA) is the most frequently detected metabolite of glyphosate in plants. The objective this study was to determine if there any correlation metabolism AMPA different plant species and their natural level resistance glyphosate. Greenhouse studies were conducted I50 values (rate required cause a 50% reduction growth) quantify shikimate concentrations selected leguminous nonleguminous treated with at respective rates. Coffee senna [Cassia occidentalis (L.) Link]...
Barnyardgrass biotypes from Arkansas (AR1 and AR2) Mississippi (MS1) have evolved cross-resistance to imazamox, imazethapyr, penoxsulam. Additionally, AR1 MS1 bispyribac-sodium. Studies were conducted determine if resistance acetolactate synthase (ALS)-inhibiting herbicides in these is target-site or non-target-site based. Sequencing analysis of a 1701 base pair ALS coding sequence revealed Ala122 Val Thr substitutions AR2, respectively. The imazamox concentrations required for 50%...
Greenhouse and laboratory studies were conducted to confirm quantify glyphosate resistance, pyrithiobac investigate interaction between flumiclorac mixtures on control of Palmer amaranth from Mississippi. The GR 50 (herbicide dose required cause a 50% reduction in plant growth) values for two glyphosate-resistant biotypes, C1B1 T4B1, glyphosate-susceptible (GS) biotype 1.52, 1.3, 0.09 kg ae ha −1 glyphosate, respectively. This indicated that the T4B1 biotypes 17- 14-fold resistant...
Metabolomics and biochemical assays were employed to identify physiological perturbations induced by a commercial formulation of glyphosate in susceptible (S) resistant (R) biotypes Amaranthus palmeri. At 8 h after treatment (HAT), compared the respective water-treated control, cellular metabolism both similarly perturbed glyphosate, resulting abundance most metabolites including shikimic acid, amino acids, organic acids sugars. However, 80 HAT metabolite pool glyphosate-treated R-biotype...
Experiments were conducted to determine (1) dose response of glyphosate-resistant (GR) and -susceptible (non-GR) soybean [Glycine max (L.) Merr.] canola (Brassica napus L.) glyphosate, (2) if differential metabolism glyphosate aminomethyl phosphonic acid (AMPA) is the underlying mechanism for resistance among GR varieties, (3) extent AMPA in correlate injury from AMPA. GR50 (glyphosate required cause a 50% reduction plant dry weight) values (Asgrow 4603RR) non-GR (HBKC 5025) 22.8 kg ae ha-1...
Field studies were conducted in 2005 and 2006 to determine the most effective chemical options within three individual herbicide-based burndown programs, glyphosate, paraquat glufosinate, for controlling glyphosate-resistant horseweed Mississippi. Burndown treatments applied April 5, March 15, plants 15 30 cm height. Glyphosate at 0.86 kg ae/ha alone provided 60 65% control 4 wk after treatment (WAT). Control WAT ranged from 73 74% when glyphosate rate was increased 1.25 kg/ha. kg/ha...
A threefold glyphosate tolerance was identified in two Italian ryegrass populations, T1 and T2, from Mississippi. Laboratory experiments were conducted to characterize the mechanism of these populations. The population absorbed less 14 C-glyphosate (43% applied) compared susceptible (S) (59% at 48 h after treatment (HAT). T2 levels (56% applied HAT) that similar both S but tended be more comparable population. amount remained treated leaf significantly higher (67% absorbed) (65% populations...
2,4-D, discovered independently in the United States and Europe mid-1940s, was one of first synthetic herbicides to be used selectively for weed control (Cobb Reade 2010). Since then, several belonging different chemical classes possessing diverse mechanisms action have been synthesized marketed globally. Herbicides vastly contributed increasing world food, fiber, fuel, feed production an efficient, economic, environmentally sustainable manner. Before receiving regulatory approval, all...
Biotic and abiotic stressors often result in the buildup of amino acid pools plants, which serve as potential stress mitigators. However, role anabolic (de novo synthesis) versus catabolic (proteolytic) processes contributing to free is less understood. Using stable isotope-resolved metabolomics (SIRM), we measured de synthesis glyphosate susceptible (S-) resistant (R-) Amaranthus palmeri biotypes. In S-biotype, treatment at 0.4 kg ae/ha resulted an increase total acids, a proportional both...
Palmer amaranth (Amaranthus palmeri S. Wats.) is a troublesome agronomic weed in the southern United States, and several populations have evolved resistance to glyphosate. This paper reports on spectral signatures of glyphosate-resistant (GR) glyphosate-sensitive (GS) plants, explores potential using hyperspectral sensors distinguish GR from GS plants.GS plants higher light reflectance visible region lower infrared spectrum compared with plants. The normalized had best separability 400-500...
Conyza canadensis (L.) Cronquist syn. (horseweed) is a problematic and invasive weed with reported allelopathic properties. To identify the phytotoxic constituents of aerial parts, systematic bioactivity-guided fractionation dichloromethane extract was performed. Three active enyne derivatives, (2Z,8Z)-matricaria acid methyl ester, (4Z,8Z)-matricaria lactone, (4Z)-lachnophyllum were identified. The lactones inhibited growth monocot Agrostis stolonifera (bentgrass) dicot Lactuca sativa...
Natural tolerance of Ipomoea lacunosa to glyphosate has made it problematic in the southeastern U.S. since adoption glyphosate-resistant crops. Experiments were conducted determine (i) variability among accessions, (ii) if there is any correlation between metabolism aminomethylphosponic acid (AMPA) or sarcosine and level tolerance, (iii) involvement differential translocation glyphosate. Fourteen I. accessions had GR50 values ranging from 58 151 grams equivalent per hectare (ae/ha)...
Transfer of herbicide resistance among closely related weed species is a topic growing concern. A spiny amaranth × Palmer hybrid was confirmed resistant to several acetolactate synthase (ALS) inhibitors including imazethapyr, nicosulfuron, pyrithiobac, and trifloxysulfuron. Enzyme assays indicated that the ALS enzyme insensitive pyrithiobac sequencing revealed presence known conferring point mutation, Trp574Leu. Alignment gene for amaranth, putative hybrids sequence in rather than sequences....
Glyphosate, paraquat and acetyl CoA carboxylase (ACCase)-inhibiting herbicides are widely used in California annual perennial cropping systems. Recently, glyphosate, paraquat, ACCase- acetolactate synthase (ALS)-inhibitor resistance was confirmed several Italian ryegrass populations from the Central Valley of California. This research characterized possible mechanisms resistance.Multiple-resistant (MR1, MR2) resistant to at least three modes action. Dose-response experiments revealed that...
Yellow nutsedge is one of the most problematic sedges in Arkansas rice, requiring frequent use halosulfuron (sulfonylurea) for its control. In summer 2012, at 53 g ha(-1) (labeled field rate) failed to control yellow nutsedge. The level resistance was determined putative resistant biotype, and cross-resistance other acetolactate synthase (ALS) inhibitors from four different herbicide families. ALS enzyme assays analysis gene were used ascertain mechanism.None plants killed by a dose 13 568...
Abstract Extrachromosomal circular DNAs (eccDNAs) are found in many eukaryotic organisms. EccDNA-powered copy number variation plays diverse roles, from oncogenesis humans to herbicide resistance crop weeds. Here, we report interspecific eccDNA flow and its dynamic behavior soma cells of natural populations F1 hybrids Amaranthus sp. The glyphosate-resistance (GR) trait is controlled by eccDNA-based amplification harboring the 5-enolpyruvylshikimate-3-phosphate synthase (EPSPS) gene (eccDNA...