scholarly journals Occurrence and Characterization of Kochia (Kochia scoparia) Accessions with Resistance to Glyphosate in Montana

2014 ◽  
Vol 28 (1) ◽  
pp. 122-130 ◽  
Author(s):  
Vipan Kumar ◽  
Prashant Jha ◽  
Nicholas Reichard
Keyword(s):  
Weight Reduction ◽  
Resistance Index ◽  
Dry Weight ◽  
Glyphosate Resistance ◽  
Future Research ◽  
Kochia Scoparia ◽  
Ecological Fitness ◽  
Shoot Dry Weight ◽  
Whole Plant ◽  
Chemical Fallow

Herbicide-resistant kochia is an increasing concern for growers in the northwestern United States. Four suspected glyphosate-resistant (Gly-R) kochia accessions (referred to as GIL01, JOP01, CHES01, and CHES02) collected in fall 2012 from four different chemical-fallow fields in northern Montana were evaluated. The objectives were to confirm and characterize the level of glyphosate resistance in kochia accessions relative to a glyphosate-susceptible (Gly-S) accession and evaluate the effectiveness of various POST herbicides for Gly-R kochia control. Whole-plant dose–response experiments indicated that the four Gly-R kochia accessions had 7.1- to 11-fold levels of resistance relative to the Gly-S accession on the basis of percent control ratings (I50values). On the basis of shoot dry weight response (GR50values), the four Gly-R kochia accessions exhibited resistance index (R/S) ratios ranging from 4.6 to 8.1. In a separate study, the two tested Gly-R accessions (GIL01 and JOP01) showed differential response (control and shoot dry weight reduction) to various POST herbicides 21 d after application (DAA). Paraquat, paraquat + linuron, carfentrazone + 2,4-D, saflufenacil alone or with 2,4-D, and bromoxynil + fluroxypyr effectively controlled (99 to 100%) and reduced shoot dry weight (88 to 92%) of the GIL01 accession, consistent with the Gly-S kochia accession; however, bromoxynil + MCPA and bromoxynil + pyrasulfotole provided 76% control and 83% shoot dry weight reduction of the GIL01 accession and were lower compared with the Gly-S accession. The JOP01 accession exhibited lower control or shoot dry weight reduction to all herbicides tested, except dicamba, diflufenzopyr + dicamba + 2,4-D, paraquat + linuron, and bromoxynil + pyrasulfotole, compared with the Gly-S or GIL01 population. Furthermore, paraquat + linuron was the only treatment with ≥ 90% control and shoot dry weight reduction of the JOP01 kochia plants. Among all POST herbicides tested, glufosinate was the least effective on kochia. This research confirms the first evolution of Gly-R kochia in Montana. Future research will investigate the mechanism of glyphosate resistance, inheritance, ecological fitness, and alternative strategies for management of Gly-R kochia.

scholarly journals Whole-plant Response of Six Poinsettia Cultivars to Three Fertilizer and Two Irrigation Regimes

1996 ◽  
Vol 121 (1) ◽  
pp. 69-76 ◽  
Author(s):  
Ursula Schuch ◽  
Richard A. Redak ◽  
James Bethke
Keyword(s):  
Leaf Area ◽  
Chlorophyll Content ◽  
Dry Weight ◽  
Shoot Biomass ◽  
Vegetative Development ◽  
Chlorophyll Contents ◽  
Shoot Dry Weight ◽  
Irrigation Regimes ◽  
Whole Plant ◽  
Leaf N

Six cultivars of poinsettia (Euphorbia pulcherrima Wind.), `Angelika White', `Celebrate 2', `Freedom Red', `Lilo Red', `Red Sails', and `Supjibi Red' were grown for 9 weeks during vegetative development under three constant-feed fertilizer treatments, 80,160, or 240 mg N/liter and two irrigation regimes, well-watered (high irrigation) or water deficient (low irrigation). Plants fertilized with 80 or 240 mg N/liter were 10% to 18% shorter, while those fertilized with 160 mg N/liter were 25 % shorter with low versus high irrigation. Leaf area and leaf dry weight increased linearly in response to increasing fertilizer concentrations. Low irrigation reduced leaf area, leaf, stem, and shoot dry weight 3670 to 41%. Cultivars responded similarly to irrigation and fertilizer treatments in all components of shoot biomass production and no interactions between the main effects and cultivars occurred. Stomatal conductance and transpiration decreased with increasing fertilizer rates or sometimes with low irrigation. Highest chlorophyll contents occurred in leaves of `Lilo Red' and `Freedom Red'. Leaves of plants fertilized with 80 mg N/liter were deficient in leaf N and had 40 % to 49 % lower leaf chlorophyll content compared to plants fertilized with 160 or 240 mg N/liter. Irrigation had no effect on leaf N or chlorophyll content. At the end of the experiment leaves of `Supjibi Red' and `Angelika White' contained higher concentrations of soluble proteins than the other four cultivars.

Confirmation of Glyphosate-Resistant Horseweed (Conyza canadensis) in Montana Cereal Production and Response to POST Herbicides

2017 ◽  
Vol 31 (6) ◽  
pp. 799-810 ◽  
Author(s):  
Vipan Kumar ◽  
Prashant Jha ◽  
Amit J. Jhala
Keyword(s):  
Great Plains ◽  
Dose Response ◽  
Best Management Practices ◽  
Management Practices ◽  
Dry Weight ◽  
Shoot Dry Weight ◽  
Greenhouse Study ◽  
Whole Plant ◽  
Cereal Production ◽  
Sites Of Action

In recent years, horseweed has become an increasing problem in Montana. To confirm and characterize the level of glyphosate resistance, seeds were collected from putative glyphosate-resistant (GR) horseweed (GR-MT) plants in a wheat–fallow field in McCone County, MT. Known GR (GR-NE) and glyphosate-susceptible (GS-NE) horseweed accessions from Lincoln, NE, were included for comparison in dose–response and shikimate accumulation studies. Whole-plant glyphosate dose–response experiments conducted at the early- (5- to 8-cm diameter) and late- (12- to 15-cm diameter) rosette stages of horseweed indicated that GR-MT accessions had a 2.5- to 4.0-fold level of resistance to glyphosate relative to the GS-NE accession, on the basis of shoot dry weight (GR50values). The level of resistance was 3.1- to 7.9-fold on the basis of visually assessed injury estimates (I50values). At the whole-plant level, about 2.1- to 4.5-fold higher shikimate accumulation was observed in the GS-NE accession compared with the GR-MT and GR-NE accessions over a 10-d period after glyphosate was applied at 1,260 g ae ha−1. In a separate greenhouse study, all three horseweed accessions were also screened with alternate POST herbicides registered for use in wheat–fallow rotations. The majority of the tested herbicides provided ≥90% injury at the field-use rates for all three horseweed accessions 3 wk after treatment. This is the first published report on the occurrence of GR horseweed in Montana cereal production. Increased awareness and adoption of best management practices, including the use of diversified (based on multiple sites of action) herbicide programs highlighted in this study, would aid in mitigating the further spread of GR horseweed in the cereal production fields of the U.S. Great Plains.

Phytotoxicity of 2,4-D and 2,4-Dichlorophenol to Red Clover (Trifolium pratense)

Weed Science ◽  
1989 ◽  
Vol 37 (6) ◽  
pp. 825-829 ◽  
Author(s):  
S. G. Taylor ◽  
D. G. Shilling ◽  
K. H. Quesenberry ◽  
G. R. Chaudhry
Keyword(s):  
Trifolium Pratense ◽  
Callus Tissue ◽  
Red Clover ◽  
Dry Weight ◽  
Shoot Dry Weight ◽  
Whole Plant ◽  
The Difference ◽  
Plant Level

Whole plant and tissue culture experiments were conducted to determine the difference in phytotoxicity of 2,4-D and its metabolite, 2,4-DCP, to red clover. At the whole plant level, the mean concentration of 2,4-DCP (10 mM) required to cause 50% growth inhibition (I50) of shoot dry weight was 24 times greater than for 2,4-D (0.42 mM). Using callus tissue, the I50value for 2,4-DCP (0.28 mM) was 22 times greater than for 2,4-D (0.013 mM) based on dry weights. The callus tissue was 36 and 32 times more sensitive to 2,4-DCP and 2,4-D than shoot tissue based on dry weights, respectively. These data indicate that 2,4-DCP was less phytotoxic than 2,4-D to red clover both in vitro and in vivo.

Shoot and Root Interference of Common Cocklebur (Xanthium strumarium) and Soybean (Glycine max)

Weed Science ◽  
1993 ◽  
Vol 41 (1) ◽  
pp. 34-37 ◽  
Author(s):  
Robert C. Bozsa ◽  
Lawrence R. Oliver
Keyword(s):  
Field Experiments ◽  
Plant Root ◽  
Soybean Seed ◽  
Growth Period ◽  
Dry Weight ◽  
Porous Membrane ◽  
Xanthium Strumarium ◽  
Shoot Dry Weight ◽  
Whole Plant ◽  
Plant Interference

Field experiments were conducted in 1986 and 1987 to determine the effects of shoot and root interference of common cocklebur and soybean. Plants were grown in porous membrane envelopes. Common cocklebur plants had a longer vegetative growth period than soybean and were twice as tall as soybean at maturity. Soybean root and shoot dry weight and seed yield were reduced by shoot and whole plant (root and shoot) interference of common cocklebur, with whole plant interference giving the greatest reduction. Common cocklebur growth was affected little by soybean interference. Common cocklebur shoot interference alone reduced total soybean seed weight by 48%, the amount caused by common cocklebur whole plant interference.

scholarly journals EPSPS Gene Copy Number and Whole-Plant Glyphosate Resistance Level in Kochia scoparia

PLoS ONE ◽  
2016 ◽  
Vol 11 (12) ◽  
pp. e0168295 ◽  
Author(s):  
Todd A. Gaines ◽  
Abigail L. Barker ◽  
Eric L. Patterson ◽  
Philip Westra ◽  
Eric P. Westra ◽  
...  
Keyword(s):  
Copy Number ◽  
Gene Copy Number ◽  
Glyphosate Resistance ◽  
Gene Copy ◽  
Kochia Scoparia ◽  
Resistance Level ◽  
Epsps Gene ◽  
Whole Plant

scholarly journals Confirmation of Glyphosate- and Acetolactate Synthase (ALS)-Inhibitor-Resistant Kochia (Kochia scoparia) in Nebraska

2016 ◽  
Vol 8 (10) ◽  
pp. 54
Author(s):  
Neha Rana ◽  
Amit J. Jhala
Keyword(s):  
Great Plains ◽  
Acetolactate Synthase ◽  
The United States ◽  
Future Research ◽  
Kochia Scoparia ◽  
Whole Plant ◽  
Fold Level ◽  
Evolution Of Resistance ◽  
Resistance To Herbicides ◽  
Als Inhibitor

<p>Kochia is an early emerging weed of increasing concern across the Great Plains region of the United States due to the evolution of resistance to herbicides. Greenhouse studies were conducted to confirm and characterize the level of glyphosate and acetolactate synthase (ALS)-inhibiting herbicide resistance in kochia biotype collected from a field in Sheridan County in Nebraska. The response of kochia biotype to 9 rates (0 to 16×) of tribenuron and glyphosate was evaluated in a whole plant dose-response bioassay. On the basis of the values at the 90% effective dose (ED<sub>90</sub>), the putative-resistant kochia biotype had a 6- and 15-fold level of resistance to glyphosate and tribenuron, respectively. Future research will evaluate strategies for the management of glyphosate- and ALS-resistant kochia under field conditions.</p>

scholarly journals Variable response of kochia [Kochia scoparia (L.) Schrad.] to auxinic herbicides dicamba and fluroxypyr in Montana

2015 ◽  
Vol 95 (5) ◽  
pp. 965-972 ◽  
Author(s):  
Prashant Jha ◽  
Vipan Kumar ◽  
Charlemagne A. Lim
Keyword(s):  
Great Plains ◽  
Dose Response ◽  
Weed Management ◽  
Dry Weight ◽  
Northern Great Plains ◽  
Variable Response ◽  
Kochia Scoparia ◽  
Management Tools ◽  
Herbicide Resistant ◽  
Shoot Dry Weight

Jha, P., Kumar, V. and Lim, C. A. 2015. Variable response of kochia [Kochia scoparia (L.) Schrad.] to auxinic herbicides dicamba and fluroxypyr in Montana. Can. J. Plant Sci. 95: 965–972. Herbicide-resistant kochia is an increasing concern for growers in the Northern Great Plains of United States and Canada. The objective of the research was to characterize the response of the three putative auxinic herbicide-resistant kochia inbreds (derived from accessions collected from wheat/chemical fallow fields in northern Montana) to dicamba and fluroxypyr relative to a susceptible (SUS) inbred. A dicamba dose-response study indicated that the three putative resistant inbreds (Chot-01, Chot-02, and Chot-03) had R/S ratios of 1.3 to 6.1 based on the visible control response (I50 values), and R/S ratios of 1.5 to 6.8 based on the shoot dry weight response (GR50 values). Dose-response experiments with fluroxypyr determined I50 R/S ratios of 1.4 to 5.7 and GR50 R/S ratios of 1.6 to 4.0 for the three putative resistant inbreds. The selected inbreds showed variable symptomology (phenotype) in response to dicamba and fluroxypyr. Among the three inbreds, Chot-01 exhibited the least epinasty, stem curling/swelling, and chlorosis/necrosis symptoms, and was resistant to dicamba and fluroxypyr. Growers should diversify their weed management tools to manage further spread of auxinic or multiple herbicide-resistant kochia in the region.

Glyphosate-Resistant Russian-thistle (Salsola tragus) Identified in Montana and Washington

2017 ◽  
Vol 31 (2) ◽  
pp. 238-251 ◽  
Author(s):  
Vipan Kumar ◽  
John F. Spring ◽  
Prashant Jha ◽  
Drew J. Lyon ◽  
Ian C. Burke
Keyword(s):  
Best Management Practices ◽  
Management Practices ◽  
Field Experiments ◽  
Dry Weight ◽  
Effective Control ◽  
Best Management ◽  
Shoot Dry Weight ◽  
Greenhouse Study ◽  
Whole Plant ◽  
Site Field

Two putative glyphosate-resistant (GR) Russian-thistle accessions were collected from fallow fields (wheat-fallow rotation): one from Choteau County, MT (MT-R), and a second from Columbia County, WA (WA-R) in summer/fall of 2015. Greenhouse and outdoor/field whole-plant dose-response studies were conducted to confirm and characterize the levels of glyphosate resistance in these GR accessions relative to known glyphosate-susceptible accessions (MT-S and WA-S from MT and WA, respectively). Based on GR50values of the progeny plants, the MT-R accession exhibited 4.5-fold and 5.9-fold resistance to glyphosate relative to the MT-S accession under greenhouse and outdoor conditions, respectively. The WA-R accession showed 3.0- to 5.0-fold resistance relative to the WA-S accession in greenhouse experiments, and 1.9- to 7.5-fold resistance in multi-site field experiments. In a separate greenhouse study on alternative POST herbicides to control GR Russian-thistle, bicyclopyrone plus bromoxynil, bromoxynil plus fluroxypyr, bromoxynil plus pyrasulfotole, bromoxynil plus MCPA, paraquat alone, paraquat plus metribuzin, saflufenacil alone, saflufenacil plus 2,4-D, and 2,4-D plus bromoxynil plus fluroxypyr provided effective control (≥95%) and shoot dry weight reduction (up to 98%) of GR accessions. This research confirms the first global case of field-evolved GR Russian-thistle. Best management practices (BMPs); including alternative, effective herbicide programs (based on multiple mechanisms of action highlighted in this study) need immediate implementation to prevent further spread of GR or evolution of multiple HR Russian-thistle populations in this region.

Cell Size and Pretransplant Nutritional Conditioning Influences Early Vine Growth and Yield of Transplanted Watermelon

HortScience ◽  
1998 ◽  
Vol 33 (4) ◽  
pp. 594e-594
Author(s):  
Charles J. Graham
Keyword(s):  
Cell Volume ◽  
Significant Influence ◽  
Field Performance ◽  
Dry Weight ◽  
Soluble Solids ◽  
Growth And Yield ◽  
Average Weight ◽  
Shoot Dry Weight ◽  
Solids Concentration ◽  
Soluble Solids Concentration

Research is needed to better understand the influence of cell volume and fertility on watermelon transplant size and field performance in order to determine the most economic production practices. `Jubilee' watermelon transplants were grown using a 4 x 4 factorial experimental design consisting of 4 cell volumes (30.7, 65.5, 147.5, and 349.6 cm3) and 4 fertility rates (0, 1/4, 1/2, and full-strength Hoagland's solution). Transplant shoot dry weight significantly increased as cell volume and fertility increased. Increasing cell volume linearly increased watermelon number/ha and tons/ha for early and total harvest in 1995. The average weight per watermelon significantly increased for early-harvested fruit but not for total harvest as cell volume increased in 1995. Soluble solids concentration linearly increased with increasing cell volume for early and total harvests in 1995. Cell volume had no significant influence on the harvest parameters measured in 1997. In 1995, increasing fertility linearly increased watermelon number/ha and tons/ha for early harvests. Increasing fertility increased the soluble solids concentration linearly for early-harvested watermelons in 1997 but not in 1995. Fertility rate had no significant influence on any of the other harvest parameters measured in 1995 and 1997. The growing conditions and disease pressure in 1997 reduced melons/ha, yield, and soluble solids content when compared to 1995 values. The half-strength Hoagland's solution produced the greatest number of watermelons/ha, tons/ha, and the highest soluble solids concentration in 1995 and 1997. Pretransplant nutritional conditioning had no significant effect on total `Jubilee' watermelon production in Louisiana for 1995 and 1997.

Effects of an Autoregulatory Senescence-inhibitor Gene Construct on Nicotiana alata Link and Otto.

HortScience ◽  
1998 ◽  
Vol 33 (3) ◽  
pp. 519d-519 ◽  
Author(s):  
Kenneth R. Schroeder ◽  
Dennis P. Stimart
Keyword(s):  
Agrobacterium Tumefaciens ◽  
Plant Height ◽  
Dry Weight ◽  
Nicotiana Alata ◽  
Wild Type ◽  
Gene Encoding ◽  
Delayed Senescence ◽  
Gene Construct ◽  
Shoot Dry Weight ◽  
Inhibitor System

Nicotiana alata Link and Otto. was transformed via Agrobacterium tumefaciens encoding a senescence-specific promoter SAG12 cloned from Arabidopsis thaliana fused to a Agrobacterium tumefaciens gene encoding isopentenyl transferase (IPT) that catalyzes cytokinin synthesis. This was considered an autoregulatory senescence-inhibitor system. In 1996, we reported delayed senescence of intact flowers by 2 to 6 d and delayed leaf senescence of transgenic vs. wild-type N. alata. Further evaluations in 1997 revealed several other interesting effects of the SAG12-IPT gene construct. Measurement of chlorophyll content of mature leaves showed higher levels of both chlorophyll a and b in transgenic material under normal fertilization and truncated fertilization regimes. At 4 to 5 months of age transgenic plants expressed differences in plant height, branching, and dry weight. Plant height was reduced by 3 to 13 cm; branch counts increased 2 to 3 fold; and shoot dry weight increased up to 11 g over wild-type N. alata. These observations indicate the system is not tightly autoregulated and may prove useful to the floriculture industry for producing compact and more floriferous plants.

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