scholarly journals Glyphosate Resistance in Perennial Ryegrass (Lolium perenneL.) is Associated with a Fitness Penalty

Weed Science ◽  
2016 ◽  
Vol 64 (1) ◽  
pp. 71-79 ◽  
Author(s):  
Marcos Yanniccari ◽  
Martín Vila-Aiub ◽  
Carolina Istilart ◽  
Horacio Acciaresi ◽  
Ana M. Castro
Keyword(s):  
Perennial Ryegrass ◽  
Water Availability ◽  
Field Experiments ◽  
Seed Mass ◽  
Selection Effect ◽  
Glyphosate Resistance ◽  
Shoot Biomass ◽  
Seed Number ◽  
Fitness Costs ◽  
Weed Species

The net selection effect of herbicides on herbicide-resistance traits in weeds is conditioned by the fitness benefits and costs associated with resistance alleles. Fitness costs play an important evolutionary role preventing the fixation of adaptive alleles and contributing to the maintenance of genetic polymorphisms within populations. Glyphosate is widely used in world agriculture, which has led to the evolution of widespread glyphosate resistance in many weed species. The fitness of glyphosate-resistant and -susceptible perennial ryegrass plants selected from within a single population were studied in two field experiments conducted during 2011 and 2012 under different soil water availability. Glyphosate-resistant plants showed a reduction in height of 12 and 16%, leaf blade area of 16 and 33%, shoot biomass of 45 and 55%, seed number of 33 and 53%, and total seed mass of 16 and 5% compared to glyphosate-susceptible plants in 2011 and 2012, respectively. The reduction in seed number per plant resulted in a 40% fitness cost associated with the glyphosate-resistance trait in perennial ryegrass. Fitness costs of glyphosate-resistant plants were expressed under both conditions of water availability. These results could be useful for designing management strategies and exploiting the reduced glyphosate-resistant perennial ryegrass fitness in the absence of glyphosate selection.

Relative Tolerance of Perennial Ryegrass (Lolium perenne) and Tall Fescue (Festuca arundinacea) to Flucarbazone

2012 ◽  
Vol 26 (4) ◽  
pp. 673-678 ◽  
Author(s):  
Patrick E. McCullough ◽  
Jialin Yu ◽  
James T. Brosnan ◽  
Gregory K. Breeden
Keyword(s):  
Lolium Perenne ◽  
Perennial Ryegrass ◽  
Tall Fescue ◽  
Festuca Arundinacea ◽  
Field Experiments ◽  
Early Summer ◽  
Growth Chamber ◽  
Shoot Biomass ◽  
Relative Tolerance ◽  
Sequential Treatments

Flucarbazone controls certain grassy weeds in wheat and may have potential for controlling perennial ryegrass in tall fescue turf. The objective of these experiments was to investigate perennial ryegrass and tall fescue tolerance to flucarbazone at two application timings. In field experiments, flucarbazone applications in May were more injurious to both species than in February and March. Single applications of flucarbazone from 30 to 60 g ai ha−1in May injured both species 35 to 50% and sequential treatments increased injury approximately twofold. Two applications of flucarbazone at 60 g ha−1in May injured both grasses > 90%, similar to sequential applications of trifloxysulfuron at 29 g ai ha−1. In growth chamber experiments, injury from flucarbazone on both grasses increased as temperature increased from 10 to 30 C. Flucarbazone reduced total shoot biomass of both grasses at all temperatures after 4 wk. Overall, perennial ryegrass and tall fescue are tolerant to flucarbazone at moderate temperatures (10 to 20 C). However, injury increased substantially under warmer conditions (30 C), suggesting flucarbazone could control perennial ryegrass and tall fescue during late spring and early summer.

Biologically-effective-dose of pyraflufen-ethyl/2,4-D, applied preplant alone or mixed with metribuzin on glyphosate-resistant horseweed in soybean

2021 ◽  
pp. 1-20
Author(s):  
David B. Westerveld ◽  
Nader Soltani ◽  
David C. Hooker ◽  
Darren E. Robinson ◽  
Peter H. Sikkema
Keyword(s):  
Effective Dose ◽  
Field Experiments ◽  
Glyphosate Resistance ◽  
Biologically Effective Dose ◽  
Weed Species ◽  
Visible Injury ◽  
Industry Standards

Abstract Glyphosate resistance in weed species has presented immense challenges for farmers in Ontario. The co-application of burndown plus residual herbicides provides control of glyphosate-resistant (GR) horseweed control in soybean. Pyraflufen-ethyl/2,4-D is a premixed herbicide formulation sold under the tradename Blackhawk®. Five field experiments were conducted over a two-year period (2019, 2020) in fields in southwestern Ontario to ascertain the biologically-effective-dose of pyraflufen-ethyl/2,4-D, applied alone, or mixed with metribuzin, for GR horseweed control when applied pre-plant to soybean. Soybean visible injury for all treatments was <15%. At 8 wk after application (WAA), the calculated doses of pyraflufen-ethyl/2,4-D for 50, 80, and 95% GR horseweed control were 390, 1148, and >2108 g ha−1, respectively. The addition of metribuzin to pyraflufen-ethyl/2,4-D reduced the doses of pyraflufen-ethyl/2,4-D for 50, 80, and 95% GR horseweed control to 19, 46 and 201 g ha−1, respectively. Pyraflufen-ethyl/2,4-D + metribuzin controlled GR horseweed 97% which is comparable to the current industry standards. Based on these results, pyraflufen-ethyl/2,4-D + metribuzin (527 + 400 g ha−1) applied preplant can be used for GR horseweed control in soybean.

Flat-cutting loosening in the system of fallow cultivation of chernozem soil and weediness of crops

2017 ◽  
Vol 1 (92) ◽  
pp. 78-84
Author(s):  
G. Koval ◽  
M. Kaliyevskiy ◽  
V. Yeshchenko ◽  
I. Martyniuk ◽  
N. Martyniuk
Keyword(s):  
Species Composition ◽  
Crop Rotation ◽  
Field Experiments ◽  
Early Spring ◽  
Weed Species ◽  
Wild Mustard ◽  
Spring Crop ◽  
White Campion ◽  
Investigation Methods ◽  
Top Soil

The article presents the results of field experiments, where on the basis of podsolized heavy loamy chernozem the influence of replacement of mouldboard ploughing with nonmouldboard cultivation over top soil weediness, weediness at the beginning and end of spring crop vegetation and weed species composition before harve sting were studied. Investigation methods of main fall ploughing under spring crops of five-course rotation: soybeans–rape–wheat–flax–barley at the depths of 15-17, 20-22, 25-27 cm were conducted after post-harvest field tillage. Analysis of data on contamination of the top soil with weed seeds have shown that with the replacement of fall main mouldboard ploughing gwith nonmouldboard cultivation the figure before sowing of all crops withdifferent tillage depthat crop rotation average increased by 131-132%. It caused the increase of actual weed infestation of all crops and at the beginning and end of spring crop vegetationafter different depths of fall nonmouldboard cultivation compared with ploughing at crop rotation average it was 120–132 and 123-138%respectively. Species composition of weeds afterthe replacement of main fall mouldboard ploughing with nonmouldboard cultivation remained mainlyunchanged; although in rape plantings the proportion of white campion and early spring weed sincreased, in wheat plantings– wild mustard andscentless mayweed, insoybean plantings– late spring weeds, in flax plantings– white campion, and in barley plantings– scarlet pimpernel.

Bio-efficacy of post emergence herbicides in boro rice nursery as well as main field and their residual effects on non-target microorganisms

2020 ◽  
Vol 57 (3) ◽  
pp. 199-210
Author(s):  
Rajib Kundu ◽  
Mousumi Mondal ◽  
Sourav Garai ◽  
Ramyajit Mondal ◽  
Ratneswar Poddar
Keyword(s):  
Weed Control ◽  
Weed Management ◽  
Field Experiments ◽  
Block Design ◽  
Resistance Index ◽  
Residual Effects ◽  
Cost Ratio ◽  
Main Field ◽  
Weed Species ◽  
Similar Treatment

Field experiments were conducted at research farm of Bidhan Chandra Krishi Viswavidyalaya, Kalyani, West Bengal, India (22°97' N latitude and 88°44' E longitude, 9.75 m above mean sea level) under natural weed infestations in boro season rice (nursery bed as well as main field) during 2017-18 and 2018-19 to evaluate the herbicidal effects on weed floras, yield, non-target soil organisms to optimize the herbicide use for sustainable rice-production. Seven weed control treatments including three doses of bispyribac-sodium 10% SC (150,200, and 250 ml ha-1), two doses of fenoxaprop-p-ethyl 9.3% EC (500 and 625 ml ha-1), one weed free and weedy check were laid out in a randomized complete block design, replicated thrice. Among the tested herbicides, bispyribac-sodium with its highest dose (250 ml ha-1) resulted in maximum weed control efficiency, treatment efficiency index and crop resistance index irrespective of weed species and dates of observation in both nursery as well as main field. Similar treatment also revealed maximum grain yield (5.20 t ha-1), which was 38.38% higher than control, closely followed by Fenoxaprop-p-ethyl (625 ml ha-1) had high efficacy against grasses, sedge and broadleaf weed flora. Maximum net return (Rs. 48765 ha-1) and benefit cost ratio (1.72) were obtained from the treatment which received bispyribac-sodium @ 250 ml ha-1. Based on overall performance, the bispyribac-sodium (250 ml ha-1) may be considered as the best herbicide treatment for weed management in transplanted rice as well as nursery bed.

Herbicide Effects on Weed Control and Shoot Growth of Young Apple (Malus sylvestris) and Peach (Prunus persica) Trees

1994 ◽  
Vol 8 (4) ◽  
pp. 840-848 ◽  
Author(s):  
Chester L. Foy ◽  
Susan B. Harrison ◽  
Harold L. Witt
Keyword(s):  
Shoot Growth ◽  
Field Experiments ◽  
Prunus Persica ◽  
Weed Species ◽  
Apple Trees ◽  
Herbicide Treatments ◽  
One Year ◽  
Broadleaf Species ◽  
Old Trees ◽  
Peach Trees

Field experiments were conducted at two locations in Virginia to evaluate the following herbicides: alachlor, diphenamid, diuron, metolachlor, napropamide, norflurazon, oryzalin, oxyfluorfen, paraquat, pendimethalin, and simazine. One experiment involved newly-transplanted apple trees; the others, three in apple and one in peach trees, involved one-year-old trees. Treatments were applied in the spring (mid-April to early-May). Control of annual weed species was excellent with several treatments. A broader spectrum of weeds was controlled in several instances when the preemergence herbicides were used in combinations. Perennial species, particularly broadleaf species and johnsongrass, were released when annual species were suppressed by the herbicides. A rye cover crop in nontreated plots suppressed the growth of weeds. New shoot growth of newly-transplanted apple trees was increased with 3 of 20 herbicide treatments and scion circumference was increased with 11 of 20 herbicide treatments compared to the nontreated control. Growth of one-year-old apple trees was not affected. Scion circumference of one-year-old peach trees was increased with 25 of 33 herbicide treatments.

A Survey of Glyphosate-Resistant Waterhemp (Amaranthus rudis) in Missouri Soybean Fields and Prediction of Glyphosate Resistance in Future Waterhemp Populations Based on In-Field Observations and Management Practices

2013 ◽  
Vol 27 (4) ◽  
pp. 656-663 ◽  
Author(s):  
Kristin K. Rosenbaum ◽  
Kevin W. Bradley
Keyword(s):  
Crop Production ◽  
Management Practices ◽  
Production Systems ◽  
Glyphosate Resistance ◽  
Continuous Cropping ◽  
Field Observations ◽  
Weed Species ◽  
Herbicide Treatment ◽  
Amaranthus Rudis

A survey of soybean fields containing waterhemp infestations was conducted just prior to harvest in 2008 and 2009 to determine the frequency and distribution of glyphosate-resistant waterhemp in Missouri, and to determine if there are any in-field parameters that may serve as indicators of glyphosate resistance in this species in future crop production systems. Glyphosate resistance was confirmed in 99 out of 144, or 69%, of the total waterhemp populations sampled, which occurred in 41 counties of Missouri. Populations of glyphosate-resistant waterhemp were more likely to occur in fields with no other weed species present at the end of the season, continuous cropping of soybean, exclusive use of glyphosate for several consecutive seasons, and waterhemp plants showing obvious signs of surviving herbicide treatment compared to fields characterized with glyphosate-susceptible waterhemp. Therefore, it is suggested that these four site parameters, and certain combinations of these parameters, serve as predictors of glyphosate resistance in future waterhemp populations.

scholarly journals Seed mass effects on germination and growth of diverse European Scots pine populations

1994 ◽  
Vol 24 (2) ◽  
pp. 306-320 ◽  
Author(s):  
P.B. Reich ◽  
J. Oleksyn ◽  
M.G. Tjoelker
Keyword(s):  
Growth Rate ◽  
Relative Growth Rate ◽  
Scots Pine ◽  
Field Experiments ◽  
Seed Mass ◽  
Growing Season ◽  
Turkish Population ◽  
Dry Mass ◽  
Relative Growth ◽  
Mass Effects

Seedlings of 24 European Scots pine (Pinussylvestris L.) populations were grown in controlled environment chambers under simulated photoperiodic conditions of 50 and 60°N latitude to evaluate the effect of seed mass on germination and seedling growth characteristics. Seeds of each population were classified into 1-mg mass classes, and the four classes per population with the highest frequencies were used. Photoperiod had minimal influence on seed mass effects. Overall, seed mass was positively related to the number of cotyledons and hypocotyl height. Populations differed significantly in seed mass effect on biomass. In northern populations (55–61°N), dry mass at the end of the first growing season was little affected by seed mass. However, dry mass in 9 of 15 central populations (54–48°N) and all southern (<45°N) populations correlated positively with seed mass. Relative growth rate was not related to seed mass within or across populations, and thus early growth is largely determined by seed mass. Relative growth rate also did not differ among populations, except for a geographically isolated Turkish population with the highest seed mass and lowest relative growth rate. After one growing season, height was positively correlated (r2 > 0.6) with seed mass in 15 populations. To check the duration of seed mass effects, height growth of 1- to 7-year-old field experiments established with the same seed lots were compared. Seed mass effects on height were strongest for 1-year-old seedlings and declined or disappeared by the age of 5–7 years among central and southern populations, but remained stable over that time in northern populations.

scholarly journals Effect of duration of weed competition and weed control on the yield of Indian spinach

1970 ◽  
Vol 33 (4) ◽  
pp. 623-629 ◽  
Author(s):  
MSA Khan ◽  
MA Hossain ◽  
M Nurul Islam ◽  
SN Mahfuza ◽  
MK Uddin
Keyword(s):  
Weed Management ◽  
Critical Period ◽  
Field Experiments ◽  
Agricultural Research ◽  
Cyperus Rotundus ◽  
Weed Competition ◽  
Weed Species ◽  
Maximum Benefit ◽  
Hand Weeding ◽  
Crop Weed Competition

Field experiments were conducted at the research farm of Bangladesh Agricultural Research Institute, Joydebpur during kharif-1 (March to July) seasons of 2005 and 2006 to identify the critical period of crop-weed competition for Indian spinach. Major weed species were Paspalurn commersoni, Echinochlaa crusgalli. Lie nv/nc india. Cyanotis axillaris and Cyperus rotundus. The lowest weed dry matter was 76.3 g m-2 in 2005 and l01.60 g m-2 in 2006 from the plots weeded up to 40 days after transplanting (DAT). The highest yields were obtained (74.82 t ha in 2005 and 48.48 t ha in 2006) from the weed free plots. The fresh yield of Indian spinach did not vary among no weeding upto 20, 30 and 40 DAT in 2006. But weeded plot upto 30 and 40 DAT produced identical yield in 2005. Maximum BCR (4.52) was obtained from weeded plots upto 30 DAT in 2005 but BCR (2.60) was same from weeded upto 30 and 40 DA F in 2006. On an average, highest BCR (3.55) was recorded from weeding upto 30 DAT. Results revealed that the critical period of crop weed competition lies between 20 and 30 DAT and two times hand weeding would be necessary within 30 DAT for maximum benefit. Key Words: Crop-weed competitions, critical period, weed management and Indian spinach. doi: 10.3329/bjar.v33i4.2306 Bangladesh J. Agril. Res. 33(4) : 623-629, December 2008

scholarly journals Nitrogen management in wheat based on the normalized difference vegetation index (NDVI)

2018 ◽  
Vol 48 (9) ◽  
Author(s):  
André Luis Vian ◽  
Christian Bredemeier ◽  
Marcos Alexandre Turra ◽  
Cecília Paz da Silva Giordano ◽  
Elizandro Fochesatto ◽  
...  
Keyword(s):  
Technical Efficiency ◽  
Vegetation Index ◽  
Normalized Difference Vegetation Index ◽  
Field Experiments ◽  
Shoot Biomass ◽  
Sensor Field ◽  
N Dose ◽  
Plant Emergence ◽  
The Moment ◽  
The Relationship

ABSTRACT: Biomass production and nitrogen (N) accumulated in wheat shoots may be used for quantifying optimal topdressing nitrogen doses. The objective of this study was to develop and validate models for estimating the amount of biomass and nitrogen accumulated in shoots and the N topdressing dose of maximum technical efficiency in wheat using the normalized difference vegetation index (NDVI) measured by an active optical canopy sensor. Field experiments were carried out in two years and treatments consisted of N doses applied at plant emergence and as topdressing. NDVI, shoot biomass and N accumulated in shoots at the growth stage of six fully expanded leaves and grain yield were evaluated, being determined the topdressing N dose of maximum technical efficiency (DMTE). The NDVI was positively correlated to shoot biomass and N content in shoots and models for the relationship between these variables were developed and validated. The DMTE was negatively correlated with the NDVI value evaluated at the moment of N topdressing application. Thus, NDVI evaluation by an active optical canopy sensor can be used for nitrogen fertilization in variable rate, allowing the adjustment of applied N doses in different areas within a field.

scholarly journals The effects of ploidy and seed mass on the emergence and early vigour of perennial ryegrass (Lolium perenne L.) cultivars

2003 ◽  
Vol 43 (5) ◽  
pp. 481 ◽  
Author(s):  
K. F. Smith ◽  
N. M. McFarlane ◽  
V. M. Croft ◽  
P. J. Trigg ◽  
G. A. Kearney
Keyword(s):  
Genetic Variation ◽  
Lolium Perenne ◽  
Perennial Ryegrass ◽  
Seed Mass ◽  
Leaf Length ◽  
Seedling Height ◽  
Seedling Vigour ◽  
Lolium Perenne L ◽  
Early Vigour ◽  
Shoot Mass

Genetic variation for seed mass and components of early vigour were measured on 120 seedlings of each of 18 diploid and 27 tetraploid perennial ryegrass (Lolium perenne L.) cultivars. Seeds of tetraploid cultivars were on average heavier (3.8 mg) than seed of diploid cultivars (2.4 mg). However, there was variation for mean seed mass both within and between ploidy classes and within cultivars. The components of early vigour measured on each of the seedlings were: date of emergence, leaf appearance rate, seedling height (10 days after germination), leaf length and width and dry matter at 33 days after emergence. Mean seed mass of a cultivar was significantly (P<0.05) positively correlated with seedling height, leaf length, leaf width, shoot length and shoot mass. Individual seed mass within a cultivar was significantly associated with all components of early vigour, except the date of emergence of the second true leaf. There was no difference in the rate of emergence of tetraploid and diploid cultivars, although tetraploid cultivars tended to have longer and wider leaves, greater seedling lengths and fewer leaves and tillers than diploid cultivars. There was also evidence of genetic variation for seedling vigour components in perennial ryegrass after seed mass and ploidy effects had been removed during analysis. These data suggest that seed mass has a large positive effect on early vigour of both diploid and tetraploid cultivars of perennial ryegrass and that, in the absence of any specific knowledge of the early vigour characteristics of a given cultivar, seed mass could be used as a surrogate when choosing between cultivars with similar adaptation and performance.

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