scholarly journals Genetic improvement and agronomy for enhanced wheat competitiveness with weeds

2001 ◽  
Vol 52 (5) ◽  
pp. 527 ◽  
Author(s):  
D. Lemerle ◽  
G. S. Gill ◽  
C. E. Murphy ◽  
S. R. Walker ◽  
R. D. Cousens ◽  
...  
Keyword(s):  
Weed Management ◽  
Competitive Ability ◽  
Yield Loss ◽  
Plant Traits ◽  
Rapid Development ◽  
Integrated Weed Management ◽  
Weed Competition ◽  
Weed Seed ◽  
Seeding Rate ◽  
Benefits And Costs

The rapid development of herbicide resistance in weeds, and environmental imperatives, have forced the consideration of non-chemical tactics such as crop competition for weed management. This review of wheat–weed competition examines the plant traits associated with wheat competitiveness, and the opportunities for plant breeding or manipulating crop agronomy to differentially favour the growth of the crop. Many studies have proven that enhancing crop competitive ability can reduce weed seed production and crop yield loss, although a number of difficulties in conducting this research are identified and suggestions are made for improvement. It remains to be seen whether crop competitiveness will be considered as a priority by farmers and plant breeders. Farmers require precise information on the reliability of agronomic factors such as increased crop seeding rate or choice of variety for enhancing crop competitive ability in different environments. Plant breeders need to know which plant traits to incorporate in varieties to increase competitive ability. A thorough analysis of the benefits and costs of enhancing wheat competitiveness is needed. Competitive wheat crops should be available as part of reliable and economical integrated weed management packages for farmers.

Crop Seeding Rate Influences the Performance of Variable Herbicide Rates in a Canola–Barley–Canola Rotation

2004 ◽  
Vol 18 (3) ◽  
pp. 733-741 ◽  
Author(s):  
John T. O'Donovan ◽  
Jeff C. Newman ◽  
K. Neil Harker ◽  
George W. Clayton
Keyword(s):  
Seed Production ◽  
Weed Management ◽  
Crop Yields ◽  
Management Practice ◽  
Soil Seed Bank ◽  
Integrated Weed Management ◽  
Weed Seed ◽  
Seeding Rate ◽  
Wild Mustard ◽  
Yield Responses

Glyphosate-resistant canola was seeded at Vegreville, Alberta, in 1997 and 1999 and barley in rotation with the canola in 1998 at three seeding rates. The effects, at each crop seeding rate, of variable glyphosate (canola) and tralkoxydim plus bromoxynil plus MCPA (barley) rates on crop yield, net economic return and seed production by wild oat, wild mustard, and wild buckwheat, and the amount of weed seed in the soil seed bank was determined. Crop seeding rate influenced the response of canola and barley yield and weed seed production to herbicide rate. At the lowest crop seeding rates, yield responses tended to be parabolic with yields increasing up to one-half and three-quarters of the recommended herbicide rates and trends toward reduced yields at the full rates. This response was not evident at the higher crop seeding rates, where, in most cases the yield reached a maximum between one-half and the full recommended rate. The effects of the herbicides on weed seed production, especially at the lowest rate, were often superior at the higher crop seeding rates. The results indicate that seeding canola and barley at relatively high rates may reduce risk associated with lower crop yields and increased weed seed production at lower than recommended herbicide rates. However, the current cost of herbicide-resistant canola seed may preclude the adoption of this integrated weed management practice by growers.

A Systems Comparison of Contrasting Organic Weed Management Strategies

Weed Science ◽  
2017 ◽  
Vol 66 (1) ◽  
pp. 109-120 ◽  
Author(s):  
Bryan Brown ◽  
Eric R. Gallandt
Keyword(s):  
Seed Production ◽  
Weed Management ◽  
Critical Period ◽  
Yield Loss ◽  
Sweet Corn ◽  
Management Strategies ◽  
Weed Competition ◽  
Weed Seed ◽  
Period System ◽  
Organic Weed Management

Weed management strategies differ in their ability to control weeds, and often have unique agroecological implications. To provide growers with an improved sense of trade-offs between weed control and ecological effects, we implemented several prominent organic weed management strategies in yellow onion in 2014 and 2015. Strategies included cultivation of weed seedlings during the early, weed-sensitive “critical period” of the crop; frequent cultivation events to ensure “zero seed rain”; and weed suppression with polyethylene or natural mulches. As expected, end-of-season weed biomass and weed seed production were greatest in the critical period system and nearly zero for the zero seed rain system. Weeds were also well controlled in natural mulch systems. Average onion yield per treatment was 50.7 Mg ha−1. In 2014, the critical period system and the polyethylene mulch systems demonstrated yield loss, likely due to weed competition and excessive soil temperature, respectively. Onion soluble solids content was also diminished in these systems in 2014, but bulb firmness was greatest in unmulched systems. Carabid beetles, earthworms, soil compaction, soil nitrate, and microbial biomass were affected by weed management strategy, with natural-mulched systems generally performing most favorably. However, these effects were not substantial enough to affect yield of a subsequent sweet corn crop grown in weed-free conditions. In contrast, sweet corn managed with only early-season cultivations demonstrated yield loss (P=0.004) in plots where the critical period treatment was implemented the prior year, indicating that weed competition resulting from abundant weed seed production in that system was the most influential legacy effect of the weed management strategies.

Ability of Potato Cultivars to Tolerate and Suppress Weeds

2009 ◽  
Vol 23 (2) ◽  
pp. 287-291 ◽  
Author(s):  
Jed B. Colquhoun ◽  
Christopher M. Konieczka ◽  
Richard A. Rittmeyer
Keyword(s):  
Weed Management ◽  
Competitive Ability ◽  
Tuber Yield ◽  
Russet Burbank ◽  
Potato Cultivars ◽  
Integrated Weed Management ◽  
Weed Competition ◽  
Russet Norkotah ◽  
Herbicide Resistant ◽  
Hand Weeding

Potato producers rely heavily on herbicides for the majority of weed control. However, recent occurrences of herbicide-resistant weed populations and the lack of new herbicide registrations have stimulated interest in alternative strategies. The choice of potato cultivars that can suppress or tolerate weed competition could be a component of an integrated weed management system to reduce reliance on herbicides. The competitive ability of 10 potato cultivars—‘Atlantic’, ‘Bannock Russet’, ‘Dark Red Norland’, ‘Goldrush’, ‘Rodeo’, ‘Russet Burbank’, ‘Russet Norkotah’, ‘Snowden’, ‘Superior’, and ‘Villetta Rose’—was evaluated in 2006 and 2007 in Hancock, WI. Weed competition treatments included (1) weedy throughout the season, (2) weed-free from emergence to 4 wk after emergence (WAE) by hand-weeding, and (3) weed-free by hand-weeding for the entire season. Potato cultivars did not differ in ability to reduce weed biomass. Early-season time of potato emergence and canopy closure, as well as weed competition treatments, were strongly related to potato tuber yield. In general, Bannock Russet yield relative to weed-free controls of the same cultivar was less than that of most other cultivars. Overall, Atlantic, Russet Burbank, Snowden, and Superior yields (relative to weed-free control yields) usually were greater than the yields of other cultivars under weedy conditions. Although the ability to suppress weeds was similar among cultivars, differences in yield among cultivars grown in the presence of weeds suggest differential tolerances of weed competition.

An Integrated Weed Management Approach to Managing Foxtail Barley (Hordeum jubatum) in Conservation Tillage Systems

1999 ◽  
Vol 13 (2) ◽  
pp. 347-353 ◽  
Author(s):  
Robert E. Blackshaw ◽  
Greg Semach ◽  
Xiangju Li ◽  
John T. O'Donovan ◽  
K. Neil Harker
Keyword(s):  
Crop Yield ◽  
Weed Management ◽  
Conservation Tillage ◽  
Wheat Yield ◽  
Integrated Weed Management ◽  
Management Approach ◽  
Row Spacing ◽  
Seeding Rate ◽  
Tillage Systems ◽  
Perennial Plants

A 4-yr field experiment was conducted to determine the merits of combining cultural and chemical controls to manage foxtail barley in reduced-tillage systems. Factors studied were crop row spacing, seeding rate, and application rate and timing of glyphosate within a spring wheat-flax cropping sequence. Glyphosate applied preseeding at 400 or 800 g/ha killed foxtail barley seedlings but only suppressed established perennial plants. Glyphosate applied postharvest at 800 g/ha killed 60 to 70% of established plants. Combinations of preseeding and postharvest glyphosate gave the greatest reductions in foxtail barley biomass and seed production and resulted in the greatest increases in crop yield. Including flax in the rotation allowed use of grass herbicides such as quizalofop or sethoxydim that effectively controlled foxtail barley seedlings and provided some suppression of perennial plants. An increase in wheat seeding rate from 75 to 115 kg/ha reduced foxtail barley growth and increased wheat yield in 3 of 4 yr. Increasing the flax seeding rate from 40 to 80 kg/ha or reducing wheat and flax row spacing from 30 to 20 cm provided little benefit in managing foxtail barley or increasing crop yield. A multiyear approach combining agronomic practices and timely use of herbicides should allow growers to effectively manage foxtail barley in annual cropping systems using conservation tillage.

Seeding rate and row spacing affect flax yields and weed interference

1996 ◽  
Vol 76 (3) ◽  
pp. 537-544 ◽  
Author(s):  
F. C. Stevenson ◽  
A. T. Wright
Keyword(s):  
Seed Yield ◽  
Weed Management ◽  
Management Practices ◽  
The Other ◽  
Integrated Weed Management ◽  
Row Spacing ◽  
Flax Seed ◽  
Seeding Rate ◽  
Weed Interference ◽  
Interference Study

Seeding rate and row spacing are management practices that affect flax seed yield. Two experiments were conducted from 1988 to 1990 to determine the influence of flax seeding rates (300, 600, and 900 seeds m−2) and row spacings (9, 18, and 27 cm). One was a flax-weed interference study (three sites) and the other was a weed-free study (13 sites). In the presence of weeds, increasing seeding rate from 300 to 900 seeds m−2 improved flax seed yield by 180 kg ha−1, and reduced broadleaf weed yields by 300 kg ha−1 and grassy weed yields by 180 kg ha−1. In weed-free conditions, seed yield was not affected by seeding rate. Row spacing did not affect flax yield and had minor effects on weed yields when weeds were not controlled. When weeds were controlled, seed yield in the 9-cm row spacing was 9% (15% in the flax-weed interference study) greater than in the two wider row spacings. Seeding rate and row spacing independently influenced flax yield, and their effect was consistent among sites with weeds present, but was not consistent when weeds were controlled. Our results showed that flax seeding rate was an important component of integrated weed management. Key words: Flax, seeding rate, row spacing, weed interference

scholarly journals Response of Barley Genotypes to Weed Interference in Australia

Agronomy ◽  
2020 ◽  
Vol 10 (1) ◽  
pp. 99 ◽  
Author(s):  
Gulshan Mahajan ◽  
Lee Hickey ◽  
Bhagirath Singh Chauhan
Keyword(s):  
Negative Correlation ◽  
Weed Management ◽  
Field Experiments ◽  
Yield Loss ◽  
Production Systems ◽  
Relative Yield ◽  
Organic Production ◽  
Integrated Weed Management ◽  
Weed Interference ◽  
Barley Genotypes

Weed-competitive genotypes could be an important tool in integrated weed management (IWM) practices. However, weed competitiveness is often not considered a priority for breeding high-yielding cultivars. Weed-competitive ability is often evaluated based on weed-suppressive ability (WSA) and weed-tolerance ability (WTA) parameters; however, there is little information on these aspects for barley genotypes in Australia. In this study, the effects of weed interference on eight barley genotypes were assessed. Two years of field experiments were performed in a split-plot design with three replications. Yield loss due to weed interference ranged from 43% to 78%. The weed yield amongst genotypes varied from 0.5 to 1.7 Mg ha−1. Relative yield loss due to weed interference was negatively correlated with WTA and WSA. A negative correlation was also found between WSA and weed seed production (r = −0.72). Similarly, a negative correlation was found between WTA and barley yield in the weedy environment (r = −0.91). The results suggest that a high tillering ability and plant height are desirable attributes for weed competitiveness in the barley genotypes. These results also demonstrated that among the eight barley genotypes, Commander exhibited superior WSA and WTA parameters and therefore, could be used in both low- and high-production systems for weed management. Westminster had a superior WSA parameter. Therefore, it could be used for weed management in organic production systems. These results also implied that genotypic ranking on the basis of WSA and WTA could be used as an important tool in strengthening IWM programs for barley.

Economic benefits of integrated weed management systems for field crops in the Dark Brown and Black soil zones of western Canada

2006 ◽  
Vol 86 (4) ◽  
pp. 1273-1279 ◽  
Author(s):  
E. G. Smith ◽  
B. M. Upadhyay ◽  
R. E. Blackshaw ◽  
H. J. Beckie ◽  
K. N. Harker ◽  
...  
Keyword(s):  
Weed Management ◽  
Fertilizer Application ◽  
Black Soil ◽  
Field Pea ◽  
Integrated Weed Management ◽  
Western Canada ◽  
Seeding Rate ◽  
Soil Zone ◽  
Seeding Date ◽  
Common Practices

Integrated weed management (IWM) systems that combine seeding date, seeding rate, herbicide rate, and timing of nitrogen (N) fertilizer application were assessed for their economic performance in the Dark Brown and Black soil zones. A barley-field pea IWM system in the Black soil zone at Lacombe, Alberta, and a wheat-canola IWM system in the Dark Brown soil zone at Lethbridge, Alberta, and Scott, Saskatchewan, were used to assess contributions of seeding date (April or May), seeding rate (recommended or 150% of recommended), fertilizer timing (fall or spring), and in-crop herbicide rate (50% or 100% of recommended). The factorial set of treatments was applied in 4 consecutive years at each site. For barley-field pea production, the highest contribution margin (CM) (returns over variable production costs) was earned with 50% of the recommended herbicide rate, spring application of N fertilizer, seeding barley later at the high seeding rate, and seeding field pea early at the recommended seeding rate. This IWM system had a CM benefit of at least $51 ha-1 compared with current common practices. The wheat-canola system results were site specific. At Lethbridge, it was more profitable to use 50% of recommended herbicide rates and to seed both crops early, with an early seeding date being very important for canola. The CM of this IWM system was $48 ha-1 higher than current common practices. At Scott, the wheat-canola system was more profitable with spring fertilizer application, 50% of the recommended herbicide rate, and an early seeding date for canola. The best IWM system had a CM $15 to $75 ha-1 higher, depending on the year, than common practices. Our results confirmed the economic merits of using IWM practices for cereal-oilseed and cereal-pulse cropping systems in these regions of western Canada. Key words: Economic, integrated weed management, contribution margin, canola, wheat, field pea, barley

scholarly journals A “Stressed” Alfalfa-Based Cropping System Leads to the Selection of Quizalofop-Resistant Italian Ryegrass (Lolium perennessp.multiflorum)

Weed Science ◽  
2016 ◽  
Vol 64 (4) ◽  
pp. 683-694 ◽  
Author(s):  
Alberto Collavo ◽  
Silvia Panozzo ◽  
Antonio Allegri ◽  
Maurizio Sattin
Keyword(s):  
Ethyl Ester ◽  
Seed Production ◽  
Weed Management ◽  
Cropping System ◽  
Italian Ryegrass ◽  
Integrated Weed Management ◽  
Forage Production ◽  
Weed Seed ◽  
Quizalofop Ethyl ◽  
Selection Of

Italian ryegrass populations investigated in this study were harvested in an alfalfa-based cropping system. In that system, the agronomic practices and chemical weed management, based on the use of aryloxyphenoxy-propionates herbicides (i.e., quizalofop ethyl ester), were optimized to obtain a dual seed–forage production. Five of seven populations tested were confirmed resistant to quizalofop ethyl ester with resistance indexes ranging from 4.5 to >209. Both target- and nontarget-site resistance mechanisms were most likely involved. Three allelic variants were detected (Ile-1781–Leu, Trp-2027–Cys, and Ile-2041–Asn) in four resistant populations, whereas no known mutations were found in one resistant population. The herbicide treatment on Italian ryegrass plants at different phenological stages suggested that to control regrowth, it is necessary to use two to fives times the herbicide dose suitable for younger plants. This situation is encountered in fields when Italian ryegrass plants need to be controlled to maximize the alfalfa seed production, and it is comparable to using a sublethal herbicide dose, leading to the selection of herbicide-resistant biotypes. In such a situation, the cropping system is not sustainable, and integrated weed management should be implemented to deplete the soil weed seed bank and prevent new weed seed production.

Productivity and quality of canola and mustard cultivars under weed competition

2008 ◽  
Vol 88 (2) ◽  
pp. 367-372 ◽  
Author(s):  
H. J. Beckie ◽  
E. N. Johnson ◽  
R. E. Blackshaw ◽  
Y. Gan
Keyword(s):  
Brassica Juncea ◽  
Seed Yield ◽  
Weed Management ◽  
Sinapis Alba ◽  
Integrated Weed Management ◽  
Weed Competition ◽  
Weed Interference ◽  
Canola Quality ◽  
Oriental Mustard

Competitive crops or cultivars can be an important component of integrated weed management systems. A study was conducted from 2003 to 2006 at four sites across semiarid prairie ecoregions in Saskatchewan and Alberta to investigate the productivity and quality of canola (Brassica napusL.) and mustard cultivars under weed competition. Four open-pollinated canola cultivars, four hybrid canola cultivars, two canola-quality mustard and two oriental mustard cultivars [Brassica juncea (L.) Czern. & Coss.], and two yellow mustard (Sinapis alba L.) cultivars were grown under weedy and weed-free conditions. When combined across site-years, crop aboveground biomass at maturity and seed yield were reduced by weed interference, except for yellow and oriental mustard. However, seed oil and protein content of cultivars were not affected by weed competition. Among crop types, yellow and oriental mustard were best able to maintain biomass and seed yield under weed interference, followed in decreasing order of competitiveness by hybrid and open-pollinated canola, then canola-quality mustard. Key words: Brassica napus, Brassica juncea, Sinapis alba, weed competition

The ability of 29 barley cultivars to compete and withstand competition

Weed Science ◽  
2006 ◽  
Vol 54 (4) ◽  
pp. 783-792 ◽  
Author(s):  
Paul R. Watson ◽  
Douglas A. Derksen ◽  
Rene C. Van Acker
Keyword(s):  
Weed Management ◽  
Competitive Ability ◽  
Correlation Coefficients ◽  
Farming Systems ◽  
Field Trials ◽  
External Input ◽  
Integrated Weed Management ◽  
Barley Cultivar ◽  
Barley Cultivars ◽  
Full Height

Using competitive crops and cultivars can be an important integrated weed management (IWM) tool, useful in both conventional and low-external-input (LEI) farming systems. Barley is considered a competitive crop, but cultivar competitiveness varies. There are two aspects of cultivar competitive ability; the ability to compete (AC) and the ability to withstand competition (AWC). However, the relationship between these aspects has not been addressed in barley. A study was conducted to explore aspects of barley cultivar competitive ability with oats, and to examine the feasibility of ranking cultivars based on either, or both, AWC and AC. Field trials were undertaken in 2001 and 2002 to determine cultivar competitive ability for 29 barley cultivars commonly grown on the Canadian prairies. Cultivars were selected from semidwarf and full height, hulled and hull-less, 2- and 6-row, and feed and malt classes. Yield loss ranged from 6 to 79% while weed seed return ranged from 10 to 83% of gross yield. As a class, semidwarf and hull-less cultivars were less competitive than full height and hulled cultivars, respectively. However, considerable variation existed within these classes, and an absolute relationship between class membership and competitive ability did not exist. Ability to withstand competition was significantly correlated with ability to compete, but correlation coefficients were not strong enough to attempt reliable co-selection within a breeding program. Ability to compete was a more consistent measure of competitive ability than AWC. Ranking barley cultivar competitive ability would make it a valuable IWM tool for farmers and extension personnel.

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