Delaying Weed Control Lengthens the Anthesis-Silking Interval in Maize

Stress caused by early weed competition is known to delay the rate of maize development which may result in a decrease in kernel number. Kernel number in maize is correlated negatively with the length of the anthesis-silking interval (ASI). A short ASI has been identified as an easily measured, visual trait which may identify enhanced drought tolerance in maize. Field studies were conducted to test whether: (1) delaying weed control would result in a lengthening of ASI in both a drought tolerant and non-drought tolerant maize hybrid and (2) the presence of drought tolerance genetics comes at a physiological cost, resulting in a greater yield reduction under weedy conditions. In this study, the response of a drought tolerant hybrid with its non-drought tolerant near-isoline was compared to seven different timings of weed control using wheat as a surrogate competitor. Results confirmed that there was no treatment by hybrid interaction at any site–yr for any of the parameters evaluated. Delaying weed control reduced plant height, leaf tip number, shifted and reduced biomass accumulation, kernel number and grain yield and lengthened ASI for both hybrids. Although yield losses occurred with the delay in weed control timing, no yield differences were observed between hybrids suggesting that there was no additional physiological cost associated with the drought tolerant traits. The drought tolerant hybrid, however, was found to have a shorter ASI, lower kernel number and higher kernel wt compared to the non-drought tolerant hybrid. This study confirmed that delaying weed control can influence the length of ASI, which is an important drought tolerant trait. The lengthening of ASI by early weed competition resulted in a rate of yield loss of 0.13 T ha−1growing degree days (GDD)−1when averaged across both hybrids and all treatments.

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Integration of residual herbicides with cover crop termination in soybean

Weed Technology ◽

10.1017/wet.2019.111 ◽

2019 ◽

Vol 34 (1) ◽

pp. 11-18 ◽

Cited By ~ 2

Author(s):

Derek M. Whalen ◽

Lovreet S. Shergill ◽

Lyle P. Kinne ◽

Mandy D. Bish ◽

Kevin W. Bradley

Keyword(s):

Weed Control ◽

Cover Crops ◽

Cover Crop ◽

Biomass Accumulation ◽

Field Studies ◽

Italian Ryegrass ◽

Cereal Rye ◽

Herbicide Treatments ◽

Residual Herbicide ◽

Herbicide Programs

AbstractCover crops have increased in popularity in midwestern U.S. corn and soybean systems in recent years. However, little research has been conducted to evaluate how cover crops and residual herbicides are effectively integrated together for weed control in a soybean production system. Field studies were conducted in 2016 and 2017 to evaluate summer annual weed control and to determine the effect of cover crop biomass on residual herbicide reaching the soil. The herbicide treatments consisted of preplant (PP) applications of glyphosate plus 2,4-D with or without sulfentrazone plus chlorimuron at two different timings, 21 and 7 d prior to soybean planting (DPP). Cover crops evaluated included winter vetch, cereal rye, Italian ryegrass, oat, Austrian winter pea, winter wheat, and a winter vetch plus cereal rye mixture. Herbicide treatments were applied to tilled and nontilled soil without cover crop for comparison. The tillage treatment resulted in low weed biomass at all collection intervals after both application timings, which corresponded to tilled soil having the highest sulfentrazone concentration (171 ng g−1) compared with all cover crop treatments. When applied PP, herbicide treatments applied 21 DPP with sulfentrazone had greater weed (93%) and waterhemp (89%) control than when applied 7 DPP (60% and 69%, respectively). When applied POST, herbicide treatments with a residual herbicide resulted in greater weed and waterhemp control at 7 DPP (83% and 77%, respectively) than at 21 DPP (74% and 61%, respectively). Herbicide programs that included a residual herbicide had the highest soybean yields (≥3,403 kg ha−1). Results from this study indicate that residual herbicides can be effectively integrated either PP or POST in conjunction with cover crop termination applications, but termination timing and biomass accumulation will affect the amount of sulfentrazone reaching the soil.

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Mustard tolerance to clopyralid applied alone or with ethametsulfuron

Canadian Journal of Plant Science ◽

10.4141/cjps94-114 ◽

1994 ◽

Vol 74 (3) ◽

pp. 635-641

Author(s):

H. A. Loeppky ◽

R. E. Blackshaw

Keyword(s):

Weed Control ◽

Oil Content ◽

Growth Stage ◽

Field Studies ◽

The Other ◽

Yellow Mustard ◽

Crop Tolerance ◽

Drought Tolerant ◽

Control Limits ◽

Oriental Mustard

Mustard is a drought-tolerant crop well adapted to the Brown and Dark Brown soils of the Prairies; however, lack of broad-leaved weed control limits production. Two field studies were conducted at Indian Head, Saskatchewan and Lethbridge, Alberta to determine the response of brown and oriental mustard (Brassica juncea (L.) Coss), and yellow mustard (B. hirta Moench) to clopyralid. Clopyralid was applied at 0.10, 0.15, 0.20, 0.30, 0.60 kg a.i. ha−1 at the 4- or 10-leaf stage in one experiment. The other was a factorial experiment of clopyralid at 0.10, 0.20, and 0.30 kg a.i. ha−1 with ethametsulfuron at 0.01, 0.02, and 0.03 kg a.i. ha−1. Clopyralid applied at 0.15 kg a.i. ha−1, the lowest rate at which it is registered for weed control in canola, resulted in brown mustard yield reductions of 21%, oriental mustard yield reductions of 23% and yellow mustard yield reductions of 9% over 5 site years. This rate of clopyralid applied with ethametsulfuron reduced brown, oriental and yellow mustard yield by 30, 33 and 8%, respectively. Oil content was also reduced by clopyralid. Clopyralid cannot be used for weed control in mustards. Key words: Crop tolerance, growth stage, clopyralid, ethametsulfuron, seed yield, oil content

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Inheritance and mapping of drought tolerance in soybean at seedling stage using bulked segregant analysis

Plant Genetic Resources ◽

10.1017/s1479262120000052 ◽

2020 ◽

Vol 18 (2) ◽

pp. 63-70

Author(s):

V. Sreenivasa ◽

S. K. Lal ◽

P. Kiran Babu ◽

H. K. Mahadeva Swamy ◽

Raju R. Yadav ◽

...

Keyword(s):

Drought Tolerance ◽

Bulked Segregant Analysis ◽

Seedling Survival ◽

Yield Reduction ◽

Single Marker Analysis ◽

Drought Tolerant ◽

Single Marker ◽

Improvement Programs ◽

Mapping Populations ◽

Map Distance

AbstractOccurrence of drought under rainfed conditions is the foremost factor responsible for yield reduction in soybean. Developing soybean cultivars with an inherent ability to withstand drought would immensely benefit the soybean production in rainfed areas. In the present study, F2 derived mapping populations were developed by crossing drought tolerant (PK 1180, SL 46) and susceptible (UPSL 298, PK 1169) genotypes to investigate the inheritance of seedling survival drought mechanisms and to identify simple-sequence repeat (SSR) markers associated with them, using bulked segregant analysis. Parents as well as a F2 derived mapping population were screened for drought tolerance based on seedling survivability under controlled conditions. Segregation analysis of F2 population derived from a cross between PK 1180 × UPSL 298 was previously shown to have a 3:1 tolerant to susceptible ratio and a probability of 0.61 at a χ2(3:1) value of 0.258. This was confirmed in another F2 population derived from a cross between PK 1169 × SL 46 with a χ2(3:1) value of 0.145 obtained at a probability of 0.70. One SSR marker Satt277 showed polymorphism between contracting bulks (tolerant and susceptible) out of 50 polymorphic markers identified during parental polymorphism. Single marker analysis suggested that the marker, Satt277 is linked to seedling survival drought tolerance and is located on chromosome linkage group C2 (chr 6) with a map distance of 3.40 cM. The tolerant genotypes identified could be used as a donor in soybean improvement programs. The marker identified can be used in marker-assisted selection while screening large collection of germplasm.

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Weed competition in maize (Zea mays L.) as a function of the timing of hand-hoeing weed control in the southern Guinea savanna zone of Nigeria

Acta Agronomica Hungarica ◽

10.1556/aagr.60.2012.3.8 ◽

2012 ◽

Vol 60 (3) ◽

pp. 257-264 ◽

Cited By ~ 2

Author(s):

F. Takim

Keyword(s):

Grain Yield ◽

Weed Control ◽

Seedling Emergence ◽

Dry Weight ◽

Field Studies ◽

Growth And Yield ◽

Weed Competition ◽

Maize Crop ◽

Weed Interference ◽

The University

Field studies were conducted in 2010 and 2011 at the Teaching and Research Farm of the University of Ilorin, Nigeria (9°29′ N, 4°35′ E) to evaluate the effect of early weed competition on the growth and yield of maize. The experiment was designed as a randomized complete block (RCBD) with a split-plot arrangement and three replications. The main plots consisted of three weed control treatments included weedy (no herbicide), grass weeds (pre-emergence atrazine) and broadleaf weeds (pre-emergence metolachlor), while the sub-plots consisted of six durations of weed infestation (3, 4, 5, 6, 7 and 8 weeks after emergence). The pre-emergence herbicides had a greater effect on weed density and weed dry weight. Weed seedling emergence and weed dry weight increased significantly with an increase in the duration of weed interference. The grasses and broadleaf weeds had a similar influence on the growth and grain yield of maize. Three to five weeks of weed interference gave similar grain yields, which were significantly higher than those obtained in plots that had 6-8 weeks of weed interference. These results suggest that the maize crop must be kept free of weeds for 6-8 weeks after the application of pre-emergence herbicide to minimize weed-crop competition and harvest a good grain yield.

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HERBICIDES FOR WEED CONTROL IN SAFFLOWER (Carthamus tinctorius)

Canadian Journal of Plant Science ◽

10.4141/cjps90-026 ◽

1990 ◽

Vol 70 (1) ◽

pp. 237-245 ◽

Cited By ~ 9

Author(s):

R. E. BLACKSHAW ◽

H.-H. MUENDEL ◽

D. A. DERKSEN

Keyword(s):

Weed Control ◽

Seed Yield ◽

Seed Weight ◽

Oil Content ◽

Field Studies ◽

Carthamus Tinctorius ◽

Severe Injury ◽

Weed Competition ◽

Herbicide Application ◽

Crop Tolerance

Field studies were conducted in 1986, 1987 and 1988 at Lethbridge, Alberta and in 1987 and 1988 at Indian Head, Saskatchewan to determine herbicides suitable for selective control of weeds in safflower (Carthamus tinctorius L.). Safflower exhibited acceptable tolerance to trifluralin, ethalfluralin, sethoxydim, fluazifop-p-butyl, clethodim, diclofop methyl, difenzoquat, imazamethabenz, chlorsulfuron, thiameturon, metsulfuron and DPX-A7881 over all years and locations. These herbicides offer the grower the option of preplant incorporated or postemergent herbicide application or a combination of the two. A mixture of thiameturon plus DPX-L5300 caused severe injury to safflower, reducing yield, oil content, and seed weight. Desmedipham, phenmedipham, and mixtures of these herbicides injured safflower at Lethbridge but not at Indian Head. Weeds reduced safflower yield by 39–73% over the 3 yr of the study. Control of weeds in safflower is essential to obtain optimum yields.Key words: Crop tolerance, seed yield, oil content, seed weight, weed competition

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Weed Management in Wide- and Narrow-Row Glyphosate-Resistant Sugarbeet

Weed Technology ◽

10.1614/wt-d-10-00033.1 ◽

2010 ◽

Vol 24 (4) ◽

pp. 523-528 ◽

Cited By ~ 10

Author(s):

Jon-Joseph Q. Armstrong ◽

Christy L. Sprague

Keyword(s):

Weed Control ◽

Weed Management ◽

Field Studies ◽

Weed Competition ◽

Yield And Quality ◽

Row Width ◽

Herbicide Treatments ◽

Narrow Row

Planting glyphosate-resistant sugarbeet in narrow rows could improve weed control with fewer herbicide applications and cultivations. Field studies were conducted in 2007 and 2008 at multiple locations in Michigan to compare weed management and sugarbeet yield and quality in glyphosate-resistant sugarbeet planted in 38-, 51-, and 76-cm rows. At all locations, weed densities and biomass were less after glyphosate treatments than after conventional herbicide treatments. Weed densities and biomass also were less in 38- and 51-cm rows compared with 76-cm rows following a single glyphosate application when weeds were 10 cm tall. Averaged over row width, sugarbeet treated with glyphosate when weeds first reached 2 cm in height and again as needed thereafter yielded similarly to sugarbeet treated when weeds were 5 to 10 cm tall. However, root yields were reduced when glyphosate application was delayed until weeds averaged 15 cm in height. Sugarbeet root and sugar yields were greater from 38- and 51-cm row widths than from the 76-cm row widths, averaged over all herbicide treatments. Regardless of row width, initial glyphosate applications should be made before weeds reach 10 cm in height to maximize yield and minimize weed competition with sugarbeet.

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A review on integrated approach for the management of weeds in Cowpea (Vigna unguiculata)

Journal of Applied and Natural Science ◽

10.31018/jans.v12i4.2386 ◽

2020 ◽

Vol 12 (4) ◽

pp. 504-510

Author(s):

Sinchana J.K. ◽

Sheeja K Raj

Keyword(s):

Weed Control ◽

Vigna Unguiculata ◽

Integrated Approach ◽

Yield Reduction ◽

Weed Competition ◽

Initial Growth ◽

Net Returns ◽

Cultural Methods ◽

Manual Weeding ◽

Crop Weed Competition

Cowpea (Vigna unguiculata) is the most important leguminous crop raised as pulse as well as a vegetable crop in India. The slow initial growth and wider spacing necessitate weed control in the early stages of crop growth. The critical period of crop weed competition in cowpea was 20 to 30 DAS. Season-long crop weed competition resulted in a yield reduction of 40 to 90 per cent in cowpea depending on the intensity of weed infestation, weed flora, season, location, and the climatic condition prevailed. Mulching, manual weeding and stale seedbed are the different cultural methods which can be adopted for weed control in cowpea. Chemical method of weed control is the cheapest and economically viable option for weed control in cowpea. Both Pre-emergence herbicides viz., pendimethalin, diclosulam and imazethapyr and post-emergence herbicides viz., imazethapyr, quizalofop-p-ethyl can be used for weed control in cowpea. Studies revealed that pre-emergence application of herbicide (imazethapyr/pendimethalin or diclosulam) followed by manual weeding or post-emergence application of herbicides (quizalofop-p-ethyl or imazethapyr) or mulching followed by post-emergence application of herbicides (quizalofop-p-ethyl or imazethapyr) were found to be more effective for the broad-spectrum weed control in cowpea. The integrated approach of weed control has resulted in a higher yield, net returns and B: C ratio in cowpea.

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The Effect of Drought on Transcriptome and Hormonal Profiles in Barley Genotypes With Contrasting Drought Tolerance

Frontiers in Plant Science ◽

10.3389/fpls.2020.618491 ◽

2020 ◽

Vol 11 ◽

Author(s):

Amal Harb ◽

Craig Simpson ◽

Wenbin Guo ◽

Ganesan Govindan ◽

Vijaya Gopal Kakani ◽

...

Keyword(s):

Drought Tolerance ◽

Expression Profiles ◽

Gene Expression Profiles ◽

Biomass Accumulation ◽

Net Photosynthesis ◽

Betaine Aldehyde Dehydrogenase ◽

Transcriptional Responses ◽

Drought Tolerant ◽

Hormonal Profiles ◽

Barley Genotypes

Like many cereal crops, barley is also negatively affected by drought stress. However, due to its simple genome as well as enhanced stress resilient nature compared to rice and wheat, barley has been considered as a model to decipher drought tolerance in cereals. In the present study, transcriptomic and hormonal profiles along with several biochemical features were compared between drought-tolerant (Otis) and drought-sensitive (Baronesse) barley genotypes subjected to drought to identify molecular and biochemical differences between the genotypes. The drought-induced decrease in the leaf relative water content, net photosynthesis, and biomass accumulation was relatively low in Otis compared to Baronesse. The hormonal profiles did not reveal significant differences for majority of the compounds other than the GA20 and the cis-zeatin-o-glucoside (c-ZOG), whose levels were greatly increased in Otis compared to Baronesse under drought. The major differences that emerged from the transcriptome analysis are; (1), the overall number of differentially expressed genes was relatively low in drought-tolerant Otis compared to drought-sensitive Baronesse; (2), a wax biosynthesis gene (CER1), and NAC transcription factors were specifically induced in Otis but not in Baronesse; (3), the degree of upregulation of betaine aldehyde dehydrogenase and a homeobox transcription factor (genes with proven roles in imparting drought tolerance), was greater in Otis compared to Baronesse; (4) the extent of downregulation of gene expression profiles for proteins of the reaction center photosystem II (PSII) (D1 and D2) was low in Otis compared to Baronesse; and, (5), alternative splicing (AS) was also found to differ between the genotypes under drought. Taken together, the overall transcriptional responses were low in drought-tolerant Otis but the genes that could confer drought tolerance were either specifically induced or greatly upregulated in the tolerant genotype and these differences could be important for drought tolerance in barley.

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The Value of the Stay-green Traits with Grain Yield of Post Flowering Drought Tolerance in Rabi Sorghum

International Journal of Bio-resource and Stress Management ◽

10.23910/1.2021.2153 ◽

2021 ◽

Vol 12 (1) ◽

pp. 059-063

Author(s):

D. Dev Kumar ◽

◽

V. Padma ◽

H. S. Talwar ◽

Farzana Jabeen ◽

...

Keyword(s):

Drought Tolerance ◽

Grain Yield ◽

Grain Filling ◽

Moisture Stress ◽

Indian Institute ◽

Yield Reduction ◽

Stay Green ◽

Drought Tolerant ◽

Sorghum Genotypes ◽

Plot Design

An experiment was conducted during rabi 2012-13 at research farm of Indian Institute of Millet Research (IIMR), Rajendranagar, Hyderabad, Telengana State, India. The experiment was laid out in a split plot design, replicated thrice, with 10 Sorghum genotypes as main treatment Well-watered (WW) and Water-stress (WS) conditions) to examine the potential of Sorghum genotypes to adapt to the post flowering drought. 10 genotypes are sub-treatments CRS 4, CRS 19, CRS 20, PEC 17, CSV 18, M 35-1, Phule chitra, Phule moulee, EP 57 and CRS 1). Among the four stages viz., 10, 20, 30 and 40 days after flowering (DAF), the GLAR (stay green trait) at 10 DAF had a positive and higher significant correlation with grain yield (r=0.66). So, GLAR at 10 DAF is most appropriate stage to screen for post flowering drought tolerance. Among the yield components, number of grains per panicle, grain weight panicle-1 and harvest index (HI) are significantly and positively correlated with grain yield and therefore it can be ascribed that the genotypes, which partitioned more assimilates into economic parts and in which grain filling is high, recorded more grain yield. The overall yield reduction due to moisture stress during the post flowering drought was 10% and it ranged between 8-12% among the genotypes. This indicates that the genotypes used in the present study are relatively drought tolerant. The genotypes CSV 18 and Phule moulee registered least yield reduction (8%) in grain yield due to post flowering drought followed by PEC 17 and M 35-1 which registered 9% yield reduction. However, the overall grain yield of PEC 17 and M 35-1 was more than CSV 18 and Phule moulee even under moisture stress conditions.

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Evaluation of Herbicides for Chemical Weed Control in Lily Bulb Production

Weed Technology ◽

10.1614/wt-09-055.1 ◽

2010 ◽

Vol 24 (4) ◽

pp. 483-488

Author(s):

Pablo Marinangeli ◽

Ramón Lopez Castro ◽

Cecilia Facchinetti ◽

Lucio Reinoso ◽

Jorge Irigoyen ◽

...

Keyword(s):

South America ◽

Effective Treatment ◽

Weed Control ◽

No Reduction ◽

Field Studies ◽

Yield Reduction ◽

Main Symptom ◽

Phytotoxic Effect ◽

Lily Bulb ◽

Bulb Yield

Information on chemical weed control in lily bulb production in South America is scarce. Greenhouse and field studies were conducted to evaluate the phytotoxic effect and weed control of herbicides applied PRE and POST in lily bulb production in Argentina. In greenhouse studies, bromoxynil, 415 g ai ha−1; fluroxypyr, 200 g ai ha−1; metsulfuron, 3 g ai ha−1; iodosulfuron-methyl-sodium, 3 g ai ha−1 + metsulfuron, 3 g ai ha−1; oxyfluorfen, 240 g ai ha−1; ioxynil, 529 g ai ha−1; and linuron, 750 g ai ha−1, produced severe phytotoxicity or death of bulbs. Glyphosate at 720 g ai ha−1 and aclonifen at 720 g ai ha−1 produced little to no symptoms and were considered safe to apply to lilies. In field conditions, PRE herbicides metolachlor, 960 g ai ha−1 + atrazine, 1,500 g ai ha−1, and metolachlor, 960 g ai ha−1 + flumetsulam, 80 g ai ha−1, provided good weed control but were phytotoxic for lily plants, with chlorosis as the main symptom. Metolachlor plus linuron resulted in little or no symptoms of injury and no reduction in bulb yield. Diuron, 800 g ai ha−1 POST was the most effective treatment without phytotoxicity, and, in combination with metolachlor, 960 g ai ha−1 + linuron, 750 g ai ha−1 PRE, controlled weeds until 40 d after diuron application without yield reduction. Results obtained with glyphosate indicate that the Lilium genus presents some tolerance to this herbicide, which justifies further evaluation for weed control in lily bulb production.

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