Thresholds for Injury, Growth, and Yield Loss Caused by Ozone on Field Corn Hybrids

Resistance Evaluation of Chillipepper Cultivars for Cucumber Mosaic Virus and Chilli Veinal Mottle Virus. The use of resistance culivars is an important strategy for management of virus infection in chillipepper. A research was undergone to study the effect of single and mix infection of CMV and ChiVMV on the disease incidence and on the growth and yield of nine chillipepper cultivars, i.e. Cilibangi 4, Cilibangi 5, Cilibangi 6, Helem, Jatilaba, Tit Bulat, Tit Segitiga, Tit Super and Tampar. Mechanical inoculation was conducted to transmit the virus. Infection of the virus was then confirmed with DAS-ELISA. In general, inoculated chillipepper cultivars developed similar symptoms, i.e. mosaic type for CMV and mottle type for ChiVMV. More severe symptom was not always observed from mix infection of CMV and ChiVMV. Disease incidence occurred in the range of 16.67 – 86.0% and this caused 18.3 – 98.6% yield loss. Based on symptom expression, ELISA result, and reduction on yield, it can be concluded that all chillipepper cultivars used in this study could not hold up the virus infection. However, several cultivars showed tolerance response : Jatilaba, Tit Super, and Tampar for CMV; Cilibangi 4 for ChiVMV; Tit Super for mix infection; and Cilibangi 5 for CMV, ChiVMV, and mix infection. Further evaluation and investigation involving different chillipepper cultivars should be conducted.

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Using Estimates of Weed Pressure to Establish Crop Yield Loss Equations

Weed Technology ◽

10.1017/s0890037x00039294 ◽

1994 ◽

Vol 8 (1) ◽

pp. 114-118 ◽

Cited By ~ 9

Author(s):

R. Gordon Harvey ◽

Clark R. Wagner

Keyword(s):

Linear Regression ◽

Crop Yield ◽

Yield Loss ◽

Sweet Corn ◽

Crop Yields ◽

Yield Reduction ◽

Weed Species ◽

Field Corn ◽

Efficacy Trials ◽

Total Crop

Herbicide efficacy trials in field corn, sweet corn, and soybean were conducted at three locations in Wisconsin over a 6-yr period. Percent weed pressure (WP) was determined by visually estimating the contribution of all weed species present to the total crop and weed volume in each plot. Crop yields in each plot were measured. Percent crop yield reduction (YLDRED) was calculated by comparing mean yields of individual treatments with those of the highest yielding treatment in each trial. Linear regression analyses of YLDRED and WP data from 1640 field corn and 138 sweet corn treatments were significant. Nonlinear regression analysis of YLDRED and WP data from all 1374 soybean treatments was significant; however, a linear regression of those 1154 soybean treatments with WP ratings of 30 or less produced a more easily interpreted regression equation.

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Commercial Safened ALS-herbicide Formulation Effects on ALS-sensitive Field Corn Hybrids

cftm ◽

10.2134/cftm2017.03.0019 ◽

2017 ◽

Vol 3 (1) ◽

pp. cftm2017.03.0019

Author(s):

Oliver W. Carter ◽

Eric P. Prostko ◽

Jerry W. Davis

Keyword(s):

Corn Hybrids ◽

Field Corn

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Velvetleaf (Abutilon theophrasti) Effect on Corn (Zea mays) Growth and Yield in South Dakota

Weed Technology ◽

10.1017/s0890037x00024027 ◽

1995 ◽

Vol 9 (4) ◽

pp. 665-668 ◽

Cited By ~ 9

Author(s):

Chad Scholes ◽

Sharon A. Clay ◽

Kalyn Brix-Davis

Keyword(s):

South Dakota ◽

Yield Loss ◽

Maximum Yield ◽

Abutilon Theophrasti ◽

Growth And Yield ◽

Yield Reduction ◽

Corn Yield ◽

Total Biomass ◽

Area Index ◽

Large Yield

Studies were conducted at two sites in South Dakota in 1992 and at one site in 1993 to measure the effect of velvetleaf on corn growth and yield. Velvetleaf was overseeded in corn rows and thinned to densities of 0, 1.3, 4, 12, and 24 plants/m2. Velvetleaf leaf area index and total biomass were positively correlated with velvetleaf density. Biomass per velvetleaf plant and corn biomass were correlated negatively with velvetleaf density. The percent corn yield reduction was similar for locations and years in spite of large yield differences. Maximum yield loss estimated by a hyperbolic yield reduction model was 37.2% with a loss of 4.4% per unit velvetleaf density.

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Evaluation of Postemergence Weed Control Strategies in Herbicide-Resistant Isolines of Corn (Zea mays)

Weed Technology ◽

10.1614/wt-04-253r1.1 ◽

2006 ◽

Vol 20 (1) ◽

pp. 172-178 ◽

Cited By ~ 7

Author(s):

Karen A. Zuver ◽

Mark L. Bernards ◽

James J. Kells ◽

Christy L. Sprague ◽

Case R. Medlin ◽

...

Keyword(s):

Weed Control ◽

Control Strategies ◽

Post Treatment ◽

Growth And Yield ◽

Yield Potential ◽

Corn Yield ◽

Corn Hybrids ◽

Herbicide Resistant ◽

Giant Ragweed ◽

Pre Treatment

Herbicide-resistant corn hybrids offer additional options for POST weed control in corn, and growers may benefit from information on the consistency of these weed-control strategies. Studies were conducted in Indiana, Illinois, Michigan, and Ohio, in 2000 and 2001, to evaluate weed control among herbicide strategies for imidazolinone-resistant, glufosinate-resistant, glyphosate-resistant, and conventional corn. Isogenic hybrids were utilized to minimize variation in growth and yield potential among hybrids. The glyphosate-resistant corn postemergence (glyphosate-POST) treatment provided more consistent control of giant foxtail than the PRE, conventional corn postemergence (conventional-POST), glufosinate-resistant corn postemergence (glufosinate-POST), and imidazolinone-resistant corn postemergence (imi-POST) treatments. All four POST treatments were more consistent and provided greater control than the PRE treatment of the large-seeded broadleaf weeds velvetleaf, giant ragweed, common cocklebur, and morningglory species. Conventional-POST and imi-POST were more consistent than glufosinate-POST and glyphosate-POST treatments in controlling giant ragweed. There were no statistical differences in the variability of PRE or POST treatments for control of common lambsquarters, common ragweed, and redroot pigweed. Corn yield varied among locations and years. The glyphosate-POST treatment did not reduce yield relative to the weed-free treatment, the imi-POST and glufosinate-POST treatments each reduced yield in one of eight locations, and the conventional-POST treatment reduced yield in three of eight locations.

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Effect of Cowpea severe mosaic virus on Crop Growth Characteristics and Yield of Cowpea

Plant Disease ◽

10.1094/pd-89-0515 ◽

2005 ◽

Vol 89 (5) ◽

pp. 515-520 ◽

Cited By ~ 9

Author(s):

H. M. Booker ◽

P. Umaharan ◽

C. R. McDavid

Keyword(s):

Mosaic Virus ◽

Leaf Area ◽

Growth Phase ◽

Field Experiments ◽

Yield Loss ◽

Crop Growth ◽

Growth And Yield ◽

Exponential Growth Phase ◽

Area Index ◽

The Impact

Field experiments were carried out in St. Augustine, Trinidad & Tobago, West Indies to determine the effects of time of inoculation of Cowpea severe mosaic virus (CPSMV) and cultivar on crop growth and yield in cowpea (Vigna unguiculata). Crop growth and yield loss were investigated through growth analysis and yield component analysis on three cultivars in two seasons (wet and dry). Time of inoculation had the most profound impact on yield. Inoculations during the early log phase (seedling stage), 12 days after seeding (DAS), consistently had the greatest impact (50 to 85% yield loss) compared with those inoculated during the exponential growth phase (24 DAS; 22 to 66% yield loss) or linear growth phase (35 DAS; 2 to 36% yield loss). The effects were particularly pronounced in the dry season and in the more determinate cultivar, H8-8-27. Reduction in maximum leaf area index, leaf area duration, or maximum vegetative dry matter explained reductions in yield. Yield reductions resulted primarily from reduced pod number per plant and, to a lesser extent, from reduced average pod dry weight. The results show that CPSMV control measures should be aimed at delaying infection by CPSMV to minimize the impact on cowpea yield.

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Cotton Growth and Yield Response to Simulated 2,4-D and Dicamba Drift

Weed Technology ◽

10.1614/wt-08-061.1 ◽

2009 ◽

Vol 23 (4) ◽

pp. 503-506 ◽

Cited By ~ 37

Author(s):

John D. Everitt ◽

J. Wayne Keeling

Keyword(s):

Good Predictor ◽

Field Experiments ◽

Yield Loss ◽

Lint Yield ◽

Growth And Yield ◽

Yield Response ◽

Growth Stages ◽

Cotton Lint ◽

Late Season ◽

Crop Injury

Field experiments were conducted in Hale Co., TX, in 2005 and 2006 to determine the effects of 2,4-D amine and dicamba applied at varying rates and growth stages on cotton growth and yield, and to correlate cotton injury levels and lint yield reductions. Dicamba or 2,4-D amine was applied at four growth stages including cotyledon to two-leaf, four- to five-leaf, pinhead square, and early bloom. Dicamba and 2,4-D amine were applied at 1/2, 1/20, 1/200, and 1/2000 of the recommended use rate. Crop injury was recorded at 14 days after treatments and late-season, and cotton lint yields were determined. Across all growth stages, 2,4-D caused more crop injury and yield loss than dicamba. Cotton lint was reduced more by later applications (especially pinhead square) and injury underestimated yield loss with 2,4-D. Visual estimates of injury overestimated yield loss when 2,4-D or dicamba was applied early (cotyledon to two leaf) and was not a good predictor of yield loss.

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Southern Root-Knot Nematode (Meloidogyne incognita) Affects Common Cocklebur (Xanthium strumarium) Interference with Cotton

Weed Science ◽

10.1614/ws-06-182.1 ◽

2007 ◽

Vol 55 (2) ◽

pp. 143-146 ◽

Cited By ~ 2

Author(s):

Theodore M. Webster ◽

Richard F. Davis

Keyword(s):

Yield Loss ◽

Plant Biomass ◽

Maximum Yield ◽

Growth And Yield ◽

Xanthium Strumarium ◽

Cotton Yield ◽

Root Knot Nematode ◽

Cotton Plants ◽

Southern Root Knot Nematode ◽

The Relationship

Southern Root-Knot nematode and common cocklebur interfere with cotton growth and yield. A greater understanding of the interaction of these pests with cotton growth and yield is needed for effective integrated pest management (IPM). An additive design was used in outdoor microplots with five common cocklebur densities (0, 1, 2, 4, and 8 plants per plot) growing in competition with cotton, with and without the presence of southern Root-Knot nematode. Differences in cotton height could not be detected among common cocklebur densities or nematode presence at 3 wk after transplanting (WAT); however, differences in crop height were observed at 5 WAT between nematode treatments. In the absence of nematodes, the relationship between cotton yield loss and common cocklebur density was described by a rectangular hyperbolic regression model (P < 0.0001). Maximum yield loss from common cocklebur in the absence of nematodes exceeded 80%. In the presence of nematodes, there was a linear relationship between cotton yield loss and common cocklebur density (P = 0.0506). The presence of nematodes at each common cocklebur density increased cotton yield loss 15 to 35%. Common cocklebur plant biomass was 25% greater in nematode treatments, likely because of the reduced competitiveness of the cotton plants in these plots. This study demonstrates that multiple pests can interact to cause an additive reduction in crop yield.

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Disease Severity and Yield of Sweet Corn Hybrids with Resistance to Northern Leaf Blight

Plant Disease ◽

10.1094/pdis.1998.82.1.57 ◽

1998 ◽

Vol 82 (1) ◽

pp. 57-63 ◽

Cited By ~ 14

Author(s):

J. K. Pataky ◽

R. N. Raid ◽

L. J. du Toit ◽

T. J. Schueneman

Keyword(s):

Disease Severity ◽

Partial Resistance ◽

Yield Loss ◽

Sweet Corn ◽

Correlation Coefficients ◽

Inbred Lines ◽

Leaf Blight ◽

Northern Leaf Blight ◽

Corn Hybrids ◽

Highly Correlated

Reactions of supersweet (sh2) sweet corn to northern leaf blight (NLB) and associated yields were evaluated in Belle Glade, Florida and Urbana, Illinois in yield-loss trials, hybrid evaluations, and evaluations of breeding materials. Hybrids differed significantly for NLB in all trials. Severity of NLB ranged from 0 to 66% on 35 sh2 hybrids in yield-loss trials, and from 0 to 60% on 80 sh2 hybrids in hybrid evaluations. NLB ratings ranged from 1 to 9 (approximately 0 to 80% severity) on 375 hybrids and 186 inbred lines in evaluations of breeding materials. Various methods of rating NLB and ratings from multiple dates were highly correlated, with correlation coefficients ranging from 0.76 to 0.98. Yield, measured as weight of ears and number of marketable ears from inoculated plots as a percentage of that from control plots, decreased as disease severity increased. Linear or quadratic regression models explained 31 to 70% of the variation in percent yield as a function of disease severity at harvest. The effects of NLB on yield were limited by NLB-resistance in several hybrids, including CCO 3268, Chieftain, Crisp N Sweet 710A, Day Star, Envy, Forever, GSS 1526, Jupiter, Midship, Prime Plus, Sch 5005, and SummerSweet 7630. Although high levels of partial resistance to NLB were prevalent among 375 new experimental sh2 hybrids and 186 sh2 inbred lines evaluated in 1995, use of the gene HtN may increase in the near future as breeders are incorporating this resistance into new inbreds and hybrids. Breeders and plant pathologists would be wise to continue improving partial resistance to NLB without using the gene HtN in genotypes with adequate levels of partial resistance, because the widespread use of the gene HtN will select for virulent races of Exserohilum turcicum which occur in Florida, or for races with new combinations of virulence.

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