Effect on scald (Rhynchosporium secalis (Oud.) J. Davis) infection on yield response of Stirling barley to various sowing rates

1988 ◽  
Vol 28 (2) ◽  
pp. 263 ◽  
Author(s):  
TN Khan
Keyword(s):  
Yield Loss ◽  
Plant Density ◽  
Grain Weight ◽  
Yield Response ◽  
Rhynchosporium Secalis ◽  
Yield Losses ◽  
Significant Yield

The effect of a range of sowing rates on scald infection and yield in barley cv. Stirling was studied to investigate if increased plant density will lead to more ears/m2 and therefore compensate for yield losses due to scald. Increased sowing rate (50 v. 100 kg/ha) did not compensate for yield loss due to scald. However, significant yield increases (3.0 v. 4.0 t/ha) with increased sowing rates (25 v. 125 kg/ha) occurred when scald was controlled. Such yield in creases were accompanied by increases in the number of ears/m2 and number of grains/ha, but decreases in number of grains/ear and 100-grain weight. The severity of scald infection was not affected by sowing rates.

Ethametsulfuron Interactions with Grass Herbicides on Canola (Brassica napus, B. rapa)

1995 ◽  
Vol 9 (1) ◽  
pp. 91-98 ◽  
Author(s):  
K. Neil Harker ◽  
Robert E. Blackshaw ◽  
Ken J. Kirkland
Keyword(s):  
Brassica Napus ◽  
Brassica Rapa ◽  
Field Experiments ◽  
Yield Loss ◽  
Growth And Yield ◽  
Yield Response ◽  
Sulfonylurea Herbicides ◽  
Yield Losses ◽  
Significant Yield ◽  
Injury Potential

Field experiments were conducted from 1986 to 1988 at Lacombe and Lethbridge, Alberta and Scott, Saskatchewan to determine growth and yield response of canola to mixtures of ethametsulfuron with specific grass herbicides. Ethametsulfuron did not usually cause canola injury when mixed with sethoxydim. However, ethametsulfuron mixtures with the following grass herbicides listed in decreasing order of injury potential, often caused canola injury and yield loss: haloxyfop > fluazifop > fluazifop-P > quizalofop > quizalofop-P. Canola yield losses were severe in some experiments, ranging from 59% with quizalofop mixtures to 97% with haloxyfop mixtures; in other experiments, the same mixtures did not cause significant yield losses. ‘Tobin,’ aBrassica rapacultivar, tended to be more susceptible to injury than theB. napuscultivars ‘Pivot’ and ‘Westar.’ Canola injury symptoms were consistent with those expected from sulfonylurea herbicides. Therefore, we suggest that specific grass herbicides differentially impair the ability of canola to metabolize ethametsulfuron to inactive forms.

scholarly journals Response of Sensitive and Resistant Snap Bean Genotypes to Nighttime Ozone Concentration

2020 ◽  
Vol 145 (6) ◽  
pp. 331-339
Author(s):  
Kirsten L. Lloyd ◽  
Donald D. Davis ◽  
Richard P. Marini ◽  
Dennis R. Decoteau
Keyword(s):  
Leaf Age ◽  
Acute Injury ◽  
Yield Response ◽  
Yield Losses ◽  
Foliar Injury ◽  
Snap Bean ◽  
Stirred Tank Reactors ◽  
First Results ◽  
Significant Yield ◽  
The Impact

Effects of nighttime (2000 to 0700 hr) O3 on the pod mass of sensitive (S156) and resistant (R123) snap bean (Phaseolus vulgaris) genotypes were assessed using continuous stirred tank reactors located within a greenhouse. Two concentration-response relationship trials were designed to evaluate yield response to nighttime O3 exposure (10 to 265 ppb) in combination with daytime exposure at background levels (44 and 62 ppb). Three replicated trials tested the impact of nighttime O3 treatment at means of 145, 144, and 145 ppb on yields. In addition, stomatal conductance (gS) measurements documented diurnal variations and assessed the effects of genotype and leaf age. During the concentration-response experiments, pod mass had a significant linear relationship with the nighttime O3 concentration across genotypes. Yield losses of 15% and 50% occurred at nighttime exposure levels of ≈45 and 145 ppb, respectively, for S156, whereas R123 yields decreased by 15% at ≈150 ppb. At low nighttime O3 levels of ≈100 ppb, R123 yields initially increased up to 116% of the treatment that received no added nighttime O3, suggesting a potential hormesis effect for R123, but not for S156. Results from replicated trials revealed significant yield losses in both genotypes following combined day and night exposure, whereas night-only exposure caused significant decreases only for S156. The gS rates ranged from less than 100 mmol·m−2·s−1 in the evening to midday levels more than 1000 mmol·m−2·s−1. At sunrise and sunset, S156 had significantly higher gS rates than R123, suggesting a greater potential O3 flux into leaves. Across genotypes, younger rapidly growing leaves had higher gS rates than mature fully expanded leaves when evaluated at four different times during the day. Although these were long-term trials, gS measurements and observations of foliar injury development suggest that acute injury, occurring at approximately the time of sunrise, also may have contributed to yield losses. To our knowledge, these are the first results to confirm that the relative O3 sensitivity of the S156/R123 genotypes is valid for nighttime exposure.

Influence of Johnsongrass (Sorghum halepense) Density and Period of Competition on Cotton Yield

Weed Science ◽  
1987 ◽  
Vol 35 (1) ◽  
pp. 63-67 ◽  
Author(s):  
David C. Bridges ◽  
James M. Chandler
Keyword(s):  
Yield Loss ◽  
Sorghum Halepense ◽  
Yield Potential ◽  
Yield Response ◽  
Cotton Yield ◽  
Critical Periods ◽  
East Central ◽  
Central Texas ◽  
Competition Period ◽  
Significant Yield

Research was conducted from 1982 through 1984 on a Shipps clay soil (Udic chromustert) in east-central Texas to determine the density-dependent effects and critical periods of johnsongrass [Sorghum halepense(L.) Pers. # SORHA] competition with cotton (Gossypium hirsutumL.). Two experiments were conducted each year, one to assess cotton yield response to increasing johnsongrass density and the second to establish the johnsongrass-free requirement of cotton and the johnsongrass competition period. A critical minimum density of 2 plants/9.8 m of row was observed. Full-season johnsongrass competition densities exceeding 2 plants/9.8 m of row resulted in seed cotton yield reductions each year. Yield decline was most rapid as density increased from 2 to 8 plants/9.8 m of row. Yield loss averaged 1, 4, 14, 40, 65, and 70% for johnsongrass densities of 1, 2, 4, 8, 16, and 32 plants/9.8 m of row, respectively. Percent yield loss was proportional to yield potential at johnsongrass densities of 4 and 8 plants/9.8 m of row. Three to four weeks of rhizome johnsongrass competition or 6 weeks of seedling johnsongrass competition resulted in significant yield reductions. Maintaining cotton johnsongrass free for 4 weeks did not prevent significant yield reductions.

scholarly journals Density and Time of Emergence of Yellow Nutsedge Affect Squash Yield

HortScience ◽  
2004 ◽  
Vol 39 (4) ◽  
pp. 845D-846
Author(s):  
J. Pablo Morales-Payan* ◽  
William M. Stall
Keyword(s):  
Crop Yield ◽  
Cucurbita Pepo ◽  
Yield Loss ◽  
Cyperus Esculentus ◽  
Yield Losses ◽  
Crop Season ◽  
Yellow Nutsedge ◽  
Live Oak ◽  
Significant Yield ◽  
Direct Seeded

A field experiment was conducted in Live Oak, Fla., to determine the effect of yellow nutsedge (Cyperus esculentus L.) (YN) density and time of emergence on the yield of direct-seeded squash (Cucurbita pepo L.). YN densities (0, 20, 40, 60, and 100 plants/m2) were established from tubers planted at different times onto polyethylene-mulched beds, so that YN would emerge the same day as the crop or 5, 15, or 25 days later than the crop (DLTC). YN was not controlled after its emergence. The extent of squash yield loss was affected by YN density and time of emergence. When YN emerged the same day as the crop, the yield of squash was reduced by ≈7% (20 YN/m2) to 20% (100 YN/m2). When YN emerged 15 DLTC, crop yield loss was ≈13% at the density of 100 YN/m2>. Regardless of density, YN emerging 25 DLTC did not significantly reduce crop yield as compared to weed-free squash. Thus, in soils with high YN densities (≈100 viable tubers/m2) herbicides and/or other means of YN suppression in squash should be effective for at least 25 days after crop emergence to prevent significant yield loss. If squash yield losses <5% were acceptable, YN control may not be necessary when densities <20 YN/m2 emerge at any time during the squash season or when <100 YN/m2 emerge >25 DLTC. However, YN emerging during the first 15 days of the squash season may produce tubers, which could increase the YN population at the beginning of the following crop season.

Lettuce big-vein disease: sources, patterns of spread, and losses

2004 ◽  
Vol 55 (2) ◽  
pp. 125 ◽  
Author(s):  
L. J. Latham ◽  
R. A. C. Jones ◽  
S. J. McKirdy
Keyword(s):  
Weight Loss ◽  
Yield Loss ◽  
Yield Losses ◽  
Fresh Weight ◽  
Straight Line ◽  
Sigmoid Curve ◽  
History Of ◽  
Significant Yield ◽  
Vein Disease ◽  
Leaf Symptoms

Most batches of lettuce seedlings taken over an 18-month period from a vegetable nursery were infested with lettuce big-vein disease (LBVD) with an up to 31% incidence. Using lettuce seedlings in bait tests, contamination was detected at the nursery in potting mix composted for different periods and in dirt from under the benches, and at the bark supplier's site in this ingredient of the potting mix and waste 'bark' from the ground. In a field experiment in which lettuce seedlings from the infested nursery were inoculated with infested roots or left uninoculated before transplanting into subplots on land with no history of lettuce planting, disease progress followed a sigmoid curve with the former but an almost straight line with the latter. However, significant clustering of symptomatic plants was found only in the subplot with the uninoculated plants. Leaf symptoms of LBVD were more severe in lettuces infested later, whereas symptoms in those infested earlier were obvious initially but then became milder. The disease impaired formation of hearts: the proportion of symptomatic plants that lacked hearts was 24–36% when leaf symptoms first appeared 5–7 weeks after transplanting, but 14–16% after 8–9 weeks. When leaf symptoms first appeared at 5–6 weeks, there was a fresh weight loss of 14–15% for heads (all plants) and 39% for hearts (excluding plants without hearts). When leaf symptoms first appeared 7 weeks after transplanting, there was no significant yield loss for heads and only a 14% loss for hearts. At 8–9 weeks, there were no significant yield losses for heads or hearts.

Commercial generations of Brassica napus cause greater yield loss in Triticum aestivum, than volunteer B. napus generations

2010 ◽  
Vol 90 (5) ◽  
pp. 777-783 ◽  
Author(s):  
N J Seerey ◽  
S J Shirtliffe
Keyword(s):  
Triticum Aestivum ◽  
Brassica Napus ◽  
Generational Differences ◽  
Yield Loss ◽  
Plant Density ◽  
Wheat Yield ◽  
Yield Losses ◽  
Large Area ◽  
Seedling Mortality ◽  
Brassica Napus L

Volunteer canola (Brassica napus L.) has become a common weed in producer fields, due to the large area cropped, and inherent harvest losses. Commonly grown B. napus varieties which segregate in subsequent generations to create volunteers with unknown competitive capabilities are developed by hybrid genetics. The objective of this study was to evaluate the effect of volunteer B. napus variety and generation on competition yield loss in hard red spring wheat (Triticum aestivum L.). Two hybrid and one open-pollinated B. napus varieties with three consecutive generations produced from each variety were grown at varying densities in a wheat stand over 5 site-years. Yield loss depended on the density of B. napus in relation to total plant density. Generational differences in B. napus seedlings resulted in differences in wheat yield losses. Brassica napus densities at maturity provided a more robust model of wheat yield loss, as there were differences in wheat yield losses due to the interaction of generation and variety of B. napus. Commercial seed generations were the most competitive plants, while volunteer generations were less competitive. The amount of yield loss caused by volunteer B. napus was highly variable. The availability of low-priced herbicides, and the competitive ability of volunteer B. napus may allow for economic thresholds concerning weed control to be surpassed at low densities of volunteer B. napus populations. Key words: Competition, hybrid, open-pollinated, volunteer weed, seedling mortality, mature density, seedling density, feral

Comparison of different methods used in calculating the effect of stripe rust on wheat grain yields

2007 ◽  
Vol 55 (1) ◽  
pp. 89-98
Author(s):  
N. Bolat ◽  
F. Altay
Keyword(s):  
Stripe Rust ◽  
Yield Loss ◽  
Agricultural Research ◽  
Yellow Rust ◽  
Yield Reduction ◽  
Yield Losses ◽  
Grain Yields ◽  
Unit Increase ◽  
Significant Yield ◽  
Disease Free

One of the most important diseases of wheat in Turkey is yellow rust. The severe epidemic in the 1997–1998 growing season, which caused significant yield reductions, and the absence of infection at the Hamidiye Substation of the Anatolian Agricultural Research Institute made it possible to calculate the yield losses due to stripe rust. This calculation was based on yield differences between genotypes at infected and disease-free locations using various methods.Using the method suggested by Campbell et al. (1975) the calculated yield loss due to stripe rust varied among genotypes and locations with an overall range of 12.7 to 87.0%.By the second method, entries were divided into five groups according to their Average Coefficients of Infection (ACI) and the yield losses in each group were calculated. Yield reductions when ACI was over 70 reached up to 57.5 % in Regional Yield Trials.In the third method, regression analysis was applied to estimate the effect of ACI on grain yields. A highly significant linear relationship was found between the ACI values of the entries and their grain yields, with an estimate of 21.4 kg/ha yield reduction per unit increase in ACI.

scholarly journals Epidemics and Yield Losses due to Corynespora cassiicola on Cotton

Plant Disease ◽  
2018 ◽  
Vol 102 (12) ◽  
pp. 2494-2499 ◽  
Author(s):  
Kira L. Bowen ◽  
Austin K. Hagan ◽  
Malcolm Pegues ◽  
Jarrod Jones ◽  
H. Brad Miller
Keyword(s):  
Disease Onset ◽  
Yield Response ◽  
Corynespora Cassiicola ◽  
Yield Losses ◽  
Fungicide Application ◽  
Target Spot ◽  
Significant Yield ◽  
Epidemic Development ◽  
Gompertz Growth Model ◽  
Better Than

Target spot, caused by Corynespora cassiicola, has recently emerged as a problematic foliar disease of cotton. This pathogen causes premature defoliation during boll set and maturation that can subsequently impact yield, and on certain cotton cultivars loss can be substantial. This study sought to better understand target spot epidemics and disease-incited yield losses on cotton. In order to establish a range of disease, varying numbers of fungicide applications were made to each of two cotton cultivars in each of four site-years. Target spot intensity was rated over several dates beginning in late July or early August and continuing into September. Yield of seed plus lint (seed cotton) was recorded at harvest. When analyzed across cultivars, a second or third fungicide application increased yield compared with no treatment. Lack of significant yield response with a single fungicide application may have been due to timing of that application which preceded disease onset. The cultivar PhytoGen 499 WRF had consistently greater defoliation than any of the three Deltapine cultivars grown in each site-year. However, yields of both cultivars responded similarly to the fungicide regimes. Yield loss models based on late August defoliation were only predictive at site-years where conditions favored target spot development, i.e., abundant rain and moderate temperatures. Epidemic development fit the Gompertz growth model better than it did a logistic model. Knowledge of the underlying mathematical character of the epidemiology of target spot will prove useful for development of a predictive model for the disease.

scholarly journals Interference of Broadleaf Buttonweed and White-Eye in Soybean

2020 ◽  
Vol 38 ◽  
Author(s):  
F. DIESEL ◽  
M.M. TREZZI ◽  
M. GALLON ◽  
P.H.F. MIZERSKI ◽  
S.C. BATISTEL ◽  
...  
Keyword(s):  
Grain Yield ◽  
Yield Loss ◽  
Block Design ◽  
Grain Weight ◽  
Weed Competition ◽  
Yield Losses ◽  
Weed Species ◽  
Randomized Block Design ◽  
Crop Weed Competition ◽  
1000 Grain Weight

ABSTRACT: Weed species is one of the factors contributing to grain yield losses due to crop-weed competition. Two of the most common weeds of soybean fields in Brazil are from the Rubiaceae family: Borreria latifolia and Richardia brasiliensis. This study aimed to evaluate the effects of B. latifolia and R. brasiliensis on plant development, yield components, and soybean productivity. Two assays were conducted in a randomized block design with four replications, using a two-level factorial design, in which the first factor consisted of the species B. latifolia and R. brasiliensis and the second factor consisted of the densities 0, 2, 4, 6, 8, 10, and 12 plants m-2. Plant height, leaf area and total chlorophyll in the V6 and R5 stages, number of pods per plant, number of grains per pod, 1000-grain weight, and grain yield loss were evaluated in both cultivars. Grain yield of both soybean cultivars was negatively affected by the interference with B. latifolia and R. brasiliensis. The species B. latifolia was more competitive with soybean when compared to R. brasiliensis, causing higher reductions for all variables. Each B. latifolia plant per square meter is able to reduce the yield of soybean by 3 a 4.4%, while each R.brasiliensis plant reduces yield by 2 a 2.6%. For both species, the reduction in soybean yield due to competition was caused by a decrease in the number of pods per plant, number of grains per pod, and 1000-grain weight.

scholarly journals Incidence, yield losses and symptomatology of sclerotinia stem rot (SSR) of Indian mustard (Brassica juncea L.) incited by Sclerotinia sclerotiorum

2021 ◽  
Vol 16 (2) ◽  
pp. 103-108
Author(s):  
Irfan Khan ◽  
Pokhar Rawal ◽  
Roop Singh
Keyword(s):  
Yield Loss ◽  
Disease Incidence ◽  
Indian Mustard ◽  
Disease Outbreak ◽  
Yield Losses ◽  
Sclerotinia Stem Rot ◽  
Mustard Crop ◽  
White Mycelium ◽  
Significant Yield ◽  
Minimum Yield

SSR hamper successful cultivation and causes significant yield losses globally including India. The SSR disease incidence ranged from 3.59 to 18.50 per cent in mustard growing areas of Rajasthan and Bharatpur district having the highest (18.50%) disease incidence. However, the Udaipur district had the lowest (3.59%) disease outbreak. SSR was responsible to cause 18.80 per cent overall yield losses in two consecutive years (Rabi 2016-17 and 2017-18). Highest yield loss (43.82%) was observed from Bharatpur district while minimum yield loss (3.51%) had recorded from Udaipur district. Characteristics symptoms, formation of white mycelium on host stem and development of sclerotia on/inside the stem, of SSR on mustard crop were noted during survey.

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