Economic evaluation of seeding decisions in hybrid and open-pollinated herbicide-resistant canola (Brassica napus)

2005 ◽  
Vol 85 (4) ◽  
pp. 761-769 ◽  
Author(s):  
B. M. Upadhyay ◽  
E. G. Smith ◽  
G. W. Clayton ◽  
K. N. Harker ◽  
J. T. O’Donovan ◽  
...  
Keyword(s):  
Brassica Napus ◽  
Plant Density ◽  
Western Canada ◽  
Net Return ◽  
Herbicide Resistant ◽  
Net Returns ◽  
Late Fall ◽  
Wide Range ◽  
Early Fall ◽  
Canada Data

Herbicide-resistant canola (Brassica napus) is widely cultivated in western Canada. Data from a multi-year field experiment conducted at three locations in Alberta were used to investigate the effect of canola cultivar, time of seeding, polymer seed coating (PSC) on profitability and the net return risk. Cultivars included hybrid and open pollinated. Time of seeding was early and late fall, and early and normal spring. The hybrid canola generally had higher mean net return than the open-pollinated cultivar. The probability of thin canola stand was higher for fall dormant seeding compared with spring seeding. The use of PSC for early fall dormant seeding reduced the likelihood of thin canola stand, which translated into risk-efficient decision. However, PSC use for late fall seeding had mixed results. Early and normal spring seeding was generally risk-efficient at all locations. In exceptional cases, net returns from late fall dormant seeding (with or without PSC) were similar to that of spring seeding. Re-seeding of fall seeded canola in the spring could be beneficial, if the plant density was below 20 plant m-2. Seeding decisions were robust across a wide range of canola prices, based on the probability of negative net returns. Key words: Canola, fall seeding, net returns, polymer seed coat, re-seeding, risk

Polymer seed coating of early- and late-fall-seeded herbicide-tolerant canola (Brassica napus L.) cultivars

2004 ◽  
Vol 84 (4) ◽  
pp. 971-979 ◽  
Author(s):  
G. W. Clayton ◽  
K. N. Harker ◽  
J. T. O’Donovan ◽  
R. E. Blackshaw ◽  
L. Dosdall ◽  
...  
Keyword(s):  
Brassica Napus ◽  
Seed Coat ◽  
Plant Density ◽  
Soil Conditions ◽  
Seed Coating ◽  
Brassica Napus L ◽  
Late Fall ◽  
Seeding Date ◽  
Herbicide Tolerant ◽  
Early Fall

Polymer seed coatings offer an opportunity to fall seed Brassica napus earlier in October, thus avoiding difficult seeding conditions (wet/frozen soils) common in late October or early November. A multi-year field experiment was conducted at four locations in Alberta, Canada, to investigate the effect of early (mid-October) and late fall (late October-early November) canola seeding with and without a germination-inhibiting polymer seed coat. Yield and yield components were determined in glufosinate (hybrid and open-pollinated), glyphosate (open-pollinated), and imidazolinone (open-pollinated) herbicidetolerant canola cultivars. Early-seeded canola without the polymer coat had a reduced plant density of 58% compared to late-fall-seeded canola. Application of the polymer coat on early-seeded canola increased plant density by 80% compared to uncoated seed. Seed yield and dockage were not affected by seeding date when a polymer seed coating was used. Without the polymer seed coat, canola yield was reduced 42% and dockage increased 6% when seeding occurred in early vs. late fall. Increased pod production from early-fall-seeded uncoated canola compared to other seeding dates could only partially compensate for canola yield. Cultivar interactions generally were not agronomically important. The use of polymer seed coatings with all these herbicide-tolerant cultivars will allow producers to seed earlier in fall, rather than waiting for cooler soil conditions in late fall. Key words: Canola (Brassica napus L.), dormant seeding, polymer seed coating

Estimating the economic optimal target density of hybrid canola based on data from a western Canadian meta-analysis

2020 ◽  
Author(s):  
Murray D. Hartman ◽  
Scott R. Jeffrey
Keyword(s):  
Plant Density ◽  
Meta Analysis ◽  
Yield Response ◽  
Western Canada ◽  
Seeding Rate ◽  
Optimal Density ◽  
Herbicide Resistant ◽  
Plant Densities ◽  
Optimal Target ◽  
The Relationship

Canola production in western Canada has expanded such that in many regions canola area rivals the area seeded to wheat. This change can be mainly attributed to adoption of herbicide resistant hybrid varieties, and resulting higher relative profitability. Producers responded to higher seed prices by reducing seeding rates, leading to plant densities that were often lower than industry recommendations. The study objectives were to examine canola yield response to plant density and assess economically optimal density levels relative to industry recommendations and grower practices. A meta-analysis approach was applied to yield response and plant density data with herbicide resistant hybrid canola from multiple studies. Three alternative marginal yield-density functions were estimated and used to calculate economically optimal plant density. Sensitivity of results to key parameters was assessed. Resulting optimal density levels under recent average prices, seed size and emergence were 62-73 plants m-2, consistent with industry recommendations for western Canada. Recent field surveys report lower densities than this range, suggesting that producers are seeding at less than optimal rates. However, there is significant uncertainty associated with canola production, and interaction of seeding rate with other factors. These would impact on optimal plant density, although much of the uncertainty remains until well after seeding. The empirical results represent a foundation for development of more detailed models, highlight the significance of the relationship between plant density and economically optimal yield, and suggest the need to develop decision making tools to support producers in making canola planting decisions.

Comparison of a Glyphosate-Resistant Canola (Brassica napusL.) System with Traditional Herbicide Regimes

2006 ◽  
Vol 20 (2) ◽  
pp. 494-501 ◽  
Author(s):  
John T. O'Donovan ◽  
K. Neil Harker ◽  
George W. Clayton ◽  
Robert E. Blackshaw
Keyword(s):  
Weed Control ◽  
Active Ingredient ◽  
Field Experiments ◽  
The Other ◽  
Western Canada ◽  
Net Return ◽  
Herbicide Resistant ◽  
Resistant Cultivars

Herbicide-resistant cultivars account for over 90% of the canola grown in western Canada and cultivars resistant to glyphosate dominate the market. Field experiments were conducted at three locations in Alberta to compare the glyphosate system with more traditional herbicide regimes. Glyphosate applied before seeding in spring resulted in better weed control, lower dockage, and higher canola yield and net return than 2,4-D applied in the fall. Glyphosate applied once (two- to four-leaf canola) or twice (two- to four-leaf followed by five- to six-leaf canola) in-crop provided similar weed control, dockage, and canola yield as ethalfluralin applied PRE in the fall followed by an in-crop mixture of sethoxydim, ethametsulfuron, and clopyralid; and superior weed control and canola yield and lower dockage than ethalfluralin alone or an in-crop mixture of sethoxydim and ethametsulfuron. The in-crop glyphosate applications resulted in higher net revenues than the other treatments. There was little or no advantage to applying glyphosate twice compared with once in-crop. The amount of active ingredient entering the environment varied with the herbicide regime but was lower with the glyphosate system than with most of the traditional regimes, especially when glyphosate was applied only once in-crop.

THE FINANCIAL RETURN OF CEREAL FARMING FOR SMALLHOLDER FARMERS IN THE CENTRAL HIGHLANDS OF ETHIOPIA

2009 ◽  
Vol 46 (2) ◽  
pp. 137-153 ◽  
Author(s):  
LALISA ALEMAYEHU DUGUMA ◽  
IKA DARNHOFER ◽  
HERBERT HAGER
Keyword(s):  
Smallholder Farmers ◽  
Labour Productivity ◽  
Important Variable ◽  
Farm Size ◽  
Financial Return ◽  
Net Return ◽  
Net Returns ◽  
The Poor ◽  
Central Highlands ◽  
The Rich

SUMMARYA study was conducted in Suba area, central highlands of Ethiopia, to assess the net return, land and labour productivity, and the return to scale of cereal farming practice. Seventy-five farmers belonging to three local wealth classes (poor, medium and rich) were randomly selected and interviewed about inputs and outputs related to cereal farming for the production year 2007/2008. Farm soil properties were investigated to check the variability in soil quality among the wealth classes. Benefit:cost ratio (BCR), net returns and annual profit were used to indicate the worthiness of the cereal farming activity. The return to scale was estimated by using the Cobb–Douglas production function. The results show that cereal farming is a rewarding practice, with the rich households gaining more profit than the poor. Farm size was the most important variable that affects the net return. There is an increasing return to scale. However, it is unlikely that farmers will have more land than they own at present because of the land shortage problem in the country caused by the increasing human population. Thus, attention should be given to minimizing the costs of production through proper regulation of domestic fertilizer costs and increasing labour productivity especially for the poor and medium households. The use of manure and compost as an additional fertilizer should also be promoted.

Canola seed yield and phenological responses to plant density

2016 ◽  
Vol 96 (1) ◽  
pp. 151-159 ◽  
Author(s):  
Gan Yantai ◽  
K. Neil Harker ◽  
H. Randy Kutcher ◽  
Robert H. Gulden ◽  
Byron Irvine ◽  
...  
Keyword(s):  
Seed Yield ◽  
Plant Density ◽  
Block Design ◽  
Positive Association ◽  
High Yield ◽  
Western Canada ◽  
Flowering Period ◽  
Canola Seed ◽  
Randomized Complete Block Design ◽  
Plant Densities

Optimal plant density is required to improve plant phenological traits and maximize seed yield in field crops. In this study, we determined the effect of plant density on duration of flowering, post-flowering phase, and seed yield of canola in diverse environments. The field study was conducted at 16 site-years across the major canola growing area of western Canada from 2010 to 2012. The cultivar InVigor® 5440, a glufosinate-resistant hybrid, was grown at five plant densities (20, 40, 60, 80, and 100 plants m−2) in a randomized complete block design with four replicates. Canola seed yield had a linear relationship with plant density at 8 of the 16 site-years, a quadratic relationship at 4 site-years, and there was no correlation between the two variables in the remaining 4 site-years. At site-years with low to medium productivity, canola seed yield increased by 10.2 to 14.7 kg ha−1 for every additional plant per square metre. Averaged across the 16 diverse environments, canola plants spent an average of 22% of their life cycle flowering and another 27% of the time filling seed post-flowering. Canola seed yield had a negative association with duration of flowering and a positive association with the days post-flowering but was not associated with number of days to maturity. The post-flowering period was 12.7, 14.7, and 12.6 d (or 55, 68, and 58%) longer in high-yield experiments than in low-yield experiments in 2010, 2011, and 2012, respectively. We conclude that optimization of plant density for canola seed yield varies with environment and that a longer post-flowering period is critical for increasing canola yield in western Canada.

scholarly journals Response of Nagpur mandarin (Citrus reticulata Blanco) to high density planting systems

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
M. S. Ladaniya ◽  
R. A. Marathe ◽  
A. A. Murkute ◽  
A. D. Huchche ◽  
A. K. Das ◽  
...  
Keyword(s):  
Plant Density ◽  
High Density ◽  
Citrus Reticulata ◽  
Plant Canopy ◽  
Area Index ◽  
Rangpur Lime ◽  
Net Returns ◽  
Area Basis ◽  
Crop Harvest ◽  
Major Nutrients

AbstractHigh density planting system i.e. accommodating a higher number of plants than routine in a given area is an innovative agro-technology to increase yield and thereby early net returns. Due to conventional wide spacing plantation in Nagpur mandarin (Citrus reticulata Blanco), the land remains unutilized as the plant canopy gradually increases over the years. In the present study, Nagpur mandarin (Citrus reticulata Blanco) budded on Rangpur lime rootstock was evaluated under six different planting spacings. It was observed that the organic carbon (1.10–1.82%) and major nutrients viz. N (309–430 kg ha−1), P (20–54 kg ha−1) and K (291–810 kg ha−1) increased vis-à-vis plant density and was highest under 2 × 2 m spacing. Plants were tallest at 2 × 2 m spacing with the higher PAR interception (88.2) and the lowest leaf area index (1.09). Fruit yield on area basis, under 2 × 2 m spacing was 26, 7.1, 4.6 times more as compared to conventional plantation during the first, second and third year, respectively. At fifth year of crop harvest, the highest B:C ratio (6.36) was recorded in 6 × 3 m followed by 4 × 2 m and 2 × 2 m.

scholarly journals Quantifying seed production by volunteer canola (Brassica napus) and Sinapis arvensis

2011 ◽  
Vol 29 (3) ◽  
pp. 489-497
Author(s):  
E Soltani ◽  
A Soltani ◽  
S Galeshi ◽  
F Ghaderi-far ◽  
E Zeinali
Keyword(s):  
Brassica Napus ◽  
Seed Production ◽  
Cropping Systems ◽  
Plant Size ◽  
Quantitative Information ◽  
Sinapis Arvensis ◽  
Soil Seed Banks ◽  
Sowing Dates ◽  
Wide Range ◽  
Close Relationship

Volunteer canola (Brassica napus) and Sinapis arvensis are well identified weeds of different cropping systems. Quantitative information on regarding seed production by them is limited. Such information is necessary to model dynamics of soil seed banks. The aim of this work was to quantify seed production as a function of the size of those weeds. A wide range of plant size was produced by using a fan seeding system performed at two sowing dates (environments). Plant size varied from 3 to 167 g per plant for canola and from 6 to 104 g per plant for S. arvensis. Seed production ranged from 543 to14,773 seeds per plant for canola, and from 264 to 10,336 seeds per plant for S. arvensis. There was a close relationship between seed production per plant and plant size which was well-described by a power function (y = 130.6x0.94; R² = 0.93 for canola and y = 28x1.27; R² = 0.95 for S. arvensis). There was also strong relationships among the number of pods produced in individual plants and the quantity of seeds produced (g per plant) with the size of the plant. The relationships found in this study can be used in dynamic seed bank models of volunteer canola and S. arvensis.

scholarly journals Patterns of tillering and grain production of winter wheat at a wide range of plant densities.

1978 ◽  
Vol 26 (4) ◽  
pp. 383-398 ◽  
Author(s):  
A. Darwinkel
Keyword(s):  
Winter Wheat ◽  
Grain Yield ◽  
Harvest Index ◽  
Plant Density ◽  
Fold Increase ◽  
Grain Production ◽  
Higher Plant ◽  
Grain Number ◽  
Wide Range ◽  
Plant Densities

The effect of plant density on the growth and productivity of the various ear-bearing stems of winter wheat was studied in detail to obtain information on the pattern of grain production of crops grown under field conditions. Strong compensation effects were measured: a 160-fold increase in plant density (5-800 plants/m2) finally resulted in a 3-fold increase in grain yield (282 to 850 g DM/m2). Max. grain yield was achieved at 100 plants/m2, which corresponded to 430 ears/m2 and to about 19 000 grains/m2. At higher plant densities more ears and more grains were produced, but grain yield remained constant. Tillering/plant was largely favoured by low plant densities because these allowed tiller formation to continue for a longer period and a greater proportion of tillers produced ears. However, at higher plant densities more tillers/unit area were formed and, despite a higher mortality, more ears were produced. The productivity of individual ears, from main stems as well as from tillers, decreased with increasing plant density and with later emergence of shoots. In the range from 5 to 800 plants/m2 grain yield/ear decreased from 2.40 to 1.14 g DM. At 800 plants/m2 nearly all ears originated from main stems, but with decreasing plant density tillers contributed increasingly to the number of ears. At 5 plants/m2, there were 23 ears/plant and grain yield/ear ranged from 4.20 (main stem) to 1.86 g DM (late-formed stems). Grain number/ear was reduced at higher densities and on younger stems, because there were fewer fertile spikelets and fewer grains in these spikelets. At the low density of 5 plants/m2, plants developed solitarily and grain yield/ear was determined by the number of grains/ear as well as by grain wt. Above 400 ears/m2, in this experiment reached at 100 plants/m2 and more, grain yield/ear depended solely on grain number, because the wt. of grains of the various stems were similar. The harvest index showed a max. of about 44% at a moderate plant density; at this density nearly max. grain yield was achieved. At low plant densities the harvest index decreased from 45% in main stems to about 36% in late-formed stems. However, no differences in harvest index existed between the various ear-bearing stems if the number of ears exceeded 400/m2. (Abstract retrieved from CAB Abstracts by CABI’s permission)

scholarly journals Effects of cis-Jasmone Treatment of Brassicas on Interactions With Myzus persicae Aphids and Their Parasitoid Diaeretiella rapae

2021 ◽  
Vol 12 ◽  
Author(s):  
Jamin Ali ◽  
Anca D. Covaci ◽  
Joe M. Roberts ◽  
Islam S. Sobhy ◽  
William D. J. Kirk ◽  
...  
Keyword(s):  
Brassica Napus ◽  
Myzus Persicae ◽  
Methyl Salicylate ◽  
Plant Defence ◽  
Diaeretiella Rapae ◽  
Methyl Isothiocyanate ◽  
Volatile Emission ◽  
Brassica Crops ◽  
Wide Range ◽  
Promising Treatment

There is a need to develop new ways of protecting plants against aphid attack. Here, we investigated the effect of a plant defence activator, cis-jasmone (CJ), in a range of cultivars of Brassica napus, Brassica rapa and Brassica oleracea. Plants were sprayed with cis-jasmone or blank formulation and then tested with peach potato aphids (Myzus persicae Sulzer) (Hemiptera: Aphididae) and their parasitoid Diaeretiella rapae (M'Intosh) (Hymenoptera: Braconidae). CJ treated plants had significantly lower aphid settlement than control plants in a settlement bioassay. Conversely, in a foraging bioassay, D. rapae parasitoids spent a significantly longer time foraging on CJ treated plants. Our results reveal that CJ treatment makes plants less attractive to and less suitable for M. persicae but more attractive to D. rapae in a range of brassica cultivars. It is likely that these effects are due to changes in volatile emission indicating activation of defence and presence of conspecific competitors to aphids but presence of prey to parasitoids. Increases in volatile emission were found in CJ induced plants but varied with genotype. Among the synthetic volatile compounds that were induced in the headspace of CJ treated brassica cultivars, methyl isothiocyanate, methyl salicylate and cis-jasmone were most repellent to aphids. These results build on earlier studies in Arabidopsis and show that tritrophic interactions are influenced by CJ in a wide range of brassica germplasm. The implication is that CJ is a promising treatment that could be used in brassica crops as part of an integrated pest management system.

Conquest summer rape

2001 ◽  
Vol 81 (1) ◽  
pp. 107-108
Author(s):  
G. R. Stringam ◽  
D. F. Degenhardt ◽  
M. R. Thiagarajah ◽  
V. K. Bansal
Keyword(s):  
Brassica Napus ◽  
Seed Yield ◽  
Oil Content ◽  
Western Canada ◽  
Blackleg Disease ◽  
Lodging Resistance ◽  
Roundup Ready ◽  
Cultivar Description ◽  
Canola Quality ◽  
High Seed Yield

Conquest is a Roundup-ready canola quality Brassica napus cultivar adapted to the canola-growing areas in western Canada. It has high seed yield, high oil content, good lodging resistance, excellent resistance to blackleg disease, and is superior in all these traits to the average of AC Excel, Defender and Legacy. Key words: Rape (summer), cultivar description, yield, blackleg resistant, Roundup Ready, lodging resistant

Sign in / Sign up

Export Citation Format

Share Document