Germinação de sementes de Conyza canadensis e Conyza bonariensis em diferentes condições de temperatura e luminosidade

Yamashita, Oscar Mitsuo; Guimarães, Sebastião Carneiro

doi:10.1590/s0100-83582011000200011

Cited by 7 publications

(3 citation statements)

References 22 publications

(26 reference statements)

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“…Environmental conditions such as light, temperature and water potential in the soil are the main environmental factors that regulate seed germination and seedling emergence. For C. canadensis (Nandula et al ., ; Vidal et al ., ) and for C. bonariensis (Vidal et al ., ; Yamashita & Guimarães, ; Zambrano‐Navea et al ., ), the optimum temperature for germination is between 20 and 25°C. These environmental conditions are common throughout the year in temperate regions of the world; thus, the Conyza spp.…”

Section: Introductionmentioning

confidence: 99%

Impact of Conyza bonariensis density and establishment period on soyabean grain yield, yield components and economic threshold

et al. 2014

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Conyza spp. have become a major weed around the world, mainly because of weed resistance issues. The objective of this work was to test the hypothesis that the soyabean crop yield is dependent on the density of Conyza bonariensis and on the timing of weed establishment in relation to the crop sowing date. It was also theorised that these variables affect soyabean crop yield components and the economic threshold of C. bonariensis on soyabean. Field experiments were conducted during 2010 and 2011 using a randomised complete block design. In each experiment, several densities (0, 3, 6, 12, 24, 48, 96 and 192 plants m À2 ) of C. bonariensis were established in soyabean fields. Conyza bonariensis establishment dates varied considerably between the experiments [81, 38 and 0 days before soyabean sowing (DBSS)]. Conyza bonariensis plants were first cultivated in a glasshouse and then transplanted to the field at the three-leaf growth stage. At the lower densities, each C. bonariensis plant decreased soyabean yield by 36%, 12% and 1.0%, when established at 81, 38 and 0 DBSS respectively. The economic thresholds based on sensitivity analysis were below 0.5 plant m À2 when C. bonariensis was introduced at 81 and 38 DBSS; in contrast, they were between 2 and 4 plants m À2 when the weed was established at the crop sowing time. The results emphasise the importance of proper C. bonariensis management prior to soyabean sowing and highlight the need for residual herbicides to avoid grain yield losses.

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Section: Introductionmentioning

confidence: 99%

Impact of Conyza bonariensis density and establishment period on soyabean grain yield, yield components and economic threshold

et al. 2014

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“…Among the weed management, crop rotation is an alternative to the reduction of the plant density, since it facilitates the herbicides rotation. Covering plants or predecessor crops have a potential for reduction on germination and development of the hairy fleabane, since they are positive photoblastic seeds (VIDAL et al, 2007;YAMASHITA;GUIMARÃES, 2011). The cultivation of wheat and black oats are important alternatives for reducing the hairy fleabane density, as well as reducing plant height (PAULA et al, 2011).…”

Section: Resultsmentioning

confidence: 99%

Soybean yield loss and economic thresholds due to glyphosate resistant hairy fleabane interference

2018

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The interference of glyphosate resistant hairy fleabane (Conyza bonariensis) has caused yield losses in soybean crop. Knowledge of the economic threshold is an important aspect for the economic management of resistant weeds. Because of it, the interference of the glyphosate resistant hairy fleabane density on the soybean yield loss was evaluated, as well as to estimate the economic threshold. Two experiments were conducted to verify the effect of different weed densities on the yield of two soybean cultivars (BRS Estância and BMX Turbo). Weed density ranged from 0 to 124 plants m-2. The yield of the BRS Estância decreased by 1.4% to the increase of one single plant, while for the BMX Turbo the loss was 25.9%. Soybean yield and economic threshold were lower for the BMX Turbo cultivar compared to the cultivar BRS Estância, which can be attributed to the genotype, competitive ability, weed development stage and/or environment. Increases in crop yield expectation, soybean price and herbicide efficiency reduce the economic threshold, indicating that the adoption of control measures should be taken when the weed density is low. Due to the high cost of hairy fleabane control, it is only feasible at high densities.

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“…Abundance of two distinct ruderal species, Conyza canadensis and C. bonariensis (Yamashita & Guimaraes ), reached a peak in the reforested sites in the second year after the fire. Although these two ruderals are common on roadsides and agricultural fields, their cover was little affected by MSP and they could not be observed after a year.…”

Section: Discussionmentioning

confidence: 99%

Post‐fire regeneration inMediterranean reforested sites as affected by mechanical site preparation: lessons for restoration

Hibsher

Moshe

Bney-Moshe

et al. 2013

Applied Vegetation Science

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Question The importance of silvicultural site preparation techniques in determining vegetation succession is increasingly recognized. We studied the effects of mechanical site preparation (MSP) on post‐fire vegetation regeneration within reforested sites in Mediterranean Israel. Location Upper Galilee region, Israel. Methods Vegetation cover and composition, ruderal species colonization and pine regeneration were monitored in four reforested sites for 3 yr following wildland fires that burned mature Pinus brutia and P. halepensis plantations. In each reforested site, a 50 m × 50 m monitoring area was assigned and measurements were conducted within five subplots (2 m × 50 m) encompassing three MSP patch types: ploughed patches (P), unploughed patches (UP) and planting mounds (M) that combined ploughing, pit digging and wood‐chip mulching. Results Recovery of vegetation cover (excluding pines) was rapid. The MSP patch type significantly affected vegetation cover in the first spring following the fire: cover was lowest on M, intermediate on P and highest on UP. However, these differences became minor by the third spring following the fire. Total woody species richness was not affected by MSP patch type, although there were minor effects on relative abundance of woody species. Two ruderal species were found, but their abundance became untraceable by the third year. Patterns of MSP effects on pine regeneration were similar for P. halepensis and P. brutia. Density of emerging seedlings of both pine species during the first year following the fire was significantly affected by MSP patch type: lower in P and M than in UP by more than 50% and 90%, respectively. However, emergence and/or survival during the following 2 yr was higher in P and M than in UP, with overall outcome of pine regeneration still about 50% lower in P and M than in UP. Conclusions The MSP treatments had only a minor, short‐term effect on post‐fire regeneration and colonization of vegetation, except for pine recruitment, which was more severely affected.

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Germinação de sementes de Conyza canadensis e Conyza bonariensis em diferentes condições de temperatura e luminosidade

Cited by 7 publications

References 22 publications

Impact of Conyza bonariensis density and establishment period on soyabean grain yield, yield components and economic threshold

Impact of Conyza bonariensis density and establishment period on soyabean grain yield, yield components and economic threshold

Soybean yield loss and economic thresholds due to glyphosate resistant hairy fleabane interference

Post‐fire regeneration inMediterranean reforested sites as affected by mechanical site preparation: lessons for restoration

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