scholarly journals MANAGEMENT OF GLYPHOSATE-RESISTANT HAIRY FLEABANE AND CONTRIBUTION OF THE PHYSIOLOGICAL POTENTIAL OF SEEDS TO RESISTANCE

2021 ◽  
Vol 34 (1) ◽  
pp. 68-79
Author(s):  
TIAGO EDU KASPARY ◽  
FABIANE PINTO LAMEGO ◽  
CRISTIANO BELLÉ ◽  
ADALIN CEZAR MORAES DE AGUIAR ◽  
LUAN CUTTI
Keyword(s):  
Developmental Stages ◽  
Accelerated Aging ◽  
Cold Test ◽  
Dry Mass ◽  
Adverse Conditions ◽  
Ammonium Glufosinate ◽  
Conyza Bonariensis ◽  
Chlorimuron Ethyl ◽  
And Control ◽  
Hairy Fleabane

ABSTRACT Hairy fleabane (Conyza bonariensis L.) is a major weed of the conventional crop systems. Therefore, the objectives of the present study were to assess the responses of glyphosate-susceptible (S) and -resistant (R) C. bonariensis at various developmental stages and evaluate the physiological potential of seeds to propose alternative herbicides for the control of this weed. Two experiments were performed in replicates. The first experiment was performed in a greenhouse, arranged in a 2 x 3 x 10 factorial design. Specifically, two hairy fleabane biotypes (S and R) at different developmental stages (I, II, and III) were subjected to various treatments (glyphosate, chlorimuron-ethyl, metsulfuron-methyl, diclosulam, ammonium glufosinate, paraquat, paraquat+diuron, diquat, 2,4-D, and control). Percentage control was evaluated at 7, 14, 21, and 28 days after the application of the treatments (DAT), and shoot dry mass (SDM) was measured at 28 DAT. The second experiment was performed in a laboratory to evaluate the physiological potential of seeds based on the weight of 1000 seeds (TSW); shoot length (SL), radicle length (RL), total length (TL), fresh seedling mass (FSM), dry seedling mass (DSM), accelerated aging (AA) and cold test (CT), and germination (G) in response to cold and accelerated aging. The alternative herbicides tested effectively controlled biotype R up to the stage -I. Seeds of biotype R showed higher physiological potential in terms of all analyzed variables and exhibited greater tolerance to adverse conditions during seedling establishment. Therefore, strategies for the management of glyphosate-resistant hairy fleabane should aim at preventing new seed production.

scholarly journals Physiological Quality of Carioca Bean Seeds Submitted to the Application of Desiccant Herbicides in Two Periods

2019 ◽  
Vol 37 ◽  
Author(s):  
C.T. CASTOLDI ◽  
L.L. RADUNZ ◽  
L. GALON ◽  
I. ASPIAZÚ ◽  
C.T. FORTE ◽  
...  
Keyword(s):  
Water Content ◽  
Accelerated Aging ◽  
Cold Test ◽  
Dry Mass ◽  
Additional Treatment ◽  
Control Treatment ◽  
Average Dose ◽  
Ammonium Glufosinate ◽  
Physiological Quality

ABSTRACT: The use of herbicides for bean crop desiccation aiming seed production, is an alternative management because it allows harvesting when the seeds present high vigor, germination and dry mass, however this technique can cause damages to the seeds. The objective of this study was to evaluate the physiological quality of bean seeds, of the Carioca type, with the application of desiccant herbicides doses at different periods, aiming at the anticipation of the harvest. The bean plants, Pérola cultivar, were desiccated when the seeds had 42 and 30% water content, with ammonium glufosinate, saflufenacil and diquat at doses of 0, 50, 75 and 100% in relation to the recommended average dose for desiccation, respectively for each of the herbicides. The control treatment without desiccant application was harvested on the same date as desiccation. The additional treatment, also without desiccant application, was harvested only when the seeds had a water content of 18%. The variables analyzed were germination, first germination count, germination speed index, cold test, accelerated aging, seedling and radicle length, and dry mass. The herbicides applied in the first period (42% water), at the highest doses, impair the physiological quality of the seeds, and the seeds with water contents of 30 and 42%, without the use of desiccants, promote high vigor and germination. Satisfactory results were obtained when the saflufenacil herbicide was applied in period 2 (30% water), using 50% of the recommended average dose of this herbicide.

scholarly journals Germination of melon seeds under water and thermal stress

2017 ◽  
Vol 39 (4) ◽  
pp. 440-447 ◽  
Author(s):  
Daniel Teixeira Pinheiro ◽  
Denise Cunha Fernandes dos Santos Dias ◽  
Joyce de Oliveira Araújo
Keyword(s):  
Thermal Stress ◽  
Water Stress ◽  
Seedling Emergence ◽  
Accelerated Aging ◽  
Cold Test ◽  
Dry Mass ◽  
Stress Conditions ◽  
Peg 6000 ◽  
And Performance ◽  
Melon Seeds

Abstract: Seeds vigor can influence seed performance under stress conditions. The objectives of this study were to evaluate the effect of water and thermal stress on germination and performance of melon seedlings, and to verify if germination under stress conditions is an efficient parameter to evaluate the vigor of these seeds. Four lots of ‘Golden Mine’ melon had their initial quality characterized by germination, first count, accelerated aging and seedling emergence tests. Germination under water stress was performed on a paper moistened with PEG 6000 solution at 0.06, -0.3, -0.6 and -0.9 MPa. The percentage and speed of germination, length and dry mass of the seedlings were evaluated. For the thermal stress experiment, cold test and germination at sub- (15 ºC) and supra-optimal (35 ºC) temperatures were performed, as well as at the ideal temperature (25 ºC). The germination of melon seeds under water stress induced by PEG 6000 at -0.3 and -0.6 MPa is an efficient method to detect differences in the physiological potential of lots of melon seeds, but these differences disappear under severe water stress (-0.9 MPa). Germination under sub-optimal temperatures also allows to identify differences in seeds performance and to classify them according to the vigor level.

scholarly journals Physiological and sanitary quality of soybean seeds harvested at different periods and submitted to storage1

2017 ◽  
Vol 47 (3) ◽  
pp. 312-320 ◽  
Author(s):  
Alan Mario Zuffo ◽  
Joacir Mario Zuffo Júnior ◽  
Everton Vinicius Zambiazzi ◽  
Fábio Steiner
Keyword(s):  
Mechanical Damage ◽  
Accelerated Aging ◽  
Dry Mass ◽  
Seed Vigor ◽  
Soybean Seeds ◽  
Adverse Conditions ◽  
Physiological Quality ◽  
Total Plant ◽  
Plant Dry Mass

ABSTRACT Delayed harvesting may affect the physiological quality of soybean seeds, due to adverse conditions in the field. This study aimed to evaluate the physiological and sanitary quality of soybean seeds (BRS 820 RR® cultivar) harvested at eight periods (0; 5; 10; 15; 20; 25; 30; and 35 days after the R8 phenological stage - full maturity) and stored for two periods (0 and 8 months). The following evaluations were carried out: moisture content, germination and emergence rate, emergence speed index, total plant dry mass, accelerated aging, electrical conductivity, mechanical damage, vigor and viability (tetrazolium) and sanitary quality of the seeds. The delayed harvesting of soybean seeds from 10 days after R8 impairs seed vigor and germination, in addition to increase the incidence of pathogens. Regardless of the harvesting period, the soybean seeds stored for eight months showed a reduction in their physiological quality, with an increase in the incidence of Phomopsis spp.

scholarly journals Microbiolization of Seeds and Aerial Application With Yeasts for Disease Control in Wheat

2020 ◽  
Vol 12 (10) ◽  
pp. 307
Author(s):  
Rayssa H. da Silva ◽  
Renata F. Barabasz ◽  
Monica C. Sustakowski ◽  
Odair J. Kuhn ◽  
Jeferson C. Carvalho ◽  
...  
Keyword(s):  
Flag Leaf ◽  
Accelerated Aging ◽  
Rhodotorula Glutinis ◽  
Cold Test ◽  
Production Quality ◽  
Cryptococcus Laurentii ◽  
Aerial Application ◽  
Seed Health ◽  
And Control

Wheat productivity is compromised by the number of diseases that affect it. The diseases control is basically effected by the use of fungicides, however, biological control has become important due especially to the demand for foods free of chemical compounds. The objective of this work was to evaluate the efficiency of yeasts in reducing diseases through the treatment of wheat seeds and the spraying of plants in the field. The tests were carried out in the field and laboratory, with the yeasts Candida albicans, Cryptococcus laurentii, Pichia guilliermondii, Rhodotorula glutinis, Zygoascus hellenicus and Saccharomyces cerevisiae compared with fungicide (carbendazim) and control with water. In the laboratory, seed health, germination, germination speed index, cold test and accelerated aging were analyzed. In the field, seed treatment and aerial application were carried out when the flag leaf was emitted and the occurrence of diseases, chlorophyll content, production components, productivity and production quality was evaluated. For the variables of production and quality of the wheat in field, the yeast Z. hellenicus was efficient for productivity resembling the fungicide. For the severity of diseases in field, parameters related to germination and seed health, yeasts were not efficient.

scholarly journals Pre-soaking with gibberellin in sweet corn seed lots with different levels of vigor

2021 ◽  
Vol 42 (2) ◽  
pp. 539-552
Author(s):  
Jéssica de Lucena Marinho ◽  
◽  
Altamara Viviane de Souza Sartori ◽  
Evandro João Rodrigues ◽  
José Henrique Bizzarri Bazzo ◽  
...  
Keyword(s):  
Gibberellic Acid ◽  
Water Deficit ◽  
Sweet Corn ◽  
Accelerated Aging ◽  
Cold Test ◽  
Dry Mass ◽  
Corn Seed ◽  
Normal Seedling ◽  
Field Emergence ◽  
Student’S T

The poor longevity and performance of sweet corn seeds justify the adoption of practices that enhance their quality, such as pre-soaking. Thus, this study aimed to evaluate the effects of pre-soaking with gibberellin on the physiological potential of two sweet corn seed lots with contrasting vigor levels under ideal and water-deficit conditions. Initially, the seed lots were characterized for germination and physiological potential through first count, germination, accelerated aging, cold test, normal seedling length, normal seedling dry mass, field emergence, emergence speed index, and tetrazolium test. Subsequently, the seeds were pre-soaked with water and 0.4 and 0.8 g L−1 gibberellic acid, in addition to the control (without pre-soaking), randomly in a 2×4 factorial scheme with four replications. Then, the moisture content, first count, germination, field emergence, and emergence speed index of the seeds were evaluated under conditions of simulated water deficiency. The data obtained were subjected to analysis of variance and comparison of means, using Tukey’s test and Student’s t-test, for comparisons between treatments and lots, respectively. Pre-soaking favored germination speed and percentage in sweet corn seeds, particularly under water-deficit conditions. Pre-soaking the most vigorous lot with water and the least vigorous lot with 0.4 g L−1 gibberellic acid favored the physiological performance.

scholarly journals Carrot seed germination and vigor in response to temperature and umbel orders

2008 ◽  
Vol 65 (2) ◽  
pp. 145-150 ◽  
Author(s):  
Roseane Sousa Pereira ◽  
Warley Marcos Nascimento ◽  
Jairo Vidal Vieira
Keyword(s):  
Seed Germination ◽  
High Temperatures ◽  
Seedling Emergence ◽  
Accelerated Aging ◽  
Cold Test ◽  
Seed Vigor ◽  
Daucus Carota L ◽  
Adverse Conditions ◽  
Stand Establishment ◽  
Carrot Seed

Several factors may influence carrot (Daucus carota L.) crop establishment. High temperatures (35 - 40°C), for instance, may delay or inhibit carrot seed germination in the field and so compromise the stand establishment. Carrot seeds from superior umbel orders usually have better physiological quality than those of lower umbel orders. These seeds from superior umbel orders may also show a better performance in adverse conditions. In addition, seeds from different ages show differences in vigor, which affect the stand establishment, mainly under adverse conditions. The aim of this study was to verify the germination at high temperatures and the carrot seed vigor of different umbel orders of 'Brasília', as well as the different 'Alvorada' seed lots. Preliminarily, 'Brasilia' seeds were incubated at temperatures ranging from 20 to 36°C. Also, seeds from the primary, secondary and tertiary umbel orders harvested separately from a basic seed production field and seeds from lots harvested in 1998, 1999 and 2000 were analyzed to the following tests: germination at 20°C (optimum) and 35°C (adverse), accelerated aging, cold test, seedling emergence in greenhouse and mass of 100 seeds. High temperatures reduced carrot seed germination. Seeds germinated better at 20°C than 35 or 36ºC. Seeds from primary and secondary orders, as well as less aged seed lots, had higher vigor and germination at high temperature.

scholarly journals Accelerated Aging Test in Thyme Seeds (Thymus vulgaris L.)

2020 ◽  
Vol 9 (1) ◽  
pp. 32
Author(s):  
Flávia Mendes dos Santos Lourenço ◽  
Marco Eustáquio de Sá ◽  
Oscar Mitsuo Yamashita ◽  
Vinícius Martins Silva ◽  
Juliana Trindade Martins ◽  
...  
Keyword(s):  
Exposure Time ◽  
Saline Solution ◽  
Seed Quality ◽  
Accelerated Aging ◽  
Cold Test ◽  
Dry Mass ◽  
Thymus Vulgaris ◽  
Aging Period ◽  
Accelerated Aging Test ◽  
Aging Test

Evaluating seed quality with precision and accuracy is one of the priorities for obtaining high quality material. This study aimed to evaluate whether the variations in the performance of the accelerated aging test, in terms of exposure time and temperature, in the traditional form or in saline solution, would result in an efficient combination to evaluate the physiological quality of thyme seeds (Thymus vulgaris L.). The seeds were submitted to the tests of total germination, germination speed index, first germination count, seedlings emergence, seedling length, seedling dry mass, cold test, electrical conductivity, variations in the conduction of the accelerated aging test and the water content of the seeds was performed after each accelerated aging period. The treatments were the combination of temperatures (36, 38, 40 and 42 ºC), exposure time (24, 36, 48 and 72 hours) and two procedures (traditional and saline), with four replications for each batch. Traditional accelerated aging test at 42 ºC and 24 hours of exposure time, and saline solution accelerated aging test at 38 ºC and 24 hours of exposure time showed sensibility to evaluate physiological potential for thyme seed. For both saline solution and traditional accelerated aging test, the exposition time of 24 hours was efficient to evaluate physiological potential of thyme seeds.

scholarly journals Stressful Conditions Affect Seed Quality in Glyphosate Resistant Conyza bonariensis (L.)

Agronomy ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 1706
Author(s):  
Gabriel da Silva Amaral ◽  
Ricardo Alcántara-de la Cruz ◽  
Flávia Regina da Costa ◽  
Cileide Maria Medeiros Coelho ◽  
Rafael De Prado ◽  
...  
Keyword(s):  
Seed Quality ◽  
Shikimic Acid ◽  
Seed Viability ◽  
Accelerated Aging ◽  
Glyphosate Resistance ◽  
Cold Test ◽  
High Temperature Stress ◽  
Stress Tests ◽  
Germination Potential ◽  
Conyza Bonariensis

Conyza bonariensis (L.) Cronquist is one of the main glyphosate-resistant weeds in no-till fields in Brazil. Here, the seed quality of glyphosate-resistant (R) and -susceptible (S) C. bonariensis biotypes, collected from different sites, was evaluated under stressful conditions by different seed tests. Glyphosate resistance was confirmed by dose-response and shikimate accumulation assays. The resistance factors were 6.9 (R1/S1), 4.5 (R2/S2), and 5.8 (R3/S3). Biotypes S1, S2, and S3 accumulated 2.7, 2.4, and 2.8 times more shikimic acid than biotypes R1, R2, and R3, respectively. Stress-free seed viability and germination potential ranged from 39% to 57% and from 37% to 57%, respectively, with no difference between R and S biotypes within each collection site. Seed incubation at 8 °C over 7 days (cold test) promoted greater germination in S biotypes (54% to 79%) compared to R ones (28% to 39%). In the accelerated aging tests (incubation at 42 °C over 48 hours), the germination decreased in both S (11% to 27%) and R (6% to 16%) biotypes. In the high-temperature stress tests, there were no differences in germination within biotypes at 35 and 45 °C; however, at 60 °C, the germination of the S1, R1, S2, R2, S3, and R3 biotypes was reduced by approximately 51%, 54%, 63%, 59%, 40%, and 30%, respectively. Under non-stressful conditions, germination potential and seed viability were similar in R and S biotypes; however, under cold or heat stress conditions, R biotypes reduced their germination rates, revealing that glyphosate resistance causes a fitness penalty in C. bonariensis at the seed level. However, because seed viability was not determined after experiments, it cannot be stated that such reduction in germination was due to the death or only a dormant phase of the seeds.

Dry chip feedrate control using online chip moisture

TAPPI Journal ◽  
2018 ◽  
Vol 17 (05) ◽  
pp. 295-305
Author(s):  
Wesley Gilbert ◽  
Ivan Trush ◽  
Bruce Allison ◽  
Randy Reimer ◽  
Howard Mason
Keyword(s):  
Production Rate ◽  
Control Strategy ◽  
Rate Control ◽  
Near Infrared ◽  
Dry Mass ◽  
The Other ◽  
Process Variability ◽  
Moisture Sensor ◽  
Feedback Control Strategy ◽  
And Control

Normal practice in continuous digester operation is to set the production rate through the chip meter speed. This speed is seldom, if ever, adjusted except to change production, and most of the other digester inputs are ratioed to it. The inherent assumption is that constant chip meter speed equates to constant dry mass flow of chips. This is seldom, if ever, true. As a result, the actual production rate, effective alkali (EA)-to-wood and liquor-to-wood ratios may vary substantially from assumed values. This increases process variability and decreases profits. In this report, a new continuous digester production rate control strategy is developed that addresses this shortcoming. A new noncontacting near infrared–based chip moisture sensor is combined with the existing weightometer signal to estimate the actual dry chip mass feedrate entering the digester. The estimated feedrate is then used to implement a novel feedback control strategy that adjusts the chip meter speed to maintain the dry chip feedrate at the target value. The report details the results of applying the new measurements and control strategy to a dual vessel continuous digester.

Lack of Cross-Resistance of Paraquat-Resistant Hairy Fleabane (Conyza bonariensis) to Other Toxic Oxygen Generators Indicates Enzymatic Protection is Not the Resistance Mechanism

Weed Science ◽  
1989 ◽  
Vol 37 (1) ◽  
pp. 5-11 ◽  
Author(s):  
Kevin C. Vaughn ◽  
Martin A. Vaughan ◽  
Patrick Camilleri
Keyword(s):  
Electron Microscopy ◽  
Chlorophyll Fluorescence ◽  
Resistance Mechanism ◽  
Cross Resistance ◽  
Oxygen Generator ◽  
Conyza Bonariensis ◽  
Singlet Oxygen Generator ◽  
Chlorophyll Bleaching ◽  
Direct Measures ◽  
Hairy Fleabane

Cross-resistance of the paraquat-resistant (R) hairy fleabane to other compounds that accept electrons from photosystem I (PSI) or produce toxic oxygen species was determined by chlorophyll loss, electron microscopy, and chlorophyll fluorescence suppression. Although the R bioype is approximately 100 x more resistant to paraquat than the susceptible (S) biotype based upon the assays for tissue damage, little or no cross-resistance was observed to a number of other PSI electron acceptors, including the bipyridilium herbicide morfamquat. A low level of resistance (approximately 10-fold) was noted to diquat and the singlet oxygen generator rose bengal. As measured by chlorophyll fluorescence suppression, the R biotype was about 100-fold resistant to paraquat, but only 10-fold resistant to diquat, and exhibited no resistance to morfamquat. Because differences observed with this protocol are direct measures of the ability of the herbicide to reach the active site and the results correlate with the level of resistance observed by chlorophyll bleaching or electron microscopy, these data suggest that compartmentalization is the major factor in paraquat resistance in hairy fleabane.

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