Wild Oat (Avena fatua) andAvena sterilisMorphological Characteristics and Response to Herbicides

Weed Science ◽  
1984 ◽  
Vol 32 (3) ◽  
pp. 353-359 ◽  
Author(s):  
Carol N. Somody ◽  
John D. Nalewaja ◽  
Stephen D. Miller
Keyword(s):  
United States ◽  
Surface Area ◽  
Southern California ◽  
Leaf Surface ◽  
The United States ◽  
Avena Fatua ◽  
Propanoic Acid ◽  
Wild Oat ◽  
Avena Sterilis ◽  
Leaf Surface Area

Wild oat (Avena fatuaL. ♯3AVEFA) andAvena sterilisL. ♯ AVEST accessions from the United States were screened for tolerance to diallate [S-(2,3-dichloroallyl) diisopropylthiocarbamate], triallate [S-(2,3,3-trichloroallyl) diisopropylthiocarbamate], barban (4-chloro-2-butynylm-chlorocarbanilate), diclofop {2-[4-(2,4-dichlorophenoxy) phenoxy] propanoic acid}, difenzoquat (1,2-dimethyl-3,5-diphenyl-1H-pyrazolium), flamprop [N-benzoyl-N-(3-chloro-4-fluorophenyl)-DL-alanine], and MSMA (monosodium methanearsonate). Some accessions were tolerant to more than one herbicide but none were tolerant to all herbicides. Tolerance to a herbicide was not restricted to certain areas of origin of the accessions, and tolerant accessions occurred even in locations that had not been treated previously with the herbicide. In general, accessions from Southern California and Arizona were shorter, produced more tillers, and required the least number of days to panicle emergence. However, accessions from within individual areas were nearly as variable in these characteristics as the entire 1200 accessions. Tolerance of accessions to flamprop, difenzoquat, MSMA, and diclofop was not due to low leaf surface area, since the tolerant accessions usually had the most leaf surface area. All the accessions tolerant to difenzoquat, MSMA, and flamprop, and three of the four accessions tolerant to diclofop, tillered less than the susceptible accessions.

scholarly journals Patterns of Virulence in Natural Populations of Puccinia coronata on Wild Oat in Israel and in Agricultural Populations on Cultivated Oat in the United States

2004 ◽  
Vol 94 (5) ◽  
pp. 505-514 ◽  
Author(s):  
K. J. Leonard ◽  
Y. Anikster ◽  
J. Manisterski
Keyword(s):  
United States ◽  
Resistance Genes ◽  
Natural Populations ◽  
The United States ◽  
Puccinia Coronata ◽  
Indigenous Populations ◽  
Wild Oat ◽  
Avena Sterilis ◽  
Oat Cultivars ◽  
Highly Virulent

Crown rust (Puccinia coronata) in indigenous populations of Avena sterilis has been cited as an example of stability of wild pathosystems that consist of natural mixtures of resistance and virulence. This study confirmed that virulence/avirulence polymorphisms in P. coronata on A. sterilis in Israel are highly diverse and that super races do not dominate. Isolates of P. coronata from Israel in 1991 to 1996 were polymorphic for virulence to 35 of 36 differential oat lines with resistance genes from A. sterilis. On average, isolates of P. coronata were more highly virulent to differentials with Pc genes from A. sterilis accessions from Israel than to differentials with Pc genes from other countries. Isolates from Israel also were more virulent on average to 10 additional differentials with Pc genes derived from A. sativa than to differentials with Pc genes from A. sterilis. Frequencies of virulence were usually higher in collections of P. coronata from Israel than in collections from cultivated oat in the United States, even though several of the Pc genes in the differentials have been used extensively in American oat cultivars. Mean virulence complexity of P. coronata from eight regions of Israel was not correlated with the distribution of resistance among collections of A. sterilis from previous surveys in the same areas, probably because pathogen migration between regions within Israel is sufficient to obscure effects of selection locally.

SOOTY MOULD DISEASES OF SOME TREES FROM AURANGABAD DISTRICT, MAHARASHTRA (INDIA)

2017 ◽  
Vol 23 (2) ◽  
Author(s):  
NAVALSINGH J. TODAWAT
Keyword(s):  
Surface Area ◽  
Fungal Pathogens ◽  
Leaf Surface ◽  
Severity Of Disease ◽  
Sooty Mould ◽  
Leaf Surface Area

Sooty mould diseases of Tress from Aurangabad district were surveyed. During the survey of tress, 5 species were found infected by fungal pathogens causing sooty mould diseases. Disease is easily identifiable by the presence of a black, velvety growth covering the leaf surface area. The fungus produces mycelium which is superficial and dark grows on the flowers, leaf, stem and sometime on fruits also. The severity of disease depends on the honeydew secretions by insects. The diseases were found to be caused by 5 species of fungi viz. Capnodium anonae, C. ramosum, Capnodium sp., Meliola bangalorensis and Meliola ranganthii.

INFLUENCE OF GROWTH REGULATORS AND LED IRRADIATORS ON PINE STRAWBERRY ADAPTATION

1970 ◽  
pp. 12-15
Author(s):  
M. G. Markova ◽  
E. N. Somova
Keyword(s):  
Surface Area ◽  
Growth Regulators ◽  
Leaf Surface ◽  
Combined Treatment ◽  
Fragaria X Ananassa ◽  
Leaf Surface Area ◽  
External Conditions ◽  
Light Effects ◽  
Control Version

Work on going through the adaptation stage of rooted micro-stalks comes down to searching for new growth regulators and studying the influence of external conditions, which include, among other things, light effects. The data of 2018-2019 on the effect of growth regulators Siliplant, EcoFus and experimental LED phytoradiators on the adaptation of rooted micro-stalks of garden strawberries (Fragaria x ananassa duch) in vivo are presented. The object of research is rooted micro-stalks of garden strawberries of the Korona variety. It was revealed that, at the adaptation stage of rooted micro-stalks of strawberries, the most effective was the treatment of plants by spraying with Siliplant at a concentration of 1.0 ml/l and the combined treatment with Siliplant and EcoFus at concentrations of 0.5 ml/l: regardless of lighting, the survival rate averaged 99.4 - 99.7%, the leaf surface area increased significantly from 291.85 mm2 to 334.4 mm2. The number of normally developed leaves of strawberry microplants increased significantly after treatment with all preparations from 3.5 to 6.0, 5.8 and 6.5 pcs/plant, and a significant increase in the height of strawberry rosettes was facilitated by treatment with Siliplant and Siliplant together with EcoFus. Regardless of growth regulators, the most effective was the experimental LED phyto-irradiator with a changing spectrum, which contributed to an increase in leaf surface area, height of rosettes and the number of normally developed leaves in strawberry microplants. When illuminated with a flashing phytoradiator, these indicators are lower than in the control version, but not significantly. By the end of the rooting stage, all microplants of garden strawberries corresponded to GOST R 54051-2010.

Genetic Diversity of Wild Oat (Avena fatua)Populations from China and the United States

Weed Science ◽  
2007 ◽  
Vol 55 (2) ◽  
pp. 95-101 ◽  
Author(s):  
Runzhi Li ◽  
Shiwen Wang ◽  
Liusheng Duan ◽  
Zhaohu Li ◽  
Michael J. Christoffers ◽  
...  
Keyword(s):  
United States ◽  
Genetic Diversity ◽  
Gene Diversity ◽  
Genetic Relationships ◽  
The United States ◽  
Mantel Test ◽  
Wild Oat ◽  
Chinese Populations ◽  
Nei's Distance ◽  
The Impact

Weed genetic diversity is important for understanding the ability of weeds to adapt to different environments and the impact of herbicide selection on weed populations. Genetic diversity within and among six wild oat populations in China varying in herbicide selection pressure and one population in North Dakota were surveyed using 64 polymorphic alleles resulting from 25 microsatellite loci. Mean Nei's gene diversity (h) for six wild oat populations from China was between 0.17 and 0.21, and total diversity (HT) was 0.23. A greater proportion of this diversity, however, was within (Hs= 0.19) rather than among (Gst= 0.15) populations. For the wild oat population from the United States,h= 0.24 andHT= 0.24 were comparable to the values for the six populations from China. Cluster analysis divided the seven populations into two groups, where one group was the United States population and the other group included the six Chinese populations. The genetic relationships among six populations from China were weakly correlated with their geographic distribution (r= 0.22) using the Mantel test. Minimal difference in gene diversity and small genetic distance (Nei's distance 0.07 or less) among six populations from China are consistent with wide dispersal of wild oat in the 1980s. Our results indicate that the wild oat populations in China are genetically diverse at a level similar to North America, and the genetic diversity of wild oat in the broad spatial scale is not substantially changed by environment, agronomic practices, or herbicide usage.

Particle size, leaf pubescence and condition of humidity at leaf surfaces are key factors determining the retention of volcanic ash on crop foliage.

2021 ◽  
Author(s):  
Noa Ligot ◽  
Benoît Pereira ◽  
Patrick Bogaert ◽  
Guillaume Lobet ◽  
Pierre Delmelle
Keyword(s):  
Particle Size ◽  
Surface Area ◽  
Leaf Surface ◽  
Volcanic Risk ◽  
Chilli Pepper ◽  
Leaf Pubescence ◽  
Leaf Surfaces ◽  
Plant Foliage ◽  
Leaf Surface Area ◽  
Ash Deposit

<p>Volcanic ashfall negatively affects crops, causing major economic losses and jeopardising the livelihood of farmers in developing countries where agriculture is at volcanic risk. Ash on plant foliage reduces the amount of incident light, thereby limiting photosynthesis and plant yield. An excessive ash load may also result in mechanical plant damages, such as defoliation and breakage of the stem and twigs. Characterising crop vulnerability to ashfall is critical to conduct a comprehensive volcanic risk analysis. This is normally done by describing the relationship between the ash deposit thickness and the corresponding reduction in crop yield, i.e. a fragility function. However, ash depth measured on the ground surface is a crude proxy of ash retention on plant foliage as this metrics neglects other factors, such as ash particle size, leaf pubescence and condition of humidity at leaf surfaces, which are likely to influence the amount of ash that stays on leaves.</p><p>Here we report the results of greenhouse experiments in which we measured the percentage of leaf surface area covered by ash particles for one hairy leaf plant (tomato, Solanum lycopersicum L.) and one hairless leaf plant (chilli pepper, Capsicum annuum L.) exposed to simulated ashfalls. We tested six particle size ranges (≤ 90, 90-125, 125-250, 250-500, 500-1000, 1000-2000 µm) and two conditions of humidity at leaf surfaces, i.e. dry and wet. Each treatment consisted of 15 replicates. The tomato and chilli pepper plants exposed to ash were at the seven- and eight-leaf stage, respectively. An ash load of ~570 g m<sup>-2 </sup>was applied to each plant using a homemade ashfall simulator. We estimated the leaf surface area covered by ash from pictures taken before and immediately after the simulated ashfall. The ImageJ software was used for image processing and analysis.</p><p>Our results show that leaf coverage by ash increases with decreasing particle size. Exposure of tomato and chilli pepper to ash ≤ 90 μm always led to ~90% coverage of the leaf surface area. For coarser particles sizes (i.e. between 125 and 500 µm) and dry condition at leaf surfaces, a significantly higher percentage (on average 29 and 16%) of the leaf surface area was covered by ash in the case of tomato compared to chilli pepper, highlighting the influence of leaf pubescence on ash retention. In addition, for particle sizes between 90 and 500 µm, wetting of the leaf surfaces prior to ashfall enhanced the ash cover by 19 ± 5% and 34 ± 11% for tomato and chilli pepper, respectively.</p><p>These findings highlight that ash deposit thickness alone cannot describe the hazard intensity accurately. A thin deposit of fine ash (≤ 90 µm) will likely cover the entire leaf surface area, thereby eliciting a disproportionate effect on plant foliage compared to a thicker but coarser deposit. Similarly, for a same ash depth, leaf pubescence and humid conditions at the leaf surfaces will enhance ash retention, thereby increasing the likelihood of damage. Our study will contribute to improve the reliability of crop fragility functions used in volcanic risk assessment.</p>

scholarly journals Guerreiro Ramos in the United States: his life through the lens of political exile

2016 ◽  
Vol 18 (1) ◽  
pp. 207
Author(s):  
Diana De Groat Brown
Keyword(s):  
United States ◽  
Southern California ◽  
The United States ◽  
University Of Southern California ◽  
Political Exile

http://dx.doi.org/10.5007/2175-8034.2016v18n1p207Neste artigo são explorados os anos de exílio de Guerreiro Ramos nos Estados Unidos (1966-1982), questionando como um intelectual esquerdista brasileiro, de ascendência africana, lidou com o clima social e político dos Estados Unidos nesse período. O foco está em duas questões: sua carreira na Escola de Administração Pública da University of Southern California (USC), onde ele permaneceu até sua morte, e sua relação, como um brasileiro de cor, com a política racial radical nos Estados Unidos nesse período. Argumenta-se que, na USC, o pragmatismo e a habilidade de Guerreiro Ramos de produzir sucesso em circunstâncias adversas, aprendidos durante sua carreira no Brasil, possibilitaram-lhe fazer o mesmo na USC – transformar a adversidade do exílio em um sucesso criativo equiparável. Seu brilho e carisma como intelectual e como professor granjearam-lhe admiração, respeito, popularidade e uma carreira acadêmica segura. Sua criatividade e abertura a novas ideias permitiram-lhe abraçar o campo da sociologia americana, mesmo quando continuava a se opor ao imperialismo americano e a trazer a sociologia para a crítica da administração pública americana. Quanto a sua relação com a política racial americana desse período, mesmo no Brasil, ele já havia se afastado do engajamento anterior com as questões raciais e isso continuou nos Estados Unidos. A especulação aqui é que sua identidade como um estrangeiro exótico o protegeu de sofrer, diretamente, a discriminação racial direcionada aos afro-americanos. Finalmente, seu exílio aumentou seu senso de ser um “de fora”, um “homem entre parêntesis” tanto no Brasil como nos Estados Unidos.

SPRAY DROPLET DISTRIBUTION AND HERBICIDE UPTAKE IN SEQUENTIAL APPLICATIONS OF DICLOFOP-METHYL AND MCPA FOR WEED CONTROL IN BARLEY

1979 ◽  
Vol 59 (1) ◽  
pp. 93-98 ◽  
Author(s):  
F. A. QURESHI ◽  
W. H. VANDEN BORN
Keyword(s):  
Acetic Acid ◽  
Leaf Surface ◽  
Avena Fatua ◽  
Wild Oat ◽  
Spray Application ◽  
Spray Droplet ◽  
Wild Oats ◽  
Droplet Distribution ◽  
Spray Droplets ◽  
Spray Volume

Uptake of 14C-diclofop-methyl {methyl 2-[4-(2,4-dichlorophenoxy)phenoxy propanoate]} by leaves of wild oats (Avena fatua L.) was reduced significantly in the presence of MCPA {[(4-chloro-o-tolyl)oxy]acetic acid]}, especially the dimethylamine formulation. If the herbicides were applied separately, the degree of interference with uptake depended on the extent of overlap of droplets of the two spray preparations on the leaf surface. Spray volume and direction of spray application were important factors in minimizing the mixing of spray droplets on the leaves if the two herbicides were applied separately with a tandem arrangement of two sprayers. Such a sequential application of MCPA ester and diclofop-methyl in a field experiment provided significantly greater wild oat control than could be obtained with a tank mix of the same two herbicides, but the results were not consistent enough to recommend the procedure for practical use.

scholarly journals Growth and productivity of wheat plants under drought in the critical phase of ontogenesis

2021 ◽  
Vol 29 ◽  
pp. 35-40
Author(s):  
O. I. Zhuk ◽  
O.O. Stasik
Keyword(s):  
Triticum Aestivum ◽  
Winter Wheat ◽  
Surface Area ◽  
Leaf Surface ◽  
Triticum Aestivum L ◽  
Grain Number ◽  
Plant Weight ◽  
Inhibition Of Growth ◽  
Critical Phase ◽  
Leaf Surface Area

Aim. The goal of this work was to study the effect of drought in the critical phase of ontogenesis on the growth and productivity of breed winter wheat plants (Triticum aestivum L.). Methods. Wheat plants of cultivars Darunok Podillya and Podolyanka were grown under optimal nutrition and well-water conditions until the earing-flowering phase, after that the experimental plants were transferred to drought regime for 8 days, after that the optimal water supply was restored to the end of vegetation. During the experiment, the leaf surface area, the mass of internodes and ear were determined. Ripened plants were analyzed according to the structure of the yield. Results. It was established that the effect of drought in the critical phase of ontogenesis the earing-flowering caused to the decreasing in leaf surface area, mass of internodes, ear, mass and number of grains in the ear and plant, weight of 1000 grains. Conclusions. Water deficit in the soil in the critical phase of earing-flowering led to a decrease in the productive of breed winter wheat plants due to the inhibition of growth of ear, decreasing grain number and the mass of ear and grains. Keywords: Triticum aestivum L., internode, ear, productivity, drought.

Sign in / Sign up

Export Citation Format

Share Document