RENDEMENT EN GRAINS DE PARCELLES DE CEREALES DE PRINTEMPS ORIGINANT DE SEMENCES CONTAMINEES PAR DES Fusarium spp

1983 ◽  
Vol 63 (3) ◽  
pp. 617-621 ◽  
Author(s):  
LUC COUTURE

Seed lots from different cultivars of oats (Avena sativa), barley (Hordeum vulgare) and wheat (Triticum aestivum) were compared in yield tests at two sites in Quebec. For each cultivar, two seed lots were used, one with a low level of seed-borne Fusarium (average 4%) and the other with a high level (average 47%). Yield increases or decreases in the presence of Fusarium were observed according to cultivars. Positive or negative trend in yield was similar at both sites but with different magnitudes. Barley was the most affected cereal with three out of four cultivars undergoing yield decrease. One wheat cultivar out of three sustained yield decrease and none of the three oats suffered damage by Fusarium. Seed germination appears to be a factor to consider in selecting lots for such comparisons.Key words: Yield, Avena sativa, Hordeum vulgare, Triticum aestivum, Fisarium, cultivars

1990 ◽  
Vol 68 (6) ◽  
pp. 1249-1253 ◽  
Author(s):  
Y. Tosa ◽  
T. Akiyama ◽  
H. Ogura

The progress of infection in leaves of wheat (Triticum aestivum), rye (Secale cereale), wheatgrass (Agropyron tsukushiense), barley (Hordeum vulgare), and oat (Avena sativa) inoculated with Erysiphe graminis f.sp. tritici, secalis, agropyri, and hordei was observed using a fluorescence microscope. Relative compatibility of each host–parasite combination was estimated by the incidence of cell wall penetration. Formae speciales tritici, secalis, and agropyri were highly compatible with any accession of wheat, rye, and wheatgrass, but less compatible with barley. On the other hand, f.sp. hordei was highly compatible with any of these four hosts. The four formae speciales had very low compatibility with oat, although f.sp. hordei was relatively more compatible with this host. These results suggested that (i) f.sp. tritici, secalis, and agropyri are phylogenetically very close; (ii) f.sp. hordei is less close to f.sp. tritici, secalis, and agropyri, and closer than these to the ancestral form of E. graminis; (iii) f.sp. avenae is remote from f.sp. tritici, secalis, agropyri, and hordei, but relatively less remote from f.sp. hordei than from the other three formae speciales.


Insects ◽  
2021 ◽  
Vol 12 (11) ◽  
pp. 996
Author(s):  
Muhammad Zaryab Khalid ◽  
Sohail Ahmed ◽  
Ibrahim Al-ashkar ◽  
Ayman EL Sabagh ◽  
Liyun Liu ◽  
...  

Cotton is a major crop of Pakistan, and Bemisia tabaci (Homoptera: Aleyrodidae) is a major pest of cotton. Due to the unwise and indiscriminate use of insecticides, resistance develops more readily in the whitefly. The present study was conducted to evaluate the resistance development in the whitefly against the different insecticides that are still in use. For this purpose, the whitefly population was selected with five concentrations of each insecticide, for five generations. At G1, compared with the laboratory susceptible population, a very low level of resistance was observed against bifenthrin, cypermethrin, acetamiprid, imidacloprid, thiamethoxam, nitenpyram, chlorfenapyr, and buprofezin with a resistance ratio of 3-fold, 2-fold, 1-fold, 4-fold, 3-fold, 3-fold, 3-fold, and 3-fold, respectively. However, the selection for five generations increased the resistance to a very high level against buprofezin (127-fold), and to a high level against imidacloprid (86-fold) compared with the laboratory susceptible population. While, a moderate level of resistance was observed against cypermethrin (34-fold), thiamethoxam (34-fold), nitenpyram (30-fold), chlorfenapyr (29-fold), and acetamiprid (21-fold). On the other hand, the resistance was low against bifenthrin (18-fold) after selection for five generations. A very low level of resistance against the field population of B. tabaci, at G1, showed that these insecticides are still effective, and thus can be used under the field conditions for the management of B. tabaci. However, the proper rotation of insecticides among different groups can help to reduce the development of resistance against insecticides.


2019 ◽  
Vol 3 (1) ◽  
pp. 72-77
Author(s):  
María Mesén ◽  
William Sánchez

La presente investigación se realizó en el año 1996, en el distrito Cot, cantón Oreamu-no, provincia Cartago. La topografía de la finca es irregular y se ubica a una altitud de 2.100 msnm. El objetivo del estudio fue evaluar la adaptabilidad de una colección de 13 ce-reales forrajeros, nueve variedades de Avena (Avena sativa), tres de Trigo (un Triticum se-cale y dos Triticum aestivum) y una de Cebada (Hordeum vulgare). El diseño experimental utilizado, fue de bloques completos al azar, con tres repeticiones, representando cada cul-tivar un tratamiento. Las variables evaluadas fueron: cobertura, altura, plagas, producción de biomasa y valor nutritivo. En cuanto a las variables cobertura y altura los valores fueronaltos en todos los cultivares cosechados, superiores a 90% y 75 cm respectivamente, losTriticum y la Hordeum vulgare fueron inferiores a las avenas en ambos aspectos. La única enfermedad que se presentó fue la Puccinia sp. eliminando por completo las avenas Ne-huén, Dula, Gaviota y Llaofén y afectando levemente (5% del follaje afectado) los cereales Culgoa II, Águila y Triticum secale. Los demás cereales no fueron dañados por ninguna pla-ga. La producción de biomasa en los diferentes cultivares osciló en un rango de 6,8 y 15,5 t/ha/corte. El análisis de varianza para esta variable mostró diferencias entre cultivaresP=0,01 y P=0,001 para t/ha/corte y tasa de crecimiento respectivamente. Según los altos rendimientos de materia seca, adecuado valor nutritivo y ausencia de plagas, se puede con-cluir que los cereales que mejor se adaptaron a la zona en estudio fueron las avenas Riel, Nobby y Amby. Se debe continuar investigando con los cultivares sobresalientes bajo pas-toreo y en sustitución de alimentos balanceados.


Author(s):  

Abstract A new distribution map is provided for Wheat dwarf virus. Geminiviridae: Mastrevirus. Hosts: wheat (Triticum aestivum), barley (Hordeum vulgare), oat (Avena sativa). Information is given on the geographical distribution in Europe (Austria, Bulgaria, Czech Republic, Finland, France, Germany, Hungary, Italy, Poland, Romania, Slovakia, Slovenia, Spain, Sweden, UK, Ukraine), Asia (China, Hebei, Qinghai, Shaanxi, Shanxi, Sichuan, Yunnan, Iran, Syria, Turkey), Africa (Tunisia Zambia).


2001 ◽  
Vol 26 (1) ◽  
pp. 39-44 ◽  
Author(s):  
GRACIELA A. TRUOL ◽  
TOMIO USUGI ◽  
JUTARO HIRAO ◽  
JOEL D. ARNEODO ◽  
M. PAZ GIMÉNEZ PECCI ◽  
...  

Entre las enfermedades que afectan al cultivo de maíz (Zea mays) en Argentina, la producida por el virus del mal de Río Cuarto (MRCV) es la más importante. El MRCV pertenece a la familia Reoviridae, género Fijivirus, y su propagación en la naturaleza es realizada por Delphacodes kuscheli (Hemiptera: Delphacidae). La modalidad de transmisión para los miembros de este género de virus es persistente propagativa. Se estableció la necesidad de ajustar un sistema de transmisión eficiente del virus para estudios de caracterización, partiendo de poblaciones libres de virus criadas en laboratorio, para lo cual se ensayaron distintos períodos de adquisición, latencia e inoculación, evaluándose además un rango de hospedantes diferenciales. Se lograron obtener insectos libres de virus en cantidad suficiente para llevar a cabo los trabajos, mediante su cría en fitotrones y cámaras aclimatadas. La transmisión experimental del MRCV se efectuó exitosamente, bajo idénticas condiciones, empleando períodos de adquisición, latencia e inoculación de dos, 10 y uno día respectivamente para los cereales de grano fino y de dos, 10 y dos días para el maíz. Se infectaron de este modo las siguientes especies: maíz, cebada (Hordeum vulgare), avena (Avena sativa), trigo (Triticum aestivum), centeno (Secale cereale), grama rhodes (Chloris gayana) y alpiste (Phalaris canariensis). La detección del virus en las plantas inoculadas se efectuó mediante pruebas serológicas, análisis de dsRNA en electroforesis en gel de poliacrilamida (obteniéndose las 10 bandas típicas de los fijivirus) y microscopía electrónica, detectándose las partículas isométricas de entre 60 y 70 nm de diámetro.


Weed Science ◽  
1970 ◽  
Vol 18 (4) ◽  
pp. 492-496 ◽  
Author(s):  
Paul N. P. Chow

In the greenhouse, five crops were grown in soil containing trichloroacetic acid (TCA) at 3 to 24 ppm. Based on seedling yields, corn (Zea mays L., var. Morden 88) and oats (Avena sativa L., var. Rodney) were relatively tolerant to TCA at all rates, barley (Hordeum vulgare L., var. Conquest) and rye (Secale cereale L., var. Antelope) were tolerant at lower rates, but wheat (Triticum aestivum L., var. Manitou) suffered injury at all rates. When TCA-2-14C was applied to the roots of wheat and oats seedlings in water or nutrient solution, wheat seedlings absorbed more TCA-2-14C than oats. Potassium cyanide (KCN) and 2,4-dichlorophenoxyacetic acid (2,4-D) decreased TCA-2-14C absorption by wheat more than that by oats. From 5 to 21 days after application, wheat retained two to four times as much TCA-2-14C as oats. Thus, half of the TCA-2-14C in shoots and roots of wheat disappeared in 11.3 and 11.4 days, respectively, compared with 7.9 and 3.5 days for oats. Based on this investigation, the difference in susceptibility of wheat and oats to TCA appeared to be governed by the metabolic processes involved in absorption and dissipation.


2012 ◽  
Vol 58 (No. 12) ◽  
pp. 534-539 ◽  
Author(s):  
G.Q. Wu ◽  
L.N. Zhang ◽  
Y.Y. Wang

 To investigate the responses of growth and antioxidant enzymes to osmotic stress in two different wheat cultivars, one drought tolerant (Heshangtou, HST) and the other drought sensitive (Longchun 15, LC15), 15-day-old wheat seedlings were exposed to osmotic stress of –0.25, –0.50, and –0.75 MPa for 2 days. It is found that osmotic stress decreased shoot length in both wheat cultivars, whereas to a lesser degree in HST than in LC15. The contents of malondialdehyde (MDA) and the activities of superoxide dismutase (SOD), peroxidase (POD), and catalase (CAT) of shoot in both wheat cultivars were increased by osmotic stress. It is clear that MDA contents increased less in the more drought tolerant cultivar HST than in drought sensitive one LC15. On the contrary, POD and CAT activities increased more in HST than LC15 under osmotic stress. As the activity of SOD, however, no significant differences were found between HST and LC15. These results suggest that wheat cultivar HST has higher activities of antioxidant enzymes such as POD and CAT to cope with oxidative damage caused by osmotic stress compared to sensitive LC15.  


Author(s):  
ANDERSON LUIZ NUNES ◽  
RIBAS ANTONIO VIDAL

A determinação da concentração de compostos no solo por meio de plantas quantificadoras apresenta como principal vantagem detectar somente resíduos biologicamente ativos, não havendo necessidade de instrumentos onerosos e de prévia extração dos resíduos do solo. Dessa forma, este trabalho teve como objetivo selecionar plantas quantificadoras da presença de herbicidas residuais (pré emergentes) para o uso em bioensaios. Utilizou-se delineamento experimental completamente casualizado com arranjo bifatorial 8 x 6, com cinco repetições. O fator A consistiu de espécies cultiváveis e o fator B de herbicidas aplicados em pré emergência. Os resultados evidenciaram que a sensibilidade na detecção do herbicida no solo depende da espécie utilizada. A sensibilidade das espécies Lactuca sativa L. e Raphanus sativus var. sativus L. não permitiu condições de quantificar a presença dos herbicidas atrazina, cloransulam, imazaquin, metribuzin e S-metolacloro. Raphanus sativus var. oleiferus Metzger é potencial quantificador de imazaquin e S metolacloro. Plantas de Curcubita pepo L. são promissoras na bioavaliação de metribuzin. A espécie Cucumis sativus L. mostrou-se potencial bioindicadora de cloransulan e imazaquin. Avena sativa L. apresentou-se como potencial quantificadora de imazaquin e metribuzin. Hordeum vulgare L. pode quantificar o metribuzin e Triticum aestivum L. é promissor na detecção da biodisponibilidade de atrazina.


2019 ◽  
Vol 74 (11) ◽  
pp. 3252-3259 ◽  
Author(s):  
Anaïs Soares ◽  
Kévin Alexandre ◽  
Fabien Lamoureux ◽  
Ludovic Lemée ◽  
François Caron ◽  
...  

Abstract Background Eradicating bacterial biofilm without mechanical dispersion remains a challenge. Combination therapy has been suggested as a suitable strategy to eradicate biofilm. Objectives To evaluate the efficacy of a ciprofloxacin/amikacin combination in a model of in vitro Pseudomonas aeruginosa biofilm. Methods The antibacterial activity of ciprofloxacin and amikacin (alone, in combination and successively) was evaluated by planktonic and biofilm time–kill assays against five P. aeruginosa strains: PAO1, a WT clinical strain and three clinical strains overexpressing the efflux pumps MexAB-OprM (AB), MexXY-OprM (XY) and MexCD-OprJ (CD), respectively. Amikacin MIC was 16 mg/L for XY and ciprofloxacin MIC was 0.5 mg/L for CD. The other strains were fully susceptible to ciprofloxacin and amikacin. The numbers of total and resistant cells were determined. Results In planktonic cultures, regrowth of high-level resistant mutants was observed when CD was exposed to ciprofloxacin alone and XY to amikacin alone. Eradication was obtained with ciprofloxacin or amikacin in the other strains, or with the combination in XY and CD strains. In biofilm, bactericidal reduction after 8 h followed by a mean 4 log10 cfu/mL plateau in all strains and for all regimens was noticed. No regrowth of resistant mutants was observed whatever the antibiotic regimen. The bacterial reduction obtained with a second antibiotic used simultaneously or consecutively was not significant. Conclusions The ciprofloxacin/amikacin combination prevented the emergence of resistant mutants in low-level resistant strains in planktonic cultures. Biofilm persister cells were not eradicated, either with monotherapy or with the combination.


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