scholarly journals Evaluation of Various Sources of Viral Infection in Strawberry Fields of Quebec, Canada

2019 ◽  
Vol 112 (6) ◽  
pp. 2577-2583
Author(s):  
Phanie Bonneau ◽  
Richard Hogue ◽  
Stéphanie Tellier ◽  
Valérie Fournier
Keyword(s):  
Insect Vectors ◽  
Relative Importance ◽  
Fragaria Ananassa ◽  
Viral Contamination ◽  
Persistent Viruses ◽  
Strawberry Vein Banding Virus ◽  
Before And After ◽  
Fragaria Virginiana ◽  
Wild Strawberry ◽  
Sources Of Contamination

Abstract The decline of cultivated strawberry (Fragaria × ananassa Duchesne ex Rozier; Rosaceae) observed in the province of Quebec, Canada, between 2012 and 2014 was mostly caused by persistent viruses: strawberry mild yellow edge virus (SMYEV) (Potexvirus; Alphaflexiviridae) and strawberry crinkle virus (SCV) (Cytorhabdovirus; Rhabdoviridae); and semi-persistent viruses: strawberry mottle virus (SmoV) (Secoviridae), strawberry vein banding virus (SVBV) (Caulimovirus; Caulimoviridae), and strawberry pallidosis virus (SPaV) (Crinivirus: Closteroviridae) transmitted by insect vectors. The objective of this study was to determine the sources of viral contamination in commercial strawberry fields in Quebec. Specifically, we wished to 1) determine the prevalence of persistent viruses in winged strawberry aphid Chaetosiphon fragaefolii (Cockerell) (Hemiptera: Aphididae) specimens captured; 2) determine the prevalence of all viruses in wild strawberry Fragaria virginiana Miller plants near commercial plantings; and 3) evaluate the viral contamination of strawberry transplants obtained from nurseries and tested before and after planting in commercial strawberry fields. Results indicated high percentage (38%) of the aphids (n = 205) and high percentage (67%) of F. virginiana patches (n = 12) were infected by strawberry viruses. Ultimately, our results showed a low percentage (5%) of the plants from various nurseries (n = 56) were infected before planting, whereas a third (29%) of the healthy exposed plants in the fields (n = 96) became rapidly infected by insect vectors within a year of having been planted. This study provides significant insights on the relative importance of the various sources of contamination in Quebec strawberry fields: C. fragaefolii versus F. virginiana versus nurseries versus post-nursery infections through exposure to virus-carrying insects.

Sexual composition of populations of Fragaria virginiana (Rosaceae) collected from Minnesota and western Wisconsin

1995 ◽  
Vol 73 (9) ◽  
pp. 1457-1463 ◽  
Author(s):  
Margaret M. Stahler ◽  
Peter D. Ascher ◽  
James J. Luby ◽  
Alan P. Roelfs
Keyword(s):  
Plant Communities ◽  
Gender Composition ◽  
Fragaria Vesca ◽  
Fragaria Ananassa ◽  
Northern Forest ◽  
Gender Expression ◽  
Sexual Composition ◽  
Consistent Manner ◽  
Fragaria Virginiana ◽  
Collection Sites

Populations of Fragaria virginiana Miller collected from 39 sites in Minnesota and western Wisconsin were gynodioecious, in that 35% of the plants were pistillate, 65% were hermaphroditic with perfect flowers, and none were staminate, when scored for gender expression in greenhouse or field plantings. Instability of gender expression across environments was apparent in 15% of the collections and these genotypes that appeared to change gender were termed weak hermaphrodites. Variation in gender composition of collections was not related in any consistent manner with the plant communities characterizing the collection sites. The proportions of pistillate plants, total hermaphrodites, strong hermaphrodites, and weak hermaphrodites in collections from the northern forest floristic province in the northeastern part of the region were not significantly different from those of collections from the southwestern prairie-forest floristic region, although collections from the prairie-forest province were more variable for gender composition than populations from the northern forest province. Lack of staminate plants and increased percentages of hermaphrodite plants, relative to reports in the literature, suggest that the gender composition of F. virginiana populations in Minnesota has changed, perhaps as a result of introgression from hermaphroditic Fragaria ×ananassa or Fragaria vesca. Key words: Fragaria chiloensis, Fragaria vesca, Fragaria ×ananassa, dioecy, introgression, evolution.

scholarly journals Cardio-ventilatory coupling in young healthy resting subjects

2012 ◽  
Vol 112 (8) ◽  
pp. 1248-1257 ◽  
Author(s):  
Lee Friedman ◽  
Thomas E. Dick ◽  
Frank J. Jacono ◽  
Kenneth A. Loparo ◽  
Amir Yeganeh ◽  
...  
Keyword(s):  
Body Surface ◽  
Relative Importance ◽  
Statistical Relationship ◽  
Sinus Arrhythmia ◽  
Retest Reliability ◽  
Respiratory Events ◽  
Before And After ◽  
Test Retest Reliability ◽  
Degree Of Coupling ◽  
High Test

In this work, cardio-ventilatory coupling (CVC) refers to the statistical relationship between the onset of either inspiration (I) or expiration (E) and the timing of heartbeats (R-waves) before and after these respiratory events. CVC was assessed in healthy, young (<45 yr), resting, supine subjects ( n = 19). Four intervals were analyzed: time from I-onset to both the prior R-wave (R-to-I) and the following R-wave (I-to-R), as well as time from E-onset to both the prior R-wave (R-to-E) and following R-wave (E-to-R). The degree of coupling was quantified in terms of transformed relative Shannon entropy (tRSE), and χ2 tests based on histograms of interval times from 200 breaths. Subjects were studied twice, from 5 to 27 days apart, and the test-retest reliability of CVC measures was computed. Several factors pointed to the relative importance of the R-to-I interval compared with other intervals. Coupling was significantly stronger for the R-to-I interval, coupling reliability was largest for the R-to-I interval, and only tRSE for the R-to-I interval was correlated with height, weight, and body surface area. The high test-retest reliability for CVC in the R-to-I interval provides support for the hypothesis that CVC strength is a subject trait. Across subjects, a peak ∼138 ms prior to I-onset was characteristic of CVC in the R-to-I interval, although individual subjects also had earlier peaks (longer R-to-I intervals). CVC for the R-to-I interval was unrelated to two separate measures of respiratory sinus arrhythmia (RSA), suggesting that these two forms of coupling (CVC and RSA) are independent.

scholarly journals Factors Determining Transmission of Persistent Viruses by Bemisia tabaci and Emergence of New Virus–Vector Relationships

Viruses ◽  
2021 ◽  
Vol 13 (9) ◽  
pp. 1808
Author(s):  
Saptarshi Ghosh ◽  
Murad Ghanim
Keyword(s):  
Bemisia Tabaci ◽  
Plant Viruses ◽  
Tomato Yellow Leaf ◽  
Tissue Tropism ◽  
Insect Vectors ◽  
Virus Species ◽  
Yellow Leaf ◽  
Virus Diseases ◽  
Persistent Viruses ◽  
Leaf Curl Virus

Many plant viruses depend on insect vectors for their transmission and dissemination. The whitefly Bemisia tabaci (Hemiptera: Aleyrodidae) is one of the most important virus vectors, transmitting more than four hundred virus species, the majority belonging to begomoviruses (Geminiviridae), with their ssDNA genomes. Begomoviruses are transmitted by B. tabaci in a persistent, circulative manner, during which the virus breaches barriers in the digestive, hemolymph, and salivary systems, and interacts with insect proteins along the transmission pathway. These interactions and the tissue tropism in the vector body determine the efficiency and specificity of the transmission. This review describes the mechanisms involved in circulative begomovirus transmission by B. tabaci, focusing on the most studied virus in this regard, namely the tomato yellow leaf curl virus (TYLCV) and its closely related isolates. Additionally, the review aims at drawing attention to the recent knowhow of unorthodox virus—B. tabaci interactions. The recent knowledge of whitefly-mediated transmission of two recombinant poleroviruses (Luteoviridae), a virus group with an ssRNA genome and known to be strictly transmitted with aphids, is discussed with its broader context in the emergence of new whitefly-driven virus diseases.

scholarly journals Using wild strawberry of the Sakha (Yakutia) Republic in breeding garden strawberry (Fragaria × ananassa Duch.)

2021 ◽  
Vol 38 ◽  
pp. 00012
Author(s):  
Sergey Baturin ◽  
Valentina Belevtsova
Keyword(s):  
High Risk ◽  
Fragaria Ananassa ◽  
Open Pollination ◽  
Selection Technique ◽  
Resistant Cultivars ◽  
Central Yakutia ◽  
Wild Strawberry ◽  
Growing Conditions

In Central Yakutia, cultivating of Fragaria × ananassa varieties involves high risk of frost-killing. To create winter-resistant cultivars of garden strawberry there was performed open pollination under the conditions of redundant pollen background of local wild strawberry F. mandshurica Staudt. Most seedlings grown from the achenes thus developed retain specific characters of F. × ananassa. The stock of selected seedlings was established. Creation of the varieties adapted to the local growing conditions proves the selection technique to be successful.

scholarly journals Studies on the transmission of sugar-beet yellows virus by the aphis, Myzus persicae (Sulz.)

1940 ◽  
Vol 128 (853) ◽  
pp. 535-552 ◽  
Keyword(s):  
Sugar Beet ◽  
Myzus Persicae ◽  
Plant Viruses ◽  
Insect Vectors ◽  
Source Of Infection ◽  
Persistent Viruses ◽  
Beet Yellows Virus ◽  
The Relationship

Previous studies on the relationship between plant viruses and their insect vectors have been carried out which viruses which are easily mechanically transmissible and whose vectors lose their infectivity within a few hours of removal from the source of infection. This type of virus has been called (Watson and Roberts 1939) non-persistent , for it was observed that the property in which viruses of this type resemble each other, and differ from those viruses whose vectors retain their infectivity for long periods, namely, the persistent viruses. It seems that these differences must lie in the nature of the viruses themselves, for viruses of both types can be transmitted by the same vector. Sugar-beet yellows virus (Petherbridge and Stirrup 1935) seems to be a member of the persistent class, for its vector, Myzus persicae , the same insect as was used in previous work on non-persistent viruses (Watson 1936, 1938; Watson and Roberts 1939), remains infective for several days after removal from the source of infection (Roland 1939). Also it is not transmissible mechanically by any of the usual methods (Quanjer 1934, 1936). The present paper, therefore, describes some studies on the vector-virus relationships of this virus by the methods which have been used previously only on the non-persistent types.

The effects of a hurricane on seedling dynamics and abiotic interactions in a tropical lower montane wet forest

2013 ◽  
Vol 30 (1) ◽  
pp. 55-66 ◽  
Author(s):  
Denneko Luke ◽  
Kurt McLaren ◽  
Byron Wilson
Keyword(s):  
Common Species ◽  
Relative Importance ◽  
Seedling Density ◽  
Negative Effects ◽  
Lower Growth ◽  
Permanent Sample Plots ◽  
Seedling Dynamics ◽  
Before And After ◽  
Abiotic Interactions ◽  
Periodic Changes

Abstract:We assessed seedling dynamics and understorey light before and after a hurricane in five randomly selected 5 × 5-m subplots, within 30 permanent sample plots covering a total area of 3750 m2 in a lower montane wet tropical forest, Jamaica over a period of 3 y. Understorey light increased (≈ 60%) following the passage of Hurricane Dean in 2007 but decreased in 2009. Overall, seedling density was positively related to light and survivorship was positively related to both light and density. Mortality was significantly lower and most species recorded their highest growth when the canopy was open (2007–2008). However, lower diversity during this period coincided with higher (average) mortality of uncommon species. The hurricane altered the relative importance of interactions between light, seedling density and dynamics. Consequently, interactions were significant before or 2 y after but not 1 y after the hurricane and their significance varied among the years and species. Periodic changes in the importance of these interactions and the effects of the hurricane were used to separate 12 common species along a continuum of responses, which ranged from positive (lower mortality), neutral to negative (lower growth). Our results indicate that hurricanes have positive and negative effects on seedling dynamics; therefore an increase in the intensity and frequency of hurricanes will likely alter seedling composition, and hence forest structure.

Early weaning of lambs: effect of various preweaning factors on voluntary food intake before and after weaning

1981 ◽  
Vol 32 (1) ◽  
pp. 89 ◽  
Author(s):  
DM Walker ◽  
SG Hunt
Keyword(s):  
Birth Weight ◽  
Food Intake ◽  
Milk Intake ◽  
Solid Food ◽  
Relative Importance ◽  
Early Weaning ◽  
Before And After ◽  
Voluntary Food Intake

Fifty-two crossbred lambs were used in four experiments to study the relative importance of such factors as birth weight, sex, age of weaning, provision of extra salt, and restriction of milk intake, on the intake of solid food (pellets) both before and after weaning, and on the growth check after weaning. Experiment I was a 2 x 2 x 2 factorial (sex x birth weight x weaning at 21 or 42 days) with 24 lambs. All lambs were given milk to appetite until they had made an estimated gain of 23 MJ; milk intake then restricted to a maintenance level. Twelve lambs were weaned at 21 days and the remainder were given milk sufficient for maintenance up to 42 days, when the experiment was terminated. Three out of six lambs that weighed less than 2.7 kg at birth died when weaned abruptly off milk at 21 days. Lambs that were heavy at birth (> 3.4 kg) survived weaning at 21 days but had a growth check of 11 � 5 days. Both the heavy and light birth weight lambs that were given a restricted intake of milk daily from 22 to 42 days ate similar amounts of pellets between 22 and 42 days, but less than those eaten by the heavy birth weight lambs weaned at 21 days. There was no effect of sex on pellet intake or on the length of the growth check. In experiment 2 the provision of a block of salt from 10 days of age had no significant effect on pellet intake before or after weaning at 28 days. In experiments 3 and 4 the milk intake of half of the lambs in each experiment was restricted to a maintenance level for 7 days before weaning. In experiment 3 the lambs weighed more than 3.6 kg at birth and were weaned at 21 days. Restriction of milk intake was without effect either on the intake of pellets before and after weaning or on the length of the growth check. In experiment 4 the lambs weighed less than 3.2 kg at birth and were weaned at 35 days. Lambs given a restricted intake of milk from 29 to 35 days ate significantly more pellets both before and after weaning and had a significantly shorter check to growth than lambs given milk to appetite until weaning.

scholarly journals Porites superfusamortality and recovery from a bleaching event at Palmyra Atoll, USA

PeerJ ◽  
2017 ◽  
Vol 5 ◽  
pp. e3204 ◽  
Author(s):  
Kathryn Anne Furby ◽  
Jennifer Ellen Smith ◽  
Stuart Adrian Sandin
Keyword(s):  
Reproductive Output ◽  
Enso Event ◽  
Survival Strategies ◽  
Relative Importance ◽  
Coral Recruitment ◽  
Partial Mortality ◽  
Central Pacific ◽  
Life And Death ◽  
Coral Colony ◽  
Before And After

BackgroundThe demography of a coral colony is not a binary trajectory of life and death. Based on the flexibility afforded by colonial organization, most reef-building corals employ a variety of dynamic survival strategies, including growth and shrinkage. The demographic flexibility affects coral size, shape and reproductive output, among other factors. It is thus critical to quantify the relative importance of key dynamics of recruitment, mortality, growth and shrinkage in changing the overall cover of coral on a reef.MethodsUsing fixed photographic quadrats, we tracked the patterns of change in the cover of one common central Pacific coral,Porites superfusa, before and after the 2009 ENSO event.ResultsCoral colonies suffered both whole and partial colony mortality, although larger colonies were more likely to survive. In subsequent years, recruitment of new colonies and regrowth of surviving colonies both contributed to the modest recovery ofP. superfusa.DiscussionThis study is unique in its quantitative comparisons of coral recruitment versus regrowth during periods of areal expansion. Our data suggest that recovery is not limited simply to the long pathway of settlement, recruitment and early growth of new colonies but is accelerated by means of regrowth of already established colonies having suffered partial mortality.

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