scholarly journals Effects of Host Physiology on the Development of Core Rot, Caused by Alternaria alternata, in Red Delicious Apples

2012 ◽  
Vol 102 (8) ◽  
pp. 769-778 ◽  
Author(s):  
D. Shtienberg
Keyword(s):  
Environmental Conditions ◽  
Coefficient Of Variation ◽  
Alternaria Alternata ◽  
Large Variability ◽  
Yield Load ◽  
Fungicide Application ◽  
Host Physiology ◽  
Pathogen Occurrence ◽  
Core Symptoms ◽  
Morisita's Index

Alternaria alternata is the predominant fungus involved in moldy core and core rot of Red Delicious apples. The effects of environmental conditions during bloom on moldy core and core rot, and on the need for fungicide application, were examined in 10 experiments carried out in 2007. In untreated experimental plots, typical moldy core symptoms were very common, with relatively low variability (coefficient of variation: 22.2%) among experiments; core rot incidence ranged from 2 to 26% with large variability (coefficient of variation: 90.0%) among experiments. No evidence of prevailing environmental conditions during bloom affecting the development of moldy core or core rot was detected. No effect of fungicide application (a mixture of bromuconazole + captan three times a week at bloom) on moldy core or core rot was found. A random distribution of moldy core and an occasional aggregation of core rot in the orchards were indicated from Morisita's index of dispersion (Iδ). The hypothesis that core rot incidence is governed by host physiology and that yield load can be used as an indicator of trees' susceptibility was examined in a set of eight observations and four experiments. No correlation was found between tree yield load and moldy core, but core rot incidence was inversely related to yield load. Furthermore, irrespective of tree yield load, core rot was more abundant on large compared with small fruits. It is concluded that host physiology, rather than pathogen occurrence or environmental conditions at bloom stage, governs the development of core rot in Red Delicious apples caused by A. alternata in Israel.

scholarly journals Delayed effect of drought on the xylem vulnerability to cavitation in Fagus sylvatica L.

2020 ◽  
Author(s):  
Stephane Herbette ◽  
Olivia Charrier ◽  
Herve Cochard ◽  
Tete Severien Barigah
Keyword(s):  
Drought Resistance ◽  
Environmental Conditions ◽  
European Beech ◽  
Severe Drought ◽  
Delayed Effect ◽  
Large Variability ◽  
Xylem Structure ◽  
Vulnerability To Cavitation ◽  
Xylem Vulnerability ◽  
Fagus Sylvatica L

Knowledge on variations of drought resistance traits is needed to predict the potential of trees to adapt to severe drought events expected to be more intense and frequent. Xylem vulnerability to cavitation is among the most important traits related to drought-induced mortality and exhibits a large variability between species. Acclimation of this trait to environmental conditions implies changes in the xylem structure and organization, leading previous studies to investigate its variations under conditions preserving growth. In European beech saplings, we assessed the effect of droughts of on the vulnerability to cavitation in branches that develop during recovery. The newly formed branches displayed lower vulnerability to cavitation in the plants that underwent the severest droughts leading to native embolism; the pressure that induces 50% loss of conductance being of -3.98 MPa in severely droughted plants whereas it was of -3.1 MPa in control plants, respectively. Although unexpected, these results argue for an acclimation, and not a weakening, of this trait to drought events.

scholarly journals Comparative epidemiology of late blight and early blight of potato under different environmental conditions and fungicide application programs

2019 ◽  
Vol 40 (5) ◽  
pp. 1805 ◽  
Author(s):  
Henrique da Silva Silveira Duarte ◽  
Laércio Zambolim ◽  
Franklin Jackson Machado ◽  
Hitor Rafael Pereira Porto ◽  
Fabricio Avila Rodrigues
Keyword(s):  
Late Blight ◽  
Environmental Conditions ◽  
Early Blight ◽  
Block Design ◽  
Yield Losses ◽  
Yield Data ◽  
Fungicide Application ◽  
Progress Curve ◽  
Comparative Epidemiology ◽  
Application Programs

Three experiments were carried out in an experimental field from Viçosa city, Minas Gerais, Brazil, to compare late blight (LB) (Phytophthora infestans) and early blight (EB) (Alternaria grandis) epidemics under different environmental conditions and fungicide application programs. Each experiment consisted of two side-by-side trials that were arranged in a randomized complete block design with five treatments and five replications. At 30 days after planting the potato (‘Ágata’ cultivar) plants in plots of trials 1 and 2 were inoculated with an isolate of P. infestans (A2 mating type) and four isolates of A. grandis, respectively. Fungicide applications were initiated at seven days after inoculation and repeated at 7- or 15-day intervals. The severity of LB and EB was assessed every two days, and the area under disease progress curve (AUDPC) was calculated for both diseases. The yield was quantified by weighing the tubers of all the plants from each plot after their maturation. Yield data were converted into kg ha-1 and the percentage of loss was calculated for each treatment. Based on the AUDPC, the LB severity was greater than the EB severity under all three environmental conditions, and this was reflected in the yield. LB and EB caused yield losses as high as of 82 and 45%, respectively. The fungicide effects on both LB and EB and the associated yield losses changed according to the environmental conditions, therefore, indicating the importance of using tools such as a forecast system to help farmers to decide the best time for fungicide application.

Evaluation of Sample Preparation Parameters in the Compressive Strength of Cementitious Composites

2016 ◽  
Vol 869 ◽  
pp. 93-97 ◽  
Author(s):  
Ana Luiza de Figueiredo Maia ◽  
Natalia Oliveira Sena ◽  
Laura Luíza de Melo Sapori Oliveira ◽  
Gabriela Melo Pereira ◽  
Mateus Justino da Silva ◽  
...  
Keyword(s):  
Compressive Strength ◽  
Sample Preparation ◽  
Compression Strength ◽  
Environmental Conditions ◽  
Coefficient Of Variation ◽  
Experimental Evaluation ◽  
Laboratory Tests ◽  
Load Application ◽  
Cementitious Composites

This paper presents an experimental evaluation of how variations in proposed parameters interfere with compressive strength resistance of mortar and concrete specimens. The results were obtained through laboratory tests in which samples were tested under varying conditions. These conditions were as follows: speed of load application (0.25, 0.50, 0.75, and 1.00 MPa/s), environmental conditions (saturated, 2 h dried, and 24 h dried specimens), curing (dry and wet), and specimen ends preparation (sulphur, neoprene, rectification, and without regularization). Comparisons were made on the basis of the compression strength resistance results and the coefficient of variation in order to analyse the homogeneity and dispersion among variables. It was found that in the case of capping, the best results were obtained by the rectification of concrete specimens. In the case of loading speed, the best results were obtained at a speed of 1 MPa/s. Dry curing showed the best results, even though not resulting in the highest resistance. The results for specimen conditions were in accordance with the expectations, with lower dispersion for saturated specimens.

Management of Alternaria Leaf Blight in Pigeonpea through Host Plant Resistance and Micronutrient Application

2021 ◽  
Author(s):  
E. Rajeswari ◽  
P. Akiladevi ◽  
P. Jayamani
Keyword(s):  
Alternaria Alternata ◽  
Untreated Control ◽  
Field Experiments ◽  
Leaf Blight ◽  
Plant Diseases ◽  
Grain Legume ◽  
Resistant Variety ◽  
Minor Importance ◽  
Fungicide Application ◽  
Blight Disease

Background: Pigeonpea [Cajanus cajan (L.) Millsp] is one of the primary grain legume crops grown in India for its high quality vegetable protein, animal feed and fodder. It is affected by various fungal and viral diseases. Among these, leaf blight caused by Alternaria alternata is one of the most destructive diseases and recently the disease of minor importance becomes major one in Tamil Nadu. Use of resistant cultivar is the most effective, economically viable and eco-friendly tool for combating the plant diseases. The micronutrients play a key role in many physiological and biochemical functions of the plants which influences plant pathogenic interaction. The micronutrients viz., Zn.Mn,Cu and Fe found to have greater impact on reducing the plant disease severity. Developing integrated disease management strategy involving disease resistant variety, micronutrient and fungicide application would be the best sustainable method for controlling the pigeonpea leaf blightMethods: Twenty four pigeonpea genotypes along with two local varieties viz., CO5 and CO6 were evaluated in the field for their resistance against Alternaria alternata leaf blight disease, consecutively for three years from 2015-16 to 2017-18 using the disease resistance scale ranging from 0 to 9. Field experiments were also conducted for three consecutive Kharif season from 2015 to 2018 to evaluate the efficacy of the foliar application of different micronutrients and combination fungicide viz., carbendazim 12% + mancozeb 63% on the incidence of leaf blight disease. Result: A total of 24 pigeonpea genotypes were screened for their resistance against leaf blight under field condition. Among these, four genotypes viz., BDN2, IPA 8F, IPA 15F and MA6 were found resistance and nine genotypes were moderately resistant and remaining 11 genotypes showed susceptible reaction to leaf blight. The results of the field experiment on micronutrient and fungicide application revealed that foliar spraying of MnSO 4 @0.2% on 30 days after sowing and carbendazim 12%+ mancozeb 63%@ 1g / lit on 45 days after sowing recorded the lowest leaf blight incidence of 8.1 PDI (Per cent Disease Index) with the highest disease reduction of 76.9% as against 35 PDI in the untreated control plot. The above treatments also recorded the highest grain yield of 905 kg/ ha as against 703 kg/ in the untreated control.

Performance of carrot seeds possessing different germination rates within a seed lot

1988 ◽  
Vol 110 (1) ◽  
pp. 93-99 ◽  
Author(s):  
W. E. Finch-Savage ◽  
C. I. McQuistan
Keyword(s):  
Environmental Conditions ◽  
Coefficient Of Variation ◽  
Germination Rate ◽  
Seedling Emergence ◽  
Seedling Performance ◽  
Controlled Conditions ◽  
Carrot Seed ◽  
The Relationship ◽  
Fluid Drilling

SummaryThe relationship between germination rate within a carrot seed lot and subsequent seedling performance was studied in four seed lots of different viability. Seedling performance was assessed using slope tests conducted under controlled conditions and in the field following fluid drilling under a range of environmental conditions. Germination rate within a seed lot was positively related to vigour measured by slope tests, percentage emergence and seedling weight, and was negatively related to the spread of emergence times (In variance days) and the coefficient of variation (c.v.) of seedling weights. Sowing seeds selected as fast germinating resulted in greater seedling emergence percentages over a range of environmental conditions than when sowing seeds selected as slowly germinating.

DECISION-LEVEL FUSION OF PCA AND LDA-BASED FACE RECOGNITION ALGORITHMS

2006 ◽  
Vol 06 (02) ◽  
pp. 293-311 ◽  
Author(s):  
GIAN LUCA MARCIALIS ◽  
FABIO ROLI
Keyword(s):  
Face Recognition ◽  
Environmental Conditions ◽  
Principal Component ◽  
Environmental Parameters ◽  
Recognition System ◽  
Large Variability ◽  
Linear Discriminant ◽  
Decision Level ◽  
Recognition Algorithms ◽  
The Individual

In this paper, a face recognition system based on the fusion of two well-known appearance-based algorithms, namely Principal Component Analysis (PCA) and Linear Discriminant Analysis (LDA), is proposed. Fusion is performed at the decision-level, that is, the outputs of the individual face recognition algorithms are combined. Two main benefits of such fusion are shown. First, the reduction of the dependence on the environmental conditions with respect to the best individual recognizer. Secondly, the overall performance improvement over the best individual recognizer. To this end, fusion is investigated under different environmental conditions, namely, "ideal" conditions, characterized by a very limited variability of environmental parameters, and "real" conditions with large variability of lighting and face expressions.

The influence of plant raising conditions on the head weight of crisp lettuce at maturity

1982 ◽  
Vol 99 (2) ◽  
pp. 417-423 ◽  
Author(s):  
D. C. E. Wurr ◽  
Jane R. Fellows
Keyword(s):  
Environmental Conditions ◽  
Coefficient Of Variation ◽  
Artificial Lighting ◽  
Lower Amplitude ◽  
Head Weight ◽  
Similar Weight ◽  
Supplementary Lighting ◽  
And Tungsten

SUMMARYTwo experiments investigated the effects of raising crisp lettuce seedlings under different environmental conditions prior to transplanting, on transplant size and weight and head weight at maturity.The use of tungsten lighting for 4 h after the end of a 12 h period of fluorescent and tungsten lighting increased transplant size and weight and the weight of heads at maturity compared with fluorescent and tungsten lighting only. Glasshouse-raised transplants were larger than those raised under artificial lighting but gave heads of similar weight to transplants which had supplementary tungsten lighting for 2 weeks. Both these treatments gave significantly heavier heads than a drilled crop or plants raised without supplementary tungsten lighting. Increasing the number of weeks of the supplementary lighting treatment tended to increase the coefficient of variation (c.v.) of head weight. Nevertheless the drilled crop had a higher c.v. of head weight than any transplanted treatment.The variety Pennlake produced pointed (‘coned’) heads when grown in the open and its leaves were shorter and broader than those of plants grown in polyethylene tunnels, which did not show ‘coning’. It is suggested that ‘coning’ occurs primarily as a result of either lower mean temperatures or a lower amplitude of temperature when grown in the open. It occurred most frequently with glasshouse-raised plants indicating that a higher raising temperature may also contribute to the problem.

An evaluation of feedblocks as a means of providing supplementary nutrients to ewes grazing upland/hill pastures

1981 ◽  
Vol 33 (1) ◽  
pp. 51-57 ◽  
Author(s):  
M. J. Ducker ◽  
P. T. Kendall ◽  
R. G. Hemingway ◽  
T. H. McClelland
Keyword(s):  
Environmental Conditions ◽  
Individual Variation ◽  
Coefficient Of Variation ◽  
Chromium Content ◽  
Chromic Oxide ◽  
Grazing Area

ABSTRACTA series of trials was conducted to measure the extent of individual variation in feedblock intake for ewes on upland/hill farms. From 15 flocks on nine farms 4284 ewes were selected with a range of environmental conditions and levels of performance. Ewes were given either Rumevite, Norbloc or Wintawell feedblocks containing chromic oxide. Faecal grab samples were taken per rectum from individual ewes and analysed for their chromium content to obtain estimates of feedblock consumption.The results showed that provision of feedblocks does not ensure a uniform intake of supplementary nutrients by sheep in upland/hill situations. On average, 19% of the 2931 ewes sampled had not eaten the feedblock on offer. The proportion of ewes not consuming feedblock varied from flock to flock (0 to 67%). The coefficient of variation of faecal chromium concentrations varied between flocks (46 to 231%). The reasons for the large variation in intakes observed are discussed. Feedblock intake was significantly affected by the grazing area per ewe (P<0·01) and the age of ewes (P<0·05 to P< 0·001).

scholarly journals Heterothermy as the Norm, Homeothermy as the Exception: Variable Torpor Patterns in the South American Marsupial Monito del Monte (Dromiciops gliroides)

2021 ◽  
Vol 12 ◽  
Author(s):  
Roberto F. Nespolo ◽  
Carlos Mejías ◽  
Angelo Espinoza ◽  
Julián Quintero-Galvis ◽  
Enrico L. Rezende ◽  
...  
Keyword(s):  
Environmental Conditions ◽  
Field Experiments ◽  
Linear Models ◽  
Adaptive Strategy ◽  
Water Shortage ◽  
Reproductive Period ◽  
Information Criteria ◽  
Daily Torpor ◽  
Large Variability ◽  
Body Mass Changes

Hibernation (i.e., multiday torpor) is considered an adaptive strategy of mammals to face seasonal environmental challenges such as food, cold, and/or water shortage. It has been considered functionally different from daily torpor, a physiological strategy to cope with unpredictable environments. However, recent studies have shown large variability in patterns of hibernation and daily torpor (“heterothermic responses”), especially in species from tropical and subtropical regions. The arboreal marsupial “monito del monte” (Dromiciops gliroides) is the last living representative of the order Microbiotheria and is known to express both short torpor episodes and also multiday torpor depending on environmental conditions. However, only limited laboratory experiments have documented these patterns in D. gliroides. Here, we combined laboratory and field experiments to characterize the heterothermic responses in this marsupial at extreme temperatures. We used intraperitoneal data loggers and simultaneous measurement of ambient and body temperatures (TA and TB, respectively) for analyzing variations in the thermal differential, in active and torpid animals. We also explored how this differential was affected by environmental variables (TA, natural photoperiod changes, food availability, and body mass changes), using mixed-effects generalized linear models. Our results suggest that: (1) individuals express short bouts of torpor, independently of TA and even during the reproductive period; (2) seasonal torpor also occurs in D. gliroides, with a maximum bout duration of 5 days and a mean defended TB of 3.6 ± 0.9°C (one individual controlled TB at 0.09°C, at sub-freezing TA); (3) the best model explaining torpor occurrence (Akaike information criteria weight = 0.59) discarded all predictor variables except for photoperiod and a photoperiod by food interaction. Altogether, these results confirm that this marsupial expresses a dynamic form of torpor that progresses from short torpor to hibernation as daylength shortens. These data add to a growing body of evidence characterizing tropical and sub-tropical heterothermy as a form of opportunistic torpor, expressed as daily or seasonal torpor depending on environmental conditions.

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