Some factors affecting the development and biocontrol of cotton seedling disease

1995 ◽  
Vol 35 (6) ◽  
pp. 771 ◽  
Author(s):  
HJ Ogle ◽  
AM Stirling ◽  
PJ Dart
Keyword(s):  
Pythium Ultimum ◽  
Disease Development ◽  
Symptom Development ◽  
Night Temperature ◽  
Factors Affecting ◽  
Seedling Disease ◽  
Susceptibility To Infection ◽  
Temperature Regimes ◽  
Effects Of Temperature ◽  
Number Of Seeds

The effects of temperature and cultivar on disease development in cotton were investigated in addition to the duration of susceptibility to infection and the timing of infection by Pythium ultimum and Rhizoctonia solani. Symptom development was also monitored. Disease was more severe at day/night temperature regimes of 20/15, 25/20, and 30/25�C than at 35/30�C. Disease development differed significantly between cotton cvv. Deltapine 90 and Siokra 1-4 at 30/25�C and 35/30�C. In glasshouse trials in field soil, both R. solani and P ultimum were isolated from seeds as early as 2 h after inoculation, although most seeds were not infected with P. ultimum until 10 h after inoculation and with R. solani until 24 h after inoculation. Increasing the duration of exposure to inoculum increased the number of seeds infected and reduced the number of plants surviving. Seedlings were resistant to P. ultimum infection by 14 days after sowing but were not resistant to infection by R. solani until 28 days after sowing.

STUDIES ON THE SEEDLING DISEASE OF BARLEY CAUSED BY HELMINTHOSPORIUM SATIVUM P.K. & B.

1956 ◽  
Vol 34 (4) ◽  
pp. 653-673 ◽  
Author(s):  
R. A. Ludwig ◽  
R. V. Clark ◽  
J. B. Julien ◽  
D. B. Robinson
Keyword(s):  
Disease Incidence ◽  
Infested Soil ◽  
Disease Development ◽  
Toxic Activity ◽  
Factors Affecting ◽  
Seedling Disease ◽  
Nutrient Salt ◽  
Helminthosporium Sativum ◽  
Treatment Comparisons

A standard sand – cornmeal – nutrient salt medium, for use in the production of artificial inoculum of Helminthosporium sativum, is described. This inoculum induces uniform plant disease development when thoroughly incorporated with the planting soil. The results presented clearly demonstrate the necessity of using a series of infestation levels in studies of factors affecting disease development in artificially infested soil. It is shown that considerable reliance can be placed on treatment comparisons within an experiment but that comparisons between experiments are much less accurate. The role of a toxin (or toxins) in disease development in barley seedlings has been demonstrated. The toxic activity was found to be distinct from that frequently encountered on addition of organic matter to soil. Results obtained suggest that toxin adsorption by the soil may play an important role in reducing disease incidence and severity.

scholarly journals Effects of Temperature on ‘Candidatus Liberibacter solanacearum’ and Zebra Chip Potato Disease Symptom Development

Plant Disease ◽  
2012 ◽  
Vol 96 (1) ◽  
pp. 18-23 ◽  
Author(s):  
Joseph E. Munyaneza ◽  
Venkatesan G. Sengoda ◽  
Jeremy L. Buchman ◽  
Tonja W. Fisher
Keyword(s):  
Insect Vector ◽  
Symptom Development ◽  
Zebra Chip ◽  
Slow Development ◽  
Temperature Regimes ◽  
Candidatus Liberibacter ◽  
Citrus Huanglongbing ◽  
Polymerase Chain ◽  
Effects Of Temperature ◽  
Important Disease

Temperature has been shown to have a significant effect on development of liberibacter species associated with citrus Huanglongbing disease. ‘Candidatus Liberibacter africanus’ and ‘Ca. L. americanus’ are both heat sensitive, whereas ‘Ca. L. asiaticus’ is heat tolerant. The recently described ‘Ca. L. solanacearum’ is associated with zebra chip (ZC), a newly emerging and economically important disease of potato worldwide. This psyllid-transmitted liberibacter species severely affects several other solanaceous crops and carrot. Experiments were conducted to evaluate effects of temperature on development of ‘Ca. L. solanacearum’ and ZC disease. Potato plants were inoculated with ‘Ca. L. solanacearum’ by briefly exposing them to liberibacter-infective potato psyllids at various temperatures under laboratory conditions. Following insect exposure, the plants were maintained at selected temperature regimes in growth chambers, monitored for ZC symptom development, and later tested for liberibacter by polymerase chain reaction to confirm infection. Results indicated that temperatures below 17°C appear to slow development of ‘Ca. L. solanacearum’ and ZC symptoms, whereas temperatures above 32°C are detrimental to this liberibacter. Compared to Huanglongbing liberibacters, ‘Ca. L. solanacearum’ appears heat sensitive. The sensitivity of this bacterium and its insect vector to temperature may partially explain incidence, severity, and distribution of ZC in affected regions.

Factors Affecting Germination and Emergence of Dame's Rocket (Hesperis matronalis)

Weed Science ◽  
2008 ◽  
Vol 56 (3) ◽  
pp. 389-393 ◽  
Author(s):  
David J. Susko ◽  
Yara Hussein
Keyword(s):  
Cold Stratification ◽  
Continuous Darkness ◽  
Solution Ph ◽  
Factors Affecting ◽  
Dry Storage ◽  
Edaphic Conditions ◽  
Temperature Regimes ◽  
Physiological Dormancy ◽  
Effects Of Temperature ◽  
Osmotic Potentials

Laboratory experiments were conducted to determine the effects of temperature, light, cold stratification, dry storage, solution pH, solution osmotic potential, and planting depth on germination and emergence of dame's rocket. Maximal germination (> 80%) of fresh seeds occurred at alternating temperatures ≥ 25/15 C in both alternating light/dark and continuous darkness. However, < 10% of seeds germinated at or below 20/10 C, with lower germination in the presence of light than in darkness. Cold stratification at 4 C for 4 to 16 wk enhanced germination at low alternating temperatures (≤ 20/10 C), but depressed germination at warm temperature regimes (≥ 25/15 C). After 1 yr of dry storage (after-ripening), germination exceeded 94% and did not differ significantly among temperature regimes. Germination exceeded 60% in solutions with pH 3 to 10. Germination was reduced below 50% in solutions with osmotic potentials below −0.6 MPa. Percent emergence was greater than 56% at burial depths in soil of 0 to 5 cm, with maximal emergence (93 to 99%) at 0 to 2 cm. Dame's rocket seeds possess non-deep physiological dormancy at maturity, but when dormancy is alleviated, the seeds are capable of germinating in a variety of climatic and edaphic conditions.

scholarly journals Seed Developmental Temperature Regulation of Thermotolerance in Lettuce

1998 ◽  
Vol 123 (4) ◽  
pp. 700-705 ◽  
Author(s):  
Yu Sung ◽  
Daniel J. Cantliffe ◽  
Russell T. Nagata
Keyword(s):  
Temperature Limit ◽  
Lettuce Seed ◽  
Night Temperature ◽  
Temperature Regimes ◽  
Percent Germination ◽  
Lettuce Seed Germination ◽  
Growth Chambers ◽  
Effects Of Temperature ◽  
Dark Green ◽  
High Soil Temperature

Lettuce (Lactuca sativa L.) seeds can fail to germinate at temperatures above 24 °C. The degree of thermotolerance is thought to be at least partly related to the environment under which the seed developed. In order to study the effects of temperature during seed development on subsequent germination, various lettuce genotypes were screened for their ability to germinate at temperatures ranging from 20 to 38 °C. Seeds of the selected genotypes `Dark Green Boston' and `Valmaine' (thermosensitive), `Floricos 83', `Everglades', and PI 251245 (thermotolerant) were produced at 20/10, 25/15, 30/20, and 35/25 °C day/night temperature regimes in plant growth chambers. Seeds were germinated on a thermogradient bar from 24 to 36 °C under 12 h light/dark cycles. As germination temperature increased, the number of seeds that failed to germinate increased. Above 27 °C, seeds matured at 20/10 or 25/15 °C exhibited a lower percent germination than seeds that matured at 30/20 or 35/25 °C. Seeds of `Dark Green Boston' and `Everglades' that matured at 30/20 °C exhibited improved thermotolerance over those that matured at lower temperatures. Seeds of `Valmaine' produced at 20/10 °C exhibited 40% germination at 30 °C, but seeds that matured at higher temperatures exhibited over 95% germination. Germination of `Valmaine' at temperatures above 30 °C was not affected by seed maturation temperature. The upper temperature limit for germination of lettuce seed could thus be modified by manipulating the temperature during seed production. The potential thermotolerance of seed thereby increased, wherein thermosensitive genotypes became thermotolerant and thermotolerant genotypes (e.g., PI251245) germinated fully at 36 °C. This information is useful for improving lettuce seed germination during periods of high soil temperature, and can be used to study the biology of thermotolerance in lettuce.

scholarly journals Substrate Acidification by Geranium: Temperature Effects

2008 ◽  
Vol 133 (4) ◽  
pp. 508-514 ◽  
Author(s):  
Matthew D. Taylor ◽  
Paul V. Nelson ◽  
Jonathan M. Frantz
Keyword(s):  
High Temperature ◽  
Dry Weight ◽  
Night Temperature ◽  
The Third ◽  
Temperature Regimes ◽  
Higher Temperature ◽  
Effects Of Temperature ◽  
Increasing Temperature ◽  
Substrate Ph ◽  
Tissue Phosphorus

Sudden pH decline (SPD) describes the situation where crops growing at an appropriate pH rapidly (within 1–2 weeks) cause the substrate pH to shift downward one to two units. ‘Designer Dark Red’ geraniums (Pelargonium ×hortorum Bailey) were grown in three experiments to assess possible effects of temperature on SPD. The first experiment tested the effect of four day/night temperature regimes (14 °C day/10 °C night, 18 °C day/14 °C night, 22 °C day/18 °C night, and 26 °C day/22 °C night) on substrate acidification. At 63 days after transplanting (DAT), substrate pH declined from 6.8 to 4.6 as temperature increased. Tissue phosphorus (P) of plants grown at the highest three temperatures was extremely low (0.10%–0.14% of dry weight), and P stress has been reported to cause acidification. It was not possible to determine if the drop in substrate pH was a singular temperature effect or a combination of high temperature and low P. To resolve this, a second experiment tested a factorial combination of the three highest temperatures from the first experiment and five preplant P rates (0, 0.065, 0.13, 0.26, or 0.52 g·L−1 substrate). Regardless of tissue P concentrations, which ranged from deficient to above adequate, substrate pH decreased with increasing temperature. At 63 DAT, in the 0.065 and 0.13 P treatments, tissue P was deficient and pH decreased with increasing temperature from 5.6 to 4.7 and 5.9 to 4.7, respectively. In the 0.26 P treatment, tissue P was adequate at the lowest temperature and there was no acidification. At the mid- and highest temperatures, tissue P was deficient and statistically equivalent, yet pH decreased to 5.2 and 4.7, respectively. In the highest P treatment, tissue P levels were unaffected by temperature, above adequate, and pH declined with each increase in temperature from 6.5 to 5.0. The results at 63 DAT once more showed that temperature acted independent of tissue P and caused geraniums to acidify the substrate. In the third experiment, the amount of acidity produced by roots of plants grown at the two highest temperatures used in the first two experiments was quantified. Plants grown at the higher temperature produced 28% more acid per gram dry root. The results herein indicate that high temperature can induce SPD by geranium.

scholarly journals Physiology of Sugar-Cane VII. Effects of Temperature, Photoperiod Duration, and Diurnal and Seasonal Temperature Changes on Growth and Ripening

1965 ◽  
Vol 18 (1) ◽  
pp. 53 ◽  
Author(s):  
KT Glasziou ◽  
TA Bull ◽  
MD Hatch ◽  
PC Whiteman
Keyword(s):  
Sugar Cane ◽  
Temperature Effects ◽  
Interaction Effects ◽  
Seasonal Temperature ◽  
Night Temperature ◽  
Temperature Changes ◽  
Temperature Regimes ◽  
Controlled Environments ◽  
Effects Of Temperature ◽  
Period Duration

Independent and interaction effects of day and night temperature, photo-period duration, and diurnal thermoperiodicity were studied on sugar-cane grown under controlled environments. During the first 3 months of growth, day and night temperature effects were mainly additive, but at 6 months the interaction effects of all variables were numerous and complex. Many of the interaction effects could be attributed to increased responses to constant-temperature regimes with a 12-hr photoperiod. No evidence for thermoperiodicity requirements was found.

scholarly journals Susceptibility of Selected Cotton Cultivars to Seedling Disease Pathogens and Benefits of Chemical Seed Treatments

Plant Disease ◽  
1997 ◽  
Vol 81 (9) ◽  
pp. 1085-1088 ◽  
Author(s):  
Heping Wang ◽  
R. Michael Davis
Keyword(s):  
Seed Treatment ◽  
Seedling Survival ◽  
Pythium Ultimum ◽  
Field Trials ◽  
Thielaviopsis Basicola ◽  
Symptom Development ◽  
Damping Off ◽  
Seedling Disease ◽  
Low Incidence ◽  
Greenhouse Tests

The susceptibility of 12 Upland cotton cultivars to three soilborne fungi, Pythium ultimum, Rhizoctonia solani, and Thielaviopsis basicola, was evaluated in greenhouse experiments. Based on symptom development and seedling survival, cultivars highly resistant to P. ultimum included Delta Pine (DP) 6166, Prema, DP 6100, and Maxxa. A relatively low incidence of pre-emergence damping-off caused by R. solani occurred in ChemBred 7, DP 6100, and Royale, although all cultivars subsequently suffered significant post-emergence damping-off. All cultivars were equally susceptible to T. basicola. In both greenhouse and field evaluations, there were no benefits of metalaxyl seed treatment in Pythium-resistant cultivars. Seed treatment with carboxin-pentachloronitrobenzene for the control of Rhizoctonia-induced damping-off resulted in stand increases in all 12 cultivars in greenhouse tests and in 3 of 6 cultivars in field trials.

scholarly journals Effects of temperature on the behaviour and metabolism of an intertidal foraminifera and consequences for benthic ecosystem functioning

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Noémie Deldicq ◽  
Dewi Langlet ◽  
Camille Delaeter ◽  
Grégory Beaugrand ◽  
Laurent Seuront ◽  
...  
Keyword(s):  
High Temperature ◽  
Ecosystem Functioning ◽  
Photosynthetic Activity ◽  
Species Traits ◽  
Biogeochemical Cycles ◽  
Variable Environment ◽  
Sediment Reworking ◽  
Temperature Regimes ◽  
Slow Moving ◽  
Effects Of Temperature

AbstractHeatwaves have increased in intensity, duration and frequency over the last decades due to climate change. Intertidal species, living in a highly variable environment, are likely to be exposed to such heatwaves since they can be emerged for more than 6 h during a tidal cycle. Little is known, however, on how temperature affects species traits (e.g. locomotion and behaviour) of slow-moving organisms such as benthic foraminifera (single-celled protists), which abound in marine sediments. Here, we examine how temperature influences motion-behaviour and metabolic traits of the dominant temperate foraminifera Haynesina germanica by exposing individuals to usual (6, 12, 18, 24, 30 °C) and extreme (high; i.e. 32, 34, 36 °C) temperature regimes. Our results show that individuals reduced their activity by up to 80% under high temperature regimes whereas they remained active under the temperatures they usually experience in the field. When exposed to a hyper-thermic stress (i.e. 36 °C), all individuals remained burrowed and the photosynthetic activity of their sequestered chloroplasts significantly decreased. Recovery experiments subsequently revealed that individuals initially exposed to a high thermal regime partially recovered when the hyper-thermic stress ceased. H. germanica contribution to surface sediment reworking substantially diminished from 10 mm3 indiv−1 day−1 (usual temperature) to 0 mm3 indiv−1 day−1 when individuals were exposed to high temperature regimes (i.e. above 32 °C). Given their role in sediment reworking and organic matter remineralisation, our results suggest that heatwaves may have profound long-lasting effects on the functioning of intertidal muddy ecosystems and some key biogeochemical cycles.

Effects of Temperature on Leaf Expansion in Sunflower

1982 ◽  
Vol 9 (2) ◽  
pp. 209 ◽  
Author(s):  
HM Rawson ◽  
JH Hindmarsh
Keyword(s):  
Field Studies ◽  
Leaf Expansion ◽  
Photon Flux ◽  
Photon Flux Density ◽  
Leaf Position ◽  
Leaf Emergence ◽  
Temperature Regimes ◽  
Effects Of Temperature ◽  
Increasing Temperature ◽  
Relative Change

Five commercial cultivars of sunflower were grown in cabinets at three temperature regimes, 32/22, 27/17 and 22/12°C, and with 15-h and 11-h photoperiods, and expansion of leaves 5-15 was followed. Leaves appeared faster with increasing temperature (0.022 leaves day-1 °C-1) and with increasing daylength. Areas of individual leaves increased linearly up the plant profile and, although final area per leaf (Amax) decreased with increasing temperature, the relative change was similar for each leaf position. Cultivars maintained their ranking for Amax across temperatures, and these rankings agreed with those in previous field studies. Within each temperature regime, both the expansion rate of leaves and the duration of expansion increased with leaf position. As temperature increased, leaves grew for shorter periods with a change of 1.04 days °C-1, but under the photon flux density used (500 �mol m-2 s-1, or about 25% full sunlight) expansion rates were greatest at the lowest temperature. Expansion rates were only one-third of those in field studies at comparable temperatures, but durations were similar. Cultivars that achieved the largest Amax did so via faster rates of expansion and not via longer durations: only one cultivar differed from the mean (20 days) duration of leaf expansion. All cultivars reached floral initiation progressively earlier with extension of photoperiod from 10 to 15 h, with the change for the most sensitive cultivars being 8 days and for the least sensitive 5 days. Rates of leaf emergence were linked with this sensitivity.

The effect of temperature stress on grain development in wheat

1965 ◽  
Vol 16 (1) ◽  
pp. 1 ◽  
Author(s):  
RD Asana ◽  
RF Williams
Keyword(s):  
Growth Analysis ◽  
Important Determinant ◽  
Effect Of Temperature ◽  
Synthetic Activity ◽  
Grain Development ◽  
Night Temperature ◽  
Complex Interactions ◽  
Temperature Regimes ◽  
Controlled Environments ◽  
Stable Characteristic

Experiments were conducted in controlled environments to determine the effects of high temperatures on grain development and yield in wheat. Two Australian and three Indian cultivars of wheat were exposed, from a week after anthesis until maturity, to "day" temperatures of 25, 28, and 3l°C, and "night" temperatures of 9 and 12°C. There was a mean reduction in yield of 16%' for the 6° rise in day temperature, but the cultivars did not differ significantly in their response to these temperatures. There were no significant effects of night temperature on grain weight, but stem weight was less at 12°C. Senescence was hastened only slightly by high day temperature, and there were no differential effects between cultivars in this respect.In a subsidiary experiment one Indian and five Australian cultivars were subjected to three day-night temperature regimes (24/19°, 27/22°, and 30/25°C). Highly significant but complex interactions were established between temperature regime and cultivar. A growth analysis for the Australian cultivars Ridley and Diadem indicated that the developing grain of Ridley had a greater capacity for growth than that of Diadem from the earliest stage. This, together with the confirmation of grain size as a very stable characteristic for all the varieties, points to the developmental and synthetic activity of the grain as an important determinant of grain yield. The relevance of this study to the production of wheat in India is briefly discussed.

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