TEMPERATURE AND HUMIDITY EFFECTS ON THE GROWTH AND YIELD OF PEA CULTIVARS

The effects of two relative humidities and three temperature regimes on the growth and yield responses of four pea cultivars were investigated. The high day/night temperature regime of 27/17 C, compared with 17/7 C, decreased the number of pods per plant by 46, 65, 66 and 54% in the cultivars Dark Skin Perfection, Nugget, Early Sweet 11 and Elf, respectively. Continued growth at the high temperature decreased pea yield by 50% in Dark Skin Perfection and about 70% in the other cultivars. When plants were first grown at 17/7 until full bloom and then subjected to the 27/7 C regime, the high temperature treatment showed no significant effect on growth and yield. Dark Skin Perfection was the least adversely affected by high temperature. No significant differences in growth and yield were observed at 50 and 90% relative humidities.

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Systemic Infection by Fusarium verticillioides in Maize Plants Grown Under Three Temperature Regimes

Plant Disease ◽

10.1094/pdis-92-12-1695 ◽

2008 ◽

Vol 92 (12) ◽

pp. 1695-1700 ◽

Cited By ~ 36

Author(s):

A. Murillo-Williams ◽

G. P. Munkvold

Keyword(s):

High Temperature ◽

Environmental Factors ◽

Fusarium Verticillioides ◽

Systemic Infection ◽

Temperature Treatment ◽

High Temperature Treatment ◽

Kernel Infection ◽

Temperature Regimes ◽

Maize Plants ◽

Systemic Development

Fusarium verticillioides causes seedling decay, stalk rot, ear rot, and mycotoxin contamination (primarily fumonisins) in maize. Systemic infection of maize plants by F. verticillioides can lead to kernel infection, but the frequency of this phenomenon has varied widely among experiments. Variation in the incidence of systemic infection has been attributed to environmental factors. In order to better understand the influence of environment, we investigated the effect of temperature on systemic development of F. verticillioides during vegetative and reproductive stages of plant development. Maize seeds were inoculated with a green fluorescent protein-expressing strain of F. verticillioides, and grown in growth chambers under three different temperature regimes. In the vegetative-stage and reproductive-stage experiments, plants were evaluated at tasseling (VT stage), and at physiological maturity (R6 stage), respectively. Independently of the temperature treatment, F. verticillioides was reisolated from nearly 100% of belowground plant tissues. Frequency of reisolation of the inoculated strain declined acropetally in aboveground internodes at all temperature regimes. At VT, the high-temperature treatment had the highest systemic development of F. verticillioides in aboveground tissues. At R6, incidence of systemic infection was greater at both the high- and low-temperature regimes than at the average-temperature regime. F. verticillioides was isolated from higher internodes in plants at R6, compared to stage VT. The seed-inoculated strain was recovered from kernels of mature plants, although incidence of kernel infection did not differ significantly among treatments. During the vegetative growth stages, temperature had a significant effect on systemic development of F. verticillioides in stalks. At R6, the fungus reached higher internodes in the high-temperature treatment, but temperature did not have an effect on the incidence of kernels (either symptomatic or asymptomatic) or ear peduncles infected with the inoculated strain. These results support the role of high temperatures in promoting systemic infection of maize by F. verticillioides, but plant-to-seed transmission may be limited by other environmental factors that interact with temperature during the reproductive stages.

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The physiological consequences of varied heat exposure events in adultMyzus persicae: a single prolonged exposure compared to repeated shorter exposures

PeerJ ◽

10.7717/peerj.2290 ◽

2016 ◽

Vol 4 ◽

pp. e2290 ◽

Cited By ~ 10

Author(s):

Behnaz Ghaedi ◽

Nigel R. Andrew

Keyword(s):

High Temperature ◽

Recovery Time ◽

Prolonged Exposure ◽

Heat Exposure ◽

Temperature Tolerance ◽

Temperature Treatment ◽

High Temperature Treatment ◽

Exposure Group ◽

Temperature Regimes ◽

Heating Event

The study of environmental stress tolerance in aphids has primarily been at low temperatures. In these cases, and in the rare cases of high temperature tolerance assessments, all exposures had been during a single stress event. In the present study, we examined the physiological consequences of repeated high temperature exposure with recovery periods between these stress events inMyzus persicae. We subjected individuals to either a single prolonged three hour heating event, or three one hour heating events with a recovery time of 24 h between bouts. Aphids exposed to repeated bouts of high temperatures had more glucose and higher expression of proteins and osmolyte compounds, such as glycerol, compared to the prolonged exposure group. However, aphids exposed to the repeated high temperature treatment had reduced sources of energy such as trehalose and triglyceride compounds than the prolonged exposure group. Recovery time had more physiological costs (based on production of more protein and consumption of more trehalose and triglyceride) and benefits (based on production of more osmolytes) in repeated high temperature treatments. As aphids are known to respond differently to constant versus ‘natural’ fluctuating temperature regimes, conclusions drawn from constant temperature data sets may be problematic. We suggest future experiments assessing insect responses to thermal stress incorporate a repeated stress and recovery pattern into their methodologies.

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The tolerance of wheat to high temperatures during reproductive growth. III. Booting to anthesis

Australian Journal of Agricultural Research ◽

10.1071/ar9890965 ◽

1989 ◽

Vol 40 (5) ◽

pp. 965 ◽

Cited By ~ 28

Author(s):

IA Dawson ◽

IF Wardlaw

Keyword(s):

High Temperature ◽

Flag Leaf ◽

Temperature Treatment ◽

Low Fertility ◽

High Temperature Treatment ◽

Wheat Cultivars ◽

Night Temperature ◽

Grain Number ◽

Tropical Areas ◽

Pollination And Fertilization

A range of Australian and overseas wheat cultivars was grown in the naturally lighted glasshouses of the Canberra phytotron, with a standard day/night temperature regime of 18/1 3�C. Grain number per main culm ear under these standard conditions was compared with the response obtained when sets of plants were transferred to high temperature (24/19�C, or 30/25�C) over the period from flag leaf ligule to ear emergence (booting), or from ear emergence to the end of anthesis (pollination and fertilization).Some Australian lines such as Isis and Hybrid Titan were tolerant of high temperature at booting, while others such as Pinnacle and Olympic showed a marked sensitivity to high temperature at this stage. Cultivars from the Middle East and tropical areas were generally more tolerant of high temperature at booting than cultivars from regions such as North America and Europe, while the Australian lines were intermediate in their response. With the cultivar Pinnacle, it was shown that at least part of the low fertility associated with high temperature at booting was related to poor pollen development. Commencing the high temperature treatment earlier in the development of the ear and continuing this until ear emergence resulted in adaptation in the cultivar H757 from Afghanistan, which showed an increase in grain set above that of the short high temperature booting treatment. However, this contrasted with the response of the cultivar Banks when the extended high temperature treatment resulted in a further reduction, not an increase in grain set. It was shown that the presence of the rye translocation for rust resistance (1B/1R) in near isogenic lines of Condor resulted in reduced sensitivity to high temperature. This would suggest that species such as rye should be examined more closely for their sensitivity to environmental stress.Exposure to high temperature only during anthesis generally had a small effect oil grain set. Some cultivars showed an increase in grain set, whereas others showed a decrease. Part of this variation may be related to the finding that under high temperature conditions, high humidity (v.p.d. 6.7 mb) could reduce grain set. However, given the normal relation between temperature and humidity in Australia, this effect is likely to be limited to glasshouse conditions.

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