On the relation between weather variables and sorghum ergot infection

2000 ◽  
Vol 51 (3) ◽  
pp. 313 ◽  
Author(s):  
Enli Wang ◽  
Holger Meinke ◽  
Malcolm Ryley ◽  
Damian Herde ◽  
Bob Henzell
Keyword(s):  
Minimum Temperature ◽  
Flag Leaf ◽  
Pollen Viability ◽  
Daily Minimum Temperature ◽  
Starch Accumulation ◽  
Flowering Period ◽  
Weather Variables ◽  
Leaf Stage ◽  
Daily Minimum ◽  
Hourly Temperature

Sorghum ergot (Claviceps africana) has had a significant impact on seed production and breeders’ nurseries in Australia since it was first found in 1996. In this paper, 3 distinct key development stages of sorghum that are related to ergot infection were identified: flag leaf stage, pollen starch accumulation stage, and flowering period. Relationships between weather variables during these 3 stages and ergot severity as well as pollen viability were analysed using observed data from 2 field trials, a serial planting trial and a genotype trial, conducted at Gatton, Queensland. The duration of the flag leaf stage and of the flowering period was estimated from thermal time. An infection factor was introduced and calculated based on hourly temperature during the flowering period. This infection factor and the mean relative humidity at 0900 hours during the flowering period were the main factors influencing ergot infection. Mean daily minimum temperature during flag leaf stage also had a significant effect on ergot severity, although no significant relation was found between this mean daily minimum temperature and pollen viability. A linear regression model using the above 3 factors accounted for 94% of the environmentally caused variation in ergot severity observed in the genotype trial.

scholarly journals Use of Weather Variables to Quantify Sorghum Ergot Potential in South Africa

Plant Disease ◽  
1998 ◽  
Vol 82 (1) ◽  
pp. 26-29 ◽  
Author(s):  
N. W. McLaren ◽  
B. C. Flett
Keyword(s):  
Minimum Temperature ◽  
Pollen Viability ◽  
Breakdown Point ◽  
Field Trials ◽  
Maximum Temperature ◽  
Daily Maximum Temperature ◽  
Daily Maximum ◽  
Weather Variables ◽  
Data Set ◽  
Study Results

Quantification of resistance to ergot requires that the observed ergot severity within a sorghum line be compared with expected ergot severity (ergot potential) to compensate for differences in environmental favorability for the disease among flowering dates and seasons. The ergot potential required to induce the onset of disease is referred to as the ergot breakdown point of that line. In earlier studies, the ergot potential of a specific flowering date was defined as the mean ergot severity in all sorghum heads over all lines in the nursery which commenced flowering on that date in a genetically broad-based sorghum nursery. In this study, results of field trials enabled accurate prediction of ergot potential by using a multiple regression analysis which included three weather variables—namely, pre-flowering minimum temperature (mean of days 23 to 27 pre-flowering), mean daily maximum temperature, and mean daily maximum relative humidity (mean of days 1 to 5 post-flowering; R2 = 0.90; P = 0.91E-5). Evaluation of predicted and observed ergot severity in an independent data set gave an index of agreement of d = 0.94 and R2 = 0.84 (P = 0.106E-4), showing that ergot severity, assuming the presence of viable inoculum, can be accurately predicted. Low pre-flowering minimum temperature was associated with reduced pollen viability, which appeared to be the primary factor predisposing lines to ergot.

scholarly journals Conditional probability of the daily minimum temperature in certain types of circulation on a seasonal basis in the Zywiec Valley in Southern Poland

2017 ◽  
Vol 13 ◽  
pp. 18-24
Author(s):  
Paulina Szczotka
Keyword(s):  
Atmospheric Circulation ◽  
Minimum Temperature ◽  
Extreme Values ◽  
Daily Minimum Temperature ◽  
Synoptic Situation ◽  
Local Conditions ◽  
Daily Minimum ◽  
Vistula River ◽  
Circulation Types ◽  
Average Minimum Temperature

Air minimum temperature is very important for the natural environment and human activity. This paper presents certain aspects related to the variability of daily minimum temperature of air in the winter (XII, I, II) in the Zywiec Valley, in relation to the synoptic situation in the valley. The analysis is based on the results of research carried out at one point node (the grid) obtained from the base Carpat Clim database. The node is located at the bottom of the Zywiec Valley in the period 1961-2010. The study was complemented with a comprehensive analysis of local conditions for atmospheric circulation and temporal variability over a 50 years period. For this purpose, the classification of types of atmospheric circulation  (Niedźwiedź 1981) was used for the upper Vistula river basin. Extreme temperatures included an average minimum temperature of air exceeding the 90th and 95th percentile. The relationship between the extremes of air temperature and atmospheric circulation types was examined by analyzing the frequency of occurrence of extreme values and their conditional occurrence in each particular type of atmospheric circulation.

Diverse Responses of Phenology in Multi-Grassland to Environmental Factors on Qinghai-Tibetan Plateau in China

2021 ◽  
Author(s):  
Gexia Qin ◽  
Benjamin Adu ◽  
Chunbin Li ◽  
Jing Wu
Keyword(s):  
Minimum Temperature ◽  
Alpine Meadow ◽  
Growing Season ◽  
Mean Value ◽  
Daily Minimum Temperature ◽  
Spring Phenology ◽  
Change Rate ◽  
Daily Minimum ◽  
Alpine Steppe ◽  
Yearly Maximum

Abstract Revealing grassland growing season spatial patterns and their climatic controls is crucial for the understanding of the productivity change mechanism in regional terrestrial ecosystem. However, the multi-grassland phenological factors are different, which has not been well studied. In this paper, the spatio-temporal patterns of the grassland start of the growing season (SOS) and the end of growing season (EOS) were investigated using MODIS Normalized Difference Vegetation Index (NDVI) on the Qinghai-Tibetan Plateau (QTP) during 2000 to 2019. At the same time, we analyzed the factors (including extreme and mean climate, drought, solar radiation, etc.) regulating grassland phenology under ongoing climate change. The results showed that the SOS appeared first in mountain meadow, shrub-tussock, temperature steppe and desert, then in alpine steppe and alpine meadow, showed a significant advancing tendency in all types. The EOS appeared first in temperature steppe, alpine steppe and alpine meadow, then in mountain meadow, shrub-tussock and desert. Further analysis indicated that the decrease of yearly minimum value of daily minimum temperature (TNN), yearly maximum value of daily minimum temperature (TNX), Temperature vegetation dryness index (TVDI) and the increase of yearly maximum consecutive five-day precipitation (RX5day) advance the grassland spring phenology, whereas the increase of solar radiation (SR) delay the grassland spring phenology. Meanwhile, SOS and its change rate showed the trend of significant delay and decline with the increase of altitude, respectively. We also found that the decrease of TVDI, TNN and the increase of yearly mean value of temperature (MAT_MEAN), yearly mean value of daily maximum temperature (MAT_MAX) and yearly mean value of daily minimum temperature (MAT_MIN) advanced the autumn phenology. The EOS and its change rate advance and increase with increasing altitude, respectively.

scholarly journals Subarctic shores without an ice foot: Low extremes in intertidal temperature during winter

2020 ◽  
Author(s):  
Ricardo Augusto Scrosati
Keyword(s):  
Nova Scotia ◽  
Minimum Temperature ◽  
Intertidal Zone ◽  
Freezing Point ◽  
Atlantic Coast ◽  
Daily Minimum Temperature ◽  
Absolute Minimum ◽  
Daily Minimum ◽  
Air Temperatures ◽  
Intertidal Habitats

On marine shores that freeze in winter, the intertidal zone becomes covered by an ice foot. Stable ice foots insulate intertidal organisms against highly negative air temperatures. On subpolar intertidal habitats that do not freeze, the periodic inundation with seawater at temperatures near its freezing point also prevents benthic organisms from experiencing highly negative temperatures. However, low tides do expose ice-free intertidal habitats to aerial conditions, but information on how negative temperature gets there during the winter is lacking. Using data loggers, this study measured the daily lowest temperature in rocky intertidal habitats on the Atlantic coast of Nova Scotia, Canada (which does not freeze), during the winter. As a control, temperature was also monitored above the intertidal zone (on tree branches). Intertidal temperature was almost as low as supratidal temperature, as the seasonal averages of daily minimum temperature were -4.2 °C and -6.4 °C (with absolute minima of -14.1 °C and -19.1 °C), respectively. The study site on the Atlantic coast is climatically similar to a site surveyed on the Gulf of St. Lawrence coast of Nova Scotia. However, the Gulf of St. Lawrence coast, which freezes in winter, showed milder intertidal temperatures, with a winter average of daily minimum temperature of -1.9 °C and an absolute minimum of only -6.8 °C. Therefore, despite tidal influences, the absence of an ice foot exposes subpolar intertidal habitats to highly negative air temperatures.

Sign in / Sign up

Export Citation Format

Share Document