scholarly journals Distribution and Recovery of Tilletia indica Teliospores from Regulated Wheat Fields in Texas

Plant Disease ◽  
2008 ◽  
Vol 92 (3) ◽  
pp. 344-350 ◽  
Author(s):  
T. W. Allen ◽  
H. W. Maples ◽  
F. Workneh ◽  
J. M. Stein ◽  
C. M. Rush

Eight wheat fields from the Karnal bunt-regulated regions within Texas were grid sampled to gain a better understanding of the ecology and epidemiology of teliospores produced by the causal agent, Tilletia indica. Teliospores from 25-g aliquots of soil from each grid point were extracted using a size-selective sieving sucrose-centrifugation procedure. Teliospores were recovered from all eight fields and, in some cases, from every grid point within a field. Total teliospore numbers ranged from 0 to 1,305 per 25 g of soil. Over 70% of the total grid sampled points contained one or more teliospores. The relation between soil chemical and physical characteristics and teliospore numbers from each field was evaluated. In general, no consistent, significant trend could be made between soil factors and teliospore numbers. Geostatistics were used to analyze data from grid points and create contour maps. Teliospore distribution was aggregated in four of the fields, random in three of the fields, and discontinuous (neither random nor aggregated) in a single field. This is the first report of widespread distribution and high teliospore numbers from wheat field soils in the United States.

Plant Disease ◽  
2003 ◽  
Vol 87 (8) ◽  
pp. 999-1003 ◽  
Author(s):  
David Marshall ◽  
Timothy T. Work ◽  
Joseph F. Cavey

Karnal bunt of wheat (caused by Tilletia indica) was first detected in the United States in Arizona in 1996. The seed lots of infected, spring-habit, durum wheat associated with the initial detection were traced to planted fields in California, Arizona, New Mexico, and Texas. However, in the summer of 1997, the disease appeared in unrelated, winter-habit, bread wheat located over 700 km from the nearest potentially contaminated wheat from 1996 (and destroyed prior to reinfection). Here, we examined potential invasion pathways of the fungus associated with the movement of wheat into the United States. We analyzed the USDA/APHIS Port Information Network (PIN) database from 1984 through 2000 to determine likely pathways of introduction based on where, when, and how the disease was intercepted coming into the United States. All interceptions were made on wheat transported from Mexico, with the majority (98.8%) being intercepted at land border crossings. Karnal bunt was not intercepted from any other country over the 17-year period analyzed. Most interceptions were on wheat found in automobiles, trucks, and railway cars. The majority of interceptions were made at Laredo, Brownsville, Eagle Pass, and El Paso, TX, and Nogales, AZ. Karnal bunt was intercepted in all 17 years; however, interceptions peaked in 1986 and 1987. Averaged over all years, more interceptions (19.2%) were made in the month of May than in any other month. Our results indicate that Karnal bunt has probably arrived in the United States on many occasions, at least since 1984. Because of the relatively unaggressive nature of the disease and its reliance on rather exacting weather conditions for infection, we surmised that it is possible this disease has a long period of latent survival between initial arrival and becoming a thriving, established disease.


Plant Disease ◽  
1999 ◽  
Vol 83 (7) ◽  
pp. 685-689 ◽  
Author(s):  
Barry M. Cunfer ◽  
Lisa A. Castlebury

Surveys for Tilletia walkeri on annual ryegrass (Lolium multiflorum) were conducted during 1997 and 1998 in the southeastern United States, where suspect teliospores of the Karnal bunt fungus, Tilletia indica, were found in USDA-APHIS surveys of wheat (Triticum aestivum) seed in 1996. T. walkeri is morphologically similar to T. indica. Annual ryegrass is a common weed in wheat fields in the southeastern United States. Between April and June 1997, ryegrass seed samples were collected from 190 fields of wheat in 47 counties in Georgia and from 26 fields in 17 counties in Alabama and south-central Tennessee. In 1998, 70 samples were collected from 40 counties in the same regions of the three states. The teliospores from these samples were 23 to 45 μm in diameter (average about 33 μm) and ranged from light brown to dark reddish brown. They had coarse, widely spaced cerebriform ridges on the surface and were surrounded by a gelatinous sheath. The ryegrass bunt was identified as the recently described species T. walkeri, occurring on ryegrass seed from Australia and Oregon. In 1997, teliospores of T. walkeri were found in 13 samples from eight counties in central Georgia and from one field in Tennessee. In 1998, more teliospores and bunted seeds were found, possibly due to frequent rain in the region throughout the flowering period for ryegrass. Teliospores were found in 26/70 of the samples, and among these, only a small number of bunted seed were found in 12 of 13/70 samples. In one wheat field in Morgan County, Georgia, about 50% of the ryegrass seed collected was partially bunted, and a small percentage was completely bunted. Fields with teliospores were widely distributed and generally matched the locations where teliospores were found in APHIS wheat seed surveys in 1996 to 1998. T. walkeri occurs at very low levels on ryegrass in the Southeast and is the source of teliospores, initially identified as those of T. indica, associated with wheat seed in APHIS surveys. No bunted wheat seeds or teliospores of T. indica were found in the survey.


Plant Disease ◽  
2005 ◽  
Vol 89 (8) ◽  
pp. 828-833 ◽  
Author(s):  
J. M. Stein ◽  
H. W. Maples ◽  
C. M. Rush

To examine the epidemiology of Tilletia indica teliospores in naturally infested soils from wheat fields in both Karnal bunt-regulated regions in Texas, soil was grid sampled from fields that were bunted-kernel positive for Karnal bunt in 1997, 2001, both years, or never. Aliquots of soil from each point were pooled, and teliospores were extracted using a size-selective sieving-sucrose centrifugation method. Teliospores were enumerated microscopically, and low quantities (< 8 per 25 g of soil) were identified in 14 of 15 fields sampled from the regulated regions of Texas, including fields that have never tested positive for bunted kernels, indicating a widespread distribution. No teliospores were isolated from the single field examined outside of the regulated regions. The percent clay was significantly, negatively correlated with the baseline teliospore number and the estimated (extrapolated) number of teliospores per sample, indicating a potential impact of soil composition on teliospore survival. The latter factor was also significantly, positively correlated to the number of times a field had tested positive.


Plant Disease ◽  
2008 ◽  
Vol 92 (12) ◽  
pp. 1604-1610 ◽  
Author(s):  
G. L. Peterson ◽  
K. L. Kosta ◽  
D. L. Glenn ◽  
J. G. Phillips

Studies were conducted in Arizona to determine the efficacy of soil solarization for killing teliospores of the soilborne fungal wheat pathogen Tilletia indica. In a replicated study conducted in each of 3 years, T. indica teliospores and bunted wheat kernels were buried in a Karnal bunt-infested wheat field at depths of 5, 10, and 20 cm. Replicate samples were removed from under a clear plastic solarization cover at 7-day intervals and the number of viable teliospores determined. A rapid decline in teliospore viability occurred at all treatment depths over 38 days, with efficacy comparable with methyl bromide protocols using clear plastic sheeting. Initial viability rates of 43, 71, and 82% germination were reduced to 0.1, 7.7, and 0.2% after 38 days (across all depths) in 2003, 2005, and 2006, respectively. Mean daily maximum soil temperatures at 5 and 20 cm under clear plastic in 2003, 2005, and 2006 were 67, 53 and 60°C and 43, 38, and 43°C, respectively. Under current United States Department of Agriculture disease management strategies, the method may be useful for the rapid deregulation of Karnal bunt-affected fields.


Plant Disease ◽  
1997 ◽  
Vol 81 (6) ◽  
pp. 689-692 ◽  
Author(s):  
Richard W. Smiley

Tilletia indica, the causal agent of Karnal bunt of wheat, was first detected and reported in the United States in 1996. Karnal bunt occurred in the southwestern United States as early as 1992. Wheat contaminated with teliospores of T. indica is likely to have been transported from the Southwest to other regions, including the Pacific Northwest, before presence of the pathogen was discovered. Teliospore and sporidial germination and infection are highly dependent on climatic conditions. The potential for T. indica to infect wheat in the Pacific Northwest has not been reported. The objective of this study was to use published information on environmental factors favorable for infection and historical climate data for the Pacific Northwest to analyze the environmental risk for Karnal bunt to occur if wheat fields in the Pacific Northwest become contaminated by T. indica. Conditions during the past four decades appeared favorable for infection in nonirrigated wheat during 1 of every 3 years at two (Corvallis, OR, and Spokane, WA) of 13 Idaho, Oregon, and Washington locations examined, and every year at all locations where wheat is irrigated. If introduced to the area, it appears possible for T. indica to become established in selected regions of the Pacific Northwest.


Plant Disease ◽  
2009 ◽  
Vol 93 (7) ◽  
pp. 713-719 ◽  
Author(s):  
T. W. Allen ◽  
D. C. Jones ◽  
T. N. Boratynski ◽  
R. E. Ykema ◽  
C. M. Rush

A study was conducted to determine the relationship between soilborne Tilletia indica teliospore density and Karnal bunt incidence in an Arizona durum wheat field in 2005 and 2006. Soil samples were collected from 507 sample points according to a grid marked in a 7.7-ha field. Approximately 500 g of soil from the top 5 cm was collected from each sample point, and teliospores were recovered from 25-g aliquots by a modified size-selective sieving, sucrose centrifugation procedure. Twenty-five and 50 wheat heads were collected from a 1-m2 area around each sample point in May 2005 and June 2006, respectively. Wheat head samples from each sample point were bulked, threshed, and examined for the presence of bunted kernels. Additionally, data for soilborne teliospores and percent bunted kernels from 70 sample points in 2005 and 2006 that corresponded to sample points from a 2004 bunted kernel survey conducted by the USDA and Arizona Department of Agriculture were analyzed. Soilborne teliospore numbers ranged from 6 to 1,000 per 25-g soil sample in the 2-year study. No bunted kernels were recovered in 2005; however, two sample points yielded bunted kernels in 2006. Weather data from three time periods in 2004, 2005, and 2006 were applied to the humid thermal index model and suggested that a conducive environment for disease development existed in 2005. Based on the data from this research, we concluded that even though high numbers of soilborne teliospores were present in the field, and although a conducive environment was present for disease to develop on only one occasion, a direct relationship between soilborne teliospores and disease incidence may not exist.


2020 ◽  
pp. 1-14
Author(s):  
Siqiang Chen ◽  
Masahiro Toyoura ◽  
Takamasa Terada ◽  
Xiaoyang Mao ◽  
Gang Xu

A textile fabric consists of countless parallel vertical yarns (warps) and horizontal yarns (wefts). While common looms can weave repetitive patterns, Jacquard looms can weave the patterns without repetition restrictions. A pattern in which the warps and wefts cross on a grid is defined in a binary matrix. The binary matrix can define which warp and weft is on top at each grid point of the Jacquard fabric. The process can be regarded as encoding from pattern to textile. In this work, we propose a decoding method that generates a binary pattern from a textile fabric that has been already woven. We could not use a deep neural network to learn the process based solely on the training set of patterns and observed fabric images. The crossing points in the observed image were not completely located on the grid points, so it was difficult to take a direct correspondence between the fabric images and the pattern represented by the matrix in the framework of deep learning. Therefore, we propose a method that can apply the framework of deep learning viau the intermediate representation of patterns and images. We show how to convert a pattern into an intermediate representation and how to reconvert the output into a pattern and confirm its effectiveness. In this experiment, we confirmed that 93% of correct pattern was obtained by decoding the pattern from the actual fabric images and weaving them again.


2021 ◽  
pp. 1-27 ◽  
Author(s):  
Julie VanDusky-Allen ◽  
Stephen M. Utych

AbstractIn this paper, we analyze how variations in partisan representation across different levels of government influence Americans’ satisfaction with the democracy in the United States. We conduct two survey experiments and analyze data from the 2016 American National Election Study postelection survey. We find that Americans are the most satisfied with democracy when their most preferred party controls both the federal and their respective state governments. However, we also find that even if an individual’s least preferred party only controls one level of government, they are still more satisfied with democracy than if their most preferred party controls no levels of government. These findings suggest that competition in elections across both the national and state government, where winning and losing alternates between the two parties, may have positive outcomes for attitudes toward democracy.


2012 ◽  
Vol 2012 ◽  
pp. 1-12 ◽  
Author(s):  
Atul K. Gupta ◽  
J. M. Seneviratne ◽  
G. K. Joshi ◽  
Anil Kumar

Signaling pathways that activate different mitogen-activated protein kinases (MAPKs) in response to certain environmental conditions, play important role in mating type switching (Fus3) and pathogenicity (Pmk1) in many fungi. In order to determine the roles of such regulatory genes inTilletia indica, the causal pathogen of Karnal bunt (KB) of wheat, semi-quantitative and quantitative RT-PCR was carried out to isolate and determine the expression of MAP kinase homologues during fungal growth and development underin vitroculture. Maximum expression of TiFus3 and TiPmk1 genes were observed at 14th and 21st days of culture and decreased thereafter. To investigate whether the fungus alters the expression levels of same kinases upon interaction with plants, cultures were treated with 1% of host factors (extracted from S-2 stage of wheat spikes). Such treatment induced the expression of MAPks in time dependent manner compared to the absence of host factors. These results suggest that host factor(s) provide certain signal(s) which activate TiFus3 and TiPmk1 during morphogenetic development ofT. indica. The results also provides a clue about the role of host factors in enhancing the disease potential due to induction of MAP kinases involved in fungal development and pathogenecity.


2016 ◽  
Vol 7 (4) ◽  
pp. 810-822 ◽  
Author(s):  
P. Sonali ◽  
D. Nagesh Kumar

Worldwide, major changes in the climate are expected due to global warming, which leads to temperature variations. To assess the climate change impact on the hydrological cycle, a spatio-temporal change detection study of potential evapotranspiration (PET) along with maximum and minimum temperatures (Tmax and Tmin) over India have been performed for the second half of the 20th century (1950–2005) both at monthly and seasonal scale. From the observed monthly climatology of PET over India, high values of PET are envisioned during the months of March, April, May and June. Temperature is one of the significant factors in explaining changes in PET. Hence seasonal correlations of PET with Tmax and Tmin were analyzed using Spearman rank correlation. Correlation of PET with Tmax was found to be higher compared to that with Tmin. Seasonal variability of trend at each grid point over India was studied for Tmax, Tmin and PET separately. Trend Free Pre-Whitening and Modified Mann Kendall approaches, which consider the effect of serial correlation, were employed for the trend detection analysis. A significant trend was observed in Tmin compared to Tmax and PET. Significant upward trends in Tmax, Tmin and PET were observed over most of the grid points in the interior peninsular region.


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