scholarly journals Susceptibility of Wheat to Tilletia indica During Stages of Spike Development

2006 ◽  
Vol 96 (9) ◽  
pp. 962-966 ◽  
Author(s):  
Blair J. Goates ◽  
Eric W. Jackson
Keyword(s):  
Karnal Bunt ◽  
Growth Stages ◽  
Optimal Conditions ◽  
Tilletia Indica ◽  
Airborne Inoculum ◽  
Yield And Quality ◽  
Spike Development ◽  
Low Levels ◽  
Dough Stage ◽  
Different Growth Stages

Karnal bunt of wheat is caused by the fungus Tilletia indica, which partially converts kernels into sori filled with teliospores. Despite minor overall yield and quality losses, the disease is of considerable international quarantine concern. Plant development stages reported susceptible to infection vary considerably. A study was designed to better define the susceptibility period by inoculating wheat spikes at different growth stages with naturally liberated secondary sporidia under optimal conditions for disease development. Spikes of a resistant and susceptible cultivar were inoculated at eight growth stages from awns emerging to soft dough. Spikes became susceptible only after emerging from the boot and continued to be susceptible up to soft dough stage at which low levels of disease occurred. Disease severity in both cultivars peaked when spikes were inoculated after complete emergence, but before the onset of anthesis. Disease levels tapered off gradually in spikes inoculated after anthesis. The results broaden the known susceptibility period of wheat to T. indica to include stages long after anthesis, and indicate that infection from airborne inoculum is not possible during boot or awns emerging stages, which are commonly referred to as the most susceptible stages.

scholarly journals Tilletia walkeri on Annual Ryegrass in Wheat Fields in the Southeastern United States

Plant Disease ◽  
1999 ◽  
Vol 83 (7) ◽  
pp. 685-689 ◽  
Author(s):  
Barry M. Cunfer ◽  
Lisa A. Castlebury
Keyword(s):  
United States ◽  
Lolium Multiflorum ◽  
Southeastern United States ◽  
Karnal Bunt ◽  
Annual Ryegrass ◽  
Wheat Seed ◽  
Tilletia Indica ◽  
Wheat Field ◽  
South Central ◽  
Low Levels

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.

Fusarium head blight development and trichothecene accumulation in point inoculated Fusarium infected wheat heads

2012 ◽  
Vol 5 (1) ◽  
pp. 45-55 ◽  
Author(s):  
P. Gautam ◽  
R. Dill-Macky
Keyword(s):  
Fusarium Head Blight ◽  
Gibberella Zeae ◽  
Growth Stages ◽  
Wheat Cultivars ◽  
Yield Losses ◽  
Head Blight ◽  
Moderately Resistant ◽  
Dough Stage ◽  
Different Growth Stages ◽  
Important Disease

Fusarium graminearum Schwabe [teleomorph Gibberella zeae (Schwein) Petch] is the predominant causal agent of Fusarium head blight (FHB), an economically important disease of wheat, in North America. Warm and humid environments at and shortly after anthesis favour FHB. FHB results in yield losses and quality losses in infected grain due to the accumulation of mycotoxins produced by the invading fungus. The objective of this study was to characterise the influence of different F. graminearum isolates and host resistance on FHB development and mycotoxin accumulation. A series of two greenhouse experiments were established where five single isolates of F. graminearum were tested. Three wheat cultivars were examined: Alsen (moderately resistant), 2375 (moderately susceptible) and Wheaton (susceptible). In the point-inoculation experiments, ca. 1000 conidia were placed into a central spikelet of spikes at anthesis. Point-inoculated spikelets were sampled at different growth stages up to soft dough stage. Samples from both experiment series were analysed for mycotoxins. The susceptible cultivar Wheaton had both the highest FHB severity and mycotoxin accumulation. The spread of symptoms both below and above the inoculated central spikelet was significantly higher in 2375 and Wheaton than Alsen. Though deoxynivalenol (DON) did not peak and decline in all experiments, when a peak in the DON content was present it was earlier in 2375 (early milk) than in either Alsen (early dough) or Wheaton (late milk). Though the isolates did not rank similarly in all experiments and in all cultivars, generally isolates Butte86Ada-11 and B63A were more aggressive and isolates 49-3 and B45A were less aggressive in terms of disease severity and mycotoxin accumulation.

scholarly journals Effect of growth stages and fertility levels on growth, yield and quality of fodder oats (Avena sativa L.)

2017 ◽  
Vol 9 (3) ◽  
pp. 1287-1296
Author(s):  
Gurjeet Kaur ◽  
Meenakshi Goyal
Keyword(s):  
Amino Acids ◽  
Avena Sativa ◽  
Nitrogen Fertilization ◽  
Free Amino Acids ◽  
Free Amino ◽  
Ash Content ◽  
Growth Stages ◽  
Ether Extract ◽  
Yield And Quality ◽  
Different Growth Stages

A field experiment was conducted to evaluate the yield and quality parameters of oats (Avena sativa L.) at forage research farm in Punjab Agricultural University, Ludhiana. Four different nitrogen levels viz. 0 (control), 50, 75 (recommended) and 100 Kg N/ha were applied in the form of urea. Samples were collected at three different growth stages i.e. 30, 45 and 60 DAS. As the growth of plant continued decrease in total nitrogen (45%), non protein nitro-gen (37%), ether extract (13%), ash content (24%) and digestibility (23%) was observed. But increase in free amino acids (48%) and cell wall constituents i.e. ADF (19%), NDF (31%) and CF (34%)with plant’s growth was reported. The interactive effect of varying levels of inorganic fertilizer application on the chemical composition of the plant at various growth stages revealed an increase in total nitrogen (18%), non protein nitrogen (26%), ether extract (18%), free amino acids (32%), ash content (13%) and digestibility (7%) with increase in fertilizer level however ADF (7%), NDF (2%) and CF (3%)content decreased with increased levels of nitrogen fertilization. Correlation studies showed that significant negative correlation was present forin vitro dry matter digestibility with acid detergent fiber (r= -.861**), neutral detergent fiber (r= -.891**) and crude fiber (r= -.740**) at recommended dose of N fertilization. The objective of this study was to investigate the effect of different doses of nitrogen fertilization at different growth stages on quality components in oats fodder.

scholarly journals A field study of Bactericera cockerelli feeding timing in potato crops

2017 ◽  
Vol 70 ◽  
pp. 320
Author(s):  
J.N. Furlong ◽  
J. Vereijssen ◽  
A.R. Pitman ◽  
R.C. Butler
Keyword(s):  
Growth Stages ◽  
Insect Vector ◽  
Bactericera Cockerelli ◽  
Zebra Chip ◽  
Growing Seasons ◽  
Yield And Quality ◽  
Zebra Chip Disease ◽  
Candidatus Liberibacter ◽  
Potato Crops ◽  
Different Growth Stages

Since its 2006 detection in New Zealand, the tomato potato psyllid (TPP), Bactericera cockerelli, has been responsible for yield and quality-reducing damage to potatoes as well as to other solanaceous crops. TPP is best known as the insect vector for the zebra chip disease-associated bacterium Candidatus Liberibacter solanacearum (CLso), but feeding by CLso-negative TPP on potatoes is also linked to damaging effects. An improved understanding of which potato plant physiological stages are most affected by feeding of CLso-negative TPP will allow for more directed integrated pest management (IPM) plans. As part of a two-year repeated eld study to assess the effect of TPP feeding timing on potatoes, CLso-negative TPP were released into mesh cages over outdoor potato (‘Moonlight’) plantings at ve different growth stages: post-emergence, owering, post- owering, late-season, and pre-harvest. Tubers were grouped by plant at harvest. (Un)marketable numbers and weights, marketable dry matter and zebra chip severity were determined. Results from this trial and other shadehouse trials conducted previously are still being analysed but have the potential to better target IPM plans and reduce costly, labour-intensive, and environmentally impactful pesticide spray use, which is currently relied on heavily throughout growing seasons.

Influence of Drought Applied at Different Growth Stages on Kernel Yield and Quality in Maize (Zea MaysL.)

2016 ◽  
Vol 47 (19) ◽  
pp. 2225-2232 ◽  
Author(s):  
Saba Anwar ◽  
Muhammad Iqbal ◽  
Hafiz Muhammad Akram ◽  
Mubashir Niaz ◽  
Rizwan Rasheed
Keyword(s):  
Growth Stages ◽  
Yield And Quality ◽  
Different Growth Stages ◽  
Kernel Yield

scholarly journals Role of Flag Leaf and Spike Emergence Stage on the Incidence of Karnal Bunt in Wheat

Plant Disease ◽  
1998 ◽  
Vol 82 (12) ◽  
pp. 1368-1370 ◽  
Author(s):  
J. Kumar ◽  
S. Nagarajan
Keyword(s):  
Growth Stage ◽  
Flag Leaf ◽  
Resistance Breeding ◽  
Karnal Bunt ◽  
Growth Stages ◽  
Tilletia Indica ◽  
Leaf Lamina ◽  
Critical Stage ◽  
A Site

Removal of the flag leaf of wheat, earlier hypothesized to act as a site where secondary sporidia of Tilletia indica multiply and conjugate, reduced the severity of Karnal bunt. Evidence reported here suggests that sporidia reach the flag leaf from the soil by splashing, multiply on the surface of the flag leaf, and move with rain water or dew into the boot of the flag leaf to cause infection of the spikelets. Plants in growth stage 49 (first awns visible) were more vulnerable to infection by secondary sporidia than were plants at other growth stages. At growth stage 49, the flag leaf lamina was fully opened, compared with its preceding stages, which had tubular and closed lamina. Also, leaf posture of the flag leaf at growth stage 49 is erect and thus may facilitate movement of sporidial inoculum into the boot. Upon completion of stage 49, the flag leaf becomes droopy, leading to lesser inoculum movement into the emerging spike. Thus, maximum success can be achieved in artificial creation of Karnal bunt by inoculating with secondary sporidia before onset of growth stage 49. Genotypes whose maturity avoids coincidence of this critical stage of spike emergence with periods of weather favorable for infection by T. indica may be selected for resistance breeding.

Quantitative response of greenhouse tomato yield and quality to water deficit at different growth stages

2013 ◽  
Vol 129 ◽  
pp. 152-162 ◽  
Author(s):  
Jinliang Chen ◽  
Shaozhong Kang ◽  
Taisheng Du ◽  
Rangjian Qiu ◽  
Ping Guo ◽  
...  
Keyword(s):  
Water Deficit ◽  
Growth Stages ◽  
Greenhouse Tomato ◽  
Tomato Yield ◽  
Yield And Quality ◽  
Different Growth Stages ◽  
Quantitative Response
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