Puccinia triticina (wheat brown rust).

2021 ◽  
Author(s):  
Henriette Goyeau
Keyword(s):  
Leaf Rust ◽  
Yield Loss ◽  
Genetic Resistance ◽  
Puccinia Triticina ◽  
Multiple Point ◽  
Yield Losses ◽  
Flowering Stage ◽  
Crop Losses ◽  
Pathogen Virulence ◽  
Cropping Season

Abstract Leaf rust seldom kills wheat, but it is capable of causing 35-50% yield loss in endemic areas on susceptible cultivars, where severity levels of 25-40% are reached at the tillering stage and 100% at the flowering stage. The disease causes more damage worldwide than other wheat rusts. Quarantine is of no relevance as leaf rust is of worldwide occurrence and virulences spread freely between nations and zones. Crop losses are dependent on the genetic resistance of each cultivar, pathogen virulence and environmental conditions. Losses caused by leaf rust particularly originate from reductions of the wheat photosynthetic area. Infected plants normally produce a lower number of tillers, lower amounts of grains per head and smaller grains. The earlier the epidemic in the cropping season, the higher the yield losses. Mathematical models for estimating disease severity and crop losses have been developed based on multiple-point disease recording at different physiological stages of the plant (Burleigh et al., 1972; Eversmeyer and Kramer, 1998, 2000).

scholarly journals Effect of mancozeb on the control of mycosphaerella blight of field pea

2000 ◽  
Vol 80 (2) ◽  
pp. 403-406 ◽  
Author(s):  
T. D. Warkentin ◽  
A. G. Xue ◽  
D. W. McAndrew
Keyword(s):  
Yield Loss ◽  
Foliar Application ◽  
Genetic Resistance ◽  
Similar Efficacy ◽  
Field Trials ◽  
Field Pea ◽  
Mycosphaerella Pinodes ◽  
Western Canada ◽  
Flowering Stage ◽  
Plot Design

Mycosphaerella blight (MB) [Mycosphaerella pinodes (Berk. & Blox.)Vestergr.] causes substantial yield loss to field pea in western Canada in most seasons and is a disease for which genetic resistance is lacking. The objective of this research was to evaluate the effectiveness of foliar application of mancozeb for the control of MB of field pea. Field trials of split-plot design were conducted at two sites per year from 1996 to 1998 in southern Manitoba, with cultivars as main-plots and fungicide treatments as sub-plots. In most site-years, a single application of mancozeb at the early flowering stage was effective in reducing MB severity and in increasing yield. Mancozeb had similar efficacy to chlorothalonil, the only currently registered fungicide for control of MB in field pea. The beneficial effect of both fungicides was greater for the highly MB susceptible cultivars AC Tamor and Carrera than the moderately MB susceptible cultivar Radley. Key words: Pisum sativum, field pea, mycosphaerella blight, mancozeb, chlorothalonil

Cost of crop losses in processing tomato and cabbage in southwestern Ontario due to insects, weeds and/or diseases

2004 ◽  
Vol 84 (3) ◽  
pp. 915-921 ◽  
Author(s):  
J. H. Tolman ◽  
D. G. R. McLeod ◽  
C. R. Harris
Keyword(s):  
Yield Loss ◽  
Management Program ◽  
Yield Losses ◽  
Crop Losses ◽  
Control Programs ◽  
Processing Tomato ◽  
Key Words Tomato ◽  
Significant Yield ◽  
Control Disease ◽  
One Year

The relative importance of insects, weeds and diseases to yield losses in processing tomato (Lycopersicon esculentum Mill.) and cabbage (Brassica oleracea L. var. capitata L.) was measured by comparing yields in the presence and absence of appropriate control programs. In the absence of any pest control, average crop losses exceeded 80% in both crops. Average yield losses due to weeds alone approached 80% in processing tomato and 60% in cabbage. Insects alone did not significantly reduce yield of processing tomato in either year. In the absence of insect control, significant yield loss in cabbage approached 50% in only one year. When diseases were not controlled, yield of processing tomato declined significantly by nearly 30% in one trial. Failure to control disease had no significant impact on cabbage yield in this study. Monetary losses and costs of each management program were calculated. Key words: Tomato, cabbage, yield loss, insects, weeds, diseases

scholarly journals The Emergence of New Aggressive Leaf Rust Races with the Potential to Supplant the Resistance of Wheat Cultivars

Biology ◽  
2021 ◽  
Vol 10 (9) ◽  
pp. 925
Author(s):  
Reda Ibrahim Omara ◽  
Yasser Nehela ◽  
Ola Ibrahim Mabrouk ◽  
Mohsen Mohamed Elsharkawy
Keyword(s):  
Leaf Rust ◽  
Genetic Resistance ◽  
Puccinia Triticina ◽  
Wheat Cultivars ◽  
Physiological Races ◽  
Wheat Leaf ◽  
Host Genetic ◽  
Successful Control ◽  
Location Association

Characterization of the genetic structure and the physiological races of Puccinia triticina is a growing necessity to apply host genetic resistance against wheat leaf rust as a successful control strategy. Herein, we collected and identified about 130 isolates of P. triticina from 16 Egyptian commercial wheat cultivars grown at different locations, over two seasons (2019/2020 and 2020/2021). The 130 isolates of P. triticina were segregated into 17 different physiological races. TTTST and TTTKS were the most common virulent races, whereas TTTST and MTTGT were the most frequent races. The races were classified into three groups, based on their distinct DNA band sizes (150 bp, 200 bp, and 300 bp) after RAPD analysis. The new wheat cultivars (Sakha-94, Sakha-95, and Shandweel-1) infected with the most virulent race (TTTST), Gemmeiza-12, and Misr-3 were resistant to all physiological races. The resistance of these cultivars was mostly due to the presence of Lr19- and Lr28-resistant genes. Our results serve as a warning about emerging aggressive races capable of supplanting resistance to leaf rust, and help in the understanding of the pathotype–cultivar–location association and its role in the susceptibility/resistance of new wheat cultivars to P. triticina.

SCREENING OF WHEAT LR-GENES FOR RESISTANCE TO PUCCINIA TRITICINA IN THE NORTH CAUCASUS REGION CONDITIONS

1970 ◽  
pp. 54-56
Author(s):  
G. V. Volkova ◽  
O. A. Kudinova ◽  
O. F. Vaganova
Keyword(s):  
Winter Wheat ◽  
Leaf Rust ◽  
Puccinia Triticina ◽  
North Caucasus ◽  
Breeding Programs ◽  
Lr Genes ◽  
Caucasus Region ◽  
Highly Efficient ◽  
The North ◽  
Wheat Rust

Currently, more than 70 wheat rust resistance genes are known, but few of them are effective. The purpose of this work is to screen lines of Lr gene carriers for resistance to leaf rust under conditions of the North Caucasus region. Investigations were carried out in 2016-2018 at the infectious site of VNIIBZR. Research material was 49 near isogenic lines of winter wheat cultivar Thatcher. Infectious material was the combined populations of P. triticina, obtained as a result of route surveys of industrial and breeding crops of winter wheat in the areas of the Krasnodar, Stavropol Territories and the Rostov Region, conducted in 2016-2018. According to the assessment, the genes are ranked as follows: - highly efficient genes (plants with no signs of damage): Lr9, Lr42, Lr43 + 24 and Lr50; effective (1R-5R) Lr genes: 19, 24, 29, 36, 37, 38, 45, 47; moderately effective (10MR-20MR) Lr genes: 17, 18, 21, 22a, 28, 32, 41, 52. The remaining Lr-lines were susceptible to P. triticina (25 MR - 90S) to varying degrees. Highly efficient and effective genes Lr9, Lr19, Lr24, Lr29, Lr38, Lr42, Lr43 + 24, Lr47 and Lr50 showed resistance in the seedling phase and can be recommended for inclusion in breeding programs to protect wheat from leaf rust in different phases of plant ontogenesis in the North Caucasus region.

scholarly journals Pre-harvest field application of enhanced freshness formulation reduces yield loss in orange

2020 ◽  
Vol 7 (1) ◽  
Author(s):  
Jaspa Samwel ◽  
Theodosy Msogoya ◽  
Abdul Kudra ◽  
Hosea Dunstan Mtui ◽  
Anna Baltazari ◽  
...  
Keyword(s):  
Yield Loss ◽  
Sweet Orange ◽  
New Technology ◽  
Significant Negative Correlation ◽  
Field Application ◽  
Yield Losses ◽  
Factorial Experiments ◽  
Marketable Yield ◽  
Pest Damage ◽  
Marketable Fruit

Abstract Background Orange (Citrus sinensis L.) production in Tanzania is constrained by several pre-harvest factors that include pests. Hexanal, sprayed as Enhanced Freshness Formulation (EFF) is a relatively new technology that has been reported to reduce pre-harvest loss in fruits. However, the effects of hexanal on pre-harvest yield loss of orange are not known. We studied the effects of hexanal as EFF on yield losses of three sweet orange cultivars namely, Early Valencia, Jaffa, and Late Valencia. Factorial experiments tested the effects of EFF concentration, variety, and time of EFF application on number of dropped fruit, percentage of non-marketable fruit and incidence of pest damage. Results Results showed significant negative correlation (p < 0.001) between EFF and the percentage of dropped fruit, non-marketable yield, and incidence of pest damage. An increase in hexanal concentration by 1%, is expected to reduce number of dropped fruit by 50, percentage of non-marketable by 35.6, and incidences of pest damage by 36.5% keeping other factors constant. Results also show significant association (p < 0.001) between time of hexanal application and non-marketable yield. Percentage of dropped fruit is expected to increase by 1 for each day away from harvest, keeping other factors constant. Conclusion Pre-harvest application of hexanal as EFF can significantly reduce number of dropped fruits, percentage of non-marketable fruit and incidence of pest damage.

scholarly journals The impact of cultivar resistance and fungicide treatment on mycotoxin content in grain and yield losses caused by Fusarium head blight in wheat

2010 ◽  
Vol 46 (No. 1) ◽  
pp. 21-26 ◽  
Author(s):  
V. Šíp ◽  
J. Chrpová ◽  
O. Veškrna ◽  
L. Bobková
Keyword(s):  
Grain Yield ◽  
Fusarium Head Blight ◽  
Field Experiments ◽  
Yield Loss ◽  
Joint Effect ◽  
Yield Losses ◽  
Cultivar Resistance ◽  
Head Blight ◽  
Fungicide Treatment ◽  
The Impact

Reactions to artificial infection with Fusarium graminearum isolates and a new fungicide Swing Top were studied in nine winter wheat cultivars evaluated in field experiments at two sites for three years for expression of symptoms, deoxynivalenol (DON) content in grain and grain yield. The results demonstrate a pronounced and relatively stable effect of cultivar resistance on reducing head blight, grain yield losses and contamination of grain by the mycotoxin DON. It is advantageous that the moderate level of resistance to Fusarium head blight (FHB) was detected also in two commonly grown Czech cultivars Sakura and Simila. Average fungicide efficacy for DON was 49.5% and 63.9% for a reduction in yield loss, however, it was found highly variable in different years and sites. The joint effect of cultivar resistance and fungicide treatment was 86.5% for DON and even 95.4% for reducing the yield loss. A very high risk was documented for susceptible cultivars and also the effects of medium responsive cultivars were found to be highly variable in different environments and therefore not guaranteeing sufficient protection against FHB under different conditions.

scholarly journals Modeling the Competitive Effect of Euphorbia dracunculoides and Astragalus sp. in Zero Input Rainfed Chickpea

2018 ◽  
Vol 36 (0) ◽  
Author(s):  
R.M. IKRAM ◽  
A. TANVEER ◽  
R. MAQBOOL ◽  
M.A. NADEEN
Keyword(s):  
Protein Content ◽  
Critical Period ◽  
Field Experiments ◽  
Seed Protein ◽  
Yield Loss ◽  
Seed Protein Content ◽  
Yield Losses ◽  
Competition Period ◽  
Crop Competition ◽  
Weed Removal

ABSTRACT: Brown chickpea (Cicer arietinum L.) is one of the two chickpea types grown in Pakistan and other countries. The critical period for weed removal in a rainfed chickpea system is an important consideration in devising weed management strategies. Field experiments were conducted in the winter season of 2011 and 2012 to determine the extent of yield loss with different periods of weed crop competition. Seven weed crop competition periods (0, 45, 60, 75, 90, 105 and 160 days after sowing - DAS) were used to identify the critical period for weed removal in rainfed chickpea. Experimental plots were naturally infested with Euphorbia dracunculoides and Astragalus sp. in both years. Individual, composite density and dry weights of E. dracunculoides and Astragalussp. increased significantly with an increase in the competition period. However, yield and yield-contributing traits of chickpea significantly decreased with an increase in the competition period. Chickpea seed yield loss was 11-53% in different weed crop competition periods. Euphorbia dracunculoides and Astragalus sp. removed 39.9 and 36.9 kg ha-1 of N, 9.61 and 7.27 kg ha-1 of P and 38.3 and 36.9 kg ha-1 of K, respectively. Season long weed competition (160 days after sowing) resulted in 19.5% seed protein content compared with 24.5% seed protein content in weed-free chickpea. A Logistic equation was fitted to yield data in response to increasing periods of weed crop competition. The critical timing of weed removal at 5 and 10% acceptable yield losses were 26 and 39 DAS, respectively. The observed critical period suggests that in rainfed chickpea, a carefully timed weed removal could prevent grain yield losses.

scholarly journals Corn Yield Loss Due to Volunteer Soybean

Weed Science ◽  
2016 ◽  
Vol 64 (3) ◽  
pp. 495-500 ◽  
Author(s):  
Jill Alms ◽  
Sharon A. Clay ◽  
David Vos ◽  
Michael Moechnig
Keyword(s):  
Loss Function ◽  
Growth Stage ◽  
Yield Loss ◽  
Corn Yield ◽  
Yield Losses ◽  
Herbicide Resistant ◽  
Growing Seasons ◽  
Previous Season ◽  
Control Volunteer ◽  
Soybean Plants

The widespread adoption of glyphosate-resistant corn and soybean in cropping rotations often results in volunteer plants from the previous season becoming problem weeds that require alternative herbicides for control. Corn yield losses due to season-long volunteer soybean competition at several densities in two growing seasons were used to define a hyperbolic yield loss function. The maximum corn yield loss observed at high volunteer soybean densities was about 56%, whereas, the incremental yield loss (I) at low densities was 3.2%. Corn yield loss at low volunteer soybean densities was similar to losses reported for low densities of velvetleaf and redroot pigweed, with 10% yield loss estimated to occur at 3 to 4 volunteer soybean plants m−2. Several herbicides, including dicamba with or without diflufenzopyr applied at the V2 growth stage of volunteer soybean, provided > 90% control, demonstrating several economical options to control volunteer glyphosate-resistant soybean in glyphosate-resistant corn. Reevaluation of control recommendations may be needed with commercialization of other genetically modified herbicide-resistant soybean varieties.

scholarly journals Genetically Divergent Types of the Wheat Leaf Fungus Puccinia triticina in Ethiopia, a Center of Tetraploid Wheat Diversity

2016 ◽  
Vol 106 (4) ◽  
pp. 380-385 ◽  
Author(s):  
J. A. Kolmer ◽  
M. A. Acevedo
Keyword(s):  
Leaf Rust ◽  
Common Wheat ◽  
Hexaploid Wheat ◽  
Rust Fungus ◽  
Tetraploid Wheat ◽  
Low Frequency ◽  
Puccinia Triticina ◽  
Leaf Rust Resistance ◽  
Virulence Phenotype ◽  
Wheat Leaf

Collections of Puccinia triticina, the wheat leaf rust fungus, were obtained from tetraploid and hexaploid wheat in the central highlands of Ethiopia, and a smaller number from Kenya, from 2011 to 2013, in order to determine the genetic diversity of this wheat pathogen in a center of host diversity. Single-uredinial isolates were derived and tested for virulence phenotype to 20 lines of Thatcher wheat that differ for single leaf rust resistance genes and for molecular genotypes with 10 simple sequence repeat (SSR) primers. Nine virulence phenotypes were described among the 193 isolates tested for virulence. Phenotype BBBQJ, found only in Ethiopia, was predominantly collected from tetraploid wheat. Phenotype EEEEE, also found only in Ethiopia, was exclusively collected from tetraploid wheat and was avirulent to the susceptible hexaploid wheat ‘Thatcher’. Phenotypes MBDSS and MCDSS, found in both Ethiopia and Kenya, were predominantly collected from common wheat. Phenotypes CCMSS, CCPSS, and CBMSS were found in Ethiopia from common wheat at low frequency. Phenotypes TCBSS and TCBSQ were found on durum wheat and common wheat in Kenya. Four groups of distinct SSR genotypes were described among the 48 isolates genotyped. Isolates with phenotypes BBBQJ and EEEEE were in two distinct SSR groups, and isolates with phenotypes MBDSS and MCDSS were in a third group. Isolates with CCMSS, CCPSS, CBMSS, TCBSS, and TCBSQ phenotypes were in a fourth SSR genotype group. The diverse host environment of Ethiopia has selected and maintained a genetically divergent population of P. triticina.

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