scholarly journals Yield Loss Associated with Different Levels of Stem Rust Resistance in Bread Wheat

Plant Disease ◽  
2018 ◽  
Vol 102 (12) ◽  
pp. 2531-2538 ◽  
Author(s):  
Tegwe Soko ◽  
Cornelia M. Bender ◽  
Renée Prins ◽  
Zacharias A. Pretorius
Keyword(s):  
Stem Rust ◽  
Yield Loss ◽  
Field Trials ◽  
Susceptible Variety ◽  
Yield Reduction ◽  
Adult Plant ◽  
Different Types ◽  
The Mean ◽  
Disease Pressure ◽  
Different Levels

Puccinia graminis f. sp. tritici race Ug99 (syn. TTKSK) has been identified as a major threat to wheat production based on its broad virulence. Despite its importance, the effect of Ug99 on different types of resistance in wheat has not been thoroughly researched. In field trials conducted with P. graminis f. sp. tritici race PTKST (Ug99 race group) over 2 years, AUDPC differentiated the moderately susceptible variety SC Stallion (515) and susceptible entries SC Nduna (995) and Line 37-07 (1634) from those with adult plant resistance (APR). AUDPC of APR varieties W1406 (256), W6979 (399), and Kingbird (209) was higher than the mean of 25 recorded for the all stage resistant (ASR) variety SC Sky. In fungicide-protected and unprotected plots, race PTKST resulted in a mean yield loss of 21.3%, with susceptible Line 37-03 recording a 47.9% decrease in grain yield. Yield reduction in APR varieties reached 19.5% in W1406, whereas the ASR control SC Sky showed a mean loss of 6.4%. Although APR reduced the effects of stem rust on yield and yield components under conditions of high disease pressure, it did not provide the same protection as effective ASR.

Tolerance of identity preserved soybean cultivars to preemergence herbicides

2015 ◽  
Vol 95 (4) ◽  
pp. 719-726 ◽  
Author(s):  
Kimberly D. Belfry ◽  
Nader Soltani ◽  
Lynette R. Brown ◽  
Peter H. Sikkema
Keyword(s):  
Yield Loss ◽  
Field Trials ◽  
Climatic Conditions ◽  
Recommended Dose ◽  
Yield Reduction ◽  
Soybean Yield ◽  
Soybean Cultivars ◽  
Chlorimuron Ethyl ◽  
Preemergence Herbicides

Belfry, K. D., Soltani, N., Brown, L. R. and Sikkema, P. H. 2015. Tolerance of identity preserved soybean cultivars to preemergence herbicides. Can. J. Plant Sci. 95: 719–726. Six field trials were conducted over a 3-yr period (2011 to 2013) near Exeter and Ridgetown, Ontario, Canada, to assess the tolerance of seven identity-preserved (IP) soybean cultivars to preemergence (PRE) herbicides applied at 2×the recommended dose. All cultivars demonstrated excellent tolerance to dimethenamid-P, pyroxasulfone, S-metolachlor, chlorimuron-ethyl, clomazone, cloransulam-methyl, flumetsulam and imazethapyr, showing 5% or less injury. At Exeter, linuron caused as much as 13 and 18% injury at 2 and 4 wk after soybean emergence, while injury due to metribuzin was as high as 22 and 47% for the same dates, respectively. At Exeter, linuron, metribuzin and S-metolachlor plus metribuzin reduced soybean height up to 17, 41 and 24%, respectively; soybean height was generally not affected at the Ridgetown sites. At Exeter, metribuzin reduced soybean yield up to 38% for cultivars S03W4, Madison and OAC Lakeview, while S23T5 was not significantly reduced. On the contrary, metribuzin yield loss at Ridgetown was nonsignificant. Results from this study suggest that PRE application of metribuzin at 2× field dose has potential to cause unacceptable injury and yield reduction in IP soybeans under some soil and climatic conditions and may vary according to cultivar.

Quantitative effects of leaf and stem rusts on yield and quality of wheat

1971 ◽  
Vol 11 (52) ◽  
pp. 550 ◽  
Author(s):  
BR Keed ◽  
NH White
Keyword(s):  
Stem Rust ◽  
Field Experiments ◽  
Yield Loss ◽  
Maximum Yield ◽  
Yield Reduction ◽  
Maximum Loss ◽  
Yield And Quality ◽  
Australian Wheat ◽  
Individual Grains

The effects of Puccinia recondita and/or P. graminis var. tritici on the yield and quality of four Australian wheat cultivars were measured in 18 field experiments. Fortnightly applications of Dithane. S-31(R) provided almost rust-free plots for comparison with plots in which rust was allowed to develop. Leaf and stem rust intensities were assessed using the key diagram of Large and Griffin. Leaf rust caused a maximum loss of yield of 26 per cent on Mendos and 22 per cent on Gamut. Stem rust on 1156.238 caused losses of up to 49 per cent while both leaf and stem rusts on Gabo resulted in a maximum yield loss of 55 per cent. With all four cultivars, most of the yield reduction was caused by a reduction in the weight of individual grains, reflected in the losses in 1,000 grain weights. Infection by leaf or stem rust generally resulted in a reduction in bushel weight and protein content.

scholarly journals Tolerance of Glyphosate-Resistant Maize to Glyphosate Plus MCPA Amine Is Influenced by Dose and Timing

2015 ◽  
Vol 2015 ◽  
pp. 1-5
Author(s):  
Nader Soltani ◽  
Kris McNaughton ◽  
Chris L. Gillard ◽  
Robert E. Nurse ◽  
Peter H. Sikkema
Keyword(s):  
Environmental Conditions ◽  
Yield Loss ◽  
Dry Weight ◽  
Field Trials ◽  
Recommended Dose ◽  
Yield Reduction ◽  
Leaf Stage ◽  
Shoot Dry Weight ◽  
Significant Injury

There is little information on tolerance of glyphosate-resistant maize to glyphosate plus MCPA amine as influenced by dose and timing under Ontario environmental conditions. A total of seven field trials were conducted at various locations in Ontario, Canada, in 2011–2013 to evaluate tolerance of field maize to tank mixes of glyphosate (900 g a.e./ha) plus MCPA amine (79, 158, 315, 630, 1260, 2520, or 5040 g a.e./ha) at either the 4- or 8-leaf stage. The predicted dose of MCPA amine that caused 5, 10, and 20% injury was 339, 751, and 1914 g a.e./ha when applied to 4-leaf maize but only 64, 140, and 344 g a.e./ha when applied to 8-leaf maize, respectively. The predicted dose of MCPA amine that caused 5, 10, and 20% reduction in shoot dry weight of maize was 488, 844, and 1971 g a.e./ha when applied to 4-leaf maize and only 14, 136, and 616 g a.e./ha when applied to 8-leaf maize, respectively. The predicted dose of MCPA amine that caused 5, 10, and 20% yield reduction was 2557, 4247, and >5040 g a.e./ha when applied to 4-leaf maize and 184, 441, and 1245 g a.e./ha when applied to 8-leaf maize, respectively. Based on these results, glyphosate plus MCPA amine applied at the manufacturer’s recommended dose of 630 g a.e./ha applied to 4-leaf maize has potential to cause injury but the injury is transient with no significant reduction in yield. However, when glyphosate plus MCPA amine is applied to 8-leaf maize it has the potential to cause significant injury and yield loss in maize.

Components of resistance in barley to stem rust: pre- and post-penetration development in seedling and adult plant leaves

1996 ◽  
Vol 74 (8) ◽  
pp. 1305-1312 ◽  
Author(s):  
J. Q. Liu ◽  
D. E. Harder
Keyword(s):  
Stem Rust ◽  
Phenotypic Expression ◽  
Colony Growth ◽  
Host Cells ◽  
Adult Plant ◽  
Puccinia Graminis ◽  
Plant Leaves ◽  
Breeding Lines ◽  
Mother Cells ◽  
Different Levels

Seven barley (Hordeum vulgare) cultivars or breeding lines with different levels of resistance to stem rust and the susceptible wheat cultivar Little Club (Triticum aestivum) were inoculated with races QCC, QFC, and TPM of Puccinia graminis f.sp. tritici and examined using light microscopy to associate the sequence of histological events with phenotypic expression of resistance. There were no significant differences in urediniospore germination, appressorium formation, or substomatal penetration in any of the race–cultivar combinations in seedling leaves. Formation of primary haustorium mother cells (HMCs) was not affected by the presence or absence of the resistance gene Rpg1 when inoculated with race QCC, but was reduced considerably in lines possessing this gene after inoculation with races QFC and TPM. Development of all races was arrested during primary HMC formation to a greater extent in all barley lines than in Little Club wheat. The expression of resistance in barley to P. g. tritici was associated with the frequency of post-penetration abortion, the degree of reduction in colony growth, and the incidence of colony-associated necrosis of host cells. The rankings of the host lines based on these histological events were in agreement with the rankings for receptivity and urediniospore production determined previously on stem tissues of adult barley plants. Keywords: barley, stem rust, resistance, components, histology.

scholarly journals The hygienic and microbial status of Sudanese banknotes, Khartoum state, Sudan

2017 ◽  
Vol 4 (4) ◽  
pp. 923 ◽  
Author(s):  
Mohanad Hassan Mohamed Honua
Keyword(s):  
Viable Count ◽  
Contamination Rate ◽  
Biochemical Tests ◽  
Source Of Infection ◽  
Different Types ◽  
Identification Of Bacteria ◽  
The Mean ◽  
Bacteria And Fungi ◽  
Different Levels ◽  
Hand Contact

Background: Banknotes are one of the items most frequently circulating from hand to hand, and microbial contaminants of banknote may be transmitted directly, through hand-to-hand contact, or indirectly, via food or other inanimate objects. This study was designed to assess the banknotes handlers hygiene and microbial (Bacteria, Yeasts and Moulds) contamination of Sudanese banknotes in Khartoum state, Sudan. Methods: Fifty samples of Sudanese banknotes were collected randomly from handlers through (March - April / 2015). These samples were microbiologically tested for quantify bacteria, identification of bacteria and fungi (Yeasts and Moulds) by using biochemical tests for bacteria and phenotypical characteristics for fungi. Results: The study showed that the mean of total viable count (CFU/cm2) of bacteria contaminated of banknotes between ( 4.5 – 8.3 ) x 105 CFU/cm2 ,  the study showed 12 different types of bacteria and 5 types of fungi was identified from banknotes with different percentages. From statistically analyzed of 50 questionnaires there were; 76% of handlers had knowledge about contaminated banknotes as being a source of infection; 94% educated handlers at different levels; 64% of the handlers washed hands after using a toilets and before dealing with banknotes again. Conclusions: Sudanese banknotes were contaminated with different bacteria, yeast and moulds. unhygienically handled. The contamination rate was higher in lower denominations than in higher ones.

scholarly journals Sensitivity of Zasmidium citri-griseum to Fenbuconazole and Control of Citrus Greasy Spot in Panama

Agronomy ◽  
2020 ◽  
Vol 10 (10) ◽  
pp. 1577
Author(s):  
Vidal Aguilera-Cogley ◽  
Antonio Vicent
Keyword(s):  
Disease Control ◽  
Fungicide Resistance ◽  
Mycelial Growth ◽  
Yield Loss ◽  
Field Trials ◽  
Effective Concentration ◽  
Yield Reduction ◽  
Reduce Risk ◽  
And Control ◽  
Reduce Disease Severity

Citrus greasy spot, caused by Zasmidium citri-griseum ( = Mycosphaerella citri) is the most prevalent fungal disease of citrus in Panama, causing premature defoliation and yield reduction. Fungicide applications are generally needed for the control of greasy spot. In this study, the sensitivity to fenbuconazole of 34 isolates of Z. citri-griseum from Panama was determined by calculating the effective concentration needed to reduce mycelial growth by 50% (EC50). Two field trials were conducted from 2011 to 2013, to evaluate the efficacy of fenbuconazole to reduce disease severity and yield loss. The EC50 values for fenbuconazole ranged from 0.09 to 7.62 μg mL−1, with a mean EC50 value of 2.66 ± 0.36 SE μg mL−1 for mycelial growth. These data can be used for monitoring sensitivity shifts in Z. citri-griseum to fenbuconazole and reduce risk of fungicide resistance in Panama. In the field trials, sprays with fenbuconazole significantly reduced (p < 0.0001) the severity of greasy spot on leaves compared with the non-treated control. Greater disease control was obtained when three sprays of fenbuconazole were applied instead of one. Nevertheless, no significant differences (p > 0.05) were detected in yield.

scholarly journals Influence of Wheat Cultivar, Species of Fusarium, and Isolate Aggressiveness on the Efficacy of Fungicides for Control of Fusarium Head Blight

Plant Disease ◽  
2003 ◽  
Vol 87 (9) ◽  
pp. 1107-1115 ◽  
Author(s):  
Á. Mesterházy ◽  
T. Bartók ◽  
C. Lamper
Keyword(s):  
Fusarium Head Blight ◽  
Yield Loss ◽  
Wheat Cultivar ◽  
Wheat Cultivars ◽  
Cultivar Resistance ◽  
Head Blight ◽  
Winter Wheat Cultivars ◽  
Disease Pressure ◽  
Different Levels

Attempts to control Fusarium head blight (FHB) with fungicides have been highly variable. Variability is caused by cultivar resistance, fungicide efficacy, fungicide coverage, timing, and pathogen aggressiveness. In this research, fungicides were tested on winter wheat cultivars with different levels of resistance to FHB using different isolates of Fusarium graminearum and F. culmorum to evaluate the role of host resistance and isolate aggressiveness on severity of FHB. Fungicides were applied to groups of wheat heads to provide full coverage. Incidence and severity of FHB was measured by the severity of head symptoms, percentage of Fusarium-damaged kernels (FDK), yield loss, and deoxynivalenol (DON) contamination. Development of FHB was affected by fungicides, cultivars, fungal isolates, and most of the two-way interactions of these variables. Among the fungicides tested, those containing tebuconazole tended to be more effective in reducing FHB. Reduction of disease in susceptible cultivars may not be adequate to produce marketable yields under conditions of high disease pressure. In most cases, if a fungicide reduced FHB visual symptoms, similar decreases were detected in yield loss, DON concentration, and FDK reaction. In 1998, an increase in DON contamination compared with the Fusarium check was observed with azoxystrobin and carbendazim on the more susceptible cultivar. This increase in DON with some fungicide requires additional research. Research to develop more resistant cultivars, better spraying technology, and more effective fungicides is also needed.

OVARIAN ASCORBIC ACID DEPLETION TEST FOR LUTEINIZING HORMONE

1967 ◽  
Vol 56 (4) ◽  
pp. 619-625 ◽  
Author(s):  
Hans Jacob Koed ◽  
Christian Hamburger
Keyword(s):  
Ascorbic Acid ◽  
Luteinizing Hormone ◽  
Dose Response ◽  
Response Curve ◽  
Dose Response Curve ◽  
Human Origin ◽  
Response Curves ◽  
Significant Difference ◽  
The Mean ◽  
Different Levels

ABSTRACT Comparison of the dose-response curves for LH of ovine origin (NIH-LH-S8) and of human origin (IRP-HMG-2) using the OAAD test showed a small, though statistically significant difference, the dose-response curve for LH of human origin being a little flatter. Two standard curves for ovine LH obtained with 14 months' interval, were parallel but at different levels of ovarian ascorbic acid. When the mean ascorbic acid depletions were calculated as percentages of the control levels, the two curves for NIH-LH-S8 were identical. The use of standards of human origin in the OAAD test for LH activity of human preparations is recommended.

scholarly journals Characterization of Maize Genotypes (Zea mays L.) for Resistance to Striga asiatica and S. hermonthica and Compatibility with Fusarium oxysporum f. sp. strigae (FOS) in Tanzania

Agronomy ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 1004
Author(s):  
John Lobulu ◽  
Hussein Shimelis ◽  
Mark D. Laing ◽  
Arnold Angelo Mushongi ◽  
Admire Isaac Tichafa Shayanowako
Keyword(s):  
Grain Yield ◽  
Fusarium Oxysporum ◽  
Biocontrol Agent ◽  
Zea Mays L ◽  
Control Treatment ◽  
Yield Reduction ◽  
Maize Genotypes ◽  
Significant Yield ◽  
The Mean

Striga species cause significant yield loss in maize varying from 20 to 100%. The aim of the present study was to screen and identify maize genotypes with partial resistance to S. hermonthica (Sh) and S. asiatica (Sa) and compatible with Fusarium oxysporum f. sp. strigae (FOS), a biocontrol agent. Fifty-six maize genotypes were evaluated for resistance to Sh and Sa, and FOS compatibility. Results showed that FOS treatment significantly (p < 0.001) enhanced Striga management compared to the untreated control under both Sh and Sa infestations. The mean grain yield was reduced by 19.13% in FOS-untreated genotypes compared with a loss of 13.94% in the same genotypes treated with FOS under Sh infestation. Likewise, under Sa infestation, FOS-treated genotypes had a mean grain yield reduction of 18% while untreated genotypes had a mean loss of 21.4% compared to the control treatment. Overall, based on Striga emergence count, Striga host damage rating, grain yield and FOS compatibility, under Sh and Sa infestations, 23 maize genotypes carrying farmer preferred traits were identified. The genotypes are useful genetic materials in the development of Striga-resistant cultivars in Tanzania and related agro-ecologies.

scholarly journals Incidence and Characteristics of Retinoblastoma in Poland: The First Nationwide Study 2010–2017

2021 ◽  
Vol 18 (12) ◽  
pp. 6539
Author(s):  
Michał S. Nowak ◽  
Bożena Romanowska-Dixon ◽  
Iwona Grabska-Liberek ◽  
Michał Żurek
Keyword(s):  
Western Europe ◽  
External Beam Radiotherapy ◽  
Cohort Analysis ◽  
Developed Countries ◽  
Live Births ◽  
Focal Treatment ◽  
Different Types ◽  
The Mean ◽  
Birth Cohort Analysis

Background: The present study aimed to investigate the incidence and characteristics of retinoblastoma in the overall population of Poland. Methods: The retrospective survey of both National Health Fund (NHF) and National Cancer Registry (NCR) databases were performed to identify all retinoblastoma cases in Poland in the years 2010–2017. Results: During 2010–2017, the mean age-standardised incidence of retinoblastoma (the unit of incidence is per 1,000,000 person-years) was 10.15 (95% CI 7.23–13.08) among children aged 0 to 4 years and 5.39 (95% CI 4.18–6.60) in those aged 0 to 9 years. During 2010–2014 (to allow 5 years of follow-up), the mean incidence of retinoblastoma by birth cohort analysis in Poland was 4.89 (95% CI 4.04–5.74) per 100,000 live births, corresponding to an incidence of 1 per 20,561 (95% CI 15,855–25,267) live births. In Poland, 14.6% of children with retinoblastoma had enucleation of the eye globe, 76.8% received different types of chemotherapy combined with focal treatment, 5.9% were treated with external beam radiotherapy, and 2.7% were treated with focal treatments only. Conclusions: The incidence of retinoblastoma and the pattern of medical management of retinoblastoma in Poland was similar to that reported in developed countries in Western Europe, Asia, and North America.

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