scholarly journals Effects of Planting Density and the Composition of Wheat Cultivar Mixtures on Stripe Rust: An Analysis Taking into Account Limits to the Replication of Controls

2000 ◽  
Vol 90 (12) ◽  
pp. 1313-1321 ◽  
Author(s):  
K. A. Garrett ◽  
C. C. Mundt
Keyword(s):  
Stripe Rust ◽  
Plant Density ◽  
Puccinia Striiformis ◽  
Planting Density ◽  
Host Diversity ◽  
Diversity Effect ◽  
Single Genotype ◽  
Unique Pair ◽  
Single Host ◽  
Rust Severity

The effect of plant density on disease is not well understood in populations of a single host plant genotype and has been studied even less in mixtures of host genotypes. We performed an experiment to evaluate the effect of wheat planting density on infection by Puccinia striiformis in experimental plots with a single wheat genotype and in plots with two genotypes making up a range of frequencies. Stripe rust severity in single-genotype plots increased with planting density in 1997 but decreased with planting density in 1998. Disease in host mixtures was compared to the weighted mean of disease levels in the corresponding single-genotype plots. The design of the field experiment included limited replication of these reference treatments (that is, there was not a unique pair of single-genotype plots for each mixture plot); therefore, we devised an analysis based on collapsing the data into independent mean observations. Disease reduction due to host diversity was less when one genotype predominated than when both host genotypes were present at nearly equal frequencies. The greatest mean host-diversity effect for reduced disease was at the intermediate planting density of 250 seeds per m2.

scholarly journals Management of stripe rust of barley (Hordeum vulgare L.) using fungicides

2015 ◽  
Vol 7 (1) ◽  
pp. 170-174
Author(s):  
Rakesh Devlash ◽  
Naval Kishore ◽  
Guru Dev Singh
Keyword(s):  
Hordeum Vulgare ◽  
Disease Severity ◽  
Stripe Rust ◽  
Puccinia Striiformis ◽  
Field Conditions ◽  
Hordeum Vulgare L ◽  
Grain Yields ◽  
Untreated Check ◽  
Rust Severity ◽  
Barley Stripe Rust

Under field conditions, various fungicide molecules were validated for their effectiveness on barley (Hordeum vulgare L.) stripe rust Puccinia striiformis f. sp. consecutively for three years under artificial field epiphytotic conditions. Seven fungicides viz., propiconazole 25%EC (tilt @ 0.1%), tebuconazole 25.9% m/m EC (folicur @ 0.1%), triademefon 25%WP (bayleton @ 0.1%), propiconazole 25%EC (tilt @ 0.05%), tebuconazole 25.9% m/m EC (folicur @ 0.05%), triademefon 25%WP (bayleton@ 0.05%), and mancozeb 75%WP (dithane M45 @ 0.2%) with variousconcentrations were tested for their effectiveness in controlling barley stripe rust severity. All fungicide applications resulted in lower disease severity and higher grain yields than untreated check plots. All the fungicides @ 0.1% concentrations reduced disease severity ranging from 87.8% to 95.6% except Mancozeb @ 0.2% (34.4%). Significant higher yield was obtained with Propiconazole @ 0.1% (26.7 q/ha) followed by Tebuconazole @ 0.1% (25.2 q/ha) and Triademefon @ 0.1% (24.5 q/ha). The present study revealed propiconazole as the most effective fungicide for the control of stripe rust of barley under epiphytotic conditions.

scholarly journals The Effects of Host Diversity and Other Management Components on Epidemics of Potato Late Blight in the Humid Highland Tropics

2001 ◽  
Vol 91 (10) ◽  
pp. 993-1000 ◽  
Author(s):  
K. A. Garrett ◽  
R. J. Nelson ◽  
C. C. Mundt ◽  
G. Chacón ◽  
R. E. Jaramillo ◽  
...  
Keyword(s):  
Late Blight ◽  
Potato Production ◽  
Potato Late Blight ◽  
Planting Density ◽  
Susceptible Host ◽  
Host Diversity ◽  
Progress Curve ◽  
Commercial Potato ◽  
Diversity Effect ◽  
Diversity Effects

A field study at three highland sites near Quito, Ecuador, was conducted to determine whether host-diversity effects on potato late blight would be as important as recently found in studies conducted in temperate areas. We compared three potato mixtures and use of mixtures in combination with different planting densities and two fungicide regimes. Treatment comparisons were made by absolute and relative measures of host-diversity effects and incorporating a truncated area under the disease progress curve as a means of standardizing comparisons across sites. Potato-faba intercrops consisting of only 10% potato provided an estimate of the effects of dilution of susceptible host tissue. Host-diversity effects were very different across study sites, with a large host-diversity effect for reduced disease only at the site most distant from commercial potato production. Planting density had little influence on host-diversity effects or on late blight in single-genotype stands. Fungicide use in combination with potato mixtures enhanced a host-diversity effect for reduced late blight. Potato-faba intercrops produced only a small decrease in potato late blight. Effects of host diversity on yield were variable, with the greatest increase in yield for mixtures treated with fungicides at the site most distant from commercial potato production. The effects of host diversity on late blight severity may be less consistent in the tropical highlands than in the temperate zone, but can contribute to integrated disease management.

Differential Resistance to Stripe Rust (Puccinia striiformis) in Collections of Basin Wild Rye (Leymus cinereus)

2014 ◽  
Vol 15 (3) ◽  
pp. 97-102 ◽  
Author(s):  
Frank M. Dugan ◽  
Michael J. Cashman ◽  
Richard C. Johnson ◽  
Meinan Wang ◽  
Xianming Chen
Keyword(s):  
Size Effect ◽  
Stripe Rust ◽  
Puccinia Striiformis ◽  
Differential Resistance ◽  
Plant Size ◽  
Plant Germplasm ◽  
National Plant Germplasm System ◽  
Rust Severity ◽  
Leymus Cinereus

Differential resistance to stripe rust (Puccinia striiformis) in a planting of 111 wild collections of Basin wild rye (Leymus cinereus) was noted 2011-2013. In 2011, rust severity was rated on a scale of 1-9. Much lighter infection in 2012 and 2013 was rated as the number of symptomatic leaves per plant divided by plant circumference (to adjust for plant size). Effect of collection was significant in 2011 (P = 0.0042), 2012 (P = 0.0032), and 2013 (P = 0.0095), with a relatively weak (0.23) but significant (P = 0.0149) correlation between 2011 and 2012 and a stronger (0.38) and highly significant (P < 0.0001) correlation between 2012 and 2013. Correlation between results of 2011 and 2013 was near zero and insignificant unless the ratings from 2011 were adjusted for plant size. Representative resistant and susceptible collections will be conserved as accessions in the National Plant Germplasm System. Accepted for publication 19 May 2014. Published 23 June 2014

scholarly journals Utilization of the Genomewide Wheat 55K SNP Array for Genetic Analysis of Stripe Rust Resistance in Common Wheat Line P9936

2019 ◽  
Vol 109 (5) ◽  
pp. 819-827 ◽  
Author(s):  
Shuo Huang ◽  
Jianhui Wu ◽  
Xiaoting Wang ◽  
Jingmei Mu ◽  
Zhi Xu ◽  
...  
Keyword(s):  
Stripe Rust ◽  
Puccinia Striiformis ◽  
Recombinant Inbred Lines ◽  
Snp Array ◽  
Snp Markers ◽  
Stripe Rust Resistance ◽  
Biparental Population ◽  
Chinese Landrace ◽  
Allele Specific ◽  
Rust Severity

Breeding for resistance to stripe rust (caused by Puccinia striiformis f. tritici) is essential for reducing losses in yield and quality in wheat. To identify genes for use in breeding, a biparental population of 186 recombinant inbred lines (RILs) from a cross of the Chinese landrace Mingxian 169 and CIMMYT-derived line P9936 was evaluated in field nurseries either artificially or naturally inoculated in two crop seasons. Each of the RILs and parents was genotyped with the wheat 55K single-nucleotide polymorphism (SNP) ‘Breeders’ array and a genetic linkage map with 8,225 polymorphic SNP markers spanning 3,593.37 centimorgans was constructed. Two major quantitative trait loci (QTL) and two minor QTL were identified. The major QTL QYr.nwafu-3BS.2 and QYr.nwafu-7BL on chromosomes arms 3BS and 7BL were detected in all field locations and explained an average 20.4 and 38.9% of phenotypic variation stripe rust severity, respectively. QYr.nwafu-3BS.2 likely corresponds to the locus Yr30/Sr2 and QYr.nwafu-7BL may be a resistance allele identified previously in CIMMYT germplasm. The other minor QTL had limited individual effects but increased resistance when in combinations with other QTL. Markers linked to QYr.nwafu-7BL were converted to kompetitive allele-specific polymerase chain reaction markers and validated in a panel of wheat accessions. Wheat accessions carrying the same haplotype as P9936 at the identified SNP loci had lower average stripe rust severity than the average severity of all other haplotypes.

scholarly journals LED Lighting and High-Density Planting Enhance the Cost-Efficiency of Halimione portulacoides Extraction Units for Integrated Aquaculture

2021 ◽  
Vol 11 (11) ◽  
pp. 4995
Author(s):  
Marco Custódio ◽  
Paulo Cartaxana ◽  
Sebastián Villasante ◽  
Ricardo Calado ◽  
Ana Isabel Lillebø
Keyword(s):  
Plant Density ◽  
Inorganic Nitrogen ◽  
High Density ◽  
Planting Density ◽  
Nitrogen And Phosphorus ◽  
Integrated Aquaculture ◽  
Halimione Portulacoides ◽  
White Leds ◽  
Artificial Lighting ◽  
Aquaculture Effluents

Halophytes are salt-tolerant plants that can be used to extract dissolved inorganic nutrients from saline aquaculture effluents under a production framework commonly known as Integrated Multi-Trophic Aquaculture (IMTA). Halimione portulacoides (L.) Aellen (common name: sea purslane) is an edible saltmarsh halophyte traditionally consumed by humans living near coastal wetlands and is considered a promising extractive species for IMTA. To better understand its potential for IMTA applications, the present study investigates how artificial lighting and plant density affect its productivity and capacity to extract nitrogen and phosphorous in hydroponic conditions that mimic aquaculture effluents. Plant growth was unaffected by the type of artificial lighting employed—white fluorescent lights vs. blue-white LEDs—but LED systems were more energy-efficient, with a 17% reduction in light energy costs. Considering planting density, high-density units of 220 plants m−2 produced more biomass per unit of area (54.0–56.6 g m−2 day−1) than did low-density units (110 plants m−2; 34.4–37.1 g m−2 day−1) and extracted more dissolved inorganic nitrogen and phosphorus. Overall, H. portulacoides can be easily cultivated hydroponically using nutrient-rich saline effluents, where LEDs can be employed as an alternative to fluorescent lighting and high-density planting can promote higher yields and extraction efficiencies.

scholarly journals Optimizing Planting Density and Impact of Panicle Types on Grain Yield and Microclimatic Response Index of Hybrid Rice (Oryza sativa L.)

2021 ◽  
Author(s):  
Guotao Yang ◽  
Xuechun Wang ◽  
Farhan Nabi ◽  
Hongni Wang ◽  
Changkun Zhao ◽  
...  
Keyword(s):  
Relative Humidity ◽  
Light Intensity ◽  
Grain Yield ◽  
Hybrid Rice ◽  
Plant Density ◽  
Oryza Sativa L ◽  
Planting Density ◽  
Response Index ◽  
Lower Position ◽  
High Plant Density

AbstractThe architecture of rice plant represents important and complex agronomic traits, such as panicles morphology, which directly influence the microclimate of rice population and consequently grain yield. To enhance yield, modification of plant architecture to create new hybrid cultivars is considered a sustainable approach. The current study includes an investigation of yield and microclimate response index under low to high plant density of two indica hybrid rice R498 (curved panicles) and R499 (erect panicles), from 2017 to 2018. The split-plot design included planting densities of 11.9–36.2 plant/m2. The results showed that compared with R498, R499 produced a higher grain yield of 8.02–8.83 t/ha at a higher planting density of 26.5–36.2 plant/m2. The response index of light intensity and relative humidity to the planting density of R499 was higher than that of R498 at the lower position of the rice population. However, the response index of temperature to the planting density of R499 was higher at the upper position (0.2–1.4%) than at the lower position. Compared with R498, R499 at a high planting density developed lower relative humidity (78–88%) and higher light intensity (9900–15,916 lx) at the lower position of the rice population. Our finding suggests that erect panicles are highly related to grain yield microclimatic contributors under a highly dense rice population, such as light intensity utilization, humidity, and temperature. The application of erect panicle rice type provides a potential strategy for yield improvement by increasing microclimatic conditions in rice.

scholarly journals Effects of Different Planting Densities on Photosynthesis in Maize Determined via Prompt Fluorescence, Delayed Fluorescence and P700 Signals

Plants ◽  
2021 ◽  
Vol 10 (2) ◽  
pp. 276
Author(s):  
Wanying Chen ◽  
Bo Jia ◽  
Junyu Chen ◽  
Yujiao Feng ◽  
Yue Li ◽  
...  
Keyword(s):  
Electron Transport ◽  
Chlorophyll A ◽  
Chlorophyll A Fluorescence ◽  
Electron Transport Chain ◽  
Plant Density ◽  
Photosynthetic Electron Transport ◽  
Planting Density ◽  
Strong Impact ◽  
Photosynthetic Electron Transport Chain ◽  
Transport Chain

The mutual shading among individual field-grown maize plants resulting from high planting density inevitably reduces leaf photosynthesis, while regulating the photosynthetic transport chain has a strong impact on photosynthesis. However, the effect of high planting density on the photosynthetic electron transport chain in maize currently remains unclear. In this study, we simultaneously measured prompt chlorophyll a fluorescence (PF), modulated 820 nm reflection (MR) and delayed chlorophyll a fluorescence (DF) in order to investigate the effect of high planting density on the photosynthetic electron transport chain in two maize hybrids widely grown in China. PF transients demonstrated a gradual reduction in their signal amplitude with increasing planting density. In addition, high planting density induced positive J-step and G-bands of the PF transients, reduced the values of PF parameters PIABS, RC/CSO, TRO/ABS, ETO/TRO and REO/ETO, and enhanced ABS/RC and N. MR kinetics showed an increase of their lowest point with increasing high planting density, and thus the values of MR parameters VPSI and VPSII-PSI were reduced. The shapes of DF induction and decay curves were changed by high planting density. In addition, high planting density reduced the values of DF parameters I1, I2, L1 and L2, and enhanced I2/I1. These results suggested that high planting density caused harm on multiple components of maize photosynthetic electron transport chain, including an inactivation of PSII RCs, a blocked electron transfer between QA and QB, a reduction in PSI oxidation and re-reduction activities, and an impaired PSI acceptor side. Moreover, a comparison between PSII and PSI activities demonstrated the greater effect of plant density on the former.

scholarly journals Grass Hosts Harbor More Diverse Isolates of Puccinia striiformis Than Cereal Crops

2016 ◽  
Vol 106 (4) ◽  
pp. 362-371 ◽  
Author(s):  
P. Cheng ◽  
X. M. Chen ◽  
D. R. See
Keyword(s):  
Ssr Markers ◽  
Stripe Rust ◽  
Simple Sequence Repeat ◽  
Puccinia Striiformis ◽  
The United States ◽  
Grass Species ◽  
Cereal Crops ◽  
Sequence Repeat ◽  
Grass Hosts ◽  
Simple Sequence

Puccinia striiformis causes stripe rust on cereal crops and many grass species. However, it is not clear whether the stripe rust populations on grasses are able to infect cereal crops and how closely they are related to each other. In this study, 103 isolates collected from wheat, barley, triticale, rye, and grasses in the United States were characterized by virulence tests and simple sequence repeat (SSR) markers. Of 69 pathotypes identified, 41 were virulent on some differentials of wheat only, 10 were virulent on some differentials of barley only, and 18 were virulent on some differentials of both wheat and barley. These pathotypes were clustered into three groups: group one containing isolates from wheat, triticale, rye, and grasses; group two isolates were from barley and grasses; and group three isolates were from grasses and wheat. SSR markers identified 44 multilocus genotypes (MLGs) and clustered them into three major molecular groups (MG) with MLGs in MG3 further classified into three subgroups. Isolates from cereal crops were present in one or more of the major or subgroups, but not all, whereas grass isolates were present in all of the major and subgroups. The results indicate that grasses harbor more diverse isolates of P. striiformis than the cereals.

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