scholarly journals Spring wheat mixtures in northern crop production: ability of mixtures to buffer disease development and yield loss caused by Septoria nodorum

1986 ◽  
Vol 58 (1) ◽  
pp. 33-42 ◽  
Author(s):  
Reijo Karjalainen
Keyword(s):  
Spring Wheat ◽  
Crop Production ◽  
Yield Reduction ◽  
Pure Stand ◽  
Septoria Nodorum ◽  
Infection Rates ◽  
Mixed Stands ◽  
Moderate Disease ◽  
Epidemic Development ◽  
Moderately Resistant

Epidemic development of Septoria nodorum was studied in pure stands and mixtures of two spring wheat cultivars Tähti (susceptible) and Kadett (moderately resistant) in 1983—1985. Apparent infection rates in the mixture were similar to that of the more resistant pure stand. In all three years, disease levels in mixed stands were lower than the arithmetic mean of the pure stands. The yield experiments indicated that under low or moderate disease stress mixtures can buffer yield reduction effectively. However, when disease levels were high, mixtures appeared to be less effective in that respect. The results are discussed in relation to possible mechanisms of intraspecific mixtures to retard non-specialized pathogens. The use of wheat mixtures to prevent disease induced yield losses caused by S. nodorum is also discussed.

The influence of mixtures of Stylosanthes spp. accessions on the occurrence of anthracnose caused by Colletotrichum gloeosporioides

1994 ◽  
Vol 45 (1) ◽  
pp. 203 ◽  
Author(s):  
RD Davis ◽  
S Chakraborty ◽  
DF Cameron ◽  
JAG Irwin ◽  
RM Boland
Keyword(s):  
Colletotrichum Gloeosporioides ◽  
Resistant Cultivar ◽  
Pure Stand ◽  
Northern Australia ◽  
Short Term ◽  
Mixed Stands ◽  
The Mean ◽  
Moderately Resistant ◽  
Long Term Studies

The effectiveness of using accession mixtures of Stylosanthes spp. to manage anthracnose (Colletotrichum gloeosporioides) in pastures in northern Australia was examined during three consecutive years. Two mixtures containing six accessions were compared with the components grown as pure stands. No significant differences in anthracnose incidence (proportion of infected plants/plot) were indicated between the two mixtures and the mean incidence of their respective components grown in pure swards. Areas under the disease progress curves for the accessions were not significantly different between pure and mixed stands of the cultivars other than Seca and Verano. Resistant cultivar Seca developed more disease in a mixture than in a pure stand, and moderately resistant Verano had less disease in a mixture than in a pure stand. In the short term, no apparent anthracnose control advantage is achieved in highly susceptible accessions of Stylosanthes spp. when they are included in mixtures with less susceptible accessions. Long term studies involving grazing animals are necessary to adequately evaluate control of this disease through the use of mixtures.

Systematic mixed stands of spring wheat cultivars

1980 ◽  
Vol 94 (3) ◽  
pp. 529-532 ◽  
Author(s):  
R. Prasad ◽  
S. N. Sharma
Keyword(s):  
Spring Wheat ◽  
Agricultural Research ◽  
Indian Agricultural Research Institute ◽  
High Rate ◽  
New Delhi ◽  
Pure Stand ◽  
Wheat Cultivars ◽  
Nitrogen Application ◽  
Agricultural Research Institute ◽  
Mixed Stands

SummaryHeight variability in spring wheat (Triticum aestivum L.) cultivars permits growing them in systematic mixed stands and such mixtures are reported to lead to better utilization of solar radiation. Studies on such wheat mixtures are limited. A field experiment was therefore conducted for two wheat seasons (1974–5 and 1975–6) at the Indian Agricultural Research Institute, New Delhi, to compare the yield potentials of the mixed and pure stands of three spring wheat cultivars varying in plant height. Two kinds of canopy stands, namely, pyramidal and columnar, were created by making appropriate row arrangements of the cultivars while seeding. Mixed stands gave significantly higher straw yields and the grain yield was also significantly higher than the highest yielding cultivar in its pure stand at a high rate of nitrogen application (120 kg N/ha).

YIELD OF PURE AND MIXED STANDS OF TWO SPRING WHEAT CULTIVARS SOWN AT FIVE RATES OF SEEDING

1977 ◽  
Vol 57 (3) ◽  
pp. 1005-1007 ◽  
Author(s):  
R. J. BAKER
Keyword(s):  
Triticum Aestivum ◽  
Spring Wheat ◽  
Yield Components ◽  
Triticum Aestivum L ◽  
Pure Stand ◽  
Wheat Cultivars ◽  
Seeding Rate ◽  
Mixed Stands ◽  
Yield And Yield Components

Yield and yield components were measured on two spring wheat (Triticum aestivum L. em Thell) cultivars, Neepawa and Pitic 62, and a 1:1 mixture of the two sown at five rates of seeding in each of 2 yr. Lack of agreement between performance in pure and mixed stands was observed when, at the highest seeding rate, the mixture yielded higher in 1974 and lower in 1976 than either of the component cultivars grown in pure stand.

scholarly journals Inheritance of leaf resistance to Septoria nodorum Berk. in two crosses of spring wheat

1983 ◽  
Vol 55 (5) ◽  
pp. 425-430
Author(s):  
Reijo Karjalainen
Keyword(s):  
Spring Wheat ◽  
Resistance Breeding ◽  
Breeding Strategy ◽  
Symptom Expression ◽  
Septoria Nodorum ◽  
Broad Sense Heritability ◽  
Resistant Parent ◽  
Leaf Resistance ◽  
Moderately Resistant ◽  
F2 Progeny

The F2 progeny of two spring wheat crosses involving susceptible and moderately resistant parent cultivars were tested in the field for their reaction to infection by Septoria nodorum Berk. The variation in symptom expression was continuous, providing no support for the existence of individually acting major genes. The broad sense heritability values for the crosses were moderate at 0.47 and 0.34 with over half of the variation being of environmental origin. The results are discussed in relation to developing a resistance breeding strategy for wheat to S. nodorum.

scholarly journals Yield reduction of spring wheat in relation to disease development caused by Septoria nodorum

1990 ◽  
Vol 62 (3) ◽  
pp. 255-263
Author(s):  
Reijo Karjalainen ◽  
Sinikka Karjalainen
Keyword(s):  
Spring Wheat ◽  
Yield Components ◽  
Severe Disease ◽  
Severe Infection ◽  
Yield Reduction ◽  
Septoria Nodorum ◽  
Infection Level ◽  
Field Inoculation ◽  
Grain Yields ◽  
Leaf Area Duration

Effects of Septoria nodorum on the grain yields and yield components of three spring wheat cultivars were studied in Finland using artificial field inoculation over three years. At low infection level, in 1986, grain yield was reduced in all cultivars by 2—10 %, but statistically insignificantly. In 1984 severe infection reduced the grain yields of cultivars Kadett and Tähti by 27 % and 32 %, respectively, while in 1985 the yield of Tähti was reduced by 16 % and that of Kadett by 18 %. Grain weights were reduced under low disease stress by 3—5 %, while under severe disease stress the reductions were 7—20 %. Disease strongly reduced the green-leaf area duration compared with fungicide-treated plots. Examination of single tillers showed that all yield components were significantly reduced. The disease amount on second leaves correlated best with grain weight loss. Implications of these results for controlling the damage caused by S. nodorum in spring wheat are discussed.

scholarly journals The effectiveness of weed regulation methods in spring wheat cultivated in integrated, conventional and organic crop production systems

2012 ◽  
Vol 52 (4) ◽  
pp. 486-493 ◽  
Author(s):  
Beata Feledyn-Szewczyk
Keyword(s):  
Spring Wheat ◽  
Crop Production ◽  
Dry Matter ◽  
Production Systems ◽  
Integrated System ◽  
Integrated Systems ◽  
Conventional System ◽  
Weed Species ◽  
Organic System ◽  
Weed Communities

Abstract The research was conducted from 2008 to 2010, and compared the influence of different weed control methods used in spring wheat on the structure of the weed communities and the crop yield. The study was carried out at the Experimental Station of the Institute of Soil Science and Plant Cultivation - State Research Institute in Osiny as part of a long-term trial where these crop production systems had been compared since 1994. In the conventional and integrated systems, spring wheat was grown in a pure stand, whereas in the organic system, the wheat was grown with undersown clover and grasses. In the conventional system, herbicides were applied two times in a growing season, but in the integrated system - only once. The effectiveness of weed management was lower in the organic system than in other systems, but the dry matter of weeds did not exceed 60 g/m2. In the integrated system, the average dry matter of weeds in spring wheat was 4 times lower, and in the conventional system 10 times lower than in the organic system. Weed diversity was the largest in spring wheat cultivated in the organic system. In the conventional and integrated systems, compensation of some weed species was observed (Viola arvensis, Fallopia convolvulus, Equisetum arvense). The comparison of weed communities using Sorenson’s indices revealed more of a similarity between systems in terms of number of weed species than in the number of individuals. Such results imply that qualitative changes are slower than quantitative ones. The yield of grain was the biggest in the integrated system (5.5 t/ha of average). It was 35% higher than in the organic system, and 20% higher than in conventional ones.

Use of foliar-applied urea to inhibit the development of Septoria nodorum in spring wheat

1991 ◽  
Vol 10 (4) ◽  
pp. 260-264 ◽  
Author(s):  
Jari Peltonen ◽  
Sari Kittilä ◽  
Pirjo Peltonen-Sainio ◽  
Reijo Karjalainen
Keyword(s):  
Spring Wheat ◽  
Septoria Nodorum

scholarly journals Quantifying the impact of land degradation on crop production: the case of Senegal

Solid Earth ◽  
2016 ◽  
Vol 7 (1) ◽  
pp. 93-103 ◽  
Author(s):  
B. G. J. S. Sonneveld ◽  
M. A. Keyzer ◽  
D. Ndiaye
Keyword(s):  
Land Degradation ◽  
Crop Production ◽  
Crop Yields ◽  
Fertilizer Application ◽  
Yield Reduction ◽  
Sufficient Information ◽  
Persistent Problem ◽  
Confounding Variables ◽  
A Site ◽  
The Impact

Abstract. Land degradation has been a persistent problem in Senegal for more than a century and by now has become a serious impediment to long-term development. In this paper, we quantify the impact of land degradation on crop yields using the results of a nationwide land degradation assessment. For this, the study needs to address two issues. First, the land degradation assessment comprises qualitative expert judgements that have to be converted into more objective, quantitative terms. We propose a land degradation index and assess its plausibility. Second, observational data on soils, land use, and rainfall do not provide sufficient information to isolate the impact of land degradation. We, therefore, design a pseudo-experiment that for sites with otherwise similar circumstances compares the yield of a site with and one without land degradation. This pairing exercise is conducted under a gradual refining of the classification of circumstances, until a more or less stable response to land degradation is obtained. In this way, we hope to have controlled sufficiently for confounding variables that will bias the estimation of the impact of land degradation on crop yields. A small number of shared characteristics reveal tendencies of "severe" land degradation levels being associated with declining yields as compared to similar sites with "low" degradation levels. However, as we zoom in at more detail some exceptions come to the fore, in particular in areas without fertilizer application. Yet, our overall conclusion is that yield reduction is associated with higher levels of land degradation, irrespective of whether fertilizer is being applied or not.

scholarly journals Quantification of Airborne Inoculum as an Aid in the Management of Leaf Blight of Onion Caused by Botrytis squamosa

Plant Disease ◽  
2005 ◽  
Vol 89 (7) ◽  
pp. 726-733 ◽  
Author(s):  
O. Carisse ◽  
H. A. McCartney ◽  
J. A. Gagnon ◽  
L. Brodeur
Keyword(s):  
Leaf Growth ◽  
Control Plot ◽  
Leaf Blight ◽  
Yield Reduction ◽  
Lesion Development ◽  
Botrytis Squamosa ◽  
Airborne Inoculum ◽  
Significant Yield ◽  
Epidemic Development ◽  
The Relationship

Botrytis leaf blight, caused by Botrytis squamosa, is a common and frequently damaging disease of onion crops, but the severity of epidemics varies widely from year to year. The disease is initiated and spread by airborne conidia. The relationship between airborne conidium concentration (ACC) and lesion development was studied in the field. A linear relationship was found between ACC and number of lesions per leaf: ACC values of 10 to 15 and 25 to 35 conidia m-3 were associated with 1 and 2.5 lesions per leaf, respectively. In 2000 and 2001, at three sites, four different criteria were used to start a fungicide spray program and their effect on epidemic development was compared with that of a grower's conventional schedule. The criteria were: at the fourth-true-leaf growth stage; according to an inoculum production index; when the ACC reached 10 to 15 conidia m-3; and when the ACC reached 25 to 35 conidia m-3. A nonsprayed control plot was included in the trial. Fungicide programs started when the ACC reached 10 to 15 conidia m-3 were as effective as the conventional program, but used fewer sprays. A fungicide spray program based on measurements of ACC and disease severity was evaluated in 2002 and 2003 in five and three commercial onion fields, respectively. At each site, half of the field was sprayed according to the grower's schedule and, in the other half, fungicide sprays were initiated when a threshold of 10 to 15 conidia m-3 or five lesions on the lower leaf (whichever came first) was reached. Overall, the number of fungicide applications was reduced by 75 and 56% in 2002 and 2003, respectively, without causing significant yield reduction. In both years, the reduction in number of fungicide applications was due mainly to the delay in initiation of the fungicide program.

scholarly journals Storage Root Yield of Sweetpotato as Influenced by Sweetpotato leaf curl virus and Its Interaction With Sweetpotato feathery mottle virus and Sweetpotato chlorotic stunt virus in Kenya

Plant Disease ◽  
2020 ◽  
Vol 104 (5) ◽  
pp. 1477-1486
Author(s):  
Bramwel W. Wanjala ◽  
Elijah M. Ateka ◽  
Douglas W. Miano ◽  
Jan W. Low ◽  
Jan F. Kreuze
Keyword(s):  
Yield Loss ◽  
Virus Disease ◽  
Block Design ◽  
Mottle Virus ◽  
Yield Response ◽  
Yield Reduction ◽  
Root Yield ◽  
Moderately Resistant ◽  
Leaf Curl Virus ◽  
Leaf Curl

In this study, the effect of a Kenyan strain of Sweetpotato leaf curl virus (SPLCV) and its interactions with Sweetpotato feathery mottle virus (SPFMV) and Sweetpotato chlorotic stunt virus (SPCSV) on root yield was determined. Trials were performed during two seasons using varieties Kakamega and Ejumula and contrasting in their resistance to sweetpotato virus disease in a randomized complete block design with 16 treatments replicated three times. The treatments included plants graft inoculated with SPLCV, SPFMV, and SPCSV alone and in possible dual or triple combinations. Yield and yield-related parameters were evaluated at harvest. The results showed marked differences in the effect of SPLCV infection on the two varieties. Ejumula, which is highly susceptible to SPFMV and SPCSV, suffered no significant yield loss from SPLCV infection, whereas Kakamega, which is moderately resistant to SPFMV and SPCSV, suffered an average of 47% yield loss from SPLCV, despite only mild symptoms occurring in both varieties. These results highlight the variability in yield response to SPLCV between sweetpotato cultivars as well as a lack of correlation of SPLCV-related symptoms with yield reduction. In addition, they underline the lack of correlation between resistance to the RNA viruses SPCSV and SPFMV and the DNA virus SPLCV. [Formula: see text] Copyright © 2020 The Author(s). This is an open access article distributed under the CC BY 4.0 International license .

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