scholarly journals Response of susceptible, partially resistant and resistant winter wheat cultivars to Blumeria graminis f.sp. tritici – short communication

2001 ◽  
Vol 37 (No. 4) ◽  
pp. 145-148
Author(s):  
L. Věchet
Keyword(s):  
Disease Severity ◽  
Partial Resistance ◽  
Short Communication ◽  
Infection Type ◽  
Weather Conditions ◽  
Resistant Cultivar ◽  
Growth Stages ◽  
Susceptible Cultivar ◽  
Winter Wheat Cultivars ◽  
Small Plot

Response of the susceptible cultivar Kanzler, the partially resistant cultivar Mikon and the resistant cultivar Asta (genes of resistance Pm2, Pm6) to powdery, were tested in two years small plot-experiments. Disease severity was influenced by weather conditions. There were highly significant differences in disease severity, infection type and number of diseased plants between the susceptible cultivar and the cultivars with partial resistance and specific resistance. Smaller differences were between the partially resistant cultivar and the resistant cultivar than between the cultivar with partial resistance and the susceptible cultivar. The most affected leaf was the third leaf from the top in all tested cultivars. Among these cultivars were differences in the highest development of disease in single growth stages.

scholarly journals Reaction of winter wheat cultivars and breeding lines to Blumeria graminis f.sp. tritici

2010 ◽  
Vol 42 (No. 1) ◽  
pp. 15-20 ◽  
Author(s):  
L. Věchet
Keyword(s):  
Powdery Mildew ◽  
Winter Wheat ◽  
Disease Severity ◽  
Infection Type ◽  
Specific Gene ◽  
Powdery Mildew Fungus ◽  
Breeding Lines ◽  
Resistant Cultivars ◽  
Winter Wheat Cultivars ◽  
Small Plot

During 4 years, 27 cultivars and breeding lines of winter wheat (<i>Triticum aestivum</i>) were tested in small plot experiments for resistance to powdery mildew fungus. The most resistant were Frimegu, RE9607, Runal, Asset, Folke and Wasmo. The cultivars Asta (<i>Pm</i>2,6) and Vlasta (<i>Pm</i>2,6 and another not determined specific gene or minor genes of resistance) fall into resistant cultivars. It seems that the specific genes of resistance <i>Pm</i>2 and <i>Pm</i>6 are still very effective against the present Czech population of powdery mildew on wheat. Resistance of the cultivars Hereward and Tarso, having the gene of resistance <i>Pm</i>8, can be ascribed to an additional undetermined gene that is effective only in mature plants. The cultivars Mikon and Ramiro with partial resistance had a higher infection type and disease severity than resistant cultivars, but lower disease severity than the susceptible cultivar Kanzler.

scholarly journals Rational Management of Didymella rabiei in Chickpea by Integration of Genotype Resistance and Postinfection Application of Fungicides

2000 ◽  
Vol 90 (8) ◽  
pp. 834-842 ◽  
Author(s):  
D. Shtienberg ◽  
H. Vintal ◽  
S. Brener ◽  
B. Retig
Keyword(s):  
Chemical Control ◽  
Field Experiments ◽  
Ascochyta Blight ◽  
Weather Conditions ◽  
Disease Suppression ◽  
Resistant Cultivar ◽  
Systemic Fungicide ◽  
Susceptible Cultivar ◽  
Moderate Resistance ◽  
Moderately Resistant

Various aspects of the integration of genotype resistance and chemical control of Ascochyta blight (caused by Didymella rabiei) in chickpea were examined in field experiments from 1993 to 1999 and in greenhouse experiments. Four commercially available chickpea cultivars representing a range of resistance to D. rabiei were used. The efficacy of chemical control in a highly susceptible cultivar was significantly (P < 0.01) related to the conduciveness of the environment to the pathogen. Adequate disease suppression (>80% control) was achieved when weather supported mild epidemics, but insufficient control (<20%) was achieved when weather supported severe epidemics. The contribution of genotype resistance to disease suppression in a moderately susceptible cultivar varied from <10% when weather supported severe epidemics to ≈60% when weather supported mild epidemics. Spraying a moderately resistant cultivar resulted in 95% control when weather supported mild epidemics, but only 65% control was achieved when weather supported severe epidemics. The existing level of resistance in a moderately resistant cultivar resulted in 70% control when weather supported severe epidemics; fungicides improved control efficacy significantly to >95%. Under mild epidemics, moderate resistance alone provided >95% control. The level of genotype resistance available in a highly resistant cultivar was sufficient to suppress the disease under all weather conditions, even without application of fungicides. The possibility of relying on postinfection rather than prophylactic application of fungicides was tested in the greenhouse and in four field experiments. Activity of the systemic fungicide tebuconazole was detected when the fungicide was applied up to 3 days postinfection, and application of tebuconazole or difenoconazole in the field as a postinfection treatment (i.e., after rain or overhead irrigation) suppressed the disease as effectively as preventive applications and required fewer sprays. In two experiments, the interaction between genotype resistance and chemical control at various amounts of irrigation applied via overhead sprinklers (as a simulation of rain) was tested. The results show that both the level of genotype resistance and the quantity of water should be taken into account in deciding whether to apply a postinfection spray.

scholarly journals Influence of crop growth and weather conditions on speckled leaf blotch in winter wheat

2003 ◽  
Vol 56 ◽  
pp. 246-250 ◽  
Author(s):  
T. Armour ◽  
S.L.H. Viljanen-Rollinson ◽  
S.F. Chng ◽  
R.C. Butler ◽  
M.G. Cromey ◽  
...  
Keyword(s):  
Winter Wheat ◽  
Disease Severity ◽  
Weather Conditions ◽  
Crop Growth ◽  
Septoria Tritici ◽  
Yield Response ◽  
Growth Stages ◽  
Leaf Blotch ◽  
Weather Events ◽  
Significant Yield

Speckled leaf blotch (SLB) a foliar disease of winter wheat caused by Septoria tritici (teleomorph Mycosphaerella graminicola) can cause significant yield losses Wheat crops are at greatest risk during stem extension when the final three leaves emerge in close proximity to infected leaves lower in the canopy Winter wheat cv Consort was sown in May 2002 to test a model that links development of SLB in the field to weather events and to compare disease severity between plots treated with fungicide applied at three different crop growth stages Generally quite low disease levels were experienced associated with a small number of likely infection events This meant that the top three leaves were infected after they were fully emerged and SLB severity was low as there was little time for secondary cycles to occur before the leaves senesced Despite low disease severity there was a significant yield response to applied fungicide increasing with the number of applications The model requires some improvement

scholarly journals Adaptation of Winter Wheat Cultivars to Different Environments: A Case Study in Poland

Agronomy ◽  
2020 ◽  
Vol 10 (5) ◽  
pp. 632
Author(s):  
Marzena Iwańska ◽  
Jakub Paderewski ◽  
Michał Stępień ◽  
Paulo Rodrigues
Keyword(s):  
Winter Wheat ◽  
Wheat Yield ◽  
Weather Conditions ◽  
Growth Stages ◽  
Wheat Cultivars ◽  
Weather Factors ◽  
Factors Affecting ◽  
Ancova Model ◽  
Winter Wheat Cultivars ◽  
The Difference

A proper understanding of cultivar adaptation to different environments is of great relevance in agronomy and plant breeding. As wheat is the most important crop in Poland, with a total of about 22% of the total sown area, the study of its performance in environments with different productivity levels for consequent cultivar recommendation is of major importance. In this paper, we assess the relative performance of winter wheat cultivars in environments with different productivity and propose a method for cultivar recommendation, by considering the information of environmental conditions and drought stress. This is performed in the following steps: (1) calculation of expected wheat productivity, depending on environmental factors, (2) calculation of relative productivity of cultivars in the environments, and (3) recommendation of cultivars of a specific type and range of adaptation. Soil and weather conditions were confirmed as the most important factors affecting winter wheat yield. The weather factors should be considered rather in shorter (e.g., 10 day) than longer (e.g., 60 day) time periods and in relation to growth stages. The ANCOVA model with genotype and management intensity as fixed factors, and soil and weather parameters as covariates was proposed to assess the expected wheat productivity in particular environments and the expected performance of each genotype (cultivar). The recommendation of cultivars for locations of specified productivity was proposed based on the difference between the expected cultivar yield and the mean wheat productivity, and compared with the Polish official cultivar recommendation list.

scholarly journals Evaluation of Rice Responses to the Blast Fungus Magnaporthe oryzae at Different Growth Stages

Plant Disease ◽  
2019 ◽  
Vol 103 (1) ◽  
pp. 132-136 ◽  
Author(s):  
Xinglong Chen ◽  
Yulin Jia ◽  
Bo Ming Wu
Keyword(s):  
Disease Severity ◽  
Magnaporthe Oryzae ◽  
Rice Blast ◽  
Growth Stage ◽  
Disease Index ◽  
Blast Disease ◽  
Growth Stages ◽  
Japonica Rice ◽  
Rice Cultivars ◽  
Different Growth Stages

Rice blast, caused by the fungus Magnaporthe oryzae, is the most damaging disease for rice worldwide. However, the reactions of rice to M. oryzae at different growth stages are largely unknown. In the present study, two temperate japonica rice cultivars, M-202 and Nipponbare, were inoculated synchronously at different vegetative growth stages, V1 to V10. Plants of M-202 at each stage from V1 to reproductive stage R8 were inoculated with M. oryzae race (isolate) IB-49 (ZN61) under controlled conditions. Disease reactions were recorded 7 days postinoculation by measuring the percentage of diseased area of all leaves, excluding the youngest leaf. The results showed that the plants were significantly susceptible at the V1 to V4 stages with a disease severity of 26.7 to 46.8% and disease index of 18.62 to 37.76 for M-202. At the V1 to V2 stages, the plants were significantly susceptible with a disease a severity of 28.6 to 39.3% and disease index of 23.65 to 29.82 for Nipponbare. Similar results were observed when plants of M-202 were inoculated at each growth stage with a disease severity of 29.7 to 60.6% and disease index of 21.93 to 59.25 from V1 to V4. Susceptibility decreased after the V5 stage (severity 4.6% and index 2.17) and became completely resistant at the V9 to V10 stages and after the reproductive stages, suggesting that plants have enhanced disease resistance at later growth stages. These findings are useful for managing rice blast disease in commercial rice production worldwide.

scholarly journals Evaluation of Foliar Diseases for Soybean Entries in the Pan-African Trials in Malawi and Zambia

Plant Disease ◽  
2020 ◽  
Vol 104 (8) ◽  
pp. 2068-2073
Author(s):  
Christabell Nachilima ◽  
Godfree Chigeza ◽  
Mwila Chibanda ◽  
Hapson Mushoriwa ◽  
Brian D. Diers ◽  
...  
Keyword(s):  
Disease Severity ◽  
The United States ◽  
Sub Saharan Africa ◽  
Brown Spot ◽  
Soybean Rust ◽  
Growth Stages ◽  
Foliar Diseases ◽  
Pan African ◽  
Private And Public ◽  
Sub Saharan

Soybean production has expanded worldwide including countries in sub-Saharan Africa. Several national and international agencies and research groups have partnered to improve overall performance of soybean breeding stocks and have introduced new germplasm from Brazil and the United States with the goal of developing new high-yielding cultivars. Part of this effort has been to test improved soybean lines/cultivars accumulated from private and public sources in multilocational trials in sub-Saharan Africa. These trials are known as the Pan-African Soybean Variety Trials, and the entries come from both private and public breeding programs. The objective of this research was to evaluate entries in the trials that include commercial cultivars or advanced experimental lines for the incidence and severity of foliar diseases. All trials were planted in December 2018 with six located in Zambia and one in Malawi. Plants were evaluated during the reproductive growth stages using a visual pretransformed severity rating scale. Foliar disease ratings were recorded for three bacterial diseases, six fungal diseases, one oomycete, and viruses. The overall occurrence of most of the diseases was high except for soybean rust and target spot, which were only found at two and one location, respectively. However, disease severity was generally low, although there were differences in disease severity ratings among the entries at some of the locations for brown spot, downy mildew, frogeye leaf spot, red leaf blotch, and soybean rust.

scholarly journals Use of Landsat images for yield evaluation within a small plot

2014 ◽  
Vol 60 (No. 11) ◽  
pp. 501-506 ◽  
Author(s):  
J. Kumhálová ◽  
F. Zemek ◽  
P. Novák ◽  
O. Brovkina ◽  
M. Mayerová
Keyword(s):  
Winter Wheat ◽  
Water Distribution ◽  
Vegetation Indices ◽  
Wheat Yield ◽  
Moisture Stress ◽  
Stress Index ◽  
Growth Stages ◽  
Landsat Images ◽  
Topographic Attributes ◽  
Small Plot

Many factors can influence crop yield. One of the most important factors is topography, which can play a crucial role especially in dry years. Plant variability can be monitored by many methods. This paper evaluates the suitability of vegetation indices derived from satellite Landsat 5 TM data in comparison with yield, curvature and topography wetness index over a relatively small field (11.5 ha). Imageries were chosen from the years 2006 and 2010, when oat was grown and from 2005 and 2011, when winter wheat was grown. These images were taken in June in the same growth stage for every crop. It was confirmed that derived indices from Landsat images can be used for comparison with yield and selected topographic attributes and it can explain yield variability, which can be influenced by water distribution during growth stages. Correlation coefficient between moisture stress index and winter wheat yield was &ndash;0.816 in the image acquisition date of 4. 6. 2011.

scholarly journals Sensitivity of sunflower cultivar PR63E82 to tribenuron and propaquizafop in different weather conditions

2018 ◽  
Vol 64 (No. 10) ◽  
pp. 479-483
Author(s):  
Tichý Lukáš ◽  
Jursík Miroslav ◽  
Kolářová Michaela ◽  
Hejnák Václav ◽  
Andr Jiří ◽  
...  
Keyword(s):  
Czech Republic ◽  
Growth Retardation ◽  
Weather Conditions ◽  
Field Trials ◽  
Ionic Surfactant ◽  
Leaf Chlorosis ◽  
Herbicide Treatments ◽  
Small Plot ◽  
Plant Injury

The aim of this work was to verify and assess the tolerance of the PR63E82 (ExpressSun) sunflower cultivar to tribenuron, propaquizafop and their tank-mix combination in two rates under various weather conditions. Three small-plot field trials were carried out on sunflower in Prague, Czech Republic, from 2015 to 2017. High phytotoxicity (25–56%) of tribenuron (TBM) + non-ionic surfactant was observed in 2015 and 2016 when the sunflower was sown in mid-April. In 2017, phytotoxicity was significantly lower (4–6%), probably due to a later sowing of sunflower (May), and hence higher temperatures. The main symptoms of TBM phytotoxicity were leaf chlorosis, necrosis and growth retardation. Propaquizafop (PQF) injury was minimal in 2015 and 2017. A higher phytotoxicity (10–13%) was recorded in 2016, probably due to a hail which occurred 2 days after T2 (second application term (sunflower BBCH 14)) application. Plant injury had puckered leaves and also made more side branches. TBM + PQF damaged sunflower plants most of the tested herbicide treatments (phytotoxicity 3–62%). High phytotoxicity caused stem branching, increased number of sunflower heads and decreased yield.  

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