Yield losses in wheat from yellow spot: comparison of estimates derived from single tillers and plots

1982 ◽  
Vol 33 (6) ◽  
pp. 899 ◽  
Author(s):  
RG Rees ◽  
GJ Platz ◽  
RJ Mayer
Keyword(s):  
Grain Yield ◽  
Disease Severity ◽  
Yield Loss ◽  
Wheat Yield ◽  
Sprinkler Irrigation ◽  
Yellow Spot ◽  
Grain Number ◽  
Pyrenophora Tritici Repentis ◽  
Wheat Stubble ◽  
The Relationship

Losses in wheat yield associated with yellow spot (Pyrenophora tritici-repentis) have been examined in a field experiment where development of crop and disease were promoted with sprinkler irrigation. Different amounts of infected wheat stubble were applied to initiate epidemics in four treatments, while fungicide sprays were used to reduce the severity of yellow spot in a fifth treatment. The relationship between severity of yellow spot and the amount of infected stubble at first appeared to be linear but became more noticeably logarithmic as the epidemics progressed. Under conditions favouring disease development, a loss in grain yield of c. 49% was measured in the most severely diseased treatment relative to the sprayed treatment, with grain number per unit area and grain size both being reduced. The percentage loss in grain yield was less for main stems than for later heads. Regression analyses of disease severity with grain yield and its components using 50 main stems in each plot gave different estimates of yield loss, depending on the growth stage at which disease severity was assessed. These estimates of yield loss and those provided by a previously developed disease-loss relationship severely underestimated the overall loss in grain yield. However, there was better agreement between estimates derived from the regressions and loss in grain yield on main stems. Possible reasons for the discrepancies in estimates of loss in grain yield are discussed.

Yield losses in wheat from yellow spot: a disease-loss relationship derived from single tillers

1981 ◽  
Vol 32 (6) ◽  
pp. 851 ◽  
Author(s):  
RG Rees ◽  
RJ Mayer ◽  
GJ Platz
Keyword(s):  
Grain Yield ◽  
Harvest Index ◽  
Wheat Yield ◽  
Yellow Spot ◽  
Disease Development ◽  
Yield Losses ◽  
Grain Development ◽  
Pyrenophora Tritici Repentis ◽  
Percentage Loss ◽  
Average Loss

The effect of yellow spot (Pyrenophora tritici-repentis) on wheat yield has been examined with a single-tiller technique. The disease was assessed on c. 1000 tagged main stems in each of five wheat crops. Grain yield, its components, and harvest index were measured on each tiller. In most cases these response variables were significantly correlated with yellow spot levels. The disease-loss relationship, L = 0.26X, was developed where L is the percentage loss in grain yield per main head and X is the average level of yellow spot on the top two leaves at around the milk stage of grain development. From four of the crops examined, an average loss of 12.7 % in grain yield per main head was estimated. Under environmental conditions which particularly favour disease development, the losses derived from this relationship are probably underestimated.

Effectiveness of incomplete resistance to Pyrenophora tritici-repentis in wheat

1989 ◽  
Vol 40 (1) ◽  
pp. 43 ◽  
Author(s):  
RG Rees ◽  
GJ Platz
Keyword(s):  
Grain Size ◽  
Grain Yield ◽  
Yield Loss ◽  
Yellow Spot ◽  
Yield Losses ◽  
Pyrenophora Tritici Repentis ◽  
Incomplete Resistance ◽  
Disease Pressure ◽  
Moderate Yield

Severe epidemics of yellow spot (Pyrenophora tritici-repentis) reduced grain yield by c. 60% in the highly susceptible wheat cv. Banks in two experiments. About two-thirds of the yield loss was associated with reduced grain size. Milder epidemics developed in cultivars with incomplete resistance and resulted in substantially smaller effects on grain yield. The value of the resistance in a high-yielding background was illustrated by yield advantages over Banks of c. 230% for Genaro 8 1 and c. 190% for Vicam 7 1, under heavy disease pressure. Lines selected from crosses of Genaro 81/2*Banks and Vicam 7!/2*Banks had less disease than Banks and only small to moderate yield losses occurred in the best selections under heavy disease pressure. This illustrates that the resistance from these sources can be transferred readily into adapted Australian wheats and should greatly reduce yield losses from yellow spot.

Relationships between stripe rust severity and grain yield loss at Dooen, Victoria

1988 ◽  
Vol 39 (4) ◽  
pp. 563 ◽  
Author(s):  
JS Brown
Keyword(s):  
Grain Yield ◽  
Disease Severity ◽  
Stripe Rust ◽  
Growth Stage ◽  
Field Experiments ◽  
Yield Loss ◽  
Rust Severity ◽  
Cent Disease ◽  
The Relationship ◽  
Best Estimator

The relationship between stripe rust severity and grain yield loss in wheat was studied in two field experiments. Wheat cultivars varying in response to the disease were used to produce epidemics of differing severity. Regression models were used to examine the relationship between disease severity and yield loss. The best estimator of yield loss was an estimate of disease severity at the end of anthesis-early berry growth stage. The relationship between per cent yield loss (YL) and per cent disease severity (DS) at that growth stage was established to be YL = 0.479DS + 0.84.

scholarly journals Evidence for improved pollen viability as the mechanism for film antitranspirant mitigation of drought damage to wheat yield

2016 ◽  
Vol 67 (2) ◽  
pp. 137 ◽  
Author(s):  
Minuka M. Weerasinghe ◽  
Peter S. Kettlewell ◽  
Ivan G. Grove ◽  
Martin C. Hare
Keyword(s):  
Grain Yield ◽  
Field Experiments ◽  
Pollen Viability ◽  
Wheat Yield ◽  
Spray Application ◽  
Grain Number ◽  
Climatic Zones ◽  
Boot Stage ◽  
Wide Range ◽  
Drought Damage

Application of film antitranspirant to wheat during late stem extension reduces drought damage to yield, but the mechanism is unknown. Field experiments under rain shelters were conducted over 3 years to test the hypothesis that film antitranspirant applied before meiosis alleviates drought-induced losses of pollen viability, grain number and yield. The film antitranspirant di-1-p-menthene was applied at third-node stage, and meiosis occurred at the early boot stage, with a range of 11–16 days after spray application in different years. Irrigated, unsprayed plots were included under the rain-shelters, and pollen viability, measured in 2 years in these plots, averaged 95.3%. Drought reduced pollen viability to 80.1% in unirrigated, unsprayed plots, but only to 88.6% in unirrigated plots treated with film antitranspirant. Grain number and yield of irrigated plots, measured in all years, were 16 529 m–2 and 9.55 t ha–1, respectively, on average. These were reduced by drought to 11 410 m–2 and 6.31 t ha–1 in unirrigated, unsprayed plots, but only to 12 878 m–2 and 6.97 t ha–1 in unirrigated plots treated with film antitranspirant. Thus compared with unirrigated, unsprayed plots, antitranspirant gave a grain yield benefit of 0.66 t ha–1. Further work is needed to validate the pollen viability mechanism in different climatic zones and with a wide range of cultivars.

Post-anthesis sink size in a high-yielding dwarf wheat: yield response to grain number

1977 ◽  
Vol 28 (2) ◽  
pp. 165 ◽  
Author(s):  
RA Fischer ◽  
I Aguilar ◽  
DR Laing
Keyword(s):  
Grain Yield ◽  
Wheat Yield ◽  
Kernel Weight ◽  
Yield Response ◽  
High Fertility ◽  
Grain Number ◽  
Wide Range ◽  
Carbon Dioxide Fertilization ◽  
Sink Size ◽  
The One

Experiments to study the effect of grain number per sq metre on kernel weight and grain yield in a high-yielding dwarf spring wheat (Triticum aestivum cv. Yecora 70) were conducted in three seasons (1971–1973) under high-fertility irrigated conditions in north-western Mexico. Crop thinning, shading and carbon dioxide fertilization (reported elsewhere), and crowding treatments, all carried out at or before anthesis, led to a wide range in grain numbers (4000 to 34,000/m2). Results indicated the response of grain yield to changing sink size (grains per sq metre), with the post-anthesis environment identical for all crops each year, and with all but the thinner crops intercepting most of the post-anthesis solar radiation. Kernel weight fell linearly with increase in grain number over the whole range of grain numbers studied, but the rate of fall varied with the season. Grain yield, however, increased, reaching a maximum at grain numbers well above those of crops grown with optimal agronomic management but without manipulation. It was concluded that the grain yield in normal crops was limited by both sink and post-anthesis source. There was some doubt, however, as to the interpretation of results from crowded crops, because of likely artificial increases in crop respiration on the one hand, and on the other, in labile carbohydrate reserves in the crops at anthesis. Also deterioration in grain plumpness (hectolitre weight) complicates the simple inference that further gains in yield can come from increased grain numbers alone.

The relationship of several plant characters with grain yield in sorghum and their use in estimating grain loss through pest activity

1976 ◽  
Vol 16 (78) ◽  
pp. 129
Author(s):  
PN Vance
Keyword(s):  
Grain Yield ◽  
Moisture Stress ◽  
Close Correlation ◽  
Regression Equations ◽  
Grain Number ◽  
Potential Yield ◽  
Sowing Dates ◽  
Single Grain ◽  
Relationship Of ◽  
The Relationship

The relationship between grain yield and five plant characters in grain sorghum hybrid Pioneer 846 was studied. Grain yield was closely correlated with head weight, weight of a standard length of peduncle (WSP), peduncle perimeter (PP), head length and breadth. The close correlation of grain yield on WSP was shown to exist at a number of sites and for a number of varieties. However, regression equations differed for different sites, sowing dates and varieties. Of the two components of grain yield per head, single grain weight and grain number; only grain number was closely correlated with WSP. In one instance where moisture stress affected grain development, grain number but not yield was closely correlated with WSP. WSP was shown not to be affected by damage to the head and could therefore be used to estimate potential yield in agronomic trials where yield loss due to pest activity has occurred.

scholarly journals Relationship Between Eyespot Severity and Productivity of Winter Wheat in Lithuania

2014 ◽  
Vol 32 (1) ◽  
pp. 41-44 ◽  
Author(s):  
Jūratė Ramanauskienė ◽  
Irena Gaurilčikienė ◽  
Rūta Česnulevičienė
Keyword(s):  
Winter Wheat ◽  
Yield Loss ◽  
Grain Weight ◽  
Thousand Grain Weight ◽  
Grain Number ◽  
Wheat Varieties ◽  
Cropping Season ◽  
Winter Wheat Cultivars ◽  
Severity Of The Disease ◽  
The Relationship

Abstract Cereal yield loss from eyespot directly depends on the severity of the disease. The aim of this study was to establish the relationship between eyespot damage in winter wheat and components of yield of winter wheat cultivars Ada, Mulan and Tukan in Lithuania in the 2011/2012 cropping season. Several eyespot did not decrease the grain number per ear cv. of Tukan while for cvs. Ada and Mulan the decrease was 14 and 15%, respectively; however, the grain number per ear of moderately eyespot-affected stems of cv. Ada did not differ from that of visually healthy stems. For cv. Ada, the grain weight per ear of moderately affected stems was 5.8% less and that of severely affected stems was 12.8% less than that of healthy stems, while for cv. Mulan the decrease in grain weight per ear was 40.3 and 35.5%, respectively and for cv. Tukan it was 59.0 and 63.2%, respectively for moderately and severely affected stems. The decrease in thousand grain weight of moderately eyespot-affected stems of cv. Ada was less (6.5%) compared with that of cv. Mulan (31.3%) and cv. Tukan (55.8%). Thousand grain weight of severely eyespot-affected stems of cvs. Ada, Mulan and Tukan was 22.2, 26.0, and 65.0%, respectively, less than that of healthy stems. Screening of healthy, moderately and severely affected plants of the winter wheat varieties Ada, Mulan and Tukan for grain number per ear, grain weight per ear and TGW revealed that these varieties differed in tolerance to eyespot

scholarly journals Cumulative Effect of Temperature and Solar Radiation on Wheat Yield

2011 ◽  
Vol 39 (2) ◽  
pp. 146 ◽  
Author(s):  
Mukhtar AHMED ◽  
Fayyaz-ul HASSAN
Keyword(s):  
Solar Radiation ◽  
Grain Yield ◽  
Wheat Yield ◽  
Cumulative Effect ◽  
Adaptation Strategy ◽  
Effect Of Temperature ◽  
Grain Number ◽  
Sowing Time ◽  
The Impact ◽  
Determinant Factor

The impact of temperature and solar radiations were studied as determinant factor for spring wheat grain yield. The data obtained at anthesis and maturity for grain number (GN), grain weight (GW) and grain yield (Y) were examined with mean temperature at anthesis (T1) and maturity (T2), solar radiation at anthesis (SR1) and maturity (SR2) and photothermal quotient (PTQ) at anthesis (PTQ1) and maturity (PTQ2). The data obtained was subjected to Statistica 8 software and scatter plot regression model was developed at 95% confidence interval with crop data and climate variables (T1, T2, SR1, SR2, PTQ1 and PTQ2). Results clearly indicated that yield remained directly proportional to solar radiation and temperature plus solar radiation (PTQ) while inversely to temperature under optimum other environmental resources. Direct relationship between PTQ and yield parameters confirmed that it determined crop yield and its management for variable environmental conditions need to be opted by adopting suitable sowing time as an adaptation strategy under changing climate.

scholarly journals A soil test for aluminium toxicity in acidic subsoils of yellow earths in Western Australia

1991 ◽  
Vol 42 (5) ◽  
pp. 875 ◽  
Author(s):  
SJ Carr ◽  
GSP Ritchie ◽  
WM Porter
Keyword(s):  
Grain Yield ◽  
Regional Differences ◽  
Management Practices ◽  
Field Experiments ◽  
Wheat Yield ◽  
Aluminium Toxicity ◽  
Mitigating Factors ◽  
Toxic Concentrations ◽  
The Relationship ◽  
Western Australian

Many of the yellow earths in the Western Australian wheatbelt have naturally acidic subsoils which can reduce the yield of wheat grown on them. Current methods of assessing soil acidity cannot identify which soils have subsoil acidity severe enough to restrict wheat yields. We conducted 53 field experiments at 34 sites in 5 regions over 3 years to determine the relationship between yield of wheat and several different indices for identifying subsoils with toxic concentrations of aluminium, Al. Initially, we identified that the concentration of aluminium, [All, in the soil solution and in 1 : 5 0.005 M KCl extracts of soil from the 15-25 cm layer was responsible for the majority of the decrease in wheat yield. The concentration of Al in a 1 : 5 0.005 M KCl extract in the 15-25 cm layer was well correlated with grain yield of wheat grown on yellow earth soils in the Merredin region, provided the soils had similar fertilizer treatments. The ratio [All : [Na] in a 1 : 5 0.005 M KCl extract was a better predictor than [All alone of grain yield of wheat grown on yellow earths in different regions and with different fertilizer practices. The three seasons had little effect on the correlation between yield and different soil indices. The correlations determined were strongly affected by regional differences, which were probably due to differing water supply and availability. The choice of toxicity index depended on the uniformity of fertilizer management practices within a region and it appeared that both ionic strength and calcium were important mitigating factors.

scholarly journals THE INFLUENCE OF BIOORGANIC PREPARATIONS ON THE PRODUCTIVITY OF CONVENTIONALY GROWN WINTER WHEAT ACTIVATING AND SAVING THE USE OF SYNTHETIC CHEMICALS

2018 ◽  
Author(s):  
Vidmantas SPRUOGIS ◽  
Anželika DAUTARTĖ ◽  
Romualdas ZEMECKIS ◽  
Edmundas BARTKEVIČIUS ◽  
Aida STIKLIENĖ
Keyword(s):  
Winter Wheat ◽  
Grain Yield ◽  
Grain Quality ◽  
Quality Parameters ◽  
Puccinia Recondita ◽  
Wheat Crop ◽  
Grain Number ◽  
Quality Class ◽  
Pyrenophora Tritici Repentis ◽  
Synthetic Chemicals

The influence of Raskila bioorganic fertilisers on the productivity of conventional winter wheat ‘Olivin’, was investigated in order to stimulate and save synthetic herbicide Arrat and fungicide Tango Super for spring spraying. Scheme of treatment: 1. Control; 2. Winter wheat sprayed (BBCH 20-29) with fertilizer Raskila 3 l ha-1; 3. Winter wheat sprayed (BBCH 20-29) with Arrat 0.2 kg ha-1+Tango super 1.5 l ha-1; 4. Winter wheat sprayed (BBCH 20-29) with Arrat 0.2 kg ha-1+Tango super 1.5 l ha-1+Raskila 3.0 l ha-1; 5. Winter wheat sprayed (BBCH 20-29) with Arrat 0.1 kg ha-1+Tango super 0.75 l ha-1+Raskila 3.0 l ha-1. The best result in the period of 2014-2016 was received after application of the following combination in spring: Arrat + Tango super + Raskila. This combination allows to reduce the rate of pesticides in half (50%), the differences compared to control are significant, statistically reliable. A statistically significant increase in the following winter wheat ‘Olivin’ quality parameters was found: protein 13.1-14.8%, gluten 24.3-29.7%, number of falls 228-292 s, starch 65.7-70.0%. Application of Raskila fertilizers has raised the grain quality class. The best results were in variants 3 and 4, where the I class of grain quality was achieved. Combination of Raskila fertilisers and pesticides: herbicide Arrat and fungicide Tango super statistically significantly increased the following winter wheat ‘Olivin’ characteristics - plant height 101.2-104.2 cm, ear length 6.9-7.1 cm, grain number per ear 28,96- 30.02, grain yield 6.71-7.03 t ha-1. Application of Raskila fertilizer 1.0 l ha-1 and herbicide Arrat 0.1 kg ha-1 decreased the number of weeds from 62.5 to 57.6 units per m2 and the weed weight decreased from 41.30 to 33.70 g m2. Stronger wheat crop overshadowed weeds better. Combination of Raskila and Tango super reduced the prevalence and severity of diseases in winter wheat such as Septoria spp., Pyrenophora tritici-repentis, Erysiphe graminis, powdery rust (Puccinia recondita).

Sign in / Sign up

Export Citation Format

Share Document