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.

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.

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.

scholarly journals WATER USE EFFICIENCY, GROWTH AND YIELD OF WHEAT CULTIVATED UNDER COMPETITION WITH Setaria

2015 ◽  
Vol 33 (4) ◽  
pp. 679-687 ◽  
Author(s):  
M.Z. IHSAN ◽  
F.S. EL-NAKHLAWY ◽  
S.M. ISMAIL
Keyword(s):  
Drought Stress ◽  
Water Use Efficiency ◽  
Water Use ◽  
Harvest Index ◽  
Wheat Yield ◽  
Negative Association ◽  
Growth And Yield ◽  
Yield Losses ◽  
Wheat Production ◽  
Use Efficiency

ABSTRACT Understanding the critical period of weed competition is indispensable in the development of an effective weed management program in field crops. Current experiment was planned to evaluate the critical growth period ofSetaria and level of yield losses associated with delay in weeding in rain-fed drip irrigated wheat production system of Saudi Arabia. Field experiment was conducted to evaluate the effect of weeding interval (07-21, 14-28, 21-35, 28-42 and 35-49 days after sowing) and drought stress (75% and 50% of field capacity) on Setaria growth, wheat yield and water use efficiency. Season long weedy check and wellwatered (100% FC) plots were also maintained for comparison. Weeding interval and drought stress significantly (p ≤ 0.05) affected the growth and yield of Setaria and wheat. Drought stress from 75% to 50% FC resulted in reductions of 29-40% in Setaria height, 14-27% in Setaria density and 11-26% in Setaria dry biomass. All weeding intervals except 35-49 DAS significantly suppressedSetaria growth as compared with control. Delay in weeding increased weed-crop competition interval and reduced wheat yield and yield contributors. Therefore, the lowest yield of 1836 kg ha-1 was attained for weeding interval of 35-49 DAS at 50% FC. Water use efficiency and harvest index increased with decreasing FC levels but reduced with delay in weeding. Correlation analysis predicted negative association ofSetariadensity with wheat yield and yield contributors and the highest negative association was for harvest index (-0.913) and water use efficiency (-0.614). Early management of Setaria is imperative for successful wheat production otherwise yield losses are beyond economical limits.

Relationships between carbon isotope discrimination and leaf morphophysiological traits in spring-planted spring wheat under drought and salinity stress in Northern China

2008 ◽  
Vol 59 (10) ◽  
pp. 941 ◽  
Author(s):  
Lin Zhu ◽  
Zong Suo Liang ◽  
Xing Xu ◽  
Shu Hua Li ◽  
Ji Hai Jing ◽  
...  
Keyword(s):  
Grain Yield ◽  
Carbon Isotope ◽  
Harvest Index ◽  
Carbon Isotope Discrimination ◽  
Water Status ◽  
Flag Leaf ◽  
Wheat Yield ◽  
Gas Exchange Parameters ◽  
Isotope Discrimination ◽  
North East

The relationships between carbon isotope discrimination (Δ) and some morphophysiological traits such as specific leaf dry weight (SLDW), gas exchange parameters, and relative water content (RWC) were studied in a collection of 20 bread wheat cultivars (landraces, released cultivars and advanced lines) in three locations of the Ningxia region (North-East China), i.e. Yinchuan (limited irrigation conditions), Huinong (limited irrigation conditions + salinity) and Guyuan (rain-fed conditions). Relationships between Δ, grain yield (GY), and harvest index (HI) and above-ground biomass (AGB) were also analysed. Differences in the measured traits between different locations were highly related to the variation in water availability. Positive correlations were noted between Δ and HI and grain yield. Flag leaf Δ was positively correlated with RWC at anthesis, and negatively associated with SLDW at grain filling. Significant and negative correlations between Δ and dry matter weight per plant at anthesis and biomass at maturity were noted. Leaf temperature (LT) was found to be negatively correlated with Δ and gs. The findings suggest that Δ may be a useful indicator reflecting wheat yield, harvest index, and water status under irrigation and rain-fed conditions in the Ningxia region.

scholarly journals Statistical modeling for analyzing grain yield of durum wheat under rainfed conditions in Azad Jammu Kashmir, Pakistan

2022 ◽  
Vol 82 ◽  
Author(s):  
K. Abbas ◽  
Z. Hussain ◽  
M. Hussain ◽  
F. Rahim ◽  
N. Ashraf ◽  
...  
Keyword(s):  
Regression Analysis ◽  
Grain Yield ◽  
Durum Wheat ◽  
Harvest Index ◽  
Morphological Traits ◽  
Stepwise Regression ◽  
Wheat Yield ◽  
Germination Percentage ◽  
Subset Regression ◽  
1000 Grain Weight

Abstract One of the most important traits that plant breeders aim to improve is grain yield which is a highly quantitative trait controlled by various agro-morphological traits. Twelve morphological traits such as Germination Percentage, Days to Spike Emergence, Plant Height, Spike Length, Awn Length, Tillers/Plant, Leaf Angle, Seeds/Spike, Plant Thickness, 1000-Grain Weight, Harvest Index and Days to Maturity have been considered as independent factors. Correlation, regression, and principal component analysis (PCA) are used to identify the different durum wheat traits, which significantly contribute to the yield. The necessary assumptions required for applying regression modeling have been tested and all the assumptions are satisfied by the observed data. The outliers are detected in the observations of fixed traits and Grain Yield. Some observations are detected as outliers but the outlying observations did not show any influence on the regression fit. For selecting a parsimonious regression model for durum wheat, best subset regression, and stepwise regression techniques have been applied. The best subset regression analysis revealed that Germination Percentage, Tillers/Plant, and Seeds/Spike have a marked increasing effect whereas Plant thickness has a negative effect on durum wheat yield. While stepwise regression analysis identified that the traits, Germination Percentage, Tillers/Plant, and Seeds/Spike significantly contribute to increasing the durum wheat yield. The simple correlation coefficient specified the significant positive correlation of Grain Yield with Germination Percentage, Number of Tillers/Plant, Seeds/Spike, and Harvest Index. These results of correlation analysis directed the importance of morphological characters and their significant positive impact on Grain Yield. The results of PCA showed that most variation (70%) among data set can be explained by the first five components. It also identified that Seeds/Spike; 1000-Grain Weight and Harvest Index have a higher influence in contributing to the durum wheat yield. Based on the results it is recommended that these important parameters might be considered and focused in future durum wheat breeding programs to develop high yield varieties.

Effect of Intensity and Timing of Defoliation on Growth, Yield Components and Grain Yield in Maize

1991 ◽  
Vol 27 (2) ◽  
pp. 137-144 ◽  
Author(s):  
N'Guettia R. Yao ◽  
Kabrah Yeboua ◽  
Angbonou Kafrouma
Keyword(s):  
Grain Yield ◽  
Yield Components ◽  
Harvest Index ◽  
Growth Yield ◽  
Yield Losses ◽  
Area Index ◽  
Early Season ◽  
Ear Development ◽  
Leaf Emergence ◽  
Emergence Rate

SummaryEarly season defoliation of maize significantly reduced plant height and leaf area index but leaf number and leaf emergence rate were not affected. Ear development was significantly affected by both early and late season defoliation although tassel development was barely influenced. Silk growth was the phase of ear development most sensitive to defoliation. Early season defoliation significantly reduced all yield components, leading to yield losses ranging from 54 to 100%. The position of the leaves which were removed had an important effect on the final grain yield. Harvest index was affected by both the intensity and timing of defoliation.

Herbicide-Grazing Interactions in Cheat (Bromus secalinus)–Infested Winter Wheat (Triticum aestivum)1

Weed Science ◽  
1990 ◽  
Vol 38 (6) ◽  
pp. 532-535 ◽  
Author(s):  
Jeffrey A. Koscelny ◽  
Thomas F. Peeper
Keyword(s):  
Triticum Aestivum ◽  
Winter Wheat ◽  
Grain Yield ◽  
Yield Components ◽  
Harvest Index ◽  
Field Experiments ◽  
Wheat Yield ◽  
Wheat Grain ◽  
Bromus Secalinus ◽  
Herbicide Treatments

Field experiments were conducted to determine the interaction of grazing and herbicide treatments on cheat control and biomass, wheat biomass, wheat grain yield, and wheat yield components. Ethyl-metribuzin at 1120 g ai ha−1and metribuzin at 420 g ai ha−1reduced cheat biomass 91 to 99 and 97 to 98%, respectively. Grazing had no effect on herbicide efficacy. Grazing increased cheat biomass in the check by 24% at only one location but did not affect total wheat plus cheat biomass. With one exception, controlled cheat was replaced by wheat on a 1:1 biomass basis when herbicides caused no crop injury. All herbicide treatments increased grain yield, but grazing did not alter yield. At two locations, increased heads m−2and spikelets/head accounted for most of the grain yield increases, but at one location seeds/spikelet and weight/seed were also increased. Harvest index was unaffected.

scholarly journals ASSESSMENT OF YIELD COMPONENTS AND THEIR ASSOCIATION IN F2 POPULATIONS OF WHEAT

2017 ◽  
Vol 1 ◽  
pp. 326
Author(s):  
Touheed Iqbal ◽  
Ghulam Hassan, Iqbal Hussain, Saad Saeed
Keyword(s):  
Grain Yield ◽  
Harvest Index ◽  
Flag Leaf ◽  
Block Design ◽  
Wheat Yield ◽  
Wheat Breeding ◽  
Genetic Advance ◽  
Component Traits ◽  
Biological Yield ◽  
Final Yield

Keeping in view the role of wheat in Pakistan, the current research was conducted to compute the extent of transmissibility and to derive information on the correlation of grain yield with its component traits. Sixteen F2 populations of wheat and their eight parental lines were evaluated at the University of Agriculture, Peshawar-Pakistan during wheat season of 2013-14. Experiment was conducted in randomized complete block design with three replicates. Analysis of variance manifested significant differences among genotypes for all the studied traits. Similarly, mean squares due to parents, F2 populations and parents vs. F2`s were also significant for all the traits under study except harvest index. On the basis of mean performance, maximum grain yield plant-1 among parents was given by Fakhr-e-Sarhad (27.16 g) and PS-05 (26.06 g), while among F2 populations, maximum grain yield plant-1 was given by cross combinations Barsat / Siren (27.93 g), AUP-5008 / Siren (26.09 g) and Tatara / PS-05 (25.65 g). The assessments of heritability and genetic advance manifested that F2 populations, Saleem-2K / Janbaz, Tatara / F.S, AUP-5008 / PS-05 and Tatara / PS-05 had highly heritable characters along with high genetic advance, which offer an opportunity for earlier selection. Hence, more emphasis should be given to these crosses in future wheat breeding programs. Moreover, the perusal of correlation analysis revealed that traits like days to maturity, flag leaf area, plant height, fertile tillers plant-1, biological yield and harvest index appeared to be most essential sources of affecting the final yield, suggesting that upsurge in wheat yield could be admissible by selecting these traits.

scholarly journals A STUDY OF ANCESTRAL AND MODERN CANADIAN SPRING WHEATS

1987 ◽  
Vol 67 (1) ◽  
pp. 87-97 ◽  
Author(s):  
P. HUCL ◽  
R. J. BAKER
Keyword(s):  
Grain Yield ◽  
Spring Wheat ◽  
Harvest Index ◽  
Negative Impact ◽  
Wheat Yield ◽  
Triticum Aestivum L ◽  
Kernel Weight ◽  
Environment Interaction ◽  
Canadian Prairie ◽  
Spike Number

Spring wheat cultivars (Triticum aestivum L.) representing a century of crop breeding effort were evaluated in three rain-fed environments to determine which yield-related traits have been altered over time. Plant height and the length of the vegetative growth phase were shortened during the pre-Thatcher era. Spikelet number has been reduced but kernel weight increased during the period of cultivar development discussed herein. Tiller production has changed little since the turn of the century while spike number has been reduced slightly in the post-Thatcher period. Harvest indices increased with the introduction of Thatcher, but neither that trait nor crop grain yield have undergone consistent improvements since the 1930s. A significant cultivar × environment interaction resulted from adverse environment having a greater negative impact on grain yield of the older cultivars Red Fife and Marquis relative to their descendents. HY320, representing a potential new market class (Canadian Prairie Spring), yielded 25% more than standard height cultivars due to a higher biological yield and harvest index. Crop and spike grain yields were associated with kernel number/spike (r = 0.78,0.75) and days to spike emergence (r = 0.50,0.55), suggesting that high grain yield in this material is a function of maturity-dependent kernel production. Future improvements in grain yield might result from selection for higher harvest index since the latter trait is positively correlated with yield (r = 0.63) but not associated with maturity (−0.17).Key words: Old cultivars, spring wheat, yield components, harvest index, cultivar × environment interaction

GRAIN YIELD AND MORPHO-PHYSIOLOGICAL CHANGES FROM 60 YEARS OF GENETIC IMPROVEMENT OF WHEAT IN IRAN

2009 ◽  
Vol 45 (2) ◽  
pp. 149-163 ◽  
Author(s):  
HAMID REZA MIRI
Keyword(s):  
Stomatal Conductance ◽  
Grain Yield ◽  
Plant Height ◽  
Transpiration Rate ◽  
Harvest Index ◽  
Block Design ◽  
Wheat Yield ◽  
Wheat Cultivars ◽  
Grain Number ◽  
Biological Yield

SUMMARYIn order to understanding the changes in morpho-physiological traits of wheat cultivars released from 1940 to 2000 in Iran and to determine the association of these traits with grain yield, an experiment was conducted with 15 wheat cultivars released over the past 60 years using an randomized complete block design with four replications. The experiment was conducted on an experimental farm of Arsanjan Islamic Azad University in 2005/6 and 2006/7. Results indicated that cultivar grain yield was significantly correlated with year of release over the 60 years (r = 0.878, p < 0.01). Harvest index and biological yield increased significantly with increasing grain yield. The change in the photosynthesis rate was not significant during this period but transpiration rate and stomatal conductance and chlorophyll index increased significantly. Among yield components, grain number per ear increased significantly but increase in ear number was not significant. Plant height decreased significantly in new cultivars. In conclusion the results showed that wheat yield improvement in Iran is associated with increasing harvest index, grain number per ear, transpiration rate, stomatal conductance and decreasing plant height.

Sign in / Sign up

Export Citation Format

Share Document