Slow rusting and tolerance to rusts in wheat I. The progress and effects of epidemics of Puccinia graminis tritici in selected wheat cultivars

1979 ◽  
Vol 30 (3) ◽  
pp. 403 ◽  
Author(s):  
RG Rees ◽  
JP Thompson ◽  
RJ Mayer
Keyword(s):  
Infection Rate ◽  
Pattern Analysis ◽  
Grain Filling ◽  
Disease Assessment ◽  
Tolerance Index ◽  
Puccinia Graminis ◽  
Wheat Cultivars ◽  
Vertical Resistance ◽  
Slow Rusting ◽  
Progress Curve

The effectiveness of vertical resistance to rusts in wheat as generally employed is short-lived and a more durable form of resistance is required. To examine slow rusting and tolerance, the progress and effects of epidemics of stem rust (Puccinia graminis Pers, f. sp. tritici Erikss. & Henn.) in 45 wheat cultivars have been followed during two seasons. The epidemics in each cultivar have been compared by means of the average disease assessment, area below the disease progress curve, apparent infection rate, and intercept of the logit line, and by pattern analysis. Of these measures, the infection rate was the least valuable, whilst pattern analysis allowed useful grouping of cuItivars with similar epidemic patterns. The cultivars were arrayed on a resistance spectrum and ranged from highly resistant to extremely susceptible, those between possessing various levels of slow-rusting ability. Slow rusting was at a comparatively high level in cvv. Hopps, Dural, Lawrence and Celebration. In contrast cv. Mengavi was shown to be a fast ruster. The danger of developing cultivars, such as Mengavi, with a fast-rusting tendency masked by initially effective vertical resistance is discussed. The effects of the epidemics in each cultivar have also been determined to provide a tolerance index. The percentage reduction in grain-filling period, the logit-line intercept value and the delay to 10% disease relative to a susceptible reference cultivar were the main factors associated with the effect of the epidemics on grain yield.

Slow leaf rust development on durum wheat

1977 ◽  
Vol 55 (11) ◽  
pp. 1539-1543 ◽  
Author(s):  
G. D. Statler ◽  
J. T. Nordgaard ◽  
J. E. Watkins
Keyword(s):  
Durum Wheat ◽  
Leaf Rust ◽  
Bread Wheat ◽  
Infection Rate ◽  
Wheat Cultivar ◽  
Wheat Cultivars ◽  
Bread Wheat Cultivar ◽  
Slow Rusting ◽  
Apparent Infection Rate ◽  
Rust Severity

Several durum wheat (Triticitm durum) cultivars exhibiting susceptible or moderately susceptible reactions to the leaf rust fungus (Puccinia recondita tritici) were evaluated for slow rusting. Percentage severity and reactions for P. recondita tritici on each cultivar were evaluated periodically after initial infection. Logit analysis of disease progress curves was used to compare cultivars. The durum wheats consistently exhibited low rust severities in the field. The durums were always characterized by lower infection rates than the susceptible bread wheat cultivar Thatcher (Triticum aestivum). The area under the disease progress curve was smaller for the durum wheats than for Thatcher. The high correlation between apparent infection rate and the final rust severity indicated that final rust severity could be used as an indication of infection rate. The high correlation coefficient for the apparent infection rate between the two top leaves indicated that either leaf would provide an accurate evaluation of the cultivar. Yields of the durum wheat cultivars were not increased by controlling leaf rust. Yields of the susceptible bread wheat cultivar Thatcher were significantly increased by controlling leaf rust. The slow rusting displayed by the durum wheat cultivars studied apparently provide adequate protection against leaf rust under North Dakota conditions.

Slow rusting and tolerance to rusts in wheat. II. The progress and effects of epidemics in Puccinia recondita tritici in selected wheat cultivars

1979 ◽  
Vol 30 (3) ◽  
pp. 421 ◽  
Author(s):  
RG Rees ◽  
JP Thompson ◽  
EA Goward
Keyword(s):  
Leaf Rust ◽  
Pattern Analysis ◽  
Puccinia Recondita ◽  
Wheat Cultivars ◽  
Slow Rusting ◽  
Puccinia Recondita Tritici

The progress and effects of epidemics of leaf rust (Puccinia recondita Rob, ex Desm. f, sp. tritici Erikss. & Henn.) have been examined in 45 wheat cultivars over two seasons. The epidemics in each cultivar were compared by various measures and by pattern analysis. The cultivars were separated into groups ranging from highly resistant to highly susceptible with intermediate groups possessing various levels of slow-rusting ability. Cvv. Hopps, Warchief, Huguenot, Pusa 80-5c, Dural, Warput, Koolisie and Puglu were found to possess useful levels of slow-rusting ability. Fast rusting was conspicuous in Gabo and its derivatives Mendos, Mengavi, Gamenya and Gamut. The desirability of not perpetuating this defect is discussed.

Variation in harvest index of modern spring barley, oat and wheat cultivars adapted to northern growing conditions

2007 ◽  
Vol 146 (1) ◽  
pp. 35-47 ◽  
Author(s):  
P. PELTONEN-SAINIO ◽  
S. MUURINEN ◽  
A. RAJALA ◽  
L. JAUHIAINEN
Keyword(s):  
Grain Yield ◽  
Harvest Index ◽  
Stand Structure ◽  
Spring Barley ◽  
Principal Component ◽  
Grain Filling ◽  
Wheat Cultivars ◽  
Cereal Species ◽  
Growing Conditions ◽  
Cereal Cultivars

SUMMARYIncreased harvest index (HI) has been one of the principal factors contributing to genetic yield improvements in spring barley (Hordeum vulgare L.), oat (Avena sativa L.) and wheat (Triticum aestivum L.) cultivars. Although high HI demonstrates high-yielding ability when cultivars are compared, it can also indicate challenges to yield formation when comparisons are made across differing growing conditions. The present study was designed to investigate variation in HI among modern cereal cultivars relative to that brought about by a northern environment, to assess whether HI still explains the majority of the differences in grain yield when only modern cereal cultivars are compared, and to monitor key traits contributing to HI. Stability of HI was also investigated with reference to the role of tillers. Twelve experiments (3 years, two locations, two nitrogen fertilizer regimes) were carried out in southern Finland to evaluate 12 two-row spring barley, 10 six-row barley, 10 oat and 11 wheat cultivars. In addition to HI, days to heading and maturity, length of grain filling period, grain yield, test weight and 13 traits characterizing plant stand structure were measured and analysed with principal component analysis (PCA) to detect traits associated with HI and those contributing to stability of HI. Although only modern cereals were studied, differences among cultivars were significant both in mean HI and stability of HI, and HI was associated with short plant stature in all modern cereal species. Also, single grain weight was associated with HI in all species. Differences between, but not within, species in HI were partly attributable to differences in tiller performance. Grain yield was associated closely with HI except in two-row barley. It may be possible to further increase HI of wheat, as it still was relatively low. High HI did, however, not indicate the degree of success in yield determination when environments are compared.

scholarly journals Seedling Stage Resistance of Iranian Bread Wheat Germplasm to Race Ug99 of Puccinia graminis f. sp. tritici

Plant Disease ◽  
2013 ◽  
Vol 97 (3) ◽  
pp. 387-392 ◽  
Author(s):  
Mohsen Mohammadi ◽  
Davoud Torkamaneh ◽  
Mehran Patpour
Keyword(s):  
Resistance Genes ◽  
Stem Rust ◽  
Rust Resistance ◽  
Stem Rust Resistance ◽  
Puccinia Graminis ◽  
Wheat Cultivars ◽  
Breeding Lines ◽  
Wheat Germplasm ◽  
Stem Rust Resistance Genes ◽  
Rust Resistance Genes

Following emergence of Ug99, the new virulent race of Puccinia graminis f. sp. tritici in Africa, a global effort for identification and utilization of new sources of Ug99-resistant germplasm has been undertaken. In this study, we conducted replicated experiments to evaluate the resistance of Iranian wheat germplasm to the TTKSK lineage of the Ug99 race of P. graminis f. sp. tritici. We also evaluated for presence of stem rust resistance genes (i.e., Sr2, Sr24, Sr26, Sr38, Sr39, Sr31, and Sr1RSAmigo) in wheat cultivars and breeding lines widely cultivated in Iran. Our phenotyping data revealed high levels of susceptibility to Ug99 in Iranian bread wheat germplasm. Our genotyping data revealed that Iranian cultivars do not carry Sr24, Sr26, or Sr1RSAmigo. Only a few salt-tolerant cultivars and breeding lines tested positively for Sr2, Sr31, Sr38, or Sr39 markers. In conclusion, the genetic basis for resistance to Ug99 in Iranian wheat cultivars was found to be vulnerable. Acquiring knowledge about existing resistance genes and haplotypes in wheat cultivars and breeding lines will help breeders, cereal pathologists, and policy makers to select and pyramid effective stem rust resistance genes.

scholarly journals Increase in Populations of Rhizoctonia solani and Wirestem of Collard with Velvet Bean Cover Crop Mulch

Plant Disease ◽  
2003 ◽  
Vol 87 (6) ◽  
pp. 719-725 ◽  
Author(s):  
Anthony P. Keinath ◽  
Howard F. Harrison ◽  
Paul C. Marino ◽  
D. Michael Jackson ◽  
Thomas C. Pullaro
Keyword(s):  
United States ◽  
Rhizoctonia Solani ◽  
Infection Rate ◽  
Cover Crop ◽  
Southeastern United States ◽  
Soil Surface ◽  
Velvet Bean ◽  
Organic Mulch ◽  
Progress Curve ◽  
Fallow Soil

Velvet bean has been used traditionally as a summer cover crop in the southeastern United States. We investigated the use of killed velvet bean as a cover crop mulch left on the soil surface before collard was transplanted in the fall. Control treatments were weed-free fallow and velvet bean that was killed and disked into the soil before transplanting. Incidence of wirestem, caused by Rhizoctonia solani, reached a maximum of 25% in 2000 but only 4% in 2001 in cover crop mulch treatments. Nevertheless, in both years, the infection rate, area under the disease progress curve, and final incidence were significantly greater with cover crop mulch than in the fallow or disked treatments. Wirestem incidence did not differ between the disked and fallow treatments in either year. Populations of R. solani in soil were greater after cover crop mulch than in fallow plots in both years and greater in the disked treatment than in fallow soil in 2000 but not 2001. Velvet bean does not appear to be suitable as an organic mulch for fall collard production, but could be used as a summer cover crop if disked into the soil before transplanting collard.

scholarly journals Differential Growth Responses of Wheat Seedlings to Elevated CO2

2018 ◽  
Vol 10 (3) ◽  
pp. 400-409 ◽  
Author(s):  
Hamid Reza ESHGHIZADEH ◽  
Morteza ZAHEDI ◽  
Samaneh MOHAMMADI
Keyword(s):  
Leaf Area ◽  
Plant Height ◽  
Elevated Co2 ◽  
Co2 Concentration ◽  
Tolerance Index ◽  
Dry Matter Accumulation ◽  
Wheat Cultivars ◽  
Growth Responses ◽  
Differential Growth ◽  
Wheat Seedlings

Intraspecific variations in wheat growth responses to elevated CO2 was evaluated using 20 Iranian bread wheat (Triticum aestivum L.) cultivars. The plants were grown in the modified Hoagland nutrient solution at a greenhouse until 35 days of age using two levels of CO2 (~380 and 700 µmol mol–1). The shoot and root dry weights of the wheat cultivars exhibited average enhancements of 17% and 36%, respectively, under elevated CO2. This increase was associated with higher levels of chlorophyll a (25%), chlorophyll b (21%), carotenoid (30%), leaf area (54%) and plant height (49.9%). The leaf area (r = 0.69**), shoot N content (r = 0.62**), plant height (r = 0.60**) and root volume (r = 0.53*) were found to have important roles in dry matter accumulation of tested wheat cultivars under elevated CO2 concentration. However, responses to elevated CO2 were considerably cultivar-dependent. Based on the stress susceptibility index (SSI) and stress tolerance index (STI), the wheat cultivars exhibiting the best response to elevated CO2 content were ‘Sistan’, ‘Navid’, ‘Shiraz’, ‘Sepahan’ and ‘Bahar’, while the ones with poor responses were ‘Omid’, ‘Marun’, ‘Sorkhtokhm’ and ‘Tajan’. The findings from the present experiment showed significant variation among the Iranian wheat cultivars in terms of their responses to elevated air CO2, providing the opportunity to select the most efficient ones for breeding purposes.

scholarly journals Grain filling parameters in high-yielding ns wheat cultivars

2008 ◽  
pp. 53-58
Author(s):  
Milka Brdar ◽  
Marija Kraljevic-Balalic ◽  
Borislav Kobiljski
Keyword(s):  
Multivariate Analysis ◽  
Nonlinear Regression ◽  
Environmental Conditions ◽  
Dry Weight ◽  
Grain Filling ◽  
Grain Weight ◽  
Cultivar Differences ◽  
Wheat Cultivars ◽  
Estimated Parameters ◽  
Grain Filling Duration

Grain yield of wheat is dependent on grain weight, which is the result of grain filling duration and rate. The study was undertaken to examine the relation between grain weight and rate and duration of grain filling in five high-yielding NS wheat cultivars. Stepwise multivariate analysis of nonlinear regression estimated grain filling parameters was used to examine cultivar differences in grain filling. On the basis of three-year average, the highest grain dry weight had cultivar Renesansa, and the lightest grains were measured for cultivar Evropa 90. Stepwise multivariate analysis indicated that all three nonlinear regression estimated parameters (grain weight, rate and duration of grain filling) were equally important in characterizing the grain filling curves of the cultivars studied, although sequence of their significance varied in different years, which is probably caused by different environmental conditions in three years of experiment.

scholarly journals Estimation of a Time-varying Apparent Infection Rate from Plant Disease Progress Curves: A Particle Filter Approach

2019 ◽  
Author(s):  
Kaique dos S Alves ◽  
Willian B Moraes ◽  
Wellington B da Silva ◽  
Emerson M Del Ponte
Keyword(s):  
Particle Filter ◽  
Infection Rate ◽  
Plant Disease ◽  
Host Susceptibility ◽  
Time Varying ◽  
Factors Affecting ◽  
Initial Inoculum ◽  
Disease Progress ◽  
Progress Curve ◽  
Apparent Infection Rate

AbstractThe parameters of the simplest (two-parameter) epidemiological models that best fit plant disease progress curve (DPC) data are the surrogate for initial inoculum (y0) and the (constant) apparent infection rate (r), both being useful for understanding, predicting and comparing epidemics. The assumption thatris constant is not reasonable and fluctuations are expected due to systematic changes in factors affecting infection (e.g. weather favorability, host susceptibility, etc.), thus leading to a time-varyingr, orr(t). An arrangement of these models (e.g. logistic, monomolecular, etc.) can be used to obtainrbetween two time points, given the disease (y) data are available. We evaluated a data assimilation technique, Particle Filter (PF), as an alternative method for estimatingr(t). Synthetic DPC data for a hypothetical polycyclic epidemics were simulated using the logistic differential equation for scenarios that combined five patterns ofr(t) (constant, increasing, decreasing, random or sinusoidal); five increasing time assessment interval (Δt= 1, 3, 5, 7 or 9 time units - t.u.); and two levels of noise (α = 0.1 or 0.25) assigned toy(t). The analyses of 50 simulated 60-t.u. DPCs showed that the errors of PF-derivedwere lower (RMSE < 0.05) for Δt< 5 t.u. and least affected by the presence of noise in the measure compared with the logit-derivedr(t). The ability to more accurately estimater(t) using the novel method may be useful to increase knowledge of field epidemics and identify within-season drivers that may explainr(t) behaviour.

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