SAWFLY RESISTANCE IN WHEAT: II. DIFFERENCES BETWEEN WHEAT GROWN IN THE GREENHOUSE AND ON IRRIGATED LAND

1957 ◽  
Vol 37 (3) ◽  
pp. 292-299 ◽  
Author(s):  
D. W. A. Roberts
Keyword(s):  
The Other ◽  
Dry Land ◽  
Wheat Stem Sawfly ◽  
Cephus Cinctus ◽  
Variable Resistance ◽  
Lower Resistance ◽  
Stem Solidness ◽  
Golden Ball

The resistance of seven varieties of wheat to the wheat stem sawfly (Cephus cinctus Nort.) was tested in the greenhouse and on irrigated plots. In five of the seven varieties tested, namely, Rescue, H46146, Golden Ball, Red Bobs and Thatcher, the percentage of infested stems that were cut by sawflies was significantly higher in plants grown in the greenhouse in either summer or winter than in plants grown under irrigation in the field. In the other two varieties, H4191 and Melanopus, results were similar but the differences were not significant. This lower resistance of plants grown in the greenhouse was associated with a decrease in the percentage of tunnelled stems in which the older larvae had died. In percentage of infested stems cut, no significant differences were found between the varieties grown in the outdoor soil bins and those on adjacent irrigated land. In other 2-year tests on irrigated land, the variable resistance of wheat was apparently associated with variations in percentage of tunnelled stems in which the older larvae had died. Although stem solidness is usually associated with resistance on dry land, it appears that this characteristic alone cannot be relied on as a measure of sawfly resistance in a given variety when grown in diverse environments.

INHERITANCE OF SAWFLY REACTION AND STEM SOLIDNESS IN SPRING WHEAT CROSSES: SAWFLY REACTION

1965 ◽  
Vol 45 (6) ◽  
pp. 583-589 ◽  
Author(s):  
Hugh McKenzie
Keyword(s):  
Triticum Aestivum ◽  
Spring Wheat ◽  
Heading Date ◽  
Triticum Aestivum L ◽  
The Other ◽  
Major Influence ◽  
Tilletia Caries ◽  
Wheat Stem Sawfly ◽  
Cephus Cinctus ◽  
Stem Solidness

Inheritance of reaction to the wheat stem sawfly, Cephus cinctus Nort., was studied in populations of F3 and B2 lines from the cross Red Bobs × C.T. 715 (Triticum aestivum L.), and the respective backcrosses. The data supported the hypothesis that the varieties differed by three genes for sawfly reaction. A major influence was attributable to one gene. Its allele for susceptibility when homozygous was epistatic to the other two genes. Its allele for resistance was twice as effective as either of the other genes in conditioning resistance. The other two genes lacked dominance and were equal in their influence on sawfly reaction.Correlation coefficients showed that sawfly reaction was not associated with reaction to race T-2 of Tilletia caries (DC.) Tul., heading date, or awnedness. Sawfly susceptibility was weakly correlated with height.

SAWFLY RESISTANCE IN WHEAT: III. CHANGES IN RESISTANCE DURING THE DEVELOPMENT OF THE WHEAT PLANT

1960 ◽  
Vol 40 (1) ◽  
pp. 7-20 ◽  
Author(s):  
D. W. A. Roberts
Keyword(s):  
Quantitative Data ◽  
Field Experiments ◽  
Wheat Plant ◽  
Flowering Stage ◽  
Wheat Stem Sawfly ◽  
Cephus Cinctus ◽  
Stage Of Development ◽  
First Instar ◽  
Golden Ball

Quantitative data obtained in field experiments showed that the resistance of wheat to attack by the wheat stem sawfly (Cephus cinctus Nort.) depended on the stage of development of the plants at the time of oviposition. Wheat plants were usually most heavily infested for a part or all of the period from 1 week before shot blade to 1 week after the flowering stage. Rescue, H46146, H4191, Golden Ball, and Melanopus lost their resistance to the development of the eggs and first-instar larvae some time between shot blade and flowering. Thatcher and Red Bobs did not show this type of resistance. The mortality of the older larvae increased in plants infested toward maturity. The time at which this increase began depended on the variety involved and ranged from just before shot blade to just after flowering.

Cytogenetics of Sawfly Resistance in Wheat

1964 ◽  
Vol 96 (1-2) ◽  
pp. 124-124 ◽  
Author(s):  
Ruby I. Larson ◽  
M. D. MacDonald
Keyword(s):  
Common Wheat ◽  
Mechanisms Of Resistance ◽  
Wheat Stem Sawfly ◽  
Cephus Cinctus ◽  
Stem Solidness ◽  
Considerable Range

Solid-stemmed varieties of common wheat are more resistant than hollowstemmed varieties to the wheat stem sawfly, Cephus cinctus Nort. If closely related lines of wheat with a considerable range of sawfly-resistance and stem solidness were available, entomologists could use them to analyse some of the mechanisms of resistance.

Resistance of Spring Wheats to the Wheat Stem Sawfly, Cephus ductus Nort. (Hymenoptera: Cephidae) II. Resistance to the Larva

1962 ◽  
Vol 94 (4) ◽  
pp. 348-365 ◽  
Author(s):  
N. D. Holmes ◽  
L. K. Peterson
Keyword(s):  
Wheat Stem Sawfly ◽  
Cephus Cinctus ◽  
Stem Solidness

Wheats that are resistant to the wheat stem sawfly, Cephus cinctus Nort., differ in degree of resistance and in certain environments lose all or part of their resistance. The survival and behaviour of the larvae in different locations in the stems of various spring wheats have been examined with the object of determining some of the factors involved in resistance and in the variability of resistance. In the previous paper in this series (Holmes and Peterson, 1961) it was shown that resistance to hatching of the egg of the sawfly depended on the stem solidness of its host.

Differences in Survival of the Wheat Stem Sawfly, Cephus cinctus Nort. (Hymenoptera: Cephidae), from Two Geographic Areas in Varieties of Spring Wheat

1957 ◽  
Vol 89 (6) ◽  
pp. 272-275 ◽  
Author(s):  
N. D. Holmes ◽  
L. K. Peterson ◽  
A. J. McGinnis
Keyword(s):  
Spring Wheat ◽  
Late Summer ◽  
Ground Level ◽  
Genetic Variations ◽  
Wheat Stem Sawfly ◽  
Cephus Cinctus ◽  
Below Ground ◽  
Golden Ball

The larva of the wheat stem sawfly, Cephus cinctus Nort., lives inside the host stem, cuts it off at ground level in late summer, and spends the winter inside the stub below ground level. This insect can be controlled by the use of resistant spring wheats such as Rescue and Golden Ball. The possibility of the existence of a strain of C. cinctus to which these varieties are not resistant is of major importance.Platt, Farstad, and Callenbach (1948) found that the average percentages of Rescue stems cut by C. cinctus for five years were 36 at Regina, Saskatchewan, and two at Lethbridge. They suggested that this difference may have resulted from the effects of the environments in two areas, or from genetic variations between the sawflies at the two stations.

Effect of Time of Seeding Apex Wheat on Infestation and Sex Ratio of the Wheat Stem Sawfly, Cephus cinctus Nort. (Hymenoptera: Cephidae)

1952 ◽  
Vol 84 (3) ◽  
pp. 90-92 ◽  
Author(s):  
L. A. Jacobson ◽  
C. W. Farstad
Keyword(s):  
Sex Ratio ◽  
Field Experiment ◽  
Wheat Stem Sawfly ◽  
Cephus Cinctus

In 1945 a field experiment was designed at the Lethbridge laboratory to augment data on the effect of the time of seeding on infestation by the wheat stem sawfly, Cephus cinctus Nort. At that time one of the recommendations for the control of this insect was to delay seeding wheat until after May 15. The resulting crop escaped infestation because of the retarded plant during the period of the sawfly flight.

Survey of Wheat Stem Sawfly (Hymenoptera: Cephidae) Infesting Wheat in Eastern Colorado

2021 ◽  
Author(s):  
Darren M Cockrell ◽  
Terri Randolph ◽  
Erika Peirce ◽  
Frank B Peairs
Keyword(s):  
Triticum Aestivum ◽  
Wheat Variety ◽  
Triticum Aestivum L ◽  
The State ◽  
Economic Effects ◽  
Management Decisions ◽  
Wheat Stem Sawfly ◽  
Cephus Cinctus ◽  
Growing Region

Abstract From 2012 through 2020, a survey of wheat stem sawfly, Cephus cinctus Norton, was conducted in wheat (Triticum aestivum L.) fields in Eastern Colorado. In 2013, results showed sawfly infestations concentrated in the northern part of the state with only a few highly infested sites, with 38 of the 94 sampled sites having any infestation (five of which had >50% infestation levels). By 2020 sawfly had been found in all eastern counties sampled, and 72 of the 106 sites sampled were found to contain sawfly (11 of which had >50% infestation levels). The spread of this pest across the Colorado wheat-growing region will have lasting economic effects. The information gathered from this and future surveys will inform wheat variety development and aid in management decisions made by growers across the state.

Who Got There First

2000 ◽  
Author(s):  
John H. Lienhard
Keyword(s):  
Acid Solution ◽  
Electrical Current ◽  
Smithsonian Institution ◽  
Liquid Pool ◽  
The Other ◽  
Electric Contact ◽  
Variable Resistance ◽  
Scientists And Engineers ◽  
The Subject ◽  
The Common

Years ago, a curator at the Smithsonian Institution said to me, “Scientists and engineers are nutty on the subject of priority.” That was before I realized just how far-reaching that nuttiness was or how misguided the very concept of priority is. As an example, try searching out the inventor of the telephone. Instead of Alexander Graham Bell, you may get the name of a German, Johann Philipp Reis. The common wisdom is that Reis invented a primitive telephone that was only marginally functional, while Bell’s phone really worked. Reis was a twenty-six-year-old science teacher when he began work on the telephone in 1860. His essential idea came from a paper by a French investigator named Bourseul. In 1854 Bourseul had explained how to transmit speech electrically. He wrote: . . . Speak against one diaphragm and let each vibration “make or break” the electric contact. The electric pulsations thereby produced will set the other diaphragm working, and [it then reproduces] the transmitted sound. . . . Only one part of Bourseul’s idea was shaky. To send sound, the first diaphragm should not make and break contact; instead it should vary the flow of electricity to the second diaphragm continuously. While Reis had used Bourseul’s term “make or break,” his diaphragm actually drove a thin rod to varying depth in an electric coil. Instead of making and breaking the current, he really did vary it continuously. Bell faced the same problem when he began work on his telephone a decade later. First, he used a diaphragm-driven needle that entered a water-acid solution to create a continuously variable resistance and a smoothly varying electrical current. Bell got the idea from another American, inventor Elisha Gray. Of course, a liquid pool comes with two problems. One is evaporation; the other is immobility. Bell soon gave it up in favor of a system closer to Reis’ electromagnet. Still, it is clear that Gray’s variable-resistance pool had pointed the way for Bell. Next we must ask whether Bell was influenced by Reis’ invention. Reis died two years before Bell received his patent. (He was only forty, and he never got around to seeking a patent of his own.)

scholarly journals Fluoride Dentifrice Overcomes the Lower Resistance of Fluorotic Enamel to Demineralization

2019 ◽  
Vol 53 (5) ◽  
pp. 567-575
Author(s):  
Luma Fabiane Almeida ◽  
Lina María Marín ◽  
Esperanza Angeles Martínez-Mier ◽  
Jaime Aparecido Cury
Keyword(s):  
Statistical Analysis ◽  
Fluoride Concentration ◽  
The Other ◽  
Human Teeth ◽  
Cross Sectional ◽  
Low Resistance ◽  
Lower Resistance ◽  
Enamel Mineralization ◽  
Ph Cycling ◽  
Fluoride Dentifrice

We evaluated if the low resistance of fluorotic enamel to demineralization could be overcome by fluoride dentifrice (FD) treatment. Paired enamel slabs of sound and fluorotic enamel (n = 20/group) from human teeth presenting Thylstrup and Fejerskov index (TF) scores from 0 to 4 were obtained. Half of the anatomic surface of the enamel slabs was isolated and used as a control (baseline) regarding enamel mineralization and fluoride concentration. The slabs were submitted to a pH-cycling model simulating a high cariogenic challenge, and 2×/day they were treated with placebo dentifrice (PD) or FD (1,100 µg F/g, as NaF). After 10 days, the slabs were cut into two halves. Enamel demineralization was evaluated by cross-sectional microhardness in one half, and the fluoride formed (FF) concentration was determined in the other half. For statistical analysis, the data on net demineralization area (ΔΔS) and FF (µg F/g) were grouped into TF0, TF1–2, and TF3–4, and analyzed by two-way ANOVA followed by Tukey’s test (α = 5%). The factors studied were TF (0, 1–2, and 3–4) and dentifrice treatment (PD or FD). The effect of the factors was statistically significant for ΔΔS and FF (p < 0.05). In the PD group, the following pattern for ΔΔS was observed: TF3–4 > TF1–2 > TF0 (p < 0.05); however, the groups did not differ (p > 0.05) when FD was used. Regarding FF, the groups treated with PD did not differ (p > 0.05), but the greatest (p < 0.05) FF concentration was found in group TF3–4 treated with FD. These findings suggest that the higher susceptibility of fluorotic enamel to demineralization lesions is decreased by the use of FD.

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