scholarly journals Stability of Resistance in Sorghum to Calocoris angustatus (Hemiptera: Miridae)

1991 ◽  
Vol 84 (3) ◽  
pp. 1088-1094 ◽  
Author(s):  
H. C. Sharma ◽  
V. F. Lopez
Keyword(s):  
Calocoris Angustatus ◽  
Stability Of Resistance

Stability of spinosad resistance inFrankliniella occidentalis(Pergande) under laboratory conditions

2008 ◽  
Vol 98 (4) ◽  
pp. 355-359 ◽  
Author(s):  
P. Bielza ◽  
V. Quinto ◽  
C. Grávalos ◽  
E. Fernández ◽  
J. Abellán ◽  
...  
Keyword(s):  
Resistant Strain ◽  
Selection Pressure ◽  
Frankliniella Occidentalis ◽  
Western Flower Thrips ◽  
Laboratory Conditions ◽  
Flower Thrips ◽  
Factors Influencing ◽  
Stability Of Resistance ◽  
The Stability ◽  
Successive Generations

AbstractThe stability of spinosad resistance in western flower thrips (WFT),Frankliniella occidentalis(Pergande), populations with differing initial frequencies of resistance was studied in laboratory conditions. The stability of resistance was assessed in bimonthly residual bioassays in five populations with initial frequencies of 100, 75, 50, 25 and 0% of resistant individuals. There were no consistent changes in susceptibility of the susceptible strain after eight months without insecticide pressure. In the resistant strain, very highly resistant to spinosad (RF50>23,000-fold), resistance was maintained up to eight months without further exposure to spinosad. In the absence of any immigration of susceptible genes into the population, resistance was stable. In the case of the population with different initial frequency of resistant thrips, spinosad resistance declined significantly two months later in the absence of selection pressure. With successive generations, these strains did not change significantly in sensitivity. Spinosad resistance inF. occidentalisdeclined significantly in the absence of selection pressure and the presence of susceptible WFT. These results suggest that spinosad resistance probably is unstable under field conditions, primarily due to the immigration of susceptible WFT. Factors influencing stability or reversion of spinosad resistance are discussed.

scholarly journals Durable resistance against Meloidogyne chitwoodi and M. fallax

2017 ◽  
Vol 38 (SI 2 - 6th Conf EFPP 2002) ◽  
pp. 711-713
Author(s):  
F.C. Zoon ◽  
W. Golinowski ◽  
R. Janssen ◽  
D. Mugniéry ◽  
M.S. Phillips ◽  
...  
Keyword(s):  
Production Systems ◽  
Durable Resistance ◽  
Resistance Management ◽  
Resistance Mechanisms ◽  
Genetic Maps ◽  
Meloidogyne Chitwoodi ◽  
First Results ◽  
Stability Of Resistance ◽  
Nematode Virulence ◽  
The Stability

The EU-funded Project QLRT-1999-1462 DREAM (Durable Resistance Against Meloidogyne) aims to contribute to sustainable production systems by developing a strategy for durable resistance management for two polyphagous quarantine root-knot nematodes Meloidogyne chitwoodi and M. fallax. The objective will be achieved by integrating expertise in breeding, nematology, botany and molecular biology. The project combines three areas of research: 1. Identification and incorporation of resistance in important arable crops: potato, pepper, ryegrass and fodder radish, 2. Study of variation in nematode virulence and of durability of the resistance, and 3. Optimising of production systems by rotation schemes. The main results expected are: resistant germplasm, characterised pathogen collections, breeding methods, knowledge of the stability of resistance, molecular markers linked to resistance and (a)virulence, resistance mechanisms and genes, genetic maps, and improved rotation schemes. The strategy and some first results will be discussed.

scholarly journals Identification and multi-environment validation of resistance to rust (Uromyces viciae-fabae) in Vicia faba

2017 ◽  
Vol 68 (11) ◽  
pp. 1013 ◽  
Author(s):  
Josefina C. Sillero ◽  
María M. Rojas-Molina ◽  
Amero A. Emeran ◽  
Mohamed Kharrat ◽  
Johanna Winkler ◽  
...  
Keyword(s):  
Vicia Faba ◽  
Phenotypic Expression ◽  
Germplasm Collection ◽  
Environment Interaction ◽  
Genotype Environment Interaction ◽  
Complete Resistance ◽  
Stability Of Resistance ◽  
Breeding Programmes ◽  
The Mediterranean ◽  
Efficiency Of Selection

A germplasm collection of 484 accessions of Vicia faba was screened for resistance to rust (Uromyces viciae-fabae) under field conditions. Accessions varied in the levels of rust infection, although no complete resistance was identified. Stability of resistance of the 39 most-resistant accessions was tested in a multi-location experiment in Austria, Egypt, Tunisia, United Kingdom and Spain over three additional field seasons. Genotype × environment interaction accounted for 43% of the sum of squares of the multi-environment evaluation, revealing instability of the phenotypic expression across environments. This might hamper the efficiency of selection suggesting the need for selection in different environments. Three possible mega-environments were discerned in the studied area, Mediterranean (Spain, Tunisia and Egypt), Oceanic (UK) and Continental (Austria). Córdoba (Spain) and Kafr El-Sheik (Egypt) showed as ideal environments for rust resistance screenings within Mediterranean environment. Several accessions (300, 303, 311, 313, 720, 1196 and 1271) were grouped as moderately to highly resistant in the three defined mega-environments. These accessions showed clear differences both in terms of reduced disease severity and high stability, which make them good candidates for international faba bean breeding programmes. Concerning each mega-environment, accessions 300 and 311 were the most resistant and stable ones across the Mediterranean one, followed by accessions 720, 1022, 1272, 1320 and BPL261. On the contrary other accessions (313, 452, 481 and 1196) were the most resistant in Oceanic and Continental environments. However, 452 and 481 were susceptible in the Mediterranean mega-environment. This contrasting performance across the environments was also supported by contradictory performance of the checks BPL261 and Baraca in Oceanic and Continental environments, suggesting differential virulence in rust populations, which deserves further attention.

FURTHER STUDIES ON STABILITY OF RESISTANCE TO THE COMMON COLD

1947 ◽  
Vol 45 (1) ◽  
pp. 29-32
Author(s):  
FREDERICK SARGENT ◽  
OLIVE M. LOMBARD ◽  
VIRGINIA W. SARGENT
Keyword(s):  
Common Cold ◽  
Stability Of Resistance ◽  
The Common

scholarly journals Macrolide resistance in Helicobacter pylori: mechanism and stability in strains from clarithromycin-treated patients.

1997 ◽  
Vol 41 (11) ◽  
pp. 2550-2553 ◽  
Author(s):  
K Hultén ◽  
A Gibreel ◽  
O Sköld ◽  
L Engstrand
Keyword(s):  
Helicobacter Pylori ◽  
Genetic Relatedness ◽  
Macrolide Resistance ◽  
Biological Assays ◽  
Clarithromycin Resistance ◽  
Stability Of Resistance ◽  
Development Mechanism

Helicobacter pylori strains from seven patients treated with clarithromycin were investigated for development, mechanism, and stability of resistance. Genetic relatedness between pre- and posttreatment isolates was shown by arbitrary primed PCR. Clarithromycin resistance was associated with A-to-G transitions at either position 2143 or 2144 or at both positions 2116 and 2142. In four cases, the mutations were homozygous. The Cla(r) phenotype was stable after 50 subcultivations in vitro. No erythromycin-modifying enzymes or rRNA methylases were found by biological assays, PCR and sequencing, or cloning methods.

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