Journal of Economic Entomology (1995) 88, 21-26

Utami Rahardja and Mark E. Whalon (1995)
Inheritance of resistance to Bacillus thuringiensis subsp. tenebrionis CryIIIA delta-endotoxin in Colorado potato beetle (Coleoptera: Chrysomelidae)
Journal of Economic Entomology 88 (1), 21-26
Abstract: We investigated the genetic inheritance of Colorado potato beetle, Leptinotarsa decemlineata (Say), resistance to Bacillus thuringiensis CryIIIA delta-endotoxin. Standard reciprocal crosses and backcrosses between susceptible (S) and resistant (R) strains were used to determine the characteristics of resistance. Analysis of probit lines from the F₁ reciprocal crosses indicated that B. thuringiensis delta-endotoxin resistance was inherited autosomaly without maternal effects. We estimated the degree of dominance to be 0.77 And 0.76 for the (R X S) and (S X R) F₁ generations, respectively, indicating that B. thuringiensis CryIIIA delta-endotoxin resistance is conferred by incompletely dominant genes. Chi-square analysis of mortality responses of backcrossed offspring suggested that resistance might be caused by more than one locus. The stability of resistance was also studied by testing seventeen generations of resistant beetles after the selection pressure was removed. When the selection pressure was removed, the resistance level of the selected colony decreased after five generations. The resistance level did not decrease further when the selection was removed for >12 generations.
(The abstract is excluded from the Creative Commons licence and has been copied with permission by the publisher.)
Database assignments for author(s): Mark E. Whalon

Research topic(s) for pests/diseases/weeds:
biocontrol - natural enemies
Research topic(s) for beneficials or antagonists:
resistance/tolerance/defence of host

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Pest and/or beneficial records:

Beneficial	Pest/Disease/Weed	Crop/Product	Country	Quarant.
	Leptinotarsa decemlineata
Bacillus thuringiensis var. tenebrionis (entomopathogen)	Leptinotarsa decemlineata
Bacillus thuringiensis Cry3A-toxin (entomopathogen)	Leptinotarsa decemlineata