Biocontrol Science and Technology (2012) 22, 1035-1045

Samuel Ashebir Anbesse, Olaf Strauch and Ralf-Udo Ehlers (2012)
Genetic improvement of the biological control nematode Heterorhabditis bacteriophora (Rhabditidomorpha: Heterorhabditidae): heterosis effect enhances desiccation but not heat tolerance
Biocontrol Science and Technology 22 (9), 1035-1045
Abstract: The entomopathogenic nematode Heterorhabditis bacteriophora is commercially used in biological control of soil dwelling insect pests. It reproduces by autogamy (hermaphrodites) enabling the production of inbred lines, but also by amphimixis (through mating of male and female) which allows cross-breeding. When H. bacteriophora is produced in liquid culture, copulation of male and female is prevented and reproduction is solely by self-fertilisation of hermaphrodites. When reared in insects, crosses are possible resulting in heterozygous offspring. Heat and desiccation tolerance of these nematodes have been successfully improved by selective breeding. Trait deterioration was prevented by producing homozygous inbreds through consecutive reproduction in liquid culture, the method also used for commercial mass production. In this study, we investigated possible heterosis effects in desiccation and heat tolerance after cross-breeding of homozygous inbred lines of H. bacteriophora. Increased desiccation tolerance of the heterozygous progeny in comparison to homozygous inbred lines was recorded indicating that heterosis is a possible means for further improvement of this trait. In contrast, the heat tolerance of the heterozygous offspring was lower than that of the homozygous population. The results provide evidence for the tremendous potential of classical genetics to improve beneficial traits of a biological control agent and carry domestication of H. bacteriophora a significant step forward.
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Link to article at publishers website
Database assignments for author(s): Ralf-Udo Ehlers

Research topic(s) for pests/diseases/weeds:
biocontrol - natural enemies
Research topic(s) for beneficials or antagonists:
rearing/culturing/mass production
environment/habitat manipulation

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Pest and/or beneficial records:

Beneficial	Pest/Disease/Weed	Crop/Product	Country	Quarant.
Heterorhabditis bacteriophora/Photorhabdus (entomopathogen)