Russian wheat aphid resistant cultivars form the basis of an integrated programme for Russian wheat aphid control in the summer rainfall region of South Africa where this aphid is the most serious pest of wheat. By planting RWA resistant cultivars, producers are exposed to less risk as the cultivar controls the pest without the need for expensive and potentially hazardous insecticides.
In order to release competitive cultivars, high quality breeding lines containing the resistance to the prevalent Russian wheat aphid biotype are needed by breeders. Currently there are four biotypes of the Russian wheat aphid which occur in South Africa. Whether farmers plant Russian wheat aphid resistant or susceptible cultivars they should be inspected regularly for the presence of Russian wheat aphid as it is not possible to predict which biotype will occur in a specific field.
The Russian wheat aphid pre-breeding project obtains resistant accessions from international collaborators as well as from germplasm collections. These lines are screened in the glasshouse using live aphids to identify suitable donors of natural resistance against this pest. Thereafter, the most suitable resistance is transferred to well-adapted, South African germplasm using a conventional backcross method. Resistance is followed in the progeny using phenotypic screening of seedlings and once developed, germplasm is released to industry for use. Additionally, this project focusses on including resistance to cereal rusts in the Russian wheat aphid resistant germplasm that is being developed as this makes the germplasm releases more useful to breeders.
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