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March 24, 2006
Source:
CropBiotech Update
Potatoes rank number four in
the list of world food crops (after rice, wheat and maize), and
are grown worldwide. Potatoes are however affected by numerous
diseases, which threaten potato crop production, in particular
by small-scale, resource-poor farmers in developing countries
who lack access to chemical controls and certified disease-free
seeds. Classical breeding for resistance to pathogens involves
the identification of resistance genes, often harboured by wild
relatives of cultivated species. These genes are introgressed
into cultivars by crossing the “donor parent”, which carries the
resistance gene, to the “recipient parent” to be improved. The
resulting progeny is then repeatedly backcrossed to the
“recipient parent” to remove unwanted genes carried by the
“donor parent”. Knowledge of the genetic position of the
desirable traits and of closely linked DNA-based markers allows
the targeting of specific genes for introgression, and provides
a fast track to increase genetic gain in crop breeding programs.
This technique is known as
marker assisted selection.
Researchers at the
Max-Planck Institute for
Plant Breeding Research have developed potato lines that
harbor multiple resistance genes by marker assisted selection,
described in the report “Marker-assisted combination of major
genes for pathogen resistance”. The article is published in the
Online First section of the journal Theoretical Applied
Genetics. The lines generated are resistant to four important
potato pathogens: the Potato Virus Y, the soilborne fungus
Synchytrium endobioticum (responsible for potato wart), and
the root cyst nematodes Globodera rostochiensis and
Globodera pallida. The selected plants can be used as
sources of multiple resistance, and they are available from the
IPK (Institut für Pflanzengenetik und Kulturpflanzenforschung)
potato germplasm bank maintained at 18190 Groß-Lüsewitz,
Germany.
Subscribers to Theoretical and
Applied Genetics may access the PDF file of the article
“Marker-assisted combination of major genes for pathogen
resistance” at:
http://www.springerlink.com/media/99a0hcptrm6rtg4vkyvm/contributions/x/4/5/4/x45451t272267m25.pdf
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