Markergestützte Selektion auf Steinbrand-Resistenz in Weizen
Bunt in wheat is a crop disease that is caused by fungal spores, and mainly affects organically grown cultivars, since the infestation can be prevented by chemical seed treatment in conventional farming systems. With resistance breeding, it is possible to develop cultivars that are resistant to bunt and are suitable for organic cultivation. For more efficient breeding, marker-assisted selection is an important tool to save time and resources.
The aim of marker-assisted selection (MAS) for bunt resistance in wheat is to reduce the number of plants of the BC2F2 generation by selecting only those plants which have homozygous resistance in the form of resistance QTL.
In order to be able to carry out the marker-assisted selection, DNA was extracted from the leaf material of the wheat plants to be tested. After normalizing the DNA-concentration, genotyping was carried out using competitive allele-specific PCR (KASP), and the resistant alleles could be detected with the aid of molecular markers.
After evaluating the results, 163 plants from a total of 2165 plants of the BC2F2 generation were positively selected.
Since only a rough selection was conducted during pre-selection, the validation is an important step to make sure that only those plants are included in the next generation which actually inherited the allele from the resistance donors. The results show that the number of plants has been significantly reduced after validation, which also increases the chance of actual resistance. Subsequently, the bunt resistance in the positively selected wheat plants can be confirmed by infection tests in the field.