|Author: ||E. Zimnoch-Guzowska|
|Keywords: ||resistance sources, mapping, marker assisted selection, somatic fusion, resistance stability, pathogen characteristics|
To enhance late blight resistance of potato cultivars we have undertaken studies on both resistance of host plants and the characterization of P. infestans. New sources of resistance have been found among Solanum species, such as S. phureja, S. verrrucosum, S. microdontum, S. michoacanum, S. ruiz-ceballosi, S. kurtzianum and S. nigrum. Parallel to the introduction of the identified resistances into the cultivated gene-pool via recombination breeding, the research has also focused on the determination of the inheritance of resistance and on mapping the underlying genetic factors in the potato genome.
There are identified genes and QTLs responsible for leaf and tuber resistance and QTLs responsible for the length of the vegetative period.
We introduced molecular markers for selection of late blight resistant genotypes in the breeding program.
The PCR marker for the gene Rpi-phu1 is used for selection of resistant 2x and 4x breeding lines.
In recent years somatic hybrids were obtained for resistance sources not crossable to S. tuberosum. Resistance of somatic hybrids S. tuberosum × S. nigrum has been characterized.
A set of Polish resistant cultivars has been tested in various locations of Poland for several seasons to identify the ones with the most stable resistance phenotypes.
A large collection of P. infestans isolates has been characterized phenotypically and genotypically, which is representative of the Polish population of the pathogen.
For selection of resistant potato genotypes in the breeding program, both field screening under heavy infection pressure and laboratory assays are used.
We assume that approaches mentioned above and the forthcoming utilization of cisgenesis of cloned resistance genes in modification of susceptible cultivars, will lead to a significant improvement in the level of late blight resistance in future potato cultivars.
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