Pyramiding of R genes responsible for resistance to potato virus Y and potato late blight.

摘要

The main objective of the presented PhD research was to adapt the potato breeding programme at the Agricultural Institute of Slovenia to enable the introduction, effective selection, and pyramiding of R genes resistant to the most important potato diseases: potato virus Y (PVY) and late blight. The aim of the research was achieved by analysing the genealogies of resistant varieties, studying the expression of their traits and the traits of their offspring, testing their suitability for genetic recombination and crossings, studying male sterility, and analysing the possibility of exploring the molecular markers in the selection process. In the breeding program Ry genes from the species Solanum stoloniferum and S. chacoense and R genes for resistance to late blight from the species S. demissum, S. bulbocastanum, and the variety 'Sarpo Mira' were used. The results indicate that the pyramiding of several R genes can be useful in small breeding programs, although it reduces the average efficiency of progeny selection. In some cases, male sterility was not transferred from the species S. stoloniferum to the offspring. The extreme resistance was found to be effective against all isolates of PVYNTN. The method of mass selection associated with PVY enabled elimination of 60% of the susceptible genotypes in the seedling stage, whereas the remainder were eliminated in the following two years. The study confirmed the effect of age on the expression of R genes associated with resistance to late blight. R genes from the species S. demissum can still provide stable medium-term resistance to late blight, but for the long-term resistance of new genotypes it will probably be necessary to retain the resistance of the variety 'Sarpo Mira'. Thus far, we have introduced molecular markers for the identification of the genes for extreme resistance to PVY Rysto, Ry-fsto, and Rychc, and the genes for resistance to late blight R1, R2-F1, R 3, R 3a, R 3b, and BLB2. .