Peculiarities of Transfer of DNA Markers of Wild Allotetraploid Potato Species <i>Solanum stoloniferum</i> to Backcross Progenies Depending on Their Subgenomic Location and Used Schemes of Introgression

Abstract

Genomic difference between wild allotetraploid potato species Solanum stoloniferum Schltdl et Bouchet (genome AABB) and S. tuberosum L. (AAAA) is one of the factors hampering its use in breeding. However, there is practically no information on valuable genes of this species located in the subgenome B and on the way of their transfer into the genome A of cultivated potatoes. The objectives of this research were to identify subgenomic location of a set of S. stoloniferum genes using an original approach based on a difference of inheritance of DNA markers of the genes in backcross BC1 of chromosome doubled triploid hybrids (6x, AAAABB) to 4х S. tuberosum dependent on belonging to A or B subgenome; to study their inheritance in BC2 and BC3 in the framework of four introgression schemes and marker assisted selection of the gene Rpi-sto1. The markers of late blight (LB) resistance genes Rpi-sto1, R3b, R2, potato virus Y (PVY) resistance genes Rysto, Ryadg were located on the subgenome B and the marker of PVY resistance gene Rychc – on the subgenome A. We observed an appearance of unexpected sporadic hybrids free of markers in BC1 that may be explained by rare cases of homeological recombination of A and B subgenome chromosomes. The segregation of the markers in BC2 (close to 1 : 1) matched in general to that expected in the case of random transfer of the corresponding chromosomes of the subgenome B. Some promising for breeding hybrids have been selected in BC3 having the marker of the gene Rpi-sto1.