On using data from marker-assisted selection of source material and intervarietal hybrids in practical potato breeding

The success of breeding research is in many ways determined by the successful selection of parental forms for hybridization. In recent years, along with traditional approaches, the results of marker-assisted selection (MAS) are actively used for the selection of parental lines, in order to combine valuable alleles of parental genotypes. Such programs are widely used for different crops in many countries, including Russia. The use of MAS is promising both at the initial stage in the selection of parental samples for crosses and at the stages of analysis of segregating hybrid populations. In this work, the selection of parental potato varieties for crosses was carried out based on the results of MAS of initial varieties with markers of R -genes conferring resistance to various harmful organisms as well as based on their economically valuable characters. To increase the efficiency of the selection of promising hybrid genotypes obtained in intervarietal crosses, we used an integrated approach that combines MAS with markers of R- genes for resistance to various diseases and pests with traditional methods for assessing economically valuable traits of hybrid populations. The resulting hybrids of three combinations (Gusar × Charoit), (Gusar × Aliy Parus), (Gusar × Sireneviy tuman) also participated in MAS with 8 markers of 6 R- genes conferring resistance to potato virus Y ( Rysto) and potato virus X (Rx1), to golden (H1) and pale (Gpa2) potato cyst nematodes, and race-specific resistance to late blight (R1 , R3A). Almost all the hybrids had different combinations of R -gene markers. To identify the allelic composition of the R -genes in the parental varieties, the segregation of DNA markers in each combination was analyzed, which allowed us to determine the level of heterozygosity of the marked loci in the parental varieties. Main economically valuable characters of the hybrids were also evaluated in the field trials. As a result, out of 144 hybrids, 31 genotypes were identified that have one or the other economically valuable traits (yield, marketability, shape of tubers, starch content, field resistance to late blight), and 113 hybrids were rejected. In 23 of the 31 selected hybrids, productivity varied from 600 to 1525 grams per plant. Twelve of these 23 hybrid genotypes combined relatively high productivity and marketability of tubers with various combinations of Rysto , Rx1 , H1 , Gpa2 , R1 , and R3A gene markers. Thus, the use of an integrated approach that combines traditional breeding methods and MAS increases the efficiency of the selection of promising genotypes with a given set of traits.The selected hybrid genotypes are of interest for further breeding aimed at creating competitive varieties with complex resistance to various pathogens and pests, including viral and nematode resistance, that will need fewer chemical treatments to protect the crop.