Key messagePhytophthora infestansresistant somatic hybrids ofS. × michoacanum(+)S. tuberosumand autofused 4xS. × michoacanumwere obtained. Our material is promising to introgress resistance fromS. × michoacanuminto cultivated potato background.AbstractSolanum × michoacanum (Bitter.) Rydb. (mch) is a wild diploid (2n = 2x = 24) potato species derived from spontaneous cross of S. bulbocastanum and S. pinnatisectum. This hybrid is a 1 EBN (endosperm balance number) species and can cross effectively only with other 1 EBN species. Plants of mch are resistant to Phytophthora infestans (Mont) de Bary. To introgress late blight resistance genes from mch into S. tuberosum (tbr), genepool somatic hybridization between mch and susceptible diploid potato clones (2n = 2x = 24) or potato cultivar Rywal (2n = 4x = 48) was performed. In total 18,775 calli were obtained from postfusion products from which 1,482 formed shoots. The Simple Sequence Repeat (SSR), Cleaved Amplified Polymorphic Sequences (CAPS) and Random Amplified Polymorphic DNA (RAPD) analyses confirmed hybrid nature of 228 plants and 116 autofused 4xmch. After evaluation of morphological features, flowering, pollen stainability, tuberization and ploidy level, 118 somatic hybrids and 116 autofused 4xmch were tested for late blight resistance using the detached leaf assay. After two seasons of testing three somatic hybrids and 109 4xmch were resistant. Resistant forms have adequate pollen stainability for use in crossing programme and are a promising material useful for introgression resistance from mch into the cultivated potato background.