Development of chromosome-specific markers for a study on introgressive hybridization of potato with the wild Mexican allotetraploid species Solanum stoloniferum Schltdl

Abstract

In order to involve valuable germplasm of the wild Mexican allotetraploid potato species Solanum stoloniferum Schltdl. (genomic composition ААВВ) into breeding, pentaploid interspecific hybrids (ААAAВ) with cultivated potato S. tuberosum L. (АААА) and their backcross progenies are usually used. Homologous synapsis in meiosis of such hybrids is expected only between chromosomes of the A subgenome, therefore a question arose about a possibility of introgressing genetic material of the subgenome B into the A genome of cultivated potato. In this connection, development of various schemes for the B subgenome introgression into the genome of cultivated potato is considered as a topical issue. The previous research has yielded four schemes of S. stoloniferum involvement into breeding, which imply backcrossing with cultivated potato of the following interspecific hybrids: (1) hexaploids (genomic composition ААААВВ, the conventional introgression scheme), (2) tetraploids (putatively, АААВ), (3) self-pollination progeny of a 4x hybrid and (4) pentaploid hybrids with a putative genome composition of АААВВ. The present paper presents the first results of the development of chromosome-specific DNA markers for the identification of S. stoloniferum chromosomes in interspecific hybrids. An S. stoloniferum accession PI 205522 with a high degree of resistance to late blight and PVY had been found to possess several DNA-markers of the R-genes conferring resistance to these pathogens and was used in hybridization as a promising parent. A set of 23 SSR- and CAPS markers with the known chromosome location in S. tuberosum was generated. These markers detect polymorphism between parent genotypes, i.e., the diploid clone IGC 10/1.21 of cultivated potatoes S. tuberosum, and accession PI 205522 of S. stoloniferum. All the markers specific for the wild species were found in triploid (ААВ) and pentaploid (АААВВ) hybrids of S. stoloniferum × S. tuberosum. This set of markers will be used for efficiency assessment of different schemes for S. stoloniferum genetic material introgression into the obtained BC2-BC3 generations after crossing the interspecific hybrids with cultivated potato.

Keywords

• potato
• solanum tuberosum
• interspecific hybridization
• s. stoloniferum introgression
• ssr
• caps
• sts
• scar markers