|Title||Pairing analysis and in situ Hybridisation reveal autopolyploid-like behaviour in Solanum commersonii × S. tuberosum (potato) interspecific hybrids|
|Author(s)||Gaiero Guadagina, Paola; Mazzella, Cristina; Vilaró, Francisco; Speranza, Pablo; Jong, Hans de|
|Source||Euphytica 213 (2017)7. - ISSN 0014-2336 - 15 p.|
Laboratory of Genetics
Groep KoornneefGroep Koornneef
|Publication type||Refereed Article in a scientific journal|
|Keyword(s)||BAC FISH - GISH - Introgressive hybridisation - Pairing behaviour - Potato wild relatives|
Wild potato relatives are rich sources of desirable traits for introgressive hybridisation into cultivated potato. One of them, Solanum commersonii (2n = 2x = 24, 1EBN, endosperm balance number), is an important species belonging to the potato tertiary genepool. It can be used in potato breeding through bridge crosses and 2n gamete production. Triploid F1 hybrids between S. commersonii (through spontaneous 2n egg formation) and diploid 2EBN Solanum tuberosum Group Phureja were crossed with S. tuberosum Group Tuberosum, resulting in successive backcross 1, 2 and 3 progenies. The main aim of this study was to determine if there are any barriers to homoeologous pairing and recombination in the allotriploid (S. commersonii × potato) hybrids and their backcrosses, and so to predict if S. commersonii chromosomes can be transmitted to the next generation and introgressed into their recipient potato chromosomes. Microscopic observations of spread pollen mother cells suggested no preferential pairing in the triploid hybrids, while chromosome transmission and segregation in further meiotic stages were fairly balanced. Fluorescent in situ hybridisation with BAC probes (BAC FISH) was used to obtain markers to trace the meiotic behaviour of specific chromosome pairs. Moreover, genomic in situ hybridisation (GISH) demonstrated no obvious differences in fluorescence signals between the homoeologues suggesting that repetitive sequences did not diverge much between the parental species. As a consequence, we were not able to trace the course of the S. commersonii chromosomes in the successive introgressive hybridisation backcross generations. Our results strongly point at a high genomic similarity between the homoeologous chromosomes promising high suitability of S. commersonii in introgressive hybridisation breeding of potato.