POTATO GENETICS, CYTOGENETICS, DISEASE RESISTANCE, AND PRE-BREEDING UTILIZING WILD AND CULTIVATED SPECIES
Location: Vegetable Crops Research Unit
Title: Hybridization barriers between diploid Solanum tuberosum and wild Solanum raphanifolium
Submitted to: Genetic Resources and Crop Evolution
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: June 28, 2012
Publication Date: July 20, 2012
Citation: Weber, B., Hamernik, A.J., Jansky, S.H. 2012. Hybridization barriers between diploid Solanum tuberosum and wild Solanum raphanifolium. Genetic Resources and Crop Evolution. 59:1287-1293.
Interpretive Summary: Wild relatives of potato are valuable sources of genes for variety improvement. The wild relative Solanum raphanifolium exhibits high levels of resistance to early blight and expresses high quality processing traits. Crossing barriers have been encountered in attempts to move genes from this wild species to cultivated potato. However, some strategies to overcome these barriers have been developed and are being used to access this germplasm resource.
Wild potato germplasm represents a unique, diverse and accessible resource for disease and pest resistance, along with useful agronomic traits that may be introgressed into the cultivated potato (Solanum tuberosum L.). Hybridization of diploid wild Solanum species with haploids (2x) of cultivated potato (4x) is generally an effective technique for introducing genetic diversity and desirable traits into potato. However, in this study, hybridization barriers were found in crosses between S. tuberosum haploids and the wild species S. raphanifolium. Male sterility, likely due to nuclear-cytoplasmic interactions, was observed in some haploid tbr x S. raphanifolium hybrids. In addition, pollen-pistil incompatibilities were observed in backcross, F2, and reciprocal cross hybridization attempts that failed to produce seed. More crosses were successful when F1 clones were crossed as females to wild clones than to cultivated clones. When crosses were made in the other direction, with F1 hybrids used as male parents, seeds were almost never produced.