POTATO GENETICS, CYTOGENETICS, DISEASE RESISTANCE, AND PRE-BREEDING UTILIZING WILD AND CULTIVATED SPECIES
Location: Vegetable Crops Research Unit
Title: The Use of Solanum Verrucosum as a Bridge Species
Submitted to: Genetic Resources and Crop Evolution
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: March 31, 2009
Publication Date: May 20, 2009
Citation: Jansky, S.H., Hamernik, A.J. 2009. The Use of Solanum Verrucosum as a Bridge Species. Genetic Resources and Crop Evolution. 56(8):1107-1116.
Interpretive Summary: A group of wild potato species (called 1EBN species) is rich in valuable genes for potato improvement, including genes for disease and pest resistance genes and for improved tuber quality. These species would be valuable for potato improvement, but they can not be crossed to the cultivated potato. In this paper, we report that a wild potato species (Solanum verrucosum) will cross to 1EBN species and the subsequent hybrids are then crossable to the cultivated potato. This provides an efficient method to access genes for potato improvement in the 1EBN species gene pool. Potato breeders can use this method to introduce new sources of disease and pest resistance, and tuber quality, into their breeding lines. This germplasm will be contribute to the development of new superior potato cultivars with reduced requirements for chemical imputs and improved processing quality.
Wild diploid Solanum species with an endosperm balance number (EBN) of one are a rich source of disease resistance, pest resistance, and tuber quality traits. They are typically not sexually compatible with potato cultivars (4x 4EBN) or haploids derived from them (2x 2EBN). In this study, the self-compatible wild 2x 2EBN Mexican species S. verrucosum (ver) was used as a bridge species to access self-incompatible 2x 1EBN germplasm. Hybrids (V1) were created between ver as a female parent and S. cardiophyllum, S. chancayense, S. commersonii, and S. trifidum. Most of the V1 hybrids were crossable as females to diploid interspecific hybrids and to ver. The V1 hybrids segregated for male sterility. When male sterile hybrids were crossed as females to ver, the offspring segregated for male fertility. However, due to stylar barriers, V1 hybrids and V1 x ver hybrids were not crossable as males to 2x 2EBN interspecific hybrid clones. The V1 hybrids were self-incompatible, but when they were crossed to ver, their offspring were self-compatible. Additional studies are underway to determine the effectiveness of ver as a bridge to introgress specific traits from 2x 1EBN germplasm into the cultivated potato.