| Popis: |
Freezing stress affects the geographic distribution, growth, and development of potato, resulting in loss of its yield. Solanum malmeanum , a diploid wild species with strong freezing tolerance, was fused with a freezing sensitive dihaploid S. tuberosum by somatic hybridization. In our study, 980 calli were obtained, and 248 differentiate shoots from the calli. Parental-specific SSR markers were used to analyze the chromosome composition of the randomly selected 80 regenerated plants, resulting in 51 somatic hybrids. Among them, 44 somatic hybrids were tested with ploidy analysis in the years 2016 and 2020. During subculture, the genomic ploidy levels changed due to the composition of the unstable chromosome in 56.82% of the somatic hybrids. Compared with the cultivated parent, somatic hybrids showed better freezing tolerance. After freezing-tolerant somatic hybrids were selected to backcross with cultivars, we obtained some valuable breeding resources with enhanced freezing tolerance while similar tuberization capacity close to cultivars. The correlation analysis shows that freezing tolerance has no relation with tuberization capacity, which indicates that they are controlled by independent genetic loci. In all, we successfully conducted the protoplast fusion between S. malmeanum and S. tuberosum for the first time, which provided valuable resources for freezing-tolerant breeding. |
