Abstract:To obtain new potato germplasm with high yield and high starch content, the tetraploid cultivar ‘jizhangshu 12(G12)’ was crossed respectively with three cultivated diploids showing high starch content. Three cross combinations were performed and each cross combination was divided into grafting group and control group. Grafting was conducted at the seedling stage between the tetraploid cultivated species (scion) and diploid species (rootstock), and pollination by the male parent (rootstock species) at the beginning of flowering. In the grafting group, an average of 254 flowers were pollinated to produce 112 fruits, with an average fruit setting rate of 44.1%. In the control group, an average of 296 flowers were pollinated to produce from 65 fruits, with an average fruit setting rate of 22.0%. Of 177 fruits, 30 seeds were cultivated to regenerate 15 F1 plants. Nine, four and two plants were verified to be tetraploids, triploids and diploids respectively, by deployment of flow cytometry analysis, chloroplast count and pollen mother cell chromosome counting methods. Genotyping using simple sequence repeat (SSR) markers showed that all tetraploids and triploids were hybrids from both parents. All the interspecific hybrids grew well, whereas only one line succeeded to produce seeds by selfing. The potato tuber size of interspecific progenies was significantly larger than that of diploid parents, and showed light to medium on the bud eye depth, with great improvement to that of diploid parents. The color of potato flesh was mostly yellow, and some interspecific hybrids tuber skin color differed with that of their parents. In the field trials, the starch content of all tetraploid F1 lines were significantly higher than that of ‘G12’, where no significant difference in yield was observed except one line ‘SY18-6’. According to the characteristics of tuber yield, starch content and starch yield, six lines ‘SY24-1' (starch content: 21.39%), ‘SY18-1’ (21.37%), ‘SY24-5’ (18.35%), ‘SY18-4’ (20.28%), ‘SY24-3’ (18.29%) and ‘SY69-3’ (18.84%) showing high yield and high starch content were identified.