Breeding And SSR Analysis Of Hybrid F₁ Excellent Lines Of YSP-4 × Longshu No.7

In order to breed potato new varieties with good quality, high yield, strong resistance and adaptability, good tuber shape, shallow eyes, the wild potato material YSP-4 introduced from United States was used as maternal parent, and the potato material Longshu No.7 derived from China was used as paternal parent, according to the parents selection principle of traits complementarity and ecotypes-diversity between parents. After crossing by artificial emasculation and pollination, the hybrid F1 population from YSP-4× Longshu No 7 were obtained successfully.The present study focused on breeding the excellent lines from hybrid F1 individuals, and made analysis of the agronomic traits, cytogenetic characteristics, and SSR molecular markers of these lines. The main results were as follows:1. A total of 6 second generation asexual lines with excellently icomprehensive agronomic traits were selected from hybrid F1 population of YSP-4×Longshu No.7. The growth period of these 6 lines ranged from 106-123 d, the plant height from 71.8-103.6 cm, main stalk number from 1.67-4.33, the branch number from 1.00-6.50, and the stem diameter from 1.22-1.56 cm. These lines had centralized and symmetrical potato tubers, shallow tuber eyes, and had their own characteristics in potato shape, and potato skin and tuber color.2. Of the 6 lines, the tuber number each line ranged from 6-10, tuber yield each line from 0.96-1.35 kg, marketable tuber rate from 77-100%, dry matter content from 16.77-27.63%, and starch content from 12.27-23.53%(the line 4 had high starch content), Vc content from 1.31-6.16 mg/100g, reducing sugar content from 0.018-0.028%, crude protein content from 0.94-1.20%, and phenolics content from 0.35-0.69%.3. The fertile pollen rate of each line varied from 28.33-75.67%. Chromosome configuration of line 3, line 4, line 5, line 6, line 10 and line 12 was 3.2Ⅰ+7.3Ⅱ+3.7Ⅲ+4.8Ⅳ,1.6Ⅰ+9.7Ⅱ+2.2Ⅲ+5.0Ⅳ,2.1Ⅰ+8.8Ⅱ+2.6Ⅲ+5.1Ⅳ, 2.4Ⅰ+8.8Ⅱ+2.8Ⅲ+4.9Ⅳ,2.5Ⅰ+8.4Ⅱ+3.0Ⅲ+4.9Ⅳ, and 17.6Ⅰ+2.4Ⅱ+6.0Ⅲ+1.9Ⅳ.4. There was a extremely significantly positive correlation between dry matter content and starch content, a significantly positively correlation between plant height and reducing sugar content, a significantly negative correlation between main stalk number and marketable tuber rate.5. The genetic distance (GD) of 6 excellent lines and their parents ranged from 0.0597 to 0.6098. Using the GD value of 0.2736 as a threshold,8 potato materials could be clustered into 5 groups:the first group included line 3,4 and 6, the second group included line 5 and 10, the third group included line 12, the fourth group included Longshu No.7, and the fifth group included YSP-4.