Identification Of Potato Hybrids By ISSR Markers And Breeding Of Excellent New Strains With High Yield And Quality

In order to breed new potato (Solanum tuberosum L.) varieties with high yield, highquality, strong adaptability and high starch content, potato hybrids of4cross-combinationsincluding ‘J07-2’בLongshu No.7’,‘J07-4’בLongshu No.6’,‘J07-6’בLongshu No.6’,‘J07-6’בLongshu No.7’ were obtained. In order to provide materials for selecting andbreeding excellent new potato strains, the authenticity of the first clone generation of F1hybrids was identified by ISSR molecule markers. Their agronomic characteristics, yield，quality and cytogenetics at the second clone generation were studied. SSR fingerprints ofgenetically stable lines of potato F1hybrids at the third clone generation were established.The main results of the study were as follows:1. Five suitable ISSR primers(AF18549, AF18550, AW75511, AW20607andAW20617) were used for authenticity identification of23hybrids F1first clone plants. Themain identification basis was that there were paternal-specific bands in progeny’s bands. Itwas identified that the total of23clones were true hybrids.2. The results of observation and analysis of main agronomic characters showed thatfour lines of potato hybrid F1were selected from cross-combination ‘J07-2’בLongshuNo.7’ and ‘J07-6’בLongshu No.7’, including lines2-1,3-1,4-4and19-3.3. Four lines were tetraploid, with steady chromosome numbers. Chromosome pairingconfiguration of hybrid line2-1was2.1Ⅰ+12.3Ⅱ+2.7Ⅲ+3.3Ⅳ, line3-1was2.5Ⅰ+13.5Ⅱ+3.1Ⅲ+2.3Ⅳ, line4-4was2.1Ⅰ+16.2Ⅱ+1.7Ⅲ+2.1Ⅳ, line19-3was1.9Ⅰ+15.6Ⅱ+1.5Ⅲ+2.6Ⅳ.4. The pollen fertility of Line4-4and Line19-3were86.63%and81.23%. They hadplenty of pollen, tended to male parent Longshu No.7. The pollen fertility of Line2-1andLine3-1were59.90%and64.40%respectively. All of them could be used as intermediatematerials in cross-breeding.5. Four hybrid lines(Line2-1,3-1,4-4and19-3) were late-maturing type. Theirgrowth periods were in127d to130d. Their growth potentials were strong. And theiraverage plant heights were about100cm. The yield and quality of line2-1and line19-3were more prominent than the others, with high mean tuber weight, high commercial tuberrate, high yield per plant, shallow eyes, and good tuber shape. Their starch contents were19.22%and21.22%respectively. The reducing sugar contents of these2lines were 0.022%and0.045%respectively. Therefore, they were good materials for breedingvarieties of starch-processing, fried food and fresh food.6. The correlation analysis showed that the yield per plant of hybrid clones wassignificantly positively related to growth period, plant height, tuber number per plant andcommercial tuber rate. Mean tuber weight was significantly positively related to rate ofcommercial tuber. The tuber number per plant was significantly negatively correlated withmean tuber weight. The starch content was significantly positively related to dry mattercontent, and extremely significantly positively related to mean tuber weight andcommercial tuber rate.7. Four hybrid lines and their parents were amplified with3pairs of SSR primers(S7,S174and S184). There are totally201SSR bands were obtained, and the percentage ofpolymorphic loci was72.14%. SSR fingerprints of four excellent lines were established.8. The genetic distance among four hybrid lines and their parents was from0.2112to0.7222. With the GD value of0.39as threshold, seven potato materials could be clusteredinto four groups: the first group included ‘J07-2’,’J07-6’ and Line3-1, the second groupincluded Line2-1and Line4-4, the third group including ‘Longshu No.7’, the fourthgroup including Line19-3.