| In this paper, based on morphological mark and ISSR, the sweet potato genetic diversity was analysed by using 34 varieties as materials, one from Peru, one from America, nine from Japan and twenty-one from China. The results are as follows:1. According to the character of sweet potato, we have found a better CTAB method for sweet potato DNA extraction.2.An optimized PCR reaction system for ISSR analysis was established: PCR was performed in a 20μl reaction.The temperature profile used for PCR was 94℃ for 5min,followed by 45 cycles of 94℃ for 45s, 50-55℃ for 1min30s, 72 ℃ for 1min30s,and was terminated with a 7min DNA extension step at 72℃.3. The total bands were 1663 and 401 DNA polymorphic bands amplified with 15 ISSR primers, 26.73 bands per primer in average.The polymorphic percentage is 24.11%.4.At the level of D=6.54, all the 34 varieties were clustered into two major groups(groupI and groupII) , including landraces, improved varieties and foreign varieties respectively. At the level of D=4.45 the groupI were clustered six subgroup(subgroupI1,I2,I3,I4,I5 and I6),and the groupII varieties were clustered into four subgroups(subgroupII1,II2,II3 and II4).5. At the level of D=0.34, the varieties were clustered into four group,there are groutI, groupII,groupIII and groupIV.At the level of D=0.29 ,the groupl was clusterd into six subgroup(subgroupI1,I2,I3,I4,I5 and I6).6. The correlation coefficence of morphological mark and ISSR is extremely low. |
