Genetic diversity and genetic tendency of main Chinese sweetpotato cultivars.

Main sweetpotato cultivars released in different periods and different regions of China were assessed using ISSR and AFLP markers to understand their genetic diversity and tendency.17 ISSR primers and 10 AFLP primer pairs generated 410 and 203 polymorphic bands with average of 24.1 and 20.3 polymorphic bands per primer(pair),respectively.ISSR and AFLP markers both had high efficiency to analyze the genetic diversity of sweetpotato.High genetic similarity coefficients,ranging from 0.487 7 to 0.774 3 with average of 0.564 0,were shown among the tested cultivars.The UPGMA cluster analysis classified the 26 cultivars into two groups.The genetic diversity of cultivars from South area was higher than those from other areas.Low genetic differences among cultivars from North and Yangtzi River areas,and high genetic differences among those from South area and others were found.Genetic similarity coefficients were high among/between cultivars released in different periods in China.These results suggested that parents exchange between different areas should be strengthened in sweetpotato breeding in China.