中国甘薯主要育成品种的遗传多样性及遗传趋势

Genetic Diversity and Genetic Tendency of Main Chinese Sweetpotato Cultivars

用ISSR和AFLP分子标记手段，对中国不同时期不同甘薯种植区的26份主要育成品种进行遗传多样性和遗传趋势分析，结果表明：①17条ISSR引物共扩增出410条多态性谱带，平均每条引物扩增24．1条多态性谱带，10对AFLP引物共扩增出203条多态性谱带，平均每对引物组合扩增20．3条多态性谱带，2种标记均具有较高的分辨力，可以用于甘薯品种的遗传多样性分析。②甘薯主要育成品种的遗传相似系数为0．4877～0．7743，平均0．5640，表明中国甘薯主要育成品种的遗传多样性程度低，遗传相似程度高，遗传基础狭窄。通过UPGMA聚类分析，26份品种在遗传相似系数为0．55处可分为2类。③南方薯区主要育成品种的遗传多样性和遗传差异高于长江中下游薯区和北方薯区，北方薯区和长江中下游薯区主要育成品种之间的遗传差异较小，但与南方薯区主要育成品种之间的遗传差异较大。④1990年前甘薯主要育成品种的遗传相似程度高，1990年后育成品种的遗传相似程度依然很高，遗传多样性程度没有明显改变。因此，在未来甘薯遗传改良中，可以通过加强不同薯区育种亲本的交换，逐步改变目前中国育成品种遗传基础狭窄的局面。

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 cuhivars into two groups. The genetic diversity of cultivars from South area was higher than those from other areas. Low genetic differences among cuhivars 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 euhivars released in different periods in China. These results suggested that parents exchange between different areas should be strengthened in sweetpotato breeding in China.