新疆桑属植物栽培居群的遗传多样性研究

应用RAPD分子标记对新疆不同地区栽培的桑属植物2种3个分类群共11个居群进行了遗传多样性研究。结果表明，新疆桑属栽培植物中虽然存在较为丰富的遗传多样性，多态位点比率(PPB)为87．39％，Shannon多样性指数为0．3997，但在栽培居群内的遗传变异水平相对较低；在不同居群间遗传变异水平仔住很人差异，各居群的多态位点比率(PPB)为4．5％至45．95％，Shannon多样性指数为0．0312至0．2339；白桑(Morus alba L．)及其变种鞑靼桑(Morus alba L．var．tatarica)居群内的遗传变异水平远高于黑桑种(Morus nigra)。新疆桑属植物栽培居群内较低的遗传变异水平与其采用扦插等无性繁殖方式有关。分析全部的遗传变异显示，11个栽培居群之间的基因分化系数(Gst)为0．3541，其中桑及其变种9个居群间的基因分化系数为0．4597，黑桑种2个居群问的基因分化系数为0．4728。AMOVA分析表明，在全部遗传变异中，黑桑种和白桑种2个物种之间的遗传变异占59．16％，居群间遗传变异为17．46％。遗传距离和聚类分析也表明，黑桑种和白桑种及其变种鞑靼桑之间存在很大的遗传分化。

Genetic Diversity of Populations of Morus Cultivated in Xinjiang,China

The random amplified polymorphic DNA (RAPD) was uesed to examine 11 populations of Morus alba Linn. and Morus nigra Linn. cultivated in Xinjiang. 87.39% total scorable markers were polymorphic and Shannon's Information index (I) was 0.399 7 at genus level. However, the variations of inter-population were considerably lower and different among populations, with PPB ranging from 4.5% to (45.95)% and I ranging from 0.031 2 to 0.233 9. The variations of inter-population were higher in M. alba than that in M. nigra. The considerably lower inter-population variation in cultivated populations of Xinjiang might caused by the way of vegetative reproduction. The Gst showed 35.41% genetic variation among 11 populations of Morus cultivated in Xinjiang, 45.97% among 9 populations of M. alba and 47.28% among 2 populations of M. nigra. AMOVA showed 59.16% genetic variation between two species, 17.46% between different populations. Genetic distance and cluster analysis indicated that the cultivated populations of M. alba and that of M. nigra had large genetic difference.