Abstract: The genetic diversity of 90 cucumber (Cucumis sativus L. ) accessions from different countries or regions was detected by RAPD analysis. The methods of establishing the cucumber core collection based on RAPD data were studied. Firstly, six core collectionswere individually established at different samp ling rate of 10% , 15% , 20% , 25% , 35% and 45% from the original collection. The various core collectionswere compared with the original collection in the number of polymorphic loci, number of lost loci and genetic diversity index. The results showed that 25% was more ideal for develop ing cucumber core collection in this study. Secondly, three sampling strategies ( random sampling method, maximal deviation method, and maximal genetic distance method) were compared. The result demonstrated that the strategy ofmaximal genetic distance was better than others in establishing cucumber core collection with RAPD data. Further, it was verified that the core collection developed according to the sampling rate and strategy determined above could well represent the original collection, but at the same time, the reserve collection could not be neglected in germplasm conservation and utilization.

Key words: Cucumber, Germplasm, Sampling rate, Sampling strategy, Core collection, RAPD marker