Abstract: Hairy roots were obtained in vitro 10 days after inoculation of cucumber ( Cucumis sativus L. ) cotyledon explants with the strains of Agrobacterium rhiwgenes R1000 and R1601. The frequency of the cotyledon explants transformed by R1000 and R1601 was up to 87.5% and 88.9%, respectively. All hairy roots induced by the strains of R1000 and R1601 grew rapidly on solid hormone-free MS medium. The roots incited by A. rhizogenes R1000 could be divided into three phenotypes. The roots of phenotype Ⅰ were similar to the normal ones, but had more numerous lateral roots. Roots of phenotype m were much stouter and shorter, they elongated very slowly and were more highly branched than roots of phenotype Ⅰ . Roots of phenotype Ⅱ were of intermediate in appearance. However, the roots incited by A. rhizogenes R1601 appeared similar to phenotype Ⅰ roots incited by A. rhizogenes R1000. Transformation was confirmed by opine detection.

Key words: Agrobacterium rhizogenes, Cucumis sativus, Hairy root, Opines