DIRECT PLANT-REGENERATION FROM LEAF EXPLANTS IN CUCUMBER (CUCUMIS-SATIVUS L) IS FREE OF STABLE GENETIC-VARIATION

A new procedure is described for rapid and efficient plant regeneration from leaf explants of Cucumis sativus and C. anguria. The following factors were most important: young leaves, the NO3:NH4 ratio in the plant induction medium, small explants and the growth regulator combination. After about 4 weeks of culture under optimal growth conditions, the frequency of regeneration was 10-100% of explants. Six to 7 weeks were required to obtain well-rooted plants, which were mostly able to survive after transfer into soil. From a single young leaf of C. sativus cv. 'Borszczagowski', 135 plants could be regenerated. All plants transferred to a greenhouse were free of morphological or physiological abnormalities, flowered normally and bore fruits. The analysis of R(0) plants showed no genetic variation, whereas in the R, two new phenotypes, which were not transmittable to the R(2), were observed. This procedure is recommended for its production of homogeneous cucumber plants.