Confirmation and stability of population
On basis of this investigation, for the practical use of colchicine to induce polyploidy in O. basilicum, we recommended concentrations between 0.1 and 0.5% at the emergence of cotyledone leaves stage. Immediately after the treatment, the treated plants (C0 plants) were examined for presence of different morphological characteristics. Putative mixoploids was selected visually. On the basis of changes on some of the characteristics of plant (Figure 1) R. Omidbaigi et al. / International Journal of Plant Production (2010) 4(2): 87-98 93 the first leaves appearing after treatment, revealed that 123 plants, or 59% of survived plants, (of 500 treated seedlings at the emergence of cotyledone leave stage) were presumably polyploid with higher ploidy-level that they were selected as potential mixoploid for cytological examinations such as size of stomata and guard cells and stomata density per unit of leaf surface, chloroplast number in guard cells, pollen size and finally flow cytometry (FCM) analysis. These selected plants were transplanted into the field along with the diploid control and given optimal culture care. Among putative tetraploid plants, 12 plant (9% of mixoploid plants) confirmed to be autotetraploid whereas remaining were diploid and mixoploid. The seeds obtained from isolated pollination C0 tetraploid plants, was sown to order production of C1 population and production of enough tetraploid population.