Abstract:
Exacum ritigalensis has a high potential to be introduced as a floricultural plant to the floriculture industry
of Sri Lanka. In this regard, improvements of its morphological characters through genetic modifications
are important Spraying colchicine is one of the methods which can be applied to plant to alter plant
morphology. This study was conducted to find the effect of spraying different colchicine concentrations on
flower buds of E. ritigalensis. The flower buds at the same reproductive stage were treated with a drop
(lm l) of the colchicine solutions (0, 30, 60, 90 and lZOmgL1). Treated plants kept under the green house
without wetting stem and bud from other liquids. Water was applied regularly to soil. Experiment was
arranged according to the Completely Randomized Design (CRD) with five replicates per each treatment.
Observations on flower diameter (cm), color of the flower (deviation from natural colour; light, normal
and dark), days to flowering and seeds weight per pod (g) of plants were recorded. Statistical analysis was
performed with Duncan's multiple range test using SAS software (version 9.1.3) and Wilcoxon sign rank
test using SPSS statistics package (version 20). Results revealed that the spraying of colchicines on flower
buds did not have effect on flower diameter and days to flowering. But colchicine concentration lZOmgL'1
resulted in lighter colour of flowers compared to control but produced no seeds in pods.
