The objective of this study aimed to evaluate the genetic variation in physic nut (Jatropha curcas L.)
by colchicine induction in two experiments. In Experiment 1, inflorescences of physic nut were treated under
different colchicine concentrations by dropping the solution directly at the stage that the frequency of male
flower at microspore stage. In Experiment 2, seeds were soaked in different concentrations of colchicine at
various durations.
In Experiment 1 and 2, the results showed that the increasing of colchicine concentration likely to
decreased size of guard cells, plant height and stomatal density. However, significant different among those
parameters was not observed. The ploidy level determined from leaf cells of plants by flow cytometry in both
experiments showed almost of plants were disomic (2x). However, in experiment 1, incomplete aneuploidy
or mixoploid plants that mixing between trisomic (2x + 1) (at 0 mM colchicine) and tetrasomic (2x + 2)
(at 2.5 mM colchicine) with disomic were also found. In experiment 2, incomplete aneuploid plants were
composed of trisomic, tetrasomic and pentasomic (2x + 3) with disomic. The mixoploid plant of disomic,
trisomic and hexasomic (2x + 4) was also detected when concentrations of colchicine and times for soaking
duration were increased.