a bigger seed. Many researchers have reported that
different concentrations of colchicine increase
the chromosome number in many plants causing
bigger flowers and bigger seeds. Henderson
(1977) reported for watermelon that double the
chromosome (4n) number caused thicker seed
coats and bigger seeds than in normal plants (2n).
Sinchai (1978) applied one drop of a colchicine
concentration at 0.2% on the mature cotyledon
of watermelon in the morning and one drop in
the evening over 10 d and reported an increase
in the number of tetraploid (4n) plants. Adaniya
and Shirai (2001) used a colchicine concentration
at 0.2% on the shoot tip of ginger and found the
highest percentage of tetraploid plants on day 8.
The objective of the current experiment
was to study the effect of colchicine on physic
nut plants, the occurrence of tetraploid plants and