Abstract:
Globally, bitter gourd (Momordica charantia L.) cultivation largely depends on F1
hybrid seeds to ensure high yield and uniformity. The gynoecious sex form, which
produces only female flowers, plays a vital role in hybrid seed production; however, its
commercial application is constrained by the lack of cost-effective methods for
maintaining gynoecious lines, as self-pollination is not possible. Bitter gourd is a
monoecious vine exhibiting a protandrous flowering pattem, where male flowers
appear earlier than female flowers, leading to an imbalanced sex ratio and low
productivity. Developing gynoecious varieties is considered the most effective strategy
to increase yield, but seed production in these lines poses a significant challenge. Sex
expression in bitter gourd is influenced by genetic and environmental factors, including
nutrient levels and phytohormones such as ethylene and gibberellic acid (GA3). While
ethylene promotes femaleness, GA3 favors maleness. Silver nitrate (AgNO3 ), an
ethylene inhibitor, has been used to manipulate sex expression. This study evaluated
the effects of AgNO3 and GA3 on the induction of hermaphrodite and female flowers
in gynoecious bitter gourd. The experiment was conducted in a poll.tunnel at Onesh
Agri (Pvt) Ltd, Giriulla, Sri Lanka, using the gynoecious line BG 043. Eleven
treatments, including combinations of AgNO3 and GA3, were tested under a
Completely Randomized Design (CRD) with three replications. Reproductive traits
were monitored throughout flowering. Results revealed that AgNO:, especially at 600
ppm & 1200 ppm, was most effective in inducing hermaphrodite flowers with
consistent flowering patterns, while GA3 promoted female flowers without sex
reversion. The earliest appearance of hermaphrodite flowers occurred approximately
12 days after spraying. These findings confirm that silver nitrate can be effectively used
for sex modification in breeding programs. Futwe studies should extend observations
to seed development to assess the viability of hermaphrodite-induced flowers and
evaluate the potential of adopting this technique in commercial hybrid breeding.
