The endosperm culture technique can be used to boost the yield of agricultural
plants. Plant assembly with superior vegetative traits could be derived from the
triploid endosperm. This research aimed to produce callus from the Mountain
papaya endosperms with two Plant Growth Regulators (PGR) of BAP (0 ppm; 1.0
ppm and 3.0 ppm) and 2.4-D (0 ppm; 1.0; ppm; 2.0 ppm; 3.0 ppm; 4.0 ppm and
5.0 ppm). The Mountain papaya endosperms were taken as the explants which
then inoculated on Murashige and Skoog medium. Five explants were planted in
each bottle and cultured in a dark room (24-hour photoperiodism) for 56 days.
The stage of explant growth till callus formation was observed every day and at
the end of the observation, the percentage of each stage of growth was calculated.
Finally, the results showed that the application of PGR could stimulate callus
growth. However, the variety of callus in this research was not stimulated by the
concentration of the experimented PGR. The identification of endosperm callus
needs to be reviewed so that these triploid Mountain papaya plants can be further
explored.