MSc

The present investigation entitled "Regulation of sex in Garcinia
gummigutta (L.) Robs. through controlled pollination and top working" was
undertaken in the Department of Pomology and Floriculture, College of Horticulture,
Vellanikkara during 1999-2001. The trees maintained in the College Orchard and
Vegetable Research Farm were utilized for the study. The objectives of the study
included regulation of sex in G. gummigutta through controlled pollination,
conversion of sex through top working and regulation of flowering through cuItar
application. -
Cross pollination was found to be the mam mode of reproduction in
Garcinia. Fruit set did not occur by self pollination. Fertility of pollen in bisexual
flowers was very low (21.85%). A percentage fruit set of 35 and 60 was observed
under open pollinated and artificially cross pollinated conditions, respectively. Hand
pollination with pollen from male flowers could increase the fruit set compared to
open pollination. Artificially cross pollinated fruits were comparatively larger in size
than open pollinated fruits. Hand crossing or proximity to a polliniser increased fruit
size. Heavy fruit drop was observed in the absence of sufficient pollen source.
Apomictic fruit development also did not occur in kodampuli. These facts helped to
arrive at a conclusion that sufficient amount of pollen source should be present around
the female trees for good fruit set, increased fruit size and maximum fruit retention.
Therefore care should be taken to interplant male grafts, as pollinisers in an orchard of
grafts of kodampuli.
The dormancy' of the seeds of Garcinia could be overcome by sowing the
seeds after the removal of seed coat. Seeds without seed coat germinated in one
month whereas those with seed coat intact took one year for germination.
Seedlings raised by different modes of pollination did not show
morphological and physiochernical variations. Based on pigmentation viz., red, brown
and green, some differences were noticed in biochemical characters. Seedlings with
red flush colour showed a lower total phenol content when compared to green flushed

ones. Esterase and peroxidase banding pattern of the red flushed seedling was more
intense than green flushed ones. These characters of red flushed and green flushed
seedlings were comparable to that of mature female and male trees, respectively.
Morphological characters like leaf length, leaf width, number of leaves and height
were not found to be contributing towards sex expression. The seedlings have to be
established in the field and observed until flowering to verify any positive correlation
of biochemical characters and pigmentation with sex expression.
Seven per cent polyembryony was observed ill Garcinia. The
poly embryonic seeds in general produced twin seedlings, which had same
pigmentation or varied pigmentation. Variations were observed between the two
seedlings in morphological and biochemical characters. The multiple seedlings might
have originated from the cleavage of a single sexual embryo or from the sexual
embryos and pro embryos, which might have developed side by side after pollination
and fertilization.
Techniques tried for top working in Garcinia included bark grafting,
flush/cleft grafting and patch budding. Among these, bark grafting and flush/cleft
grafting were successful. Beheading was done during April and grafting was carried
out from June to October.
Two months old sprouts from the beheaded trees were considered best for
flush grafting. Matured orthotropic shoots light brown in colour and 6 to 8 months old
were the best as scion, which showed highest percentage of success.
Grafting done during July and October gave highest percentage of success.
Presence of moisture around the grafted shoot played an important role in graft
success. Percentage of graft success was 71 in bark grafts and 75 in flush grafts. The
growth rate of bark grafted and flush grafted scions were almost similar. The top
worked shoots attained on an average, a height of 117 cm and spread of 75 cm with
27 branches and profuse foliage in one year. Through this study the possibility of
transforming male kodampuli trees to productive females is revealed.

Cultar was drenched @ 3m1 and 5ml per m2 canopy diameter or spread,
60, 75 and 90 days before the expected date of flowering. The treatment with 5m1
cultar per m2 canopy diameter applied 90 days before flowering showed 20 days early
blooming followed by 5m1 cuI tar per m2 applied 75 days before flowering which
advanced flowering by 10 days. Three m1 cultar per m2 was not sufficient enough to
induce flowering in Garcinia.
Maximum fruit set of 75 per cent was observed with cultar @ 5 m1 per m2
canopy spread, applied 90 days before expected date of flowering. Cultar treatment
neither impaired nor improved any of the fruit quality attributes.