MSc

The experiment on varietal evaluation and compatibility studies in sapota
(Manilkara achras (Mill.) Fosberg) was carried out in the trees maintained in the orchard,
Department of Pomology and Floriculture, College of Horticulture, Vellanikkara.Height
of the tree was maximum in Cricket Ball and minimum in Local. Maximum girth, canopy
spread, volume of the tree was recorded in Cricket Ball. Number of flushes per metre
square, number of leaves per flush, girth of the shoot was maximum in Cricket Ball.
Length of the flush was maximum in Oval. Total duration of flushing was maximum in
Oval and Cricket Ball. There were two main seasons of flushing May- July and
September - October. PKM-l, Co-2 and Cricket Ball were early in flushing. Mean
monthly extension of growth of the shoots and percentage of shoots flowered was
maximum in June followed by October for all the varieties. Percentage of shoots
flowered was maximum in Cricket Ball. Oval and PKM-l were early flowering in nature,
maximum percentage of shoots flowered were in north orientation of tree. Maximum
number of inflorescence per metre square was recorded in PKM-l and Cricket Ball.
Number of flowers per inflorescence was maximum in Cricket Ball. Minimum number of
days taken for complete opening of an inflorescence was recorded in Oval.
Peak anthesis period occurred between 7.00 a.m. to 7.30 a.m.and anther
dehiscence was on the day before anthesis. Maximum stigma receptivity was found at
time of anthesis. Maximum pollen fertility was recorded in Cricket Ball and PKM-l.
Diameter of viable pollen was maximum in Gavarayya. Maximum pollen germination
.
and pollen tube length was recorded in sucrose 15 per cent +agar 0.5 per cent +boric acid
100 ml -1+ calcium nitrate 0.03 per cent medium. Maximum pollen germination
percentage and longest pollen tube length was recorded in Co-2 and maximum pollen
tube elongation was recorded in Cricket Ball. Maximum pollen production per anther was
in Cricket Ball. Maximum pollen germination and pollen tube elongation occurred at 9
hours after incubation. Flower bud drop was maximum in Oval. Maximum fruit set
percentage and minimum number of days taken from pollination to fruit set recorded in
the variety PKM-l. Maximum percentage of fruit drop occurred in Cricket Ball in one

month after fruit set. Maximum fruits were retained in PKM-l. Maximum fruit weight,
girth, volume, specific gravity, number of seeds per fruit, seed weight per fruit, seed
length were recorded in Cricket Ball. Fruit length, pulp: seed ratio, seed breadth was
maximum in Oval. TSS, non-reducing sugars, total sugars, and sugar: acid ratio were
maximum in PKM-l, while reducing sugar, acidity was maximum in Co-2. Number of
days taken for maturity depends on the season and heat unit requirement. Co-2 required
more number of days for maturity while PKM-l recorded minimum number of days for
maturity. Heat unit requirement was maximum for the variety Co-2 followed by Cricket
Ball and Oval. Maximum fruit yield was obtained in second season crop. PKM-l
recorded high yield in terms of number of fruits and fruit weight.
Selfing the varieties resulted very poor fruit set, while intervarietal cross
pollinations resulted in maximum fruit set in Co-2 X Gavarayya and Cricket Ball X Co-2.
Maximum fruit drop occurred in Cricket Ball X Co-2. Fruit weight, volume and specific
gravity were maximum in Cricket Ball X Co-2, fruit length in Oval X Gavarayya, fruit
girth in Co-2 X Cricket Ball, pulp: seed ratio in Oval X Co-2. TSS was maximum in
PKM-l X Gavarayya, reducing sugar in Gavarayya X Oval, non reducing sugar in
Cricket Ball X Gavarayya, total sugar and sugar: acid ratio in Cricket Ball X Oval,
acidity in Co-2 X Cricket Ball cross combinations. Number of days taken for maturity
was minimum in Local x PKM-l and maximum in Co-2 X Cricket Ball and Cricket Ball
X Co-2. Maximum seed weight per fruit was recorded in Cricket Ball X Gavarayya,
number of seeds per fruit in Cricket ball X Oval, length of seed in Cricket Ball X Co-2,
Cricket Ball X Oval, breadth of seed in Gavarayya X Local and Gavarayya X Cricket
Ball. Seed germination percentage was maximum in Oval x Co-2 and number of days
taken for seed germination was minimum in Local X PKN1-l. Co-2 X PKM-l, Co-2 X
Local, Cricket Ball X PKM-l, Cricket Ball X Local, Oval X Cricket Ball, Oval X Local,
Local X Co-2, Local X Cricket Ball, Local X Oval were found to be cross incompatible
combinations. Pollination after removing the stigma and pollinating with in vitro basal
medium, pollination with application of NAA 5 mg 1 -I, 2,4-D-O.5 mg 1, pollination with
gamma rays irradiated (40Gy, 50Gy and 75 Gy) pollen resulted in fruit set in
incompatible varieties.

Tree volume, fruit weight, fruit volume, number of fruits per tree recorded high
GCV and PCV (GCV ranged between 48.77 to 104.18 per cent while, PCV ranged
between 48.72 to 108.52 per cent). Characters like fruit volume, fruit girth, weight, seed
weight per fruit, tree girth recorded high heritability. Genetic advance recorded for the
characters showed wide variation ranging between 0.23 to 119.04 per cent. Maximum
genetic advance was observed for fruit weight followed by fruit volume. The vegetative
characters showing high positive correlation with fruit yield were tree height, tree girth
while flowering characters were number of inflorescence per metre square, number of
flowers per inflorescence and fruit characters were fruit set percentage, fruit weight and
fruit girth and fruit volume. Maximum correlation was observed between fruit set and
number of fruits per tree (rg=1.005) and hence the yield (rg = 0.463). Number of fruits
per tree was highly correlated with fruit set (rg = 1.005) and rp = 0.902) followed by
number of inflorescence per unit area (rg = 0.455 and rp = 0.423).