MSc

The experiments on "Selection index and activation of seedling growth
in Mangosteen (Garcinia mangostana L.) were conducted in the central orchard
attached to the Department of Pomology and Floriculture of the College of
Horticulture from March 2000 to February 2002 with the broad aims of
standardizing selection indices as well as activation of the seedling growth in
mangosteen. Two separate experiments, one approach envisaging growth
regulators and the .other involving arbuscular mycorrhizal fungi (Glomus mosseae
and Glomus fasciculatum and Azospirillum with single super phosphate were taken
up. The important results are as follows.
Analysis of leaf biochemical characters of the mother plants belonging
to different age groups «25, 25-50, 51-75 and >75 years) revealed that nitrogen,
phosphorus, potassium and crude protein, were highest in the lowest «25 years)
age group and least values were in the highest (>75 years) age group, except
sodium, total phenols and total carbohydrates, which were maximum in the age
group of 51-75 years.
The number of seedless fruits and almost all the morphological
characters of the fruit were highest in the age group of 51-75 years. Number of one
seeded, two seeded and three and more than three seeded fruits were also varying
among the four age groups.
All seed morphological characters and number of ungerrninated seeds
showed maximum values in the age group of 51-75 years and >75 years. Seeds
obtained from the age group of 51-75 years showed earliness in germination but
the percentage of germination was highest in the age group of 25-50 years.
The biochemical characters of seed revealed that nitrogen, phosphorus,
potassium, crude protein, total carbohydrates, total sugar and total phenols were
maximum in the age group of25-50 years, whereas sodium and abscisic acid were
highest in the age groups of less than 25 and more than 75 years, respectively.
The morphological characters of seedling such as, height, girth, total
number of leaves per seedling, total leaf area, survival rate at twelve months stage
and root characters were highest in 25-50 years age group whereas the root and
shoot dry weight were maximum in the less than 25 years group.









Nitrogen, phosphorus, potassium, crude protein and sodium levels in
the leaves of the seedling were highest in the age group of less than 25 years.
Chlorophyll a, b, total phenols, total carbohydrates and abscisic acid contents were
higher in the age group of 25-50 years.
Maximum fruit index was observed in the age group of 51-75 years but
seed and seedling index were highest in 25-50 years age group.
Most of the seed characters were positively correlated with seedling
characters. Though all the fruit characters were positively correlated with seed
characters they were negatively correlated with seedling characters.
Fruit index, seed index and seedling index were separately predicted
using the prediction models fitted by multiple regression equations of principle
components one and two with corresponding adjusted R2 values.
Dominant characters among the age of mother plant, fruit, seed and
seedling characters separately were found out by figurative plot principal
component analysis based on morphological data of the above characters
individually.
Using step wise regression major characters contributing to seedling
index were identified as age of the mother plant, seed thickness at centre, total leaf
area, survival rate, fresh weight of root and plant, root length and total number of
roots, which contributed maximum variation to seedling morphological characters
and prediction model for fruit index, seed index and seedling index were fitted.
To establish the similarities (or dissimilarities) between the four age
groups, hierarchical cluster analysis using euclidean distance was performed which
revealed that the younger two age groups (less than 25 years and 25-50 years) of
the mother plants were the closest groups with respect to all characters.
The four using discriminant functions were fitted to discriminate the
four age groups with corresponding D2 values. The criteria and criterion were
determined to describe the age groups of selected fruit, seed and seedlings
collectively.
By giving equal importance to age of the mother plant, fruit index, seed
index and seedling index the selection index was worked out and the best age
group of the mother plant for obtaining maximum growth of seedlings was
identified as 25-50 years. Based on the correlations between various characters and




growth index, the above or below average values with respect to each of the
attribute (important and visual) belonging to the fruit, seed and seedling characters
were identified. The mid values of the each attribute in the best age group were
fixed as the index for selection.
Among the growth regulator sprays for activating the slow growth in
mangosteen, the best treatments were GA 150 mg r' followed by IAA 250 mg r'.
Biochemical studies on the growth regulators treated plants revealed
that the treatment that showed maximum growth also recorded the highest values
of nitrogen, phosphorus, potassium, crude protein, chlorophyll a, b, total
chlorophyll, total phenols, total carbohydrates and abscisic acid content. The
treatment, which showed intermediate growth recorded intermediate values except
for sodium, where it was maximum. The least content was observed in the
treatments with least growth. The control plant showed intermediate values
between the. values of plant with intermediate and least growth.
Best treatment for activating the seedling growth among the treatments
with arbuscular mycorrhizal fungi and Azospirillum inoculations were identified
as, the combinations of Glomus Jasciculatum 5 g + Azospirillum 109 + single
super phosphate 109 followed by GlomusJasciculatum 5 g + Azospirillum 20 g +
single super phosphate 109.
A rhythmic pattern was observed with the treatments showing best
seedling growth also recording higher values of nitrogen, phosphorus, potassium,
crude protein, chlorophyll a, b, total chlorophyll, total phenol total carbohydrates
and the abscisic acid content, and the treatments showing in intermediate growth
recording intermediate values except sodium. The least values were in treatments
that showed least growth. The control plant showed intermediate values between
the values of the plant with intermediately and least growth.
The highest spore count was observed in the plants inoculated with
Glomus Jasciculatum 20g + single super phosphate 109 followed by Glomus
Jasciculatum20 g + Azospirillum 20 g + single super phosphate 10 g. With regard
to the root infection, plants inoculated with Glomus Jasciculatum 5 g +
Azospirillum 20 g + single super phosphate 109. and Glomus Jasciculatum 20 g +
Azospirillum 109 + single super phosphate 109 revealed maximum percentage of
infection. The Azospirillum population was maximum in the plants inoculated




Glomus fasciculatum 5 g + Azospirillum 109 + followed by Glomus mosseae 20 g
+ Azospirillum 20 g + single super phosphate 109.
The standard procedure for identification and quantification of abscisic
acid (Little et al., 1972) was modified, as clear banding patterns were not obtained.
Using the modified procedure, the characteristic-banding pattern corresponding to
standard abscisic acid was obtained and confirmed when standards of abscisic acid
were also simultaneously run with samples.
Banding patterns and quantification of samples in each of the four age
groups, the growth regulator treatments and the treatment with arbuscular
mycorrhizal fungi and Azospirillum inoculated plants were also successfully
conducted.