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Ph.D Title: Studies on
morphological and molecular characterization and
conservation of mango germplasm (2010)
C.Vasugi,
Annamali University, Chidambaram,
Guide:
Dr. M.R.Dinesh
Studies on morphological and
molecular characterization and conservation of mango
germplasm were carried out in the Department of
Horticulture, Faculty of Agriculture, Annamalai
University, during December, 2005 to December, 2009.
Four systematic experiments were carried out to
characterize the variability; to assess the genetic
diversity; to evaluate for fruit and pickling characters
and to study the effect of cryopreserved pollen.
Characterization of 43 accessions maintained in the
field gene bank of Indian Institute of Horticultural
Research based on IPGRI (Biodiversity International)
mango descriptor reveled wide variability for leaf,
fruit, flower, inflorescence, pulp and stone characters.
Genetic divergence and cluster analysis based on both
phenotypic and molecular markers were carried out.
Accessions were grouped based on
similarity/dissimilarity index. Principal Component
Analysis (PCA) indicated that fruit descriptors
contributed more towards divergence. Cryopreserved
pollen was found to be as good as fresh pollen in the
inter-specific and inter-varietal crosses. Comparative
evaluation of pickling accessions with the commercial
and polyembryonic varieties revealed that Dantimamidi
and Kovesara possessed good quality characters and was
on par with the commercial varieties used in the study.
Based on the evaluation of tender mango pickle quality,
Chansi Appe, Dodderi Jeerige, Mani Bhatta Appe, Gorana
Appe, isagoor Appe, Malange, Dantimamidi, Gurumurty Appe
and Kashimidi were identified as good pickling
accessions. Possible gene donors for specific traits
like attractive skin colour, pulp colour, fruit weight,
pulp per cent and TSS was also observed. The
morphological characterization data generated in the
present study was used to develop a Mango Information
System to run on Windows Operating System for ready
retrieval and visual comparison.
M.Sc. Title: Assessment of some
cultivars of mango (Mangifera
indica L.) for vegetative and fruit characters
(1985)
M.C.Subbaiah,
UAS, Bangalore,
Guide: Dr. C.P.A.Iyer
Observations were taken on 42
cultivars of mango collected from all over the country
on various characters including vegetative growth,
flowering and fruit characters, to obtain information on
the extent of variability and also to help in selection
of cultivars for specific purposes. The data were taken
on seven year old trees. Wide variability was observed
for number of growth flushes, length of shoots put
forward in a year, time of flowering, length of
panicles, initial fruit set, fruit number per panicle
and date of harvest. The number of fruits per tree
ranged from 5.0 in Langra to 247.5 in Pacharisi. In
terms of fruit number. Chandrhkaran, Gola, Himayat
pasand, Hyder Sahebi, Kallapadi, Kasturimamidi, Lazat
Baksh, Neelum, Pacharisi, Padiri and Panakalu were found
to be promising. In terms of fruit weight, Amini, Hyder
Sahebi, Kallapadi, Kasturimamidi, Lazat Baksh, Neelum,
Pacharisi, Padiri and Panakalu were found to be
promsing. The weight of the fruit was found vary from 63
g in Chandrhkaran to 647g in Amini. The percentage of
pulp in a fruit ranged from 39.7 (Chandrhkaran) to 74.1
(Fazli). It was found that the cultivars Fazli, Himayat
Pasand, Kallapadi, Padiri and Panakalu yielded maximum
pulp per tree. The pulp : skin + stone ratio (edible to
non-edible portion) was found to range from 0.65:1 in
Chandrhkaran to 2.86:1 in Fazli. The total soluble
ranged from 12.8º in cultivar Amini to 29.2º in cultivar
Chandrhkaran. The acidity was found to be the least in
cultivars Banganapalli, Imam Pasand, Lazath Baksh and
Peddarasam (0.06%), whereas it was maximum in cultivar
Suvarnarekha (0.65%). The total sugar content was found
to range from 8.03 in Fazli to 20.41 percent in Rataul.
Panakalu (17.63%), Amarapalli (17.24%), Langra (15.78%),
Kallapadi (15.75%) and Dashehari (15.50%) also had high
total sugar content. The sugar: acid ratio was found to
range from 16.66:1 in Mohammada Vikarabad to 270.66:1 in
Rataul. Cultivars Lazath Baksh (257.3:1) and Rataul
(270.6:1) recorded high ratio.
M.Sc. Title: Irrigation and
fertigation studies in high-density mango (Mangifera
indica L.) (2002)
Hanamanth.Y.Asangi, UAS,
Bangalore,
Guide:
Dr. K.Srinivas
The investigation on Irrigation
and fertigation studies in high-density mango (Mangifera indica L.) var. “Arka Anmol” was carried out at Indian
Institute of Horticultural Research, Bangalore during
the year 2001-2002. Seven year old mango plants of Arka
Anmol was grafted and dwarfing rootstock Vellaikulamban
and planted at a spacing of 5 m x 5 m, gives a plant
density of 400 plants per hectare. The mango plants were
subjected to two levels of irrigation (40% and 80%
evaporation replenishment rate) and three level of
fertigations (100%, 75% and 50% recommended dose of
fertilizer) applied through drip irrigation system.
Fruit yield (9.50 t/ha.), number of fruits per plant
(99.92) and fruit volume (259 cc) were higher with 80%
of evaporation replenishment rate as compared to 40% of
evaporation replenishment rate {(fruit yield (7.06
t/ha.) number of fruits per plant (63.58), and fruit
volume (232.20 cc)}. The higher fruit yield (10.65
t/ha.) and number of fruits per plant (97.88) at 100%
recommended dose of fertilizer, fruit yield (7.92
t/ha.), number of fruits per plant (64.38) were lower
under 50% recommended dose of fertilizer. However, the
interaction effect of 80% evaporation replenishment rate
and 100% of recommended dose of fertilizer reported
highest fruit yield (12.50 t/ha.), number of fruits per
plant 9113) as compared to other interactions. The
acidity (0.40%), peel weight (48.42 g), pulp weight
(178.89 g), stone weight (38.05 g), peel to pulp ratio
(3.84) and pulp to stone ratio (3.63) were higher at 80%
evaporation replenishment rate as compared to 40% of
evaporation replenishment rate. Whereas, higher TSS was
reported at 40% of evaporation replenishment rate (18.58
oBrix). Similarly, TSS (18.20
ᴼBrix),
peel weight (48.18 g), pulp weight (182.83 g), stone
weight (49.06 g), peel to pulp ratio (3.84) and pulp to
stone ratio (3.63) were higher at 100% RDF as compared
to 50% of RDF.
M.Sc. Title : Studies on nursery
and propagation techniques in polyembryonic rootstocks
of mango (Mangifera
indica L.) (2002)
Venkata Rao, UAS, Bangalore,
Guide : Dr. Y.T.N.Reddy
The investigation on “Studies on
nursery and propagation techniques in polyembryonic
rootstocks of mango (Mangifera
indica L.)” was carried out at the Indian Institute
of Horticultural Research, Hessaraghatta, Bangalore-89
during the period 2001-2002. Fourteen polyembryonic
varieties along with one monoembryonic Alphonso studied
for seedling attributes related to germination, growth
and vigour. Earliest germination was noticed in Muvandan
and whereas the maximum germination percent and rate of
germination was in Muvandan and Olour respectively. With
regard to seedling growth characters like, seedling
height, number of leaves and leaf area was maximum in
Alphonso. In osmopriming treatments, the variety
Alphonso recorded the maximum seedling height, girth,
number of leaves and leaf area in treatment GA3 at 100
ppm concentration. Bark and stem percent was maximum in
varieties Vellaikolumban and Bappakai in treatment GA3
at 100 ppm concentration. In media and biofertilizer
experiment, the seedling height, girth and number of
leaves were maximum in variety Alphonso and Muvandan in
treatment comprising of potting mixture (1:2:1
proportion) + cocopeat + VAM. The bark inverted variety
Olour recorded the minimum graft height and sprout
length whereas the seedling girth was maximum in variety
Alphonso where bark inversion was carried out. Thus
based on the different seedling growth and vigour
characters, the monoembryonic varieties Alphonso,
Totapuri and polyembryonic varieties Muvandan, Bappakai,
E.C-95862 and Mylepelian were highly vigorous, whereas
Kurukkan, Nekkare, Chandrakaran, Olour, Peach and
Kensington varieties as vigorous and the Kitchner,
Starch, Prior and Vellaikolumban varieties could be
placed under less vigorous group.
DIVISION OF POST-HARVEST TECHNOLOGY
Ph.D Title: Mineral composition
and anatomical changes in Alphonso mango during storage
with reference to internal breakdown (1992)
K.Haribabu,
UAS, Bangalore,
Guide: Dr. Shantha Krishnamurthy
The
investigations were made on (i) Physico-chemical
changes, mineral composition, histological and
histochemical changes, during growth, development,
storage and ripening and (ii) the effect of pre-harvest
spray and post harvest spray and post harvest
infiltration with calcium chloride on the above
mentioned changes and also on the occurrence of internal
breakdown (spongy tissue) in Alphonso mango. Fruit
length, diameter, weight of fruit, pulp and peel
increased gradually up to 45 days, followed by a sudden
increase to maximum of 90days and pre harvest spray of
calcium at 5000 and 10000 ppm significantly enhanced
this increase. The effect of post harvest calcium
infiltration was more prounced in delaying ripening,
reducing the weight loss and firmness, increase of peel
colour, pulp colour (carotenoids), sugars and decrease
of acidity during storage as compared to pre harvest
sprays. Analysis of calcium (Ca), Potassium (K), Sodium
(Na) and Phosphorus (P) during growth and development,
in general indicated reduction in the concentrations
from 15 days to 90days after fruit set both in the peel
in the pulp. The distribution of minerals in 6 different
pulp tissues during ripening indicated that Ca content
was maximum in the basal pulp portion as compared to
middle and apical parts. The distribution of minerals in
6 different pulp tissues during ripening indicated that
Ca content was maximum in the basal pulp portion as
compared to middle and apical parts. Further, the pulp
towards the peel showed more Ca than in the pulp towards
endocarp. In case of K & P, it was more in the pulp
nearer to endocarp and no change was seen from base to
apical portion of the pulp. Spongy tissue affected pulp
showed low Ca (19.25 mg), high K (726 mg), P (135.6 mg)
& Na (45 mg) as compared to 41.8 mg Ca, 501 mg K, 85 mg
P & 37 mg Na in the healthy tissue. Both the pre & post
harvest Ca treatments had no effect on spongy tissue
development. Histochemical studies indicated the
appearance of starch granules after 60 days of fruit set
in all the tissues of the fruit & maximum accumulation
was found after 90 days of fruit set. In pre harvest
sprays of Ca, the cell of the fruit were bigger in size
with more starch grains & degradation of these grains
was delayed during ripening. Ripening process was
initiated in mesocarp region. Development of spongy
tissue was found in pulp near endocarp. The cells in
this were small, globular & thick walled with numerous
starch grains.
M.Sc. Title: Studies on storage
of mango (Mangifera indica) (1983)
C.M.Kala, UAS, Bangalore,
Guide:
Dr. Shantha Krishnamurthy
An investigation on the effect
of using skin coating waxol, in combination with heat
treatment and fungicides on ripening and keeping quality
of the important cultivar ‘Alphonso’ mango was made. The
experiment had 10 treatments with replicates for each
treatment. The effects of treatments on physicochemical
changes, ripening and spoilage were observed during a
storage period of 20 days. Post harvest hot water
treatment of Alphonso mango at 52+ 1 ºC for 5 minutes
resulted in hastening of ripening process, reduced
spoilage and development of uniform orange surface
colour of the fruit. The use of Benlate at 500 ppm
reduced the spoilage and the extent of reduction was on
par with hot water treatment. Further reduction of
spoilage by combination of hot water and fungicides
(Benlate and T.B.Z. at 500 ppm) was not evident. Waxol
treatment retarded ripening by 5 days as compared to the
control, and retained freshness of the fruit up to 20
days of storage. Waxol treatment combined with (i) hot
water alone and (ii) with fungicides Benlate and T.B.Z.
at 500 ppm were the best, with reference to the quality
of ripe fruits and control of spoilage after 20 days of
storage at ambient conditions. Organoleptic quality of
the fruit was not affected by post harvest treatment.
M.Sc. Title: Studies on
packaging of mango (Mangifera indica L.) (1985)
V.R.Prasad.S, UAS, Bangalore,
Guide : Dr.Shantha Krishnamurthy
An investigation to compare the
effect of combination of post harvest dip treatments
with waxol (3%) and hot water with waxol, with or
without wrapping in tissue paper and polyethylene film
on physic-chemical changes and keeping quality of
Alphonso mangoes during storage at room temperature was
made. It was observed that combination treatment of hot
water alone followed with wrapping in polyethylene
(HDPE) delayed ripening as compared to the unwrapped
fruit of the corresponding treatment. Weight loss was
reduced by more than 50% in the wrapped fruits. Spoilage
was high (20%) in polyethylene wrapped fruits. Wrappers
had to be removed after 10 or 15 days of storage for
further ripening of the fruit at ambient conditions of
storage. Organoleptic evaluation of the ripe fruits in
waxol with hot water treatment showed good colour,
texture and taste as compared to the control fruits
which had shriveled by 15th day of storage.
M.Sc. Title: Changes in mineral
composition of mango fruits during storage (1991)
R.A.Reena, UAS, Bangalore,
Guide: Dr. Shantha Krishnamurthy
Changes in weight loss,
firmness, moisture, dry weight, surface colour and
minerals were studied at 5 stages of ripening in four
cultivars of mango namely Alphonso, Bangapalli, Rasapuri
and Totapuri. The weight loss during ripening ranged
from 13.4 to 17.4%. The loss of green colour was
accompanied by appearance of yellowish orange colour. At
the ripe stage, ‘L’ values ranged from 44.7 to 67.9, ‘a’
and ‘b’ values ranged from 4.0 to 8.1 and 23.4 to 34.9
respectively. Moisture content decreased with an
increase in dry weight of the fruits during ripening.
Alphonos mango recorded the lowest Ca content in both
pulp (8.2 mg) and peel (73.9 mg), lowest peel Na content
(6.0 mg) and highest P (112.4 mg) and Fe contents (100.2
ppm) in the peel and K content in the pulp (828 mg).
Bangapalli recorded the highest of (466 mg) in peel, Fe
(99 ppm) in the pulp, K (986 mg) in the peel and lowest
K of 598 mg and Na content of (5.6 mg) in the pulp.
Rasapuri recorded the low contents of all the minerals.
Calcium content in the peel and pulp were 245.9 mg and
9.4 mg. Fe content was the lowest (5.8 ppm) in the pulp
and in the peel (3.5 ppm), highest Na content in the
pulp (11.2 mg) and in the peel (12.6 mg). Totapuri
showed the highest Ca-content of 13.3 mg in pulp, P
content of 78.4 mg & the lowest peel K content of 676.7
mg. these changes have been correlated with the shelf
life of the cultivars.
DIVISION OF ENTOMOLOGY & NEMATOLOGY
M.Sc. Title: Population
dynamics, biology and management of
Amrasca splendens
Ghauri (2004)
S.Rudresh, UAS, Bangalore,
Guide : Dr. Abraham Verghese
The present investigations were
made during 2003-04 on the different aspect of
Amrasca splendens Ghauri at IIHR namely, seasonal incidence,
biology, extent of damage, management of
A . splendens
and response of leaf hopper to Alphonso, Banganapalli
and Totapuri varieties, All the aspects were summarized
below. Seasonal incidence of
A. splendens
indicated that three population peaks were observed,
with the second peak was observed during third week of
April (23.20 mean leafhoppers per shoot). The first peak
during third week of June (11.05 mean leafhoppers per
shoot) and third peak was during last week of November
(0.29 mean leafhoppers per shoot). Incidence of
A. splendens
was found on all the commercial varieties studied
namely, Alphonso, Banganapalli and Totapuri from May
2005. On these varieties the incidence gradually
increased from February to March and reached its peak
during April, from then the population started declining
and reached a minimum during July to October, July to
March and May to January, in Banganapalli, Totapuri and
Alphonso, respectively. The Incidence of
A. splendens
had showed positive significant correlation with maximum
temperature(r=0.38) minimum temp. (r=0.36) and
flushing(r= 0.67). Tender leaves were found to have
positive effect. Further, the studied showed that
co-occurrence of factors like maximum temperature at
third week prior to leafhopper incidence and flushing at
one week prior to leafhopper incidence explained the
leafhopper density up to 65 per cent. Relative humidity
and wind speed were not found to have any effect.
Studies on the biology of
A. splendens
on mango were conducted under laboratory conditions,
during April 2004. Previposition, oviposition, and post
oviposition periods lasted for 8 to 10, 10 to 12 and 4
to 6 days, respectively. The total fecundity based a
nymphal emergence ranged from 15 to 26 eggs per female.
Eggs were slightly oval and transparent and were laid in
the midrib, vienlets and occasionally in leaf lamina.
Oviposition per days varied from 1 to 4 during peak
season for per female. It took 4 to 5 days for hatching.
The nymphs passed through five instars and they lasted
for 0.69, 1.25, 1.94 and 2.63 days, respectively. During
the course of the study three predators namely
Isyndus heros Fab. And Mantis
religiosa Lab., were found attacking the different
stages of the leafhopper. However these were of no major
consequence. The female adults caused the major damage
by ovipositing in midrib towards anterior region of
tender leaf, which resulted in blockage of phloem tube
due to which, drying of leaf apex backward was observed.
However in majority of damaged leaves the dried tip just
break off leaving a typical “tip cut” symptom. After
emergence nymphs cluster on the lower side of the tender
leaves and suck sap from midrib and vienlets. Under
server infestations, the leaves of sprouting shoots
withered and ultimately fell down. The oviposition in
the midrib caused anatomical changes in the leaf midrib
and as well as in lateral veins of the leaves. The
healthy midrib stained in toluidine blue mercuric
bromophenol blue and periodic acid Schiff’s reagent has
indicated the presence of vascular bundles and other
related structures, where as in infested tissue the
staining was either blank or very lightly indicated the
degeneration of tissue or the presence of chitinaceous
materials in the midrib (left out material of chorion).
Further, it could be clearly seen that there was an
opening in the midrib to indicate the escape of nuymphs
by rupturing midrib. Studies were conducted on the
management of A.splendens during April 2005. The
botanicals namely viz., Pongamia soap 10 g/l, Neem soap
10 g/l, Neemazal 1.5ml/l, Neemark+ 1.5ml/l, Neem oil
10ml/l, NSKE 4% were used for the study. Endosulfan
2ml/l was used to compare the efficacy of botanicals.
The results showed that neem oil 10ml/l and NSKE 4%
giving 100 per cent control of the leafhoppers.
M.Sc. Title : Ecology and
management of stone weevil (2005)
D.K.Nagaraju, Kuvempu
University, Shimoga,
Guide
: Dr.Abraham Verghese
Mango stone weevil, (MSW)
Sternochetus mangiferae (Fabricius) (Coleoptera: Curculionidae) is an important monophagous pest of
mango, its ecology and ethology have escaped the
attention of entomologists, but its effects as a pest of
mango fruit is highly pronounced affecting yield and
exports. In order to understand the insect better, for
better management, there is a need to follow the insect,
into its niches like seed and bark in an intensive
manner. Hence, the present study was conducted at the
laboratory and fields of Indian Institute of
Horticultural Research (IIHR), Bangalore (12o 58’N; 77o
35’E) during 2001-2005. The different linear and
non-linear models employed could explain the variability
in infestation at harvest due to the infestation in
fallen fruits to the extent of 57 to 83% in different
varieties. Further, per cent infestation at harvest was
predicted using polynomial model order 2 equation in
Alphonso and Banganpalli, and polynomial model order 3
in Totapuri. An adult infested by
Beauveria bassiana
(Balsamo) Vuillemin was found. The natural occurrence
was < 1%, but under laboratory conditions, the fungus
gave 100% mortality of adults in 2-7 days when sprayed
at 1.3 x 109 spores per ml concentration. Carbaryl,
acephate and deltamethrin with 3.33, 6.67 and 8.15%
infestation, respectively were effective. Ethofenprox
with 14.82% infestation gave intermediate control. Fish
oil rosin soap and azadirachtin were not effective. The
study clearly brought out for the first time that
infestation begins on fruits of 2-4 cm diameter. This is
the time to initiate management interventions. The
discovery that majority of the adults eventually rest in
junctions of main trunk and primary branches augur well
to target spot application of insecticides on the main
trunk prior to fruiting, thus obviating full canopy
sprays. The fact that older trees harboured more MSW is
also crucial in being vigilant to MSW infestation. This
is environment friendly cost effective and time saving,
as trunk spot application requires only 1/5th of spray
liquid. The study showed that prediction of weevil
infestation in a variety is possible. As stretches of
mango of one variety are common in India, this will be
useful in forecast and surveillance. The efficacy of
B. bassiana
demonstrated that the eco-friendly IPM is a potential
future venture.
DIVISION
OF PLANT PHYSIOLOGY & BIOCHEMISTRY
Ph.D Title : Physiological and
biochemical basis of internal breakdown in Alphonso
mango-a study on the roles of ethylene, calcium and
oxidative stress (2006)
J.E.Nagamani,
Kuvempu University, Shimoga,
Guide
: Dr.S.Shivashankar
Reduction in ethylene evolution
in the spongy tissue was mainly due to the reduced
activity of ACC oxidase leading to the accumulation of
ACC. This might have led to the reduced ripening of the
tissues resulting in sponginess. There are many
softening enzymes and the major ones are
polygalacturonase, pectin methyl esterase and cellulase.
Results indicated the lower softening of the tissues in
the spongy tissue when compared to the healthy tissues.
In climacteric fruits like mango respiratory raise
during ripening is very important for proper ripening
and development of good aroma. The ethylene hormone
strictly controls this. In this direction an attempt has
been made to assess the respiratory enzymes to
understand whether they are affected due to the
formation of spongy tissue. Activities of starch and
sugar metabolising enzymes are decreased in spongy
tissue leading to the lower sugar formation. Study of
antioxidative enzymes in spongy tissues. Oxidative free
radicals have been associated with many membrane related
disorders. Lipid peroxidation is one of the important
effects of free radicals damage. Oxidative free radicals
combined with metallic ions like ferrous results in
greater damage due to the production of highly reactive
hydroxyl radicals. Free radicals are usually scavenged
by the antioxidative enzymes like SOD, catalyse,
peroxidase, polyphenol oxidase, ascorbate peroxidase,
glutathione reductase etc.,. However, if there is damage
to the free radical scavenging mechanism then there will
be an accumulation in free radicals resulting in the
damage of membrane. As a measure of oxidation products
MDA has been analysed and antioxidative enzymes like
super oxide dismutase, peroxidase, catalyse, polyphenopl
oxidase have been estimated in different samples. Spongy
tissue has higher oxidative products and lower activity
of antioxidative enzymes indicating the lipid
peroxidation of membranes. Minerals are essential for
the normal functioning of membranes and also for the
maintenance of turgor of the cells and for enzyme
activities. In this regard, minerals like Zn, Fe, Ca and
Mg are estimated in spongy and healthy tissues. Most of
the minerals except Ca did not show any significant
differences between the tissues. Calcium showed a
marginal reduction in spongy tissue.
M.Sc. Title : Role
of seed in spongy tissue formation in Alphonso mango
biochemical studies (2005)
Linda Louis, UAS, Bangalore,
Guide : Dr.S.Shivashankar
Biochemical Studies showed that
moisture content was significantly higher in seeds from
spongy-tissue-affected fruits (STS) than seeds from
healthy fruits (HS).Analysis of seed components revealed
that STS had significantly lower starch content (33.5%)
and higher levels of soluble sugars (27.7%) than HS. The
incidence of spongy tissue was associated with increased
seed respiration rate and amylase activity indicating
that the seed in ST fruits had switched over to
germination phase. A substantial increase in the content
of soluble protein (43.1%) in STS indicated de novo
synthesis of various enzymes associated with
germination. There was a significant increase in spongy
tissue incidence in preharvest GA3 treated fruits
(70.2%), while there was a considerable reduction in
incidence in paclobutrazol (16.4%) treated fruits as
compared to 51.5% incidence in the control. GA3treatment
also resulted in higher intensity of spongy tissue. The
seeds from HS and STS fruits were distinctly different
in their physiological status and biochemical
composition. The data clearly indicated that spongy
tissue in Alphonso mango is triggered by the onset of
seed germination associated events. These events lead to
development of spongy tissue in the pulp close to the
stone by the continuous transfer of water from pulp to
the germinating seed. This theory of seed origin of
spongy tissue is amply supported by experimental data
and more importantly this concept is able to explain all
the facts known so far about spongy tissue.
M.Sc. Title : Persistence and
mobility of paclobutrazol in soil (2004)
L.Shalini,
UAS, Bangalore,
Guide : Dr.Debi Sharma
A
field experiment was conducted at IIHR, Hessaraghatta,
Bangalore, to study the persistence and mobility of
paclobutrazol, a predominantly soil applied plant growth
regulator to counter alternate bearing in mango
following its application to mango tree basins at the
rate of 5 and 10 g as per hectare. Soil, water and mango
samples from Konkan region of Maharashtra were also
collected in order to assess the extent of paclobutrazol
residue contamination in these samples, as this area is
the largest consumer of paclobutrazol in India. Sample
were collected from both conventional soil cultivated
orchards and laterite rock cultivations. The study
indicated that paclobutrazol persisted at all soil
depths for at least 150 days and reduced to below
detectable limit at 210 days. It persisted at the
surface (0-15 cm) with half lives of 30.7 and 29.7 days
from the lower and higher treatment concentrations
respectively. It was also seen that paclobutrazol moved
quickly down the soil to reach up to or beyond 60 cm.
soon after its application. The residues of
paclobutrazol in the conventional soil cultivated mango
orchards located at Konkan region of Maharashtra ranged
below detectable limit to traces. No detectable residues
of paclobutrazol were found in soils from laterite rock
cultivated mango orchard from the same region
irrespective of the number of years for which
paclobutrazol applications had been made. The
paclobutrazol residues were either below detectable
limit or present in traces in mango whole fruits
collected from either type of orchards at harvest,
notwithstanding the frequency of its application in the
orchard. Water samples collected at the time of fruit
harvest from open wells located orchards did not contain
detectable residues of paclobutrazol.
M.Sc. Title : Factors
influencing somatic embryogenesis in mango (Mangifera
indica L.) for application in genetic transformation
(2005)
Subhasis Samanta, UAS,
Bangalore,
Guide : Dr.J.B.Mythili
Mango (Mangifera indica L.), the king of fruits, is a prized summer fruit
crop of India and Asia. The use of conventional plant
breeding approaches for mango improvement has largely
been ineffective because of its long life cycle,
allogamous and allotetraploid nature. The present
investigation was carried out with the objectives of
developing suitable and efficient protocols for
regeneration through somatic embryogenesis and to study
the feasibility of transformation of mango cv.
Vellaikolumban using a reporter gene. Young fruits of
25-30 days of age was found to be ideal for culture
initiation. Among the various media tried (MS, B5 and
RO) for initial nucellar culture establishment, the best
proliferation response was obtained in MS medium
supplemented with 2.5 mg/l, 2, 4-D. Induction of somatic
embryos from nucellar culture was optimized using B5
medium supplemented with 20% (v/v) coconut water and 250
mg/l of casein hydrolysate. Maturation of somatic
embryos of 1.0-1.5 cm. length was obtained best in M3
medium composed of B5 salts, L-glutamine (400 mg/l) and
ABA (1 mg/l). The faciation and necrosis of embryogenic
cultures could be controlled through the use of
salicylic acid at a concentration of 0.1 mg/l.
Germination of mature somatic embryos with
well-developed roots and shoots was achieved best in
semi- solid medium (B5) supplemented with 3.0 mg/l GA3.
During Kanamycin sensitivity test, It was found that
kanamycin at 200 mg/l inhibited regeneration totally in
non co-cultivated embryogenic callus derived from
nucellus. Among various stages of nucellar culture
tried, it was found that embryogenic callus is amenable
for transformation. Among various treatment tried, 150
µl acetosyringone activated bacterial culture and a
period of 3 days co- cultivation was found to give
highest percent transformation response (75%). The
presence of transgene was confirmed by GUS assay.
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