hrt 600 final
Transcript of hrt 600 final
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FLORAL BIOLOGY ANDFRUIT SET
OFMANGO,CITRUS AND
GRAPE
M.Vijayalaxmi
RHM/08-23
M.Sc(Hort)1st
yr
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BLOSSOM BIOLOGY
In many fruit crops the time of flower opening depends onthe many factors
Blossom biology constitutes
Blooming period Flower bud differentiation
Flower bud development
Inflorescence
Sex ratio
Anthesis Dehiscence
Pollen fertility
Stigma receptivity
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Mango
SN : Mangifera indica
Family : Anacardiaceae
Inflorescence : Panicle
Fruit : Drupe
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Blooming period
Factors
Physiological CHO and N reserves play a main role in fruit bud
differentiation. Environmental - optimum 20-25oC. vegetative shoots produced
in spring get sufficient time to grow and accumulate metabolites
necessary for fruit bud differentiation.
S I : January - February
N I : February March
2-3 weeks
Flower bud differentiation
October December
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Inflorescence:
the panicle consists of pefecthermophrodite and male flowers.
the percentage of perfect flowersranges from 1.25- 81.0% with astrong varietal difference.
800 9000 flowers / panicle
Male and Perfect flowers presenttowards apex
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Flower
6 8 mm in diameter
Calyx : 5 partite
Corolla : 5 (greenish yellow and
cream colour)
Androecium : 5 lobed disc
(stamens and staminoids)
Stamens and pistils may be either parallel or
oblique to each other
Ovary is sessile,one celled,oblique and slightly
compressed in its lateral aspects
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Sex ratio
Perfect to staminate
Less flowers in distal half
More perfect flowers in the distal half
1.25%Jahangir
3%Baneshan
6-11%Alphonso
16%Neelum
80%Dashehari
Percentage of perfect
flowers
Variety
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Factors affecting for more perfect flowers
Inflorescence emerging during middle and end of
flowering season (2-7 times)
Lateral inflorescence Older trees Grafted trees On year crop Ambient temperature
Mineral nutrition
Anthesis9.00AM - 10.00AM polyembryonic sps night
DehiscenceOccurs within 1 hr after anthesis after dehiscence anthers
become bluish due to pollen High RH delays dehiscence
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Pollination
Highly cross pollinated, perfect flowers are protogynous and
entemophilous
Pollen grains in mango changes shapes in different media
Possess oblong, oval and slightly broader in some varieties
3 types of pollinating agents
Melipona spp Syrphidae spp Musca domestica
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Pollen fertility
Growth and maturity reduced by cool
temperatures
Completely inhibits at below 15oc
Stigma receptivity
Up to 72 hours after opening of flower
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FRUIT SET
Development of ovary and theadjacent tissue following
blossom period
8-13% flowers setting Mango cv are usally self fruit ful
Ratio of fruit to flower is 1 :5000
fruits less than 1% reach maturity
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Factors for low fruit set
More male flowers
Un pollinated perfect flowers
Failure of pollen germination
Factors responsible for fruit set
Changes in temperature
Light intensity
Day length
Presence of functional leaves
Supply of nutrients and water
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Parthenocarpy
Not common but seen in Dashehari (5.44%)
due to low temperature during flowering andreduce the activity of pollinators
Fruit drop
Climatic conditions
Defective flowers
Self in compatibility
Lack of pollination
Zygote abortion
Pests and diseases
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Alternate bearingAlternate bearing refers to heavy fruiting In one year
Factors
5. Physiological
6. Genetical
7. Environmental8. Nutritional
Measures
Maintenance of orchard Deblossoming Ringing and girdling Smudging and chemical treatments
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Sn : Citrus spp.
Family : Rutaceae
Inflorescence : Terminal cyme
Fruit : Hesperidium
CITRUS
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Blooming period
March-april (early spring)
Sweet orange and mandrins - once in a year
(March) - NI
Sweet orange - First (Feb-Mar)
Second ( June-July ) - Bihar
Sathgudi - First (Dec-April) - SI
Second ( Sep-Dec)
Coorg mandrin - First (Mar-April)
Second ( Sep-Oct)
Thrice in central and western India June,Oct and Feb
Continuous bloom in Lemons, Lime and Citron
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Flowering in tropical regions
With no cool periods and enough soil moistures through out
the year, most of the citrus species produce some bloom on a
recurrent basis
Hence low temperature alone is not induced flowering but
dormancy induced by low moisture supply has been found
equally effective.
The flowering in citrus under Indian conditions is induced
through eitherlow temperature stress orsoil water deficit.
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In North-west India and North-East India low temperature isobserved for 10-15 days, which is sufficient to induce
dormancy.
In central and South India in the absence of low temperature,soil water deficit stress is adopted to induce flowering.
There are very few commercial citrus growing belts of global
level where soil water deficit is widely practiced to induce
flowering
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Flowering in tropical regions
Cessation of root growth, as well as low temperature,
water stress, weak root stocks and confined roots
were necessary for floral induction.
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Flower bud differentiation
Every vegetative bud in citrus is a potential flower
bud. Induction and differentiation are not seen outside
The vegetative bud in citrus is conical one withpointed apex
Cessation of vegetative growth is a pre-requisite for
induction
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It is generally observed that new flush precedes theflower bud differentiation, ordinarily in early spring
Temperature required is 16 -20o
c (Krajewski etal.,1995)
flower bud development Complete development ofbud lasts from less than 18 47 days (Inova,1990)
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Inflorescence
Inflorescence in citrus species is of cymose type.
Flowers in citrus are borne on two types of shoots
1. With leaves : new wood
2. With out leaves : old wood
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Flower
Calyx : 5 sepals, gamosepalous, inferior, quincunicial
aestivation
Corolla : 5 (white/purplish colour), polypetalous scented,
inferior, imbricate aestivation
Androecium : Indefinate, 20 - 40stamens, polydelphous,
compressed at base. Anthers oblong basifixes, introse, dithecous
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Gynoecium : Polycarpellary, syncarpous, superior
ovary, multi locular, nectar secreting, disc presentbelow ovary, axile placentation, style short, stigma
capitative7-15 celled pistils
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Flowering in Citrus:
In Israel, Eureka lemons sprayed five times with CCC at a
concentration of 1000 ppm, SADH at a concentration of 2500
ppm or BOA at a concentration of 25 ppm considerably
increased flowering and production of lemons (Monselise et al.,
1966).
Paclobutrazal (cultar) at the rate of 18 g tree-1, when applied at
the time of imposition of stress (Research Highlights of NRCC,
2005).
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SWEETORANGE
Rao(1961) observed that in Sathgudi Orange, IAA (15 ppm), 2, 4-D (10
ppm), NAA (5 and 15 ppm) and beta-naphthoxyacetic acid (10 and 15 ppm)
sprayed at bud stage significantly increased fruit set.
MANDARIN: GA 40 ppm and NAA 40 ppm have also been reported to
increase fruit set in Ladui mandarin (pastel and Soni, 1972).
Sweet orange (Cv. Washington Navel) plants were subjected to low
preflowering temperature (day/night, 15/10oC), which had resulted in delayed full
bloom by (28 days) and poor fruit set. A small increase in root temperature duringflower development to 16C (at 15/10oC) mitigated the adverse effect of low
day/night temperature on subsequent fruit set (Moss, 1974).
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For inducting of Hasta Bahar in acid lime in themonth of October- November, two sprays of
chloromequat chloride (CCC, Cycocel) at 15 days
interval or stem girdling at 0.3 cm width was
effective in giving good crop of acid lime in peaksummer months
(Research Highlights of NRCC, 2005).
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Anthesis
9.00AM - 12.00PMTerminal bud, leaf less flowers opens early
Flower exposed to sun opens early
Dehiscence
Dehiscence of anthers in citrus takes place at different times
Low humidity and high temperature are found to influence
dehiscence of anthers
High temperature accelerates the dehiscence of anthers
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Stigma receptivity
In general stigma receptivity in various citrusvarieties starts 2- 3 days earlier to anthesis withmaximum receptivity on the day of anthesis
Oozing of gummy substance on the stigmatic surfaceis the indication of stigma receptivity in citrus
Duration of stigma receptivity is influenced byprevailing weather conditions also in dry spring it isshorter than the moist spring
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Pollination
The citrus flowers are
hermaphrodite and homogamous.
A number of citrus cultivars areself incompatable and some are
cross incompatable. Under such
conditions for regular and consist ant
production of an adequate source of
pollen in addition to the pollinating
agents are very essential ( Syam
singh et al.,2001)
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FRUIT SET
1,00,000 2,00,000 flowers on maturetree
Only 1-2% of these flowers will produce
fruits
Time of anthesis is also linked to
percentage initial fruit set. Flowers open
early in the bloom period have muchlower fruit set than those open latter.
Citrus fruits develop very slowly it takes
6 13 months
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Size and number of leaves related to size of fruit
Petal fall off, drying stigma and green ovary indicate
the success of fruit set
Washington navel - sterile pollen
Lemons - more imperfect flowers
Pumellos - self incompatability
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Factors responsible for poor fruit set are pollen sterility, seedlessness,
embryosac sterility and self incompatability
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SN : Vitis vinefera
Family : Vitaceae
Inflorescence : Panicle
Fruit : Berry
GRAPE
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Flowering period
SI : 1. Apr - May
2. Oct - Nov
NI : Mar Apr
Flowering on current season growth during warmseason in NI were as the cold season in SI
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Flowering habit
Fruit buds in grape
vine are lateral,
unfolding to
produce leafy shootsthat terminate in
flower clusters
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Inflorescence
Much branchedcluster,each branchending in a terminal
flower.The inflorescence is
borne on opposite to theleaf and emerge with the
leaves when the shootsstart growing.
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Flower
Calyx :5 sepals, green,soon after
bunches appear the sepals stop
growth and dries up.
Corolla :called as calyptra 5
(greenish petals which are united
at tip therefore flower opens from
base, gets detached and drops off as
a small cap at the time ofblooming)
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Androecium :5 stamens with introse anther. At the base and between filaments
there are pad like nectaries. which produce sweet and odorous nectar. Stamens are
pollen bearing organ of flowers, stamens are opposite the petals in the arrangement
of the floral parts, small filament is present to the stamen,at the tip anther present
Gynoecium :stigma is coated with a sweet and sticky solution secreted from it to
hold the pollen grains falling on it. Ovary is bilocular with 2 ovules in each locules
Perfect Pistillate Staminate
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Anthesis
The time between leafing out and bloom is usually after 8weeks
8.00AM - 9.00AM (SI)
7.00AM - 8.00AM (NI)
Anthesis decreases during
high temperatures
Time taken for completion of anthesis varied
from half a minute to one day depending upon
the variety
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Dehiscence
5 minutes more or less same as anthesis
The walls of each lateral pair of loculi break away by their
inner and thin walled margins throwing pollen grains of the
both together toward the stigma
Stigma receptivity
This is a varietal character in grape
Stigma receptive one day before and after anthesis anddisappears on the third day
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FRUIT SET
Grape cultivar varies markedly in the extent to the fruit setting
The ratio of set berries to the number of flowers in a flower
cluster is the real measure of fruit set
Fruit set is directly proportional to theno.of mature leavesand is
reduced by the presence of immature leaves and shoot tip mainly
because the developing leaves and shoot tips are much stronger
sink for the movement of photosynthates during flower
development
The stage at which the unfertilized ovaries (small berries)
abscise is called theshatter stage
P th
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Parthenocarpy
Stimulative parthenocarpy :Black corinth
There is no ovule development beyond the time of bloom, due to
nutritional stimulous parthenocarpy may occurs.
Stenospermocarpy: Sultania
Munakka
Thompson seedless
Fertilization occurs but the embryo subsequently aborts
Empty seededness :ChaouchEndosperm shrrivelled and degenarated and leaving seeds more or
less shallow
Stages of development
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Stages of development
Bud swelling, doeskin stage with
brownish wool clearly visible
First leaf unfolded and spread
away from shoot
Five to six leaves
unfolded,
inflorescence
clearly visible 3
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Inflorescence fully
developed
Early flowering: 25% of caps
fallen
Late flowering: 80% of
caps fallen
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Fruit set: young fruits begin to swell Beginning of berry touch
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Noticeable loss of green colour also
called "Veraison" Berries ripe for harvest
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