Pract no. 9 (a) floral biology of banana

Botanical name : Musa paradisiaca L. (Fruit variety)
Musa sapientum (Vegetable variety)
Common Name : Banana, Kela
Chromosome number : 2n = 3x = 33

Banana is one of the oldest fruits and second largest growing fruit crop in the world. It is also known as “Adams Fig “and “Apple of Paradise.”

Importance :
 It is widely used as a fresh fruit.
 The central core of the pseudostem is used as a vegetable.
 The banana pseudostem is also used for manufacturing paper and boards.

1. FLORAL BIOLOGYOF BANANA

2. CLASSIFICATION
Kingdom : Plantae
Division : Angiospermae
Class : Monocotyledons
Order : Zingiberales
Family : Musaceae
Genus : Musa
Species : paradisiaca

3. IMPORTANCE
Botanicalname:MusaparadisiacaL.(Fruitvariety)
Musasapientum(Vegetablevariety)
CommonName:Banana,Kela
Chromosomenumber:2n=3x=33
Bananaisoneoftheoldestfruitsandsecondlargestgrowingfruitcropinthe
world.Itisalsoknownas“AdamsFig“and“AppleofParadise.”
Importance:
Itiswidelyusedasafreshfruit.
Thecentralcoreofthepseudostemisusedasavegetable.
Thebananapseudostemisalsousedformanufacturingpaperandboards.

4. INTRODUCTION
ThegenusMusahasabout50speciesandthisgenusisdividedintofive
sections.TheediblebananasoftheworldbelongtotheEmusasection.Thefive
sectionsare:
Emusa
Rhodochlamys
Callimusa
Australimusa
Incertaesedis
Allbananalandracesarefarmersselectionfromintraandinterspecific
hybridizationoftwodifferentspecies,Musaacuminata,donoroftheAgenome
andMusabalbisiana,donoroftheBgenome.Bothofthesespeciesbelongsto
thesectionEmusa.

5. MORPHOLOGY OF THE PLANT
Bananas can grow as tall as 19.7-23 ft (6-7 m), and typically have a crown of
leaves at the top of their greenish stem.
The banana stem is a pseudostemwhich is actually herbaceous and comprised
of the densely overlapping sheath.
Fibrous adventitious root system.

6. INFLORESCENCE
It is branched spadix.
The flowers are protected by large, brightly coloured, spirally arranged, boat
shaped bracts called spathes.
When the flowers open, the spathesroll back and finally fall off.
The flowers are polygamous ie., staminteflowers, pistillateflowers and
bisexual flowers are present in the same plant.
The male flowers lie within the upper bracts, the female flowers within the
lower bracts and the bisexual flowers within the middle bracts. Female flowers
are large in size and have well developed ovaries.

7. INFLORESCENCE
BEFORE AND AFTER FRUITING

8. FLOWERS AND PERIANTH
Flowers :
Bracteate, ebracteolate, sessile, trimerous, unisexual or bisexual, when
unisexual, the flowers are monoecious.
The flowers are zygomorphicand epigynous.
Flowers are placed in the axils of the bracts, arranged biseriatelyand number
about 12 to 20 per node.
Perianth:
Tepals6, arranged in two whorls of 3 each.
The three tepalsof the outer whorl and the two lateral tepalsof the inner whorl
are fused by valvateaestivation to form 5 toothed tube like structure.
The inner posterior tepalis alone free.
It is distinctly broad and membranous.

9. ANDROECIUM AND GYNOECIUM
Androecium:
•Stamens6,intwowhorlsof3each,arrangedoppositetothetepals.
•Only5stamensarefertileandtheinnerposteriorstameniseitherabsentor
representedbyastaminode.
•Anthersaredithecousandtheydehiscebyverticalslits.
•Thefilamentisfiliformandrudimentaryovaryorpistillodeisoftenpresentin
themaleflower.
Gynoecium:
•Ovaryisinferior,tricarpellary,syncarpous,trilocular,numerousovulesonaxile
placentation.
•Thestyleissimpleandfiliform.
•Thestigmaisthreelobed.

10. INFLORESCENCE AND FEMALE FLOWER

11. BANANA PLANT AND FLOWER PARTS

12. FRUIT AND FLORAL FORMULA
Fruit :
The fruit is technically known as berry. It turns deep green to yellow red, and
may range from 6 to 30 cm length and 2 to 6 cm width.
The common cultivated types are generally seedless with just vestiges of
ovules visible as brown specks.
Cultivated bananas are parthenocarpic, which makes them sterile and unable
to produce viable seeds.
Floral formula
Male Flower : Br, Ebrl, %, , P
(3+2) +1, A
3+2+1 staminode, G
0
Female Flower: Br, Ebrl, %, , P
(3+2) +1, A
0, G
(3)
Bisexual Flower : Br, Ebrl, %, , P
(3+2) +1, A
3+2+1 staminode, G
(3)

13. EMASCULATION AND CROSSING TECHNIQUES
Anthesisand Pollination :
The female and male flowers open by 6.30-8.00 a.m.
The ovaries contained in the first (female) flowers grow rapidly, developing
parthenocarpically(without pollination) into clusters of fruits called hands.
Occasionally, cross pollination with wild types will result in a number of seeds
in a normally seedless variety.
Emasculation and crossing techniques :
Undehiscedanthers of male flowers are collected and twisted gently to force
them to dehisce.
Using a soft hairbrush, the pollen grains are taken out and smeared gently over
the stigmatic surface of the female flowers, which opened on the day of
pollination.
The pollinated flowers are to be covered with soft cloth bag.