3. INTRODUCTION
Petunia is an annual herbaceous plant.
Petunia X hybrida belongs to the family
Solanaceae
Petunia is genus of 35 species of flowering
plants of South American origin.
It is a result of the hybridization between
two different species of petunia flowers i.e.
Petunia axillaris (a white large typed and
night scented petunia) and Petunia
integrifolia a mainly violet colure petunia.
4. Petunia axillaris X Petunia integrifolia
( Sl or SC?) (SI)
First Petunia hybrids
(Sl or SC?)
Breeders select for SC
Modern day Petunia hybrida
(Sl)
Petunia have a gametophytic system of self
incompatibility and Cytoplasmic male sterility.
Origin of self-incompatibility:-
Robbins T.P. et al, 1999
5. Uses of Petunia hybrida
Petunia is recommended for the following application :-
Container
planting
Border
edging
Hanging
baskets
Mass
planting
General
garden use
6. Types of petunia
Petunia varieties can be divided into four main groups or
categories based on flower and growth habits. The four categories
are :-
1) Grandifloras -Grandifloras are large-
flowered petunias consisting of both
single and double flowering forms.
Single grandiflora for window boxes
and hanging baskets.
Double grandiflora best suited to
containers Single grandifloras
7. Popular grandiflora petunias include
varieties in the Super cascade, Super
magic, Ultra, and Falcon Series.
2) Multiflora petunia:-
Multiflora petunias have flowers which are smaller and more
flowers than the grandifloras.
There are both single and double flowered Multiflora petunias.
Single multifloras are excellent in mass plantings in flower
beds.
Double multifloras are most suitable for containers.
petunias include varieties in the Celebrity, Primetime, and
Carpet Series.
Double grandiflora
8. 3) Milliflora petunias:-
Milliflora petunias are
compact, miniature plants that
produce large numbers of 1- to
1 1/2- inch-diameter flowers.
Their compact size makes them
an excellent choice for
containers and edging beds and
borders.
Varieties in the Fantasy Series
are widely grown milliflora
petunias.
9. 4) Spreading or “ wave” petunia:-
The first introduction in this category was 'Purple Wave.'
A 1995 All-America Selection, 'Purple Wave' grows 4 to 6 inches
tall, but can spread 2 to 4 feet. The burgundy-purple flowers
measure 2 inches across.
They are excellent choices for hanging
baskets and as an annual groundcover
Recent additions to this group are 'Pink
Wave,' 'Rose Wave,' 'Misty Lilac Wave,
and 'Coral Wave.'
10. Botany
Petunia seed is 0.6-0.7 mm in length, 0.5-0.6 mm in diameter, spheroidal-
angular, light to dark brown in color, reticulate, thin walled with a
conspicuous hilum that is the same color as the seed coat.
There are approximately 250,000 petunia seeds per ounce .
The fruit of a petunia is a capsule which varies in size, shape, and seed
count depending on the species.
The flowers of petunia are perfect with five epipetalous stamens that
terminate at various heights below the stigma .
The petunia leaves are alternate or opposite, broad-ovate to cordate
shaped, 1.5-3.0 inches long, simple, entire margins, with stems and leaves
covered
11. BREEDING OBJECTIVES
1) Developed new flower colour
2) Creating interesting and unusual flower patterns
3) Introduction of spectacular colour range in single
flowered, double flowered, grandifloras and multiflora
petunias.
4) Modification of plant growth habit in different groups
like mound, prostrate, compact and spreading growth
habit.
5) Developing of miniature trailing petunias.
12. 6) Developing dwarf petunia plants and miniature flower
for ornamental purpose
7) To induce earliness.
8) Creation of attractive petunia which will with stand a
wide variety of conditions.
9) Evaluating petunias with excellent performance in the
garden as a bedding plant.
14. The grandiflora petunia type was developed in early 1950, with the
first F1 hybrid grandiflora, 'Ballerina,' introduced in 1952
The Multiflora petunia type was developed in late 1940, with the
first F1 hybrid Multiflora, 'Comanche,' introduced in 1953.
The floribunda type resulted from recent hybridization between
grandifloras and multifloras.
Milliflora petunias developed from a chance genetic mutation from
Petunia x hybrida, resulting in a true miniature plant.
Spreading type new breed of petunia that has more of a tropical
nature than other petunia types
15. Cultivars
1) New hybrid series
Allegro, Apple Tart, Apricot Tart, Blue Danube, Coral Bells,
Dream, Grandiflora- Ballerina , Fairyland, Grape Tart, Multiflora-
Silver Medal, Polo, Orange Bells, Summer Sun, Sweet Dream,
Mini Purple
2) F1 Hybrid Grandiflora
Blue Lace, Blue Magic, Sugar Daddy, Astro, Cascade, Happiness,
Pink Cascade, Pink Magic, Pink Show, Candy Apple, Red
Cascade, Red Magic, Snow Lady, White Cascade, White Magic,
Snow jewel
3) F1 Hybrid Multiflora
Polar Cap, Orange Bells, Red Joy, Mercury, Red Plum, Satellite,
Star Fire, Star Joy, Dream Girl
16. 4) F 1 Hybrid Double Multiflora:-
Apple Tart, Cherry Tart, Peach Tart , Pink Delight, Raspberry Tart,
Snowberry
5) Cascade F1 Hybrid :-
Pink Cascade, White Cascade
17. Cytoplasmic Male sterility (CMS)
Emasculation and pollination
Self incompatibility – Pi-SLF (gene
Petunia inflata S-locus F-box) : The
gene responsible for self-
incompatibility was identified
18. Cytoplasmic male sterility
Maureen Hanson’s group at Cornell University (Ithaca, NY, USA)
has cloned a mitochondrial gene that encodes Cytoplasmic Male
Sterility (CMS) in Petunia.
The gene encodes an abnormal protein that disrupts mitochondrial
activities.
A nuclear gene (the Restorer fertility or Rf gene) is known to
interact with this mutant mitochondrial gene, reducing its
expression and thereby restoring normal fertility to male sterile
genotypes.
The group has identified the Petunia Rf gene by cloning candidate
genes from map position and demonstrating that such a gene is able
to confer fertility to CMS Petunia lines.
Subsequently, genes highly similar to the Petunia Rf have been
identified as fertility restorers in Brassica and rice.
19. S F
S
Male sterile
Male sterile
Male fertile
F1 seeds 100% male sterile
Cytoplasmic male sterility
20. 1) pollen collection
Pollen collection can be a simple procedure for plants that shed large quantities of
loose pollen grains.
Some production facilities have installed centralized vacuum pumps to allow
pollen collection by suction in the entire greenhouse as shown here.
The anthers of some flowers can be collected prior to anthesis.
These anthers are then dried, ground, and pollen grains extracted from the
remaining tissue by sieving.
Extracted pollen can be cold-stored and used for weeks and months.
The pollen should be held in air-tight containers such as glass vials during cold
storage in frostless freezers to maintain proper pollen moisture content. When
pollen quantities are limited, inert materials can be added to allow pollination of a
large number of flowers
Emasculation and pollination
21. 2) Emasculation
The petals are gently peeled back to expose the immature anthers, which are
removed by hand.
3) Pollination
The flowers are ready for pollination one or two days after emasculation.
Flower to flower pollination is practiced when fresh pollen is applied.
The pollen is placed on the stigmatic surfaces by means of a brush as seen here.
Identifying the correct location of the stigma requires training.
The receptive surface is located at the tip of the gynoecium
The timing of pollination is important for seed yield. Optimal seed set is
obtained when the flowers are pollinated at the peak of stigma receptivity.
22. Inability to set seed from application of pollen produced on
same plant or it refers to failure of viable pollen of a given
plant to fertilise the ovules of the same plant, but it capable of
fertilising effectively the ovules of the most other plant of the
same variety.
Brew baker-1957. stated that self incompatibility occurs in
more than 3000 sp belonging to 250 genera, spread in about
70 families.
Self incompatibility:
23. In petunia in the 1930’s, two separate groups (Harland and
Atteck, and Wergin) independently confirmed that the genus of
Petunia possesses a gametophytic system of self-
incompatibility (Ascher, 1984).
Gametophytic.
“SI reaction of a pollen is determined by its own
genotype not by the genotype of the plant on which
the pollen is produced”
