1. PEARL MILLET
Heterosis and Hybrid Seed Production
2. Pearl millet (bajra)
• Family:- Gramineae
• Genus:- Pennisetum
• Species:- americanum (l)k.Schum
Glaucom (l) r.Br
• Chromosome no.:- 2n=2x=14
• Related species:- P.purpureum
• Origin:- Africa
3. PLANT DESCRIPTION
•Pearl millet [pennisetum glaucum (l.) r.Br.] is a
warm season crop, planted in early summer when
soils have warmed up.
• The crop is primarily cross pollinated, and
following pollination, it takes a flower about 30
more days to develop into a mature seed.
•It has fast root development, sending extensive
roots both laterally and downward into the soil
profile to take advantage of available moisture and
nutrients.
• Uses:- hay, pasture, silage, seed crops, and food.
4. Mode of Pollination
•Pearl millet is predominately protogynous.
(The stigma is emerged before the anther
appears which facilitates cross pollination).
•Development of hybrids without Emasculation.
•Self pollination may occurs on late tillers.
•Wind is major cross pollination agent.
•Insects also effect cross pollination.
5. Controlled Pollination
• For controlled selfing
• Bag the spikes prior to emergence of
style when most part of head is in boot.
• For selfing, water repellent brown paper
bags, or kraft paper bags sealed with
waterproof adhesive, are used.
• Insecticidal dust, such as DDT putted in
bag to give insect control.
6. • Controlled cross pollinations
• Female heads are enclosed, before
emergence of styles in waterproof glassin
paper bags.
• When most of stigmas are exerted, pollen
collected from required male is dusted on
female head after removing bag.
• Bag the spike after gross pollination has
taken place.
7. Reasons for Exploitation of Heterosis
•Very high heterosis (5-250)
•Highly cross pollinated crop
•No emasculation is required
•High seed to seed ratio
•Low cost of seed production
•Availability of CMS lines
8. various trait used for exploitation of heterosis in
pearl millet-
• Days to maturity
• Plant height
• Fodder yield quality
• Grain color quality
• Panicle size
• Hybrid vigor
• Grain yield
• Threshability
• Resistance to diseases and insects are considered.
9. Seed Production
• Before the exploitation of CGMS in 1965,
pearl millet varieties were used to be
oppen pollinated.
• After 1965 the development of first ever
hybrid 'HB1' by using CMS resulted in the
hybrids with great yeild potential and
disease resistance.
11. Seed production procedures of various classes
are desribed here:-
Pearl millet varieties vary slightly with each stage of
multiplication, needed to maintain genetic purity at th
early stages, and also, there should always be onward
flow from one stage to the next.
12. Figure : Flow diagram of a three-stage seed production scheme for pearl millet varieties.
13. NUCLEUS SEED PRODUCTION
•Nucleus seed refers to the seed produced
by the breeder who developed the particular
variety and the parental lines of hybrids.
•Original seed.
•100% genetic and physical purity.
•nucleus seed is multiplied and maintained by
selecting individual pods/spikes and growing
them.
•available only in small quantity.
•NO TAG in nucleus seed.
14. Foundation seed
• Only breeder seed is used to plant these plots at
least 400 m away from the nearest pearl millet,
napier grass, and wild pearl millet fields.
• As a precautionary measure, first plant a belt of
5-10 m wide around the perimeter of the plot
with the same seed, at least 7-10 days before
planting in the center. The perimeter can be
planted dry while the center can be planted, just
after the rains.
• TAG COLOR is white.
15. BREEDERS SEED
• Breeder seed is the progeny of nucleus
seed.
• Production is controlled by the originating
plant breeder who developed the variety.
• Breeder seed is genetically so pure.
• TAG COLOR is golden brown.
16. Seed Production technology
•Planting density
•Planting ratio
•Distance from pollen source
•Planting direction
•Planting time
•Presence of off types
17. Hybrid seed production
A hybrid variety is first generation (F1) from crosses
between two
• purelines
• inbreds
• open pollinated varieties
• clones or other population that are genetically
dissimilar.
Requirements:-
• Presence of hybrid vigour.
• Elimination of fertile pollen in female parent.
• Adequate pollination by male parent.
18. Types of Hybrids
• Single cross hybrids (A x B)
• Double cross hybrids (A x B) x (C x
D)
• Three way hybrids {(A x B) X c}
• Top cross hybrids {c X OPV}
• Hybrid blends
• Inter population hybrids
• Chance hybrids
19. Hybrid Seed Production Using CGMS
• Pearl millet crops use CYTOPLASMIC-GENETIC MALE
STERILITY system in hybrid seed production that is
caused by an interaction of the sterility-inducing factors
in the cytoplasm with the genetic factors in the nucleus.
• The system is based upon:-
1. A cytoplasm that produce male-sterility.
2. A gene that restores fertility.
steps involved :-
1. multiplication of CMS(A) lines.
2. multiplication of maintainer (B) and restorer lines.
3. production of hybrid seed (AxR)
20. PARENTAL LINES
A-lines:- it is the male sterile parent line.
B-lines:- the fertile counterpart of A-line,
doesn't have fertility restoring genes and
used to maintain A-line.
R-line:-The male fertile line carries genes for
fertility restoration.
21. Maintainance of A & B-Lines
•Grow A-line and its corresponding maintainer, B-
line together in an isolated plot.
• The isolation distance for A x B production fields
is at least 1 km.
• A ratio of 1A: 1B rows is maintained.
• Pollen produced by the B-line fertilizes the male-
sterile plants (A) and the seed produced thus, gives
rise to the A-line again.
22. Maintenance of R-line
•The pearl millet R-line could be either an inbred line or
open-pollinated variety which can be multiplied as variety.
The seed of R-line are produced by multiplying the seed in
isolated plot having distance 1000 m.
•Any plant in the r-line plot appearing different from the true
R-type should be uprooted, or rogued before anthesis.
•Purity of the parental seed is very important because it
affects the quality of hybrid seed that is generated.
23. Pollen (cross)
AXB
Pollen (self)
Pollen (cross)
AXR Pollen (self)
F1
scheme for Hybrid Seed Production In pearl millet using
CGMS lines
24. Maintenance field Hybrid seed
production field
isolation
1:1 A & B rows
4:1/6:2 A &B rows Harvest of R-line
gives R-seed
Harvest of A-line
gives A-seed Harvest of A-line give
Hybrid seed (F1)
Harvest of B-line
gives B-seed
Layout of hybrid seed production plot
25. CAUTIONS
• The pollen shedders in the A-line rows must be
identified and uprooted each morning during the
flowering period.
• Normally, no more than 0.05% genetic off-type are
permitted at final inspection in foundation seed.
• Since both A-lines and B-lines exhibit synchronous
flowering, seed yields on the A-line in A/B seed
production plots are relatively better than in the A and R
(hybrid) production plots.
• Seed of the B-line harvested from the A/B production
plots might be reused for the next generation,
depending on the seed laws of the country.
26. CERTIFIED SEED
• Certified seed is the seed, which is certified by a
Seed Certification Agency notified under section
8 of indian seeds act(1966).
• Certified seed consist of two class-
1.Certified foundation seed-progeny of
breeder seed.
2.Certified seed-progeny of foundation seed.
TAG COLOR is blue.
27. R-LINE A-LINE
Pattern of R-line And A-Line For Certified Hybrid Seed Production
28. Identification of Potential Hybrid Parents
(A-, B-, and R-lines)
• Potential male and female parents for hybrid seed production are
identified by crossing male-fertile plants (inbreeds, varieties,
germplasm, breeding stocks in advanced generations, etc.) to a
male-sterile line (A-line) and observing their corresponding
hybrids in small plots of an observation nursery.
male fertile X male sterile
F1
• A few plants of each cross are subjected to a BAGGING TEST,
i.e., covering a few panicles with paper bags before anthesis,
and observing seed-set under the bag after a few weeks.
29. • A normal bisexual fertile panicle would exhibit nearly
100% seed set whereas in crosses with A-lines, the
following three types of hybrids are encountered:-
1. Hybrids have no seed-set, i.e., male-sterility is maintained in
these hybrids. The corresponding pollen parent is classified
as a non -restorer/maintainer or B-line and as a potential new
A-line.
2. Hybrids exhibiting complete seed-set under the bag, i.e.,
male fertility has been completely restored in these hybrids.
The corresponding pollen parent is classified as a potential
male-parent /restorer line or R-line and could be useful in
producing hybrids.
3. Hybrids exhibiting partial seed set under the bag. Such
hybrids and their male parents are rejected for further studies
because experience shows that it is difficult to extract stable
R-lines or B-lines from such parents.
31. HHB 50
•Highly productive under
good management
•High dry fodder yield
•Highly resistant to downy
mildew
32. HHB 60
•Tolerant to drought
•Medium maturity (70 days)
•Resistant to downy mildew
33. HHB 67
•Extra early maturity
•Most adaptive hybrid in
drought hit areas
•Suitable for inter cropping
34. HHB 68
•Early maturity
•Multiple disease resistant
•Suitable for drought hit
areas
35. HHB 146
•Combines high grain with
high biomass
•Tall height, long head
•Tolerant to lodging and
salinity
•Highly responsive to
nitrogenous fertilizers
36. HHB 67 Improved
•Extra early maturity
•Highly resistant to downy
mildew
•Improved version of HHB 67
through MAS
