Presentation by Dr IDK Atokple, CSIR Savannah Agricultural Research Institute, Tamale, Ghana Delivered at the B4FA Media Dialogue Workshop, Accra, Ghana - September 2012 www.b4fa.org

1. Hybrid Sorghum Production
Presentation at the Bioscience for Farming in Africa – Journalists
Training Course, Accra, Ghana, Sept 19-22, 2012
By
IDK Atokple

2. IMPORTANCE OF SORGHUM
Sorghum (Sorghum bicolor (L) Moench) is the fifth most
important world cereal following maize, wheat, rice and
barley.
In most West African countries, sorghum alone accounts
for 50% of the total cereal crop land area.
In northern Ghana, it is cultivated throughout the
savannah agro ecological zones, covering about 41% of
the total land area of the country

3. The crop is consumed in the form of stiff porridge (tuo
zaafi); thin porridge (koko) or fried dumpling (maasa)
and in brewing local opaque beer pito.
The leaves provide fodder for farm animals and the
stalks are also used in fencing, roofing, weaving
baskets, mats and as fuel wood.
Sorghum presently has assumed commercial status in
the breweries and has the potential in other products like
weaning food and confectioneries.
IMPORTANCE OF SORGHUM

4. Constraints to Sorghum ProductionConstraints to Sorghum Production
Insects
Anthracnose
Molds
Lodging

5. ConstraintsConstraints
Drought
Striga Poor Soil fertility

6. Low Yield Potentials
On-farm sorghum yields range between 500
and 800 kg/ha in the Northern Region and slightly
higher (between 700 and 900 kg/ha) in the Upper
Regions – resulting into regular annual deficits.
Apart from the constraints mentioned above, the
low yields are also caused by:
- Cultivation of indigenous land-race varieties,
- lack of a wide diversity of new improved
varieties and hybrids,
- Little or no use of fertilizer and low planting densities

7. Opportunities for Sorghum Hybrid Production
To meet the industrial demand and increase grain yield potential of
sorghum genotypes, the use of sorghum hybrids is one of such
technologies which could provide opportunities through the
exploitation of heterosis and access to markets
The development of agro industries using sorghum as raw
material, and the emergence of private seeds growers and
companies are incentives for development and release of high
yielding hybrids for the benefit of the sorghum industry.
CSIR-SARI has therefore drawn up hybrid production and
extension program among other strategies to increase the
productivity and production of sorghum through

8. Heterosis = F1 - P
Relative Heterosis = 100(F1 - P)/P
Hybrid Vigour is the superiority of progeny (offspring) (F1)
over the mean of its two parents (P)
heterozygous
heterosis inbreeding depression
homozygous
selfing
Concepts of Hybrid Production - Hybrid Vigour (Heterosis)

9. Heterosis
Merkmalsmaß(Leistung)
Beste
Panmixiesorte
Homozygote
Linie A
Hybride
A x B
Homozygote
Linie B
zusätzlich
nutzbare
Heterosis
Additionally
usable
heterosis
Trait(performance)
Best
OP-variety
Homozygote
Line A
Homozygote
Line B
Hybrid
A x B
Hybrid Vigour - Heterosis
Heterosis

10. 0
500
1000
1500
2000
2500
3000
3500
4000
4500
5000
1929
1933
1937
1941
1945
1949
1953
1957
1961
1965
1969
1973
1977
1981
1985
1989
1993
1997
Year
Yield(kg/ha)
United States
Inbred Varieties Hybrid Cultivars
History of Hybrids in Sorghum

11. The Concept of Hybrid
Production - Cytoplasmic
Male-Sterility Systems for
Hybrid Sorghum

12. Hybrid Seed Production
– Getting the cross
• Hybrids are produced by hand
emasculation in corn.
• In wheat, chemicals are used to
sterilize the pollen.
• Cytoplasmic male sterility (CMS) is
used for hybrid seed production in
sorghum and pearl millet.

13. • Hybrid vigor was first recognized in
sorghum in 1927 (Karper and Conner, 1927)
using hybrid seeds produced by hand-
emasculation.
• In 1948, researchers initiated studies to
look for cytoplasmic male sterility as a
method for commercial hybrid seed
production in sorghum.
• Reciprocal crosses between Milo and Kafir
produced the first evidence that a male-
sterility inducing cytoplasm had been
found (Stevens and Holland, 1954).
Quinby and Stevens, 1957. [Quinby JR. 1974.
sorghum Improvement and Genetics of Growth.
Texas A&M University Press. College Station.]
History of Hybrids in Sorghum
– The hunt for cytoplasmic male sterility

14. • Reciprocal F2 populations between Milo and Kafir
showed segregation for male sterility in the F2
generation in Milo cytoplasm.
F1
100% Fertile
Milo/Kafir Kafir/Milo
SegregrateSegregate SegregrateSegregrate SegregrateSegregate SegregrateSegregrate
100% fertile
0% male sterile
60% fertile
40% male sterile
F2
Milo Kafir MiloKafirx xParent lines
History of Hybrids in Sorghum
– The hunt for cytoplasmic male sterility

15. • CMS was used to
create male-sterile
parent lines by
crossing and
backcrossing kafir
varieties (Combine
Kafir 60 and Texas
Blackhull Kafir) with
male-sterile
progenies of the
Milo/Kafir cross.
History of Hybrids in Sorghum
– Seed parent lines
F2
Milo Kafirx
Sterile
50% Kafir
Kafirx
F1
BC1F1 Kafirx
BC2F1 Kafirx
Sterile
75% Kafir
Sterile
87% Kafir
Parents
Fertile
50% Kafir

16. Hybrid seed production
• Three different parent lines are needed
to produce hybrid seed.
Seed
parent
Maintainer Pollinator
A-line B-line R-line
Seed Parent Pollinator Parent
A-line: Male-sterile line used as the seed parent in F1 hybrid seed
production
B-line: Male-fertile maintainer that is genetically identical to the
A-line and used as a pollen source to increase the A-line
R-line: Genetically distinct sorghum with fertility restoration
genes and good combining ability for grain yield
Male-sterile Fertile Fertile

17. X
X
A-line
male sterile B-Line
maintainer
A-line
male sterile
R-line
restorer
Hybrid
Hybrid Grain Sorghum Production (3 parent lines)

18. Identification of BIdentification of BIdentification of BIdentification of B---- and Rand Rand Rand R----lineslineslineslines
Hybrids obtained by
crossing pollinators with a
male-sterile line
The testcrosses are
evaluated for the sterility
maintenance or fertility
restoration in them through
bagging test
Panicles bagged to observe for
fertility reaction
Bagging test - covering 4-6 panicles with a paper bag
before anthesis, and observing the seed-set after 2-3
weeks

19. Evaluation of test crossesEvaluation of test crossesEvaluation of test crossesEvaluation of test crosses
Reaction Conclusion Further usage
Testcrosses exhibiting
absolutely no seed-set
on all the bagged
panicles
Maintainer or non-
restorer or B-line
source of a new A-line
Testcrosses with
complete seed-set on all
bagged panicles
Potential restorer or R-
lines
Serve as male parents to
produce hybrids
Testcrosses with a
partial seed-set on all
the bagged panicles
Serve neither as
restorers nor as
maintainers
Male parents are
rejected
Testcrosses with a full
seed-set on some bagged
panicles and no seed-set
in others
Segregating for fertility-
restoration or sterility-
maintainer genes
Not pursued further

20. Production of AProduction of AProduction of AProduction of A----/B/B/B/B----LinesLinesLinesLines ––––
small scalesmall scalesmall scalesmall scale
Sowing A-/B-lines in the ratio of 4:2
Rouging in A- and B-lines
Removal of pollen shedders from A-lines
Prune the florets of A-/B-lines with protruding anthers, bag
and record date
Pollinate after 4-6 days, each B-line bag can pollinate 2-3 A-
line panicles, mark A××××B and record date
Repeat pollination after 6th or 7th day
Bags removed after 15-20 days after pollination and stapled
around peduncle
Bulk harvest the panicles in A-lines and B-lines separately
and label them clearly

22. Tapping the peduncles of
maintainers with sticks
improves seed set on A-
lines

23. Production of AProduction of AProduction of AProduction of A----/B/B/B/B----LinesLinesLinesLines ––––
large scalelarge scalelarge scalelarge scale
Sowing A-/B-lines in the ratio of
4:2
A strip of 1 m length should be
sown with the B-line across entire
field
Roguing of the off-type plants and
pollen shedders
Open pollination by wind will
ensure seed-set on the A-lines
Self-pollination takes place in the
B-lines
Harvesting of A-line and B-line at
different times, preferably one
after the other to avoid
mechanical mixing

24. The Sorghum Plant, Growth Stages and Associated
Management Practices
Training of Seed Growers in Hybrid Production

25. Training of Seed Growers in Hybrid Production
Seed growers going through the theory of Sorghum hybrid production at SARI

26. Training of Seed Growers in Hybrid Production
Crossing A and B lines Heat sterilization of pollen using polythene bag
Identifying the different parts of the sorghum plant

27. Concluding Remarks
• Although seed production continues to be
major constraint to adoption of hybrid seed
technology in Ghana, I believe that hybrid
cultivars have great potential for
addressing food security.

28. Thank
You