Sorghum Breeding in Ghana - September 2012


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

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Sorghum Breeding in Ghana - September 2012

  1. 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. 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. 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. 4. Constraints to Sorghum ProductionConstraints to Sorghum Production Insects Anthracnose Molds Lodging
  5. 5. ConstraintsConstraints Drought Striga Poor Soil fertility
  6. 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. 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. 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. 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. 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. 11. The Concept of Hybrid Production - Cytoplasmic Male-Sterility Systems for Hybrid Sorghum
  12. 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. 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. 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. 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. 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. 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. 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. 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. 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
  21. 21. Tapping the peduncles of maintainers with sticks improves seed set on A- lines
  22. 22. 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
  23. 23. The Sorghum Plant, Growth Stages and Associated Management Practices Training of Seed Growers in Hybrid Production
  24. 24. Training of Seed Growers in Hybrid Production Seed growers going through the theory of Sorghum hybrid production at SARI
  25. 25. 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
  26. 26. 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.
  27. 27. Thank You