SATrends Issue 30                                                                                                                   May 2003

  • Sorghum to Satiate the Sere
  • Sizzling, Soggy and Sweaty!
  • Vouching for Vouchers
  • Lax Panicles, Gaping Glumes – Just What the Doctor Ordered!
  • 1. Sorghum to Satiate the Sere

    In 1979, a Nigerian released sorghum variety , SK 5912, that had been improved by the Institute for Agricultural Research (IAR), Samaru, Nigeria, was found unsatisfactory by farmers as food. The variety, SK 5912, had poor taste when prepared as tuwo, the traditional stiff porridge, and unacceptable color and overnight keeping quality. The search for alternative uses for this very productive variety was on.

    IAR’s Dr AB Obilana (presently with ICRISAT), spearheaded the efforts to screen and evaluate SK 5912 along with some 500 other accessions, for grain quality traits. By 1982, the collaborative efforts to evaluate suitable varieties of Nigerian sorghum had expanded to include other partners in industry. (Left, ICRISAT sown sorghum in Africa).

    During this same period, the Nigerian Government changed its policy of gradually substituting imported industrial raw materials to one of total and immediate substitution. The effect on the brewing industry, which had been importing its entire barley malt requirement, was substantial. IAR and the Federal Institute for Industrial Research, Oshodi, capitalized on the situation and began collaborative pilot and industrial scale brewing research and development for lager beer. A series of tests were undertaken with Trophy Breweries, Double Crown Breweries, Premier Breweries and later Nigeria Breweries Ltd. By 1983, appropriate malting and brewing procedures for sorghum were established and confirmed, finally using 100% substitution.

    This R4D and industrial success in the use of sorghum and sorghum malt for brewing Lager saves the country more than US$100 million annually. In addition, it has raised the commercial production of Nigerian sorghum variety SK 5912, and two other later-released ICRISAT-bred varieties ICSV 400 and ICSV 111.

    Commercial development in Nigeria blossomed. Malting companies have mushroomed, the use of spent grains (brewers’ waste) in the poultry industry has grown, and academic training and education for degrees and diplomas in the areas of food science and technology have increased significantly. (Right, alternative sorghum products).

    Guinness Nigeria Ltd uses sorghum grain, sorghum malt and maize as adjunct in its breweries to produce stout and malt drinks., and Cadbury Nigeria Ltd. has pioneered the industrial use of sorghum for malt beverages and glucose. These developments are expected to increase the estimated sorghum requirements from the initial 67,000 tons/annum in 1989 to 225,000 in 1995 and 1,500,000 in 2005. Also, and more significantly, the malt drinks and beverages will benefit lactating mothers, children, and invalids.

    Spillover success stories are spreading across Africa – sorghum as an adjunct by the Bralirwa (Heinneken) Brewery in Rwanda; for lager beer brewing in Uganda, and ICSV 111, for Guinness Stout and malt drinks in Ghana.

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    2. Sizzling, Soggy and Sweaty!

    Fed up with nasty pests and diseases infesting your soil? Burn the little blighters out! How? Convert your field into an oven through solarization.

    Soil solarization is a method of heating soil by covering it with transparent polythene sheeting during the hottest period of the year (April/May in India). Farmers of the Deccan Plateau in India have long exploited a form of solar heating of the soil. They plow the soil deep enough to expose the subsoil, and leave it to fallow in the 40º+ temperatures of summer to kill off all sorts of disease and disruption deposited in the dark and dreary depths. ICRISAT scientists, eager to control fusarium wilt of pigeonpea and chickpea, used ideas emanating from Israel and California to enhance the heating process by mulching with polythene sheeting.

    Imagine what happens to anything covered in polythene and left out in the blazing sun for 6 weeks. The blazing temperatures – over 60º in the top 5 cm – are lethal for wilt fungus, insects, nematodes and weeds.

    Though beneficial, certain considerations govern the use of this technique. The land should be thoroughly leveled to eliminate protrusions that might tear the polythene. The land must also be irrigated (50 mm) before solarization. Clear transparent (not black or colored) sheeting of 25-100 µm thickness should be used. Thinner sheeting traps heat more effectively, but thickness should be balanced against durability. Any holes appearing in the sheeting should be sealed immediately. Silicone rubber sealant is most effective. Holes are recognized by the absence of condensed moisture on the inner surface of the polythene. (Left, a field in Patancheru being solarized this summer. Plastic bags filled with mud help to keep the sheets from being blown away by strong winds).

    The addition of fresh organic matter to solarized plots can enhance solarization effects through production of volatile organic compounds that are toxic to pathogens. However, such compounds could also be phytotoxic, so incorporation of organic matter should be experimentally tested for each crop.

    Nodulation and nitrogen fixation can be adversely affected in solarized plots because the rhizobium population declines. However, plant growth and yield can still be good because soil nitrate increases in solarized plots. Relevant rhizobial inoculants should be applied for growing legumes after solarization. Also, because the rhizobial population goes down after solarization, some scientists have used solarized plots to screen rhizobial strains in field conditions instead of in the glasshouse.

    [NB: For centuries, Somalian farmers have utilized a traditional form of solarization. Accustomed to frequent drought, they build dome-like structures over pits where they store their surplus sorghum in good years. The heat inside the domes gets so intense that insects cannot infest the stored food. After being subjected to this treatment, the seed is not viable for planting, but it remains serviceable as food. Ed.] (Right, the mound in the foreground is the dome over the sorghum pit).

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    3. Vouching for Vouchers

    Following natural disasters in Africa, NGOs and government agencies have distributed free seed to farmers, helping them rebuild their agriculture. Unfortunately, free distribution undermines the development of local markets for agricultural inputs. Traders cannot compete with an NGO that gives away seeds for free, so village retailers are reluctant to stock seed or fertilizer for sale. Then, when the relief programs end and the NGOs move on, farmers find it hard to obtain seed or fertilizer because the local market for these no longer exists. Free seed distribution also encourages the “dependency syndrome” when farmers rely on handouts and stop stocking their own seed. Predictably, farmers also tend to undervalue the handouts.

    In short, relief programs address emergency needs but all too often do nothing for long-term needs such as creating a sustainable seed supply system. ICRISAT is looking for solutions that can simultaneously address short- and long-term needs.

    Plan International, a large NGO, has been distributing free maize seed to small-scale farmers in Zimbabwe since 1996. The seed is given to families with foster children, many of them AIDS orphans. During the 2001/02 planting season, Plan teamed up with ICRISAT to test an alternative strategy. Rather than handing out free seed, they distributed vouchers that could be redeemed for seed at local retail outlets. This encouraged farmers to look for seed – and other inputs – at neighborhood retail shops, and encouraged retailers to stock these goods. (Left, exchanging vouchers for seed).

    In the first year of the program, Plan provided a few farmers with vouchers; the others got free seed as before. This allowed the NGO to work out the logistics of voucher distribution and seed stocking in retail outlets, and to compare the advantages and disadvantages of voucher versus direct seed distribution.

    More than 95% of the vouchers were successfully redeemed. While many of the participating farmers suggested improvements in the program, 49% said they preferred vouchers rather than free seed. Another 18% said they had no preferences. The retailers were universally satisfied, and expressed strong interest in continuing to participate in the voucher scheme.

    The program continued during the 2002/03 planting season. ICRISAT and Plan are monitoring program performance and obtaining feedback from farmers and input retailers for further fine-tuning. A seemingly minor change in orientation has led to major improvements, and relief efforts are now strengthening – rather than competing with – an emerging retail sector in poor, drought-prone rural communities.

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    4. Lax Panicles, Gaping Glumes – Just What the Doctor Ordered!

    The Guinea-race of sorghum is one of the five basic sorghum races identified. It accounts for the majority of sorghum produced in Africa and more than 70% in West Africa, the zone of its origin. This race possesses a “portfolio” of adaptive traits such as lax panicles and gaping glumes (which provide resistance to grain mold and insects that can devastate other races), strong photoperiod sensitivity (matches growth duration to available moisture), and resistances to low soil pH, waterlogging and drought.

    Although Guinea-race sorghums show excellent stability of production, their yield responsiveness to intensified production conditions is quite limited. The increasing intensification of sorghum-based cropping systems, particularly in association with cotton production, is creating a growing demand for more input-responsive sorghums in the region. (Right, Guinea-race sorghum in Mali).

    A promising approach to increase the productivity of Guinea-race sorghums, while retaining their required adaptive and quality traits, is the development of Guinea-race hybrids. The joint ICRISAT-Institut d’Economie Rurale (Mali) project on Guinea Sorghum Hybrids supported by The Rockefeller Foundation has provided landmark research for developing sorghum hybrids for the African Savannah zone.

    The project’s first phase shows that high heterosis can be obtained within the Guinea race, and that exciting opportunities exist for enhancing productivity through its exploitation.

    Results from a survey of heterosis showed average heterosis for grain yield of +98% in Mali and +118% in Burkina Faso for crosses onto the short female tester. There were also high levels of heterosis shown for biomass (an advantage of 1-5 tons) and grain number per panicle (an increase of 1500 grains per panicle, equivalent to 80% increase).

    Field procedures were refined that enabled rapid development of male-sterile (female) parents from highly photoperiod-sensitive guinea-race accessions. The first photoperiod-sensitive lines are now available and are being used to create the first experimental hybrids.

    A second phase of this project is planned to:

    • Define heterotic pools from which to develop parents and assure sustained genetic gains from hybrid breeding
    • Extend sampling and evaluation of Guinea landrace materials for each targeted agro-ecological zone (northern Sudanian, southern Sudanian and northern Guinean)
    • Develop techniques for Guinea-race hybrid seed production and foster expertise among seed producers

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