Cassava project launches database

Cassavabase, a database that promotes open access data sharing, was launched recently.

IITA is a major contributor of data to www.cassavabase.org and will host this information resource through the NEXTGEN Cassava project.

Cassavabase features phenotypic and genotypic data generated by cassava breeding programs involved in the NEXTGEN Cassava project at Cornell University supported by a US$25.2 million grant from the Bill & Melinda Gates Foundation and the Department for International Development of the United Kingdom.

The database makes the data immediately and openly accessible to the whole cassava community prior to publication. It is being developed by Lukas Mueller, adjunct professor of plant breeding and genetics at Cornell, at the Boyce Thompson Institute in Ithaca, New York.

Cassavabase provides a “one-stop shop” for cassava researchers and breeders worldwide. In addition to phenotypic and genotypic data, Cassavabase offers access to all genomic selection analysis tools and phenotyping tools developed by the NEXTGEN Cassava project, and links to auxiliary genome browsers, ontology tools and social networking tools, for the cassava community.

Biocontrol product reduces mortality in poultry

A study by scientists from IITA and the University of Ibadan, Nigeria, has found that poultry fed with maize treated with aflasafeâ„¢ experienced reduced mortality in addition to other benefits.

Results from the feeding experiment involving 1,020 broilers showed that the use of maize from aflasafeâ„¢-treated feeds reduced mortality rate by 43.9%, feed intake dropped by 10.4%, and there was an increase of 3.3% in feed conversion ratio.

The results show the impact of aflasafe™—a biological control product developed by IITA for controlling aflatoxins.

Produced by toxigenic strains of Aspergillus flavus, aflatoxins have become a menace in developing countries, contaminating about 25% of grains produced in the region. The aftermath effects of consuming aflatoxin-contaminated grains include stunting in children, liver cancer, and even death.

Ecofriendly bioherbicide approach for Striga control

Abuelgasim Elzein, a.elzein@cgiar.org, and Fen Beed

Root parasitic weeds of the genus Striga are a significant constraint to cereal and cowpea production in sub-Saharan Africa. They can cause total crop losses particularly during drought, in infertile soils and cereal monocropping. Striga causes annual losses of US$7 billion and affects incomes, food security, and nourishment of over 100 million people mostly in sub-Saharan Africa.

Each Striga plant can produce thousands of seeds, viable for over 10 years. Their intimate interaction with different host plants prevents the development of a silver bullet control technology that subsistence farmers can adopt. Hence, it is widely accepted that an integrated approach to Striga management is required for which biocontrol represents a crucial component.

Bioherbicide innovation
A bioherbicide is a plant pathogen used as a weed biocontrol agent (BCA), which is applied at sufficient rates to rapidly cause a disease epidemic that kills or severely suppresses the target weed. The use of biocontrol technology to manage Striga is a desirable control method as it is environmentally friendly, safe to farmers and crop consumers, specific to the target host, and has the potential to be economically viable. In addition, biological control also assists in the development of a balance of nature, the creation of more biodiversity, and sustaining of complex ecological interactions.

Since the early 1990s, a series of intensive disease surveys in many countries of sub-Saharan Africa has evaluated hundreds of microorganisms for their pathogenicity and virulence against Striga. Fusarium oxysporum Schlecht isolates have been the most promising. However, the discovery of a highly effective pathogen is only one step in the process of developing bioherbicides, for which the inoculum mass production, formulation, delivery, and storage ability must be optimized, and the mode of action, host specificity, and biosafety evaluated and fully understood.

The most widely studied and used fungal isolate that met all requirements for a potential bioherbicide for Striga is F. oxysporum Schlecht f. sp. strigae Elzein et Thines (isolates Foxy2 and PSM197). These are highly virulent, attack Striga in all growth stages—from seed to germination, from seedling to flowering shoot; protect the current crop yield; and prevent seed formation and dispersal.

F. oxysporum f. sp. strigae is highly host-specific to the genus Striga, and does not produce any known mycotoxic compounds. Thus, its use does not pose health risks to farmers, input suppliers, traders or consumers or threaten crops or the environment. Its unique DNA constitution differs from other forms of F. oxysporum deposited in GenBank, known to cause crop diseases. Indeed, this ensures its biosafety and greatly facilitates its wider application and use as a bioherbicide.

In addition techniques for massive production of inoculum of F. oxysporum f. sp. strigae was optimized based on simple and low-cost methods and using inexpensive agricultural by-products available in sub-Saharan Africa. The chlamydospores produced by this fungus have the advantage of being able to survive extreme environmental events while still remaining viable. This is an important feature required for a BCA suited to hot and dry climatic conditions of cereal production in sub-Saharan Africa, and to produce stable, durable, and pathogenic propagules.

Extensive research by the University of Hohenheim (UH, Germany), IITA (Benin), McGill University (Canada), and Institute for Agricultural Research – Ahmadu Bello University (Nigeria), has enhanced application of F. oxysporum f. sp. strigae, its formulation into bioherbicidal products, and its delivery for practical field application. The Striga bioherbicide contains the Striga host-specific F. oxysporum f. sp. strigae, applied in massive doses to create a high infection and disease level to kill or severely suppress Striga.

Promotion in West Africa
The bioherbicide is a component of the IITA-led project, Achieving sustainable Striga control for poor farmers in Africa, funded by the Bill & Melinda Gates Foundation to intensively promote technologies to combat Striga in sub-Saharan Africa. The project will validate the potential of the bioherbicide seed treatment technology across major Striga-infested agroecological zones and maize-based farming systems, while also confirming the biosafety and developing molecular detection tools. Here are the highlights of the results:

Technology validation: Several multilocation trials were conducted under natural and artificial Striga infestation across two agroecological zones in northern Nigeria to evaluate the efficacy of Striga bioherbicide (F. oxysporum f. sp. strigae). The inoculum produced by UH and SUET seed company was delivered as a film-coat on maize seeds (see below).The application of the bioherbicide technology in combination with Striga resistant maize reduced Striga emergence by 73% and 39%, compared to the susceptible and resistant controls, respectively, and prevented 81% and 58% of emerged Striga plants from reaching flowering and 56% and 42% of the maize plants from attack by Striga (see next page). The combination of bioherbicide with Striga susceptible variety significantly reduced Striga emergence by 53%, resulting in 42% reduction in number of flowering plants and in 21% increase in grain yield compared to the susceptible control.

In addition, disease symptoms were recorded on emerged Striga plants parasitizing maize plants coated by the bioherbicide. The reduction in Striga emergence across maize varieties indicates the effectiveness of the bioherbicide to attack seeds under the soil surface. The synergistic effect of the bioherbicide technology combined with the Striga resistant maize is expected to reduce the Striga seedbank and thus the impact of Striga on subsequent maize crops.

Biosafety: To further ensure the safety of Striga BCA and to demonstrate and increase awareness among farmers, regulatory authorities, and stakeholders, a wide host range study was carried out using 25 crops in collaboration with IAR-ABU and the Nigerian Plant Quarantine Service (NPQS)  under field and screenhouse conditions in Nigeria. Results revealed that none of the test plants showed any infection by the biocontrol agent both in the field and screenhouse, and no detrimental growth effects were measured or visual losses to plant health recorded in any of the inoculated crops tested, i.e., inoculation with the Striga BCA did not cause any delay in emergence, and a decrease in plant height, plant vigor, chlorophyll content per leaf, shoot fresh and dry weight. Hence, the Nigerian regulatory authorities (NPQS, NAFDAC) and other stakeholders were satisfied and confident that no disease was produced on plants other than Striga by the BCAs and that it is safe to use. In addition, a mycotoxin produced by Striga bioherbicide  F. oxysporum f. sp. strigae was analyzed and evaluated by our project partner, the University of Stellenbosch in South Africa. An evaluation of existing isolates of F. oxysporum f. sp. strigae does not produce well-known mycotoxins (e.g., Fumonisin and Moniliformin) that pose a threat to animal or human health. This finding further confirms the safety of this bioherbicide.

Molecular detection tools: Development of a monitoring tool specific to the Striga bioherbicide is important to certify inoculum quality, monitor the presence and persistence of the BCA in soils, and validate its environmental biosafety. UH is developing a monitoring tool.

The AFLP fingerprinting technique was successfully used in developing a primer pair capable of differentiating the F. oxysporum f. sp. strigae group from other Fusarium species. In addition, the monitoring tool has shown a high specificity for isolate Foxy2 and was used to monitor its spread and persistence in rhizobox experiments under different management practices using Kenyan soils. This promising result provides a proper baseline to further the existing primer set.

Bioherbicide + pesticide technology: The novel combination and integration of the bioherbicide technology plus imazapyr herbicide for Striga control with pesticides in a single-dose seed treatment to control fungal pests offers farmers with maize seed that is able to achieve its yield potential. The use of each technology (BCA or imazapyr) has been shown to be effective when applied independently using seed coating techniques, but have not been integrated.

The compatibility of Striga BCAs with different pesticides (herbicides and fungicides with insecticide components) was studied in vitro in the laboratory. Striga BCAs showed excellent compatibility with imazapyr (a herbicide seed coating used in combination with IR maize to control Striga), Metsulfuron Methyl (MSM) (a herbicide seed coating developed by DuPont to control Striga in sorghum), and glyphosate (an intensively used herbicide). A similar result was also achieved with the commonly used seed treatment fungicides at the recommended application doses.

Accordingly, doses and complementary seed coating protocols for the three compatible technologies (BCA, herbicide, and fungicides) have been developed and IR maize seeds were successfully coated with a single-dose seed treatment of BCA inoculums and imazapyr. The results showed that imazapyr did not interfere with the BCA during seed coating, with BCA growth and sporulation after coating, and with IR maize seed germination. Seeds of IR maize varieties can thus be coated with the herbicide and the BCA and then fungicide and delivered to farmers using the same input pathway. Screenhouse and field trials are being carried out to generate data on the combined efficacy of the applied technologies. The demonstrated compatibility of Striga BCA with the different pesticides that contain a wide range of active ingredients indicate that the combination and delivery of the Striga bioherbicide technology with a large number of pesticide products is possible. These findings are expected to provide a triple action seed coating package for direct control of Striga and fungal diseases of maize in sub-Saharan Africa.

Suitability to African farming systems
Our strategy for scaling-up the bioherbicide innovation is based on using technology appropriate to Africa to ensure that sustained production of the bioherbicide is feasible at a cost affordable to African small-scale farmers. The seed-coating treatment requires significantly less inoculums, establishes the BCA in the cereal rhizosphere, i.e., the infection site of Striga, and provides a simple, practical, cost-effective delivery system for adoption by input suppliers to subsistence farmers. Arabic gum as a coating material has been shown to increase the rate of mycelia development and enhance BCA sporulation. Its availability in sub-Saharan Africa at a low price is an additional economic advantage. A commercial seed coating process, developed and optimized at UH with SUET Seed Company in Germany, is being transferred and adapted at IITA, Ibadan, to be used as an experimental production unit for capacity building and as a model for eventual transfer of seed treatment technology to the private sector after validation.

Outlook
One unique advantage of this bioherbicide is that the ability of Striga to become resistant to it is virtually unknown as a consequence of the suite of enzymes and secondary metabolites that the BCA produce to become pathogenic and virulent against the target (Striga). Hence after validation, delivering the bioherbicide technology in combination with resistant maize or with the herbicide imazapyr is expected to increase efficacy in controlling Striga. Bioherbicide and other compatible technologies have different modes and sites of action against Striga, and in a combination they will have a much greater chance of reducing the potential risk of development of resistance to a single technology (resistant varieties or herbicides) used separately and repeatedly.
The potential delivery of coated seeds of resistant maize with bioherbicide in one package to farmers using the same input pathway will reduce transaction and application costs and enhances the economic feasibility and adoptability of the technologies. Similarly, compatibility of BCA with imazapyr and fungicides allow seed coating of IR-maize with bioherbicide, imazapyr, and fungicides with a single-dose seed coating application.

Future plans
Currently, large-scale field testing is ongoing and is being implemented to further validate bioherbicidal efficacy across two agroecological zones where the common scenarios for maize infestation by Striga in northern Nigeria are represented. For understanding of farmers’ preferences and perceptions, socioeconomic analysis and cost-benefit analysis of bioherbicidal technology based on field data/surveys and interviews, current market information, and links with other Striga control strategies will be undertaken. After validation, dissemination and commercialization will be promoted through private sector partnerships and integrated with other control options such as resistant varieties, IR varieties combined with seed treatment with imazapayr, crop rotation with legumes, and soil fertility management practices, to achieve sustainable management of Striga.

Partners
IITA (Dr F. Beed, Dr A. Elzein & Dr A. Menkir), Institute for Agricultural Research – Ahmadu Bello University (Dr A. Zarafi), Nigeria; University of Hohenheim (Prof G. Cadisch, Dr F. Rasche & Prof J. Kroschel), Germany; The Real-IPM Company Ltd (Dr H. Wainwright), Kenya; University of Stellenbosch (Prof A. Vilioen), South Africa; and McGill University (Prof A. Watson), Canada.

References
Beed F.D., S.G. Hallet, J. Venne, and A. Watson. 2007. Biocontrol using Fusarium oxysporum; a Critical Component of Integrated Striga Management. Chapter 21 in Integrating New Technologies for Striga control: Towards ending the Witch-hunt (Ejeta, G. and J. Gressel, eds). World Scientific Publishing Co. Pte. Ltd. pp 283-301.

Ciotola, M., A. DiTommaso, and A. Watson. 2000. Chlamydospore production, inoculation methods and pathogenicity of Fusarium oxysporum M12-4A, a biocontrol for Striga hermonthica. Biocontrol Science and Technology 10: 129-145.

Ejeta, G. 2007. The Striga scourge in Africa: A growing pandemic In: Ejeta, G. and J. Gressel, eds. Integrating New Technology for Striga Control: Towards Ending the Witchhunt. World Scientific Publishing Co. Pte. Ltd., UK. pp. 3-16.

Elzein, A.E.M. 2003. Development of a granular mycoherbicidal formulation of Fusarium oxysporum “Foxy 2” for the biological control of Striga hermonthica. In: “Tropical Agriculture 12– Advances in Crop Research (2)” (J. Kroschel, ed.). Margraf Verlag, Weikersheim, Germany, 190 pp, ISBN 3-8236-1405-3.

Elzein, A., J. Kroschel, and V. Leth. 2006. Seed treatment technology: an attractive delivery system for controlling root parasitic weed Striga with mycoherbicide. Biocontrol Science and Technology, 16(1) 3-26.

Elzein, A., F. Beed, and J. Kroschel. 2012. Mycoherbicide: innovative approach to Striga management. SP-IPM Technical Innovations Brief, No. 16, March 2012.

Kroschel, J. and D. Müller-Stöver. 2004. Biological control of root parasitic weeds with plant pathogens. In: Inderjit, K. (ed.), Weed biology and management. Kluwer Academic Publishers, Dordrecht, The Netherlands, pp. 423–438.

Kroschel, J., A. Hundt, A.A. Abbasher, J. Sauerborn. 1996. Pathogenicity of fungi collected in northern Ghana to Striga hermonthica. Weed Research 36 (6), 515–520.

Marley, P.S., S.M. Ahmed, J.A.Y. Shebayan, and S.T.O. Lagoke. 1999. Isolation of Fusarium oxysporum with potential for biocontrol of the witchweed Striga hermonthica in the Nigerian Savanna. Biocontrol Science and Technology 9: 159–163.

Venne J., F. Beed, A. Avocanh, and A. Watson. 2009. Integrating Fusarium oxysporum f. sp. strigae into cereal cropping systems in Africa. Pest Management Science 65: 572–580.

Breakthroughs in maize breeding

B. Badu-Apraku, b.badu-apraku@cgiar.org, M. Oyekunle, and R.O. Akinwale

Extra-early maize inbreds and hybrids that are resistant to Striga, tolerant of low nitrogen (N) and drought at flowering and grain filling periods, and that combine tolerance for these three stresses are now available in sub-Saharan Africa as a result of the painstaking research under the Maize Improvement Program at IITA.

Maize is the most important cereal crop after rice in West and Central Africa. However, during the last two decades, its production and productivity have lagged behind population growth for several reasons. These include low soil fertility, little or no use of improved seeds, herbicides, and fertilizers, inadequate plant density, weed infestation, poor tillage practices, labor shortages, increased levels of biotic and abiotic constraints, and high costs of inputs. In addition, serious infrastructural and institutional constraints have limited the adoption of improved maize technologies. Climate change and its associated effects have also resulted in altered weather patterns leading to erratic and unreliable amounts and distribution of rainfall, resulting in drought. Presently, stresses from Striga infestation, drought, and low N are the most important biotic and abiotic factors that limit maize production in the region.

Four maturity groups are needed to satisfy the maize varietal requirements of the subregion for human consumption, poultry and livestock feed, and industrial use. These groups are the extra-early varieties (80-85 days to maturity), early (90-95 days to maturity), intermediate (100-110 days to maturity), and late (>120 days to maturity). Extra-early varieties play a unique role in filling the hunger gap in July in the Sudan savanna and the northern Guinea savanna zones after the long dry season. The extra-early varieties are also used for late planting when the rains are delayed, for intercropping with cassava, millet, and sorghum, and as “green maize” in the forest agroecology where they allow early access to the market for a premium price. The availability of early and extra-early varieties has significantly contributed to the expansion of maize to new frontiers in the savanna agroecology, replacing sorghum and millet.

A major strategy of IITA’s Maize Improvement Program is to breed cultivars that are Striga resistant and drought- and low-N tolerant to increase and stabilize maize yield production in the subregion. Two approaches have been adopted for drought tolerance. The first is to breed for extra-early maturing cultivars that are drought escaping. These cultivars are adapted to drought-prone environments in West and Central Africa; they mature and complete their life cycles before severe moisture deficit occurs or before the onset of terminal drought. The second strategy is to breed drought-tolerant cultivars with better adaptation to drought-prone environments under induced drought stress. This is achieved by introgressing or introducing into extra-early cultivars the genes for drought tolerance to enable them to withstand mid-season drought when it occurs during the flowering and grain-filling periods.

Breeding for adaptation to drought-prone environments
The goal of the IITA Maize Program is to develop open-pollinated and hybrid maize cultivars adapted to the different forms of climatic variation prevalent in West and Central Africa with emphasis on drought stress. The naturally available mechanisms for drought escape and drought tolerance in the germplasm and the prevailing production environments in West and Central Africa were exploited to develop cultivars with enhanced adaptation to stressful environments. Drought escape occurs when the plant completes critical physiological processes before drought sets in. This trait is quite desirable in cultivars to be released to farmers in areas where terminal drought is most prevalent. Adaptation to drought-prone environments, on the other hand, is under genetic control and indicates the presence of physiological mechanisms that minimize or withstand the adverse effects of drought if and when it occurs. Cultivars with enhanced adaptation to drought-prone environments are useful where drought occurs randomly and at any growth stage of the maize crop. This is quite relevant in West and Central Africa where drought occurrence is erratic, with varying timing and levels of intensity.

Using the two strategies, IITA has, during the last two decades, developed a wide range of high-yielding drought tolerant or drought-escaping extra-early Striga resistant populations (white and yellow endosperm), inbred lines, and cultivars to combat the threat posed by the weed Striga hermonthica and recurrent drought in the savannas of West and Central Africa. The extra-early populations from which the inbred lines and cultivars were derived were formed from crosses between local landraces, exotic, and introduced germplasm identified through extensive multilocation trials in West and Central Africa. They were selected based on high grain yield, earliness, and resistance to the maize streak virus (MSV), and above all on adaptation to the high temperatures and drought stress characteristic of the Sudan savanna in Burkina Faso, Mali, Mauritania, Ghana, Nigeria, and Niger.

The extra-early germplasm was expected to have adaptive traits for tolerance to these stresses in the environments where the cultivars had survived. Some of the extra-early inbred lines in the IITA Maize Program not only escaped drought stress but also seemed to possess drought tolerance genes. The inbreds, early, intermediate, and late-maturing, are also able to withstand the mid-season drought that occurs during the flowering and grain filling periods in the savannas of West and Central Africa.

Selection for tolerance for drought under managed drought stress
Selection for extra-earliness in the IITA Maize Program has been carried out in the savannas of the subregion. So far, several cultivars have been bred, some of which have been released to farmers after extensive testing in the different countries in the subregion.

Induced drought stress for selection for drought tolerance in extra-early maize is achieved by withdrawing irrigation water from 21 days after planting until maturity, with the plants relying on water stored in the soil for growth and development. Promising inbred lines selected for drought tolerance were used to develop extra-early maturing open-pollinated and hybrid cultivars with enhanced adaptation to drought-prone environments. The selected lines are also used as sources of tolerance genes for introgression into extra-early breeding populations that are undergoing recurrent selection. Using this strategy, several extra-early drought tolerant and Striga resistant cultivars with enhanced adaptation to drought-prone environments have been bred.

Selection for tolerance for low soil N
In most developing countries, maize production is carried out under conditions of low soil fertility which further compounds the problems of drought stress and Striga infestation on productivity. Estimated yield losses from N-stress alone can be as high as 50% (Wolfe et al. 1988). Therefore, the development and adoption of maize germplasm with tolerance for multiple stresses are crucial for increased productivity. Banziger et al. (1999) showed that improvement for drought tolerance also resulted in specific adaptation and improved performance under low-N conditions, suggesting that tolerance to either stress involves a common adaptive mechanism.

Identification of inbreds and hybrids with genes for tolerance for low soil N and drought
Three experiments were conducted between 2007 and 2010 in Nigeria to identify extra-early inbreds with tolerance for low N and/or drought stress at flowering and grain-filling periods, and to determine the potential of the inbreds for hybrid production and as a source of germplasm for improving breeding populations. In the first two experiments, 90 extra-early maturing maize inbred lines were evaluated in Nigeria at Ikenne (6º 53’N, 3º 42’E, 60 m altitude, 1200 mm annual rainfall) under managed drought stress and in well-watered environments during the dry seasons of 2007/2008 and 2008/2009. Similarly, the lines were evaluated in low-N (30 kg/ha) and high-N (90 kg/ha) studies at Mokwa (9º 18’N, 5º 4’E, 457 m altitude, 1100 mm annual rainfall) during the growing seasons of 2008 and 2009.

Results identified several stable and high-yielding hybrids ideal for drought environments and pinpointed the fact that the extra-early inbreds and hybrids are not only drought-escaping but also possess genes conferring drought and/or low-N tolerance. TZEEI 6, TZEEI 4, TZEEI 36, and TZEEI 38 were identified as ideal inbreds under drought. Under low N, TZEEI 19, TZEEI 96, and TZEEI 45 were top ranking with TZEEI 19 the ideal inbred. TZEEI 19, TZEEI 29, TZEEI 56, TZEEI 38, and TZEEI 79 were tolerant to both stresses. Eighteen of the 36 hybrids produced above-average yields across environments with four hybrids identified as very stable. TZEEI 29 × TZEEI 21 was the closest to the ideal genotype because it combined large mean performance with high yield stability.

Badu-Apraku et al. (2013) evaluated 17 of the 90 extra-early white maize inbreds tolerant to drought and low-N used in the earlier studies under drought, Striga, and in optimal environments at three locations in Nigeria for 2 years. Results indicated that the test environments were unique and that there were adequate genetic differences among the inbred lines to allow good progress from selection for improvements in the traits and to serve as sources of favorable alleles for improving breeding populations for drought tolerance at the flowering and grain-filling periods and Striga resistance and to serve as parents for developing superior hybrids.

Under drought stress, the mean grain yield of the hybrids ranged from 1114 kg/ha for TZEEI 14 × TZEEI 13 to 2734 kg/ha for TZEEEI 29 × TZEEI 21. The top-ranking hybrid, TZEEI 29 × TZEEI 21, outyielded by 13% the best Striga resistant and drought tolerant early maturing open-pollinated variety, TZE-W DT STR C4. Under well-watered conditions, the top-yielding hybrid was TZEEI 3 × TZEEI 13 (5868 kg/ha) while the lowest was TZEEI 14 × TZEEI 13 (2749 kg/ha). Under artificial Striga infestation, TZEEI 29 × TZEEI 14 was the top ranking hybrid, outyielding by 22% the best Striga and drought tolerant early open pollinated check, TZE-W DT STR QPM.

A stability analysis of the top 20 and worst five single-cross hybrids and four early open pollinated check cultivars revealed TZEEI 29 × TZEEI 14 as the second highest yielding and most stable single-cross hybrid across research environments; the highest-yielding single-cross hybrid, TZEEI 6 × TZEEI 14, was the least stable.

Badu-Apraku and Oyekunle (2012) also conducted two more studies for 2 years at five locations in Nigeria. TZEEI 79 × TZEEI 76 turned out to be the highest yielding and most stable hybrid across environments. It was concluded that the available extra-early yellow maize inbred lines are not only drought-escaping but also possess genes for drought tolerance at flowering and grain-filling periods.

The availability of these Striga resistant, low N and drought-tolerant extra-early inbreds and hybrids should go a long way in reducing the instability of maize yields in sub-Saharan Africa, especially in the savannas and during the second season in the forest ecologies.

References
Badu-Apraku, B. and M. Oyekunle. 2012. Genetic analysis of grain yield and other traits of extra-early yellow maize inbreds and hybrid performance under contrasting environments. Field Crops Research 129: 99–110.
Badu-Apraku., B., M.A.B. Fakorede, M. Oyekunle, and R.O. Akinwale. 2011. Selection of extra-early maize inbreds under low N and drought at flowering and grain-filling for hybrid production. Maydica 56: 29-41.
Badu-Apraku, B., M. Oyekunle, R.O. Akinwale, and M. Aderounmu. 2013. Combining ability and genetic diversity of extra-early white maize inbreds under stress and non-stress environments. Crop Science 53: 9–26.
Badu-Apraku, B., M. Oyekunle, R.O. Akinwale, and A.F. Lum. 2011. Combining ability of early-maturing white maize inbreds under stress and nonstress environments. Agronomy Journal 103: 544-557.
Badu-Apraku, B., M.A.B. Fakorede, A. Menkir, A.Y. Kamara, and A. Adam. 2004. Effects of drought screening methodology on genetic variances and covariances in Pool 16 DT maize population. Journal of Agricultural Science 142: 445-452.
Betran, F.J., J.M. Ribaut, D. Beck, and De Leon D. Gonzalez. 2003. Genetic diversity, Specific combining ability, and heterosis in tropical maize under stress and nonstress environments. Crop Science 43: 797-806.
Bänziger, M., G.O. Edmeades, and H.R. Lafitte. 1999. Selection for drought tolerance increases maize yields across a range of nitrogen levels. Crop Science 39:1035-1040.
Wolfe, D.W., D.W. Henderson, T.C. Hsiao, and A. Alvio. 1988. Interactive water and nitrogen effects on maize. 11. Photosynthetic decline and longevity of individual leaves. Agronomy Journal 80: 865−870.
Yan, W. 2001. GGE Biplot- A windows application for graphical analysis of multi-environment trial data and other types of two-way data. Agronomy Journal 93: 1111-1118.
Yan, W. and J. Frégeau-Reid. 2008. Breeding line selection based on multiple traits. Crop Science 48: 417-423.

Helping smallholder farmers reap the most from drought tolerant maize

Florence Sipalla, f.sipalla@cgiar.org

At the first sign of the short rain season, farmers know that it is time to till the land and plant. In these harsh times, when rain is scarce, some farmers opt to plant before the rain comes to take advantage of every drop. James Mativo from Makaveti Village in Kyanzasu sublocation in Machakos County is one such farmer. He proudly http://iupatdc5.org displays a healthy crop to visitors, with green maize ready for plucking. “I planted just before the season began, to ensure that the crop would sprout when the rain came,” he explains.

For many farmers in the semi-arid Eastern Province in Kenya, preparing fields ahead of the rain is not enough to guarantee a good harvest. Having the right seeds is vital too. Mativo buys certified seeds, suited to the area’s climate, from Dryland Seed Company in Machakos town. “For these dryland varieties, the first rains are very important,” explains Peter Mutua, a Dryland agronomist. “It allows the farmers to take full advantage of this scarce resource from germination. This is particularly important as most farmers in Kenya grow maize under rainfed conditions, even in the semi-arid areas.”

Just as a relay race is a team effort, so is the process of delivering quality seeds to farmers. It takes many people, working together, to ensure that farmers get the best seeds suited to the climatic conditions in their locales. Take the case of drought tolerant maize varieties: the process starts with breeders who develop the germplasm and share it with research partners. They pass the baton to the seed companies who produce large quantities of the seeds which smaller-scale farmers buy from them. The companies cross-pollinate sources of desirable traits to develop maize varieties relevant to the farmers. Often they start with sources from public research organizations such as IITA and the International Maize and Wheat Improvement Center, known by its Spanish acronym CIMMYT.

“We try to improve the existing varieties and come up with more that are better than those in the market,” says Peter Setimela, a CIMMYT maize breeder. “With climate change, varieties developed 20 years ago are no longer suitable for the changing environment.” Breeders working under the Drought Tolerant Maize for Africa Initiative led by CIMMYT have developed varieties known as the Kenya Dryland Varieties (KDV) series. KDV 1–6 varieties were released to farmers by the Kenya Agricultural Research Institute (KARI), as well as Freschco and Dryland Seed Companies. The fourth variety of the series is the one now growing on Mativo’s quarter-hectare farm.

It is not only climate change that concerns breeders; they also want to develop varieties that are disease resistant and relevant to the farmers’ other needs – proper milling and cooking quality or flavor, for example. “This is why we have farm trials,” explains Peter Setimela. These trials are done in collaboration with the national research organizations, such as KARI in Kenya. “We look for those traits that farmers prefer. In Kenya, they like white maize for making ugali. In Zimbabwe, some people prefer ZM309 because it is sweet when roasted.”

The seed companies and KARI multiply seeds to furnish supplies adequate to the farmers’ demands, but they also depend on farmers they hire to produce those seeds. “We work with groups of farmers who each have at least 5 acres (2.5 ha),” says Ngila Kimotho, Managing Director of Dryland Seed Company. The seed company clusters the farmers by sublocation and trains them. This, according to Musa Juma, a contract farmer for Dryland in Kibwezi, Eastern Province, is “risk-free planting. This is because you are planting for a known market; as you plant, you don’t have to start worrying about where to sell the produce. An additional perk is that the company provides the seeds.”

Seed companies also use local demonstration farms to show the performance of various maize varieties, winning over farmers to the new varieties that outperform traditional ones. Dryland Seed Company also uses vernacular radio programs to disseminate information on the most productive varieties. “These are interactive shows. We have farmers calling in to find out the best variety to grow, when and where to obtain the seeds,” explains Kimotho. He said that farmers prefer open-pollinated varieties that are early-maturing and drought tolerant and thus better suited to planting in the short rains in the region.

“The basic need in the dry areas is food security,” says Kimotho, adding that farmers sell the surplus grain only when they have a rare bumper harvest. To cater for the diversified market, Dryland markets seeds in packets from 100 g to 1 kg, so there is an affordable option for every farmer. The 100 g package is popular with those who are keen to try out new varieties. “Even students buy it for their parents to try,” says Kimotho. Smallholder farmers, most of whom are women, also choose this option to ensure a subsistence maize crop for their families.

By the same token, farmers are reluctant to place all their trust in a single variety. On Mativo’s farm, he spreads the risk by planting hybrids alongside beans and cowpea. “When the rains are good, the hybrids do well and have high yields, but if the rains are not so good, I still have food from the KDV,” says Mativo. “It would be very sad for a farmer to lack food. When I have food, then my neighbors are also food secure.” Mativo uses ox-drawn plows on his farm, but he also occasionally employs a few manual laborers, some of whom he pays in kind with maize grain, at their request.

In the rare years that farmers get a bumper harvest, they need to sell the surplus. But when there is a plentiful supply, the price of maize is low, and storage becomes an even more vital component of the value chain: the grain requires a pest-free mechanism that also saves the http://dailykhabarnama.com/buy/ maize from fungal infections, some of which can produce deadly toxins.

Ultimately, every participant in this value chain, the relay race, is focused on one thing–food security. “Working with partners in the national agricultural systems and seed companies, the DTMA program aims to produce 70,000 t of seeds by 2016 with drought tolerant maize varieties in 13 African countries,” said Tsedeke Abate, the Program Leader based in Nairobi. He added that this is enough to plant about 2.8 million ha, an area equivalent to the farms of about 7 million smallholder households.

New maize variety brings hope to Kenya’s drylands

Wandera Ojanji, w.ojanji@cgiar.org

Last harvest, many farmers in lower Eastern Kenya were left staring in dismay at their failed maize crops. Once again, droughts had left people in the area desperate; they must purchase maize themselves or rely on famine relief food operations.

However, a few farmers were expecting bumper maize harvests―neither via miracles nor witchcraft―thanks to a new maize variety which is both drought tolerant and resistant to stalk borers, two of the biggest production constraints in the region.

The variety, referred to as CKIR04003 (CIMMYT/Kenya Insect Resistant), represents joint breeding efforts between the Kenya Agricultural Research Institute (KARI) and CIMMYT, under the Developing Maize Resistant to Stem Borer and Storage Insect Pests for Eastern and Southern Africa – IRMA III Conventional Project (a predecessor to the Insect Resistant Maize for Africa Project). Released in 2006, CKIR04003 has the added advantage of being an open-pollinated, early maturing, and high yielding variety―31 to 45 bags/ha, according to Stephen Mugo, CIMMYT’s Maize Breeder.

One of the farmers benefiting from the new variety was Paul Ndambuki. He chose CKIR04003 because, as he said, he needed a variety that could withstand droughts as well as being resistant to stem borers. “From the information provided by KARI, I felt CKIR04003 was the variety I wanted. I did not need any further prodding before trying it out.”

It was a decision that paid off, despite less than perfect preparation. “I got the seeds towards the end of March. Because I was in a rush to plant before the onset of rains, I didn’t plant with fertilizer. I added compound fertilizer only after germination. I had hoped to top-dress with CAN fertilizer. But this did not happen as it rained for only two weeks in the entire growing season. I was a worried man,” states Ndambuki. “But my worries gradually turned into amazement. In complete contrast to my neighbors’ farms, under local varieties or other hybrids, my maize was so green and robust. It looked like a crop under irrigation.”

After six weeks, the maize remained free from stem borers. These borers normally cause huge losses in the region, and also make the attacked maize susceptible to fungal infestation and aflatoxin. Ndambuki got 35 bags of maize from his 0.8 ha of CKIR04003, compared with the 12 bags he had obtained from 1 ha the previous season.

Impressed by Ndambuki’s enthusiasm, KARI has named the variety Pamuka1, in honor of Paul, his wife Jane Mumbua, and the Kamba community.

Two extra-early maturing white maize hybrids released in Nigeria

B. Badu-Apraku, b.badu-apraku@cgiar.org, S.A. Olakojo, G. Olaoye, M. Oyekunle, M.A.B. Fakorede, B.A. Ogunbodede, and S.E. Aladele

Two extra-early maturing hybrids with combined resistance/tolerance to Striga, drought, and low soil nitrogen have been released in Nigeria by the Institute of Agricultural Research and Training (IAR &T) in Nigeria. The extra-early hybrids originally known as IITA Hybrid EEWH-21 and IITA Hybrid EEWH-26 and now designated as Ife Maizehyb-5 and Ife Maizehyb-6 were developed by IITA, and tested extensively in Nigeria in partnership with IAR & T, through the funding support of the Drought Tolerant Maize for Africa (DTMA) Project. The DTMA Project is executed by CIMMYT and IITA with funds provided by the Bill & Melinda Gates Foundation.

Early (90-95 days to maturity) and extra-early (80-85 days to maturity) maize varieties can contribute to food security especially in marginal rainfall areas of West and Central Africa. These varieties are ready for harvest early in the season when other traditional crops such as sorghum and millet are not ready, and are thus used to fill the hunger gap in July in the savanna zone when all food reserves are depleted after the long dry period. Furthermore, there is a high demand for the early and extra-early cultivars in the forest zone for peri-urban maize consumers.

These maize varieties provide farmers the opportunity to market the early crop as green maize at a premium price in addition to being compatible with cassava for intercropping (IITA 1992). However, despite the potential of early and extra-early maize to contribute to food security and increased incomes of farmers in the subregion, maize production and productivity in the savannas are severely constrained by drought, Striga parasitism and low soil-nitrogen.

During the last two decades, IITA in collaboration with national scientists in West and Central Africa, has developed a wide range of high-yielding drought-tolerant and/or escaping extra-early Striga resistant populations (white and yellow endosperm), inbred lines, and cultivars to combat these threats.

Extra-early inbreds and hybrids that are not only tolerant to low N and drought escaping (characteristics of extra earliness) but also possess genes for tolerance to drought during flowering and grain-filling periods are now available in Nigeria (Badu-Apraku and Oyekunle 2012).

Saving maize from parasitic Striga in Kenya and Nigeria

Thousands of farmers in Kenya and Nigeria are successfully battling the invasion in their farms by Striga, a deadly parasitic weed. They are now enjoying higher yields in maize, the number one staple in Kenya and an important cash crop in Nigeria.

The key to managing this weed is to combine sustainable multiple-pronged technology options being advocated by the Integrated Striga Management in Africa (ISMA) project to sustainably eliminate the weed from their fields, says Dr Mel Oluoch, ISMA project manager.

Striga attacks and greatly reduces the production of staple foods and commercial crops such as maize, sorghum, millet, rice, sugarcane, and cowpea. The weed attaches itself to the roots of plants and removes water and nutrients and can cause losses of up to 100% in farmers’ crops. Furthermore, a single flower of the weed can produce up to 50,000 seeds that can lie dormant in the soil for up to 20 years.

The weed is the number one maize production constraint in Western Kenya, and Nigeria, infesting most farmers’ fields.

The management technologies range from simple cultural practices such as intercropping maize with legumes such as groundnuts; crop rotation of maize with soybean which stimulates Striga to germinate but which later dies in the absence of the maize host to latch onto; deploying a “push-pull’ technology that involves intercropping cereals with specific Striga-suppressing desmodium forage legume; using Striga resistant maize varieties; and using CIMMYT-developed maize varieties resistant to Imazapyr—a BASF herbicide (StrigAway®), which kills the Striga seed as it germinates and before it can cause any damage; and adopting Striga biocontrol technologies which uses a naturally occurring host-specific fungal pathogen that kills the Striga at all stages without affecting other crops.

Imazapyr-resistant maize varieties with natural resistance to Striga hermonthica have been developed. The best hybrids produce 19% to 333% more grain yields under Striga infestation, sustain 17% to 57% less Striga damage, and support 63% to 98% less emerged Striga plants compared with the commercial hybrid check. In addition, new Striga resistant hybrids and open-pollinated synthetic varieties (OPVs) that combine Striga resistance with good standability have been developed. The hybrids and OPVs produce 47% to 126% more grain yields under Striga infestation, sustain 17% to 60% less Striga damage, and support 45% to 90% less emerged Striga plants compared with the common farmers’ varieties and commercial hybrids.

ISMA (http://www.iita.org/web/striga/) is funded by the Bill & Melinda Gates Foundation and is being implemented with the International Center of Insect Physiology and Ecology, CIMMYT, African Agricultural Technology Foundation, BASF Crop Protection, and other national agricultural research and extension services and private sector players in Kenya and Nigeria.

Promoting the use of drought tolerant maize in Nigeria

Tahirou Abdoulaye, t. Abdoulaye@cgiar.org and Onu Anyebe

The DTMA project of IITA-CIMMYT aims at developing and deploying drought tolerant varieties in 13 sub-Saharan African countries. In West Africa, the project, led by IITA and its national partners, is being implemented in Nigeria, Bénin, Mali, and Ghana. In Nigeria, the project covers all the maize-producing agroecologies.

As part of the promotion efforts, farmers’ groups were formed in Kano and Katsina States in northern Nigeria to demonstrate the performance of these improved varieties but also to organize the farmers so that they could have access to the critical inputs needed in maize production.

IITA introduced the drought tolerant variety EVDT 99 to the community of Ruwan Kanya in Rano Local Government Area (LGA) of Kano State, in 2009. This was done as part of the efforts of the DTMA project to inform farmers about drought tolerant maize, both established and newly developed varieties.

A maize production innovation platform was organized around EVDT 99 in the village of Ruwan Kanya. Fourteen farmers initially participated in the production of seeds. For the first year, six farmers each planted 10 kg of the improved variety and eight farmers each planted 5 kg. Other farmers saw the maize fields during the growing season and requested seeds from the participating farmers; eventually the number of participants increased to 36 in 2010. They formed an association to enable them to obtain fertilizer from the State Government.

In the following season, more farmers planted the variety. Six were able to increase their farmland; others bought inputs that increased their production. For example, Alhaji Bako Monitor bought a pair of bullocks for his farm work and for the transportation of goods to the market.

Almost four years later, the DT variety EVDT 99 is now being called Ar Ashiru (named after the president of the farmers’ group). It is grown in the 10 communities in Rano LGA, one community in Sumaila LGA, one community in Tudun Wada LGA, all in Kano State and in Soba/Risipa in Kaduna State. Other communities in Kano State that got EVDT 99 from Ruwan Kanya LGA include Gidan Zangi, Garabi, Doka, Zazaye, Takalafia, Gana, Kajorawa, Yelwa ciki, Tadesha, and Kundu.

Some farmers also planted EVDT 99 in the dry season after harvesting tomatoes between February/March. The dry season maize is harvested fresh and consumed after being roasted or boiled.

The farmers’ association in Ruwan Kanya was linked to the Kano State Government in 2010. The members were able to purchase subsidized fertilizer at 1100 naira/bag (~US$7) including transportation to the village. The following year, in 2011, the government changed; the new government did not allocate fertilizer to the farmers’ group. The farmers put their money together and the project helped by linking them with a dealer who provided good quality input. They bought the fertilizer in bulk at 5000 naira (~$31) for NPK and 5200 naira for urea and continued seed production.

The farmers say that they appreciate the productivity and earliness of the variety. EVDT 99 responds well to fertilizer and those growing it have had no problem in getting the fertilizer they need to apply.

During the new phase of DTMA, the project team is focusing on getting these farmers linked to seed companies so they can renew their seed stock and continue to purchase quality certified seeds. The drought tolerant maize varieties and hybrids are now being produced and sold by some seed companies in Nigeria, thanks to the efforts of these farmers.

Farmers need to be made aware of the need to renew their seed stock regularly including seeds for open-pollinated varieties such as EVDT to maintain the purity and productivity level of their cultivars.

Joyce MulilaMitti: Better coordination required from agriculture organizations

Dr Joyce MililaMitti is a plant breeder by training; she obtained her PhD from the Southern Illinois University in Carbondale in the USA. She has more than 20 years of experience working initially as a food legume breeder/team leader for the Food Legume Research Team for the Zambia National Agricultural Research System (NARES) and later also as a freelance consultant for several development agencies with a focus on agricultural development and particularly establishing community-based seed systems for smallholder farmers. Before joining FAO in 2007 she worked at senior management level in international NGOs. She is the Crops Officer for FAO at the Regional Office for Africa in Accra, Ghana.

Please describe your job.
My responsibilities are to provide technical support to countries in the region for increased crop production and enhanced food security. The primary objective is to contribute to the capacity development of the national systems to provide adequate technical support towards the sustainable intensification of crop production.

What are your major tasks and thrusts for the African Region (RAF)?
The major tasks cover aspects of crop production and protection and broadly encompass capacity development, technical backstopping support, coordination of regional policy development, and the harmonization of crop-related interventions. These are the key thrusts.

• Strengthening capacities for scaling up the adoption of Good Agricultural Practices (GAPs) for improved crop production and diversification. The GAPs include conservation agriculture, integrated pest and production management, integrated weed management, integrated plant nutrient system, and innovative farmer-led extension approaches.
• Improving the capacities of the National Plant Protection Organizations to implement the International Plant Protection Convention and manage transboundary pests and diseases for increased food security and safe trade in crops and crop products.
• Providing technical support for the reduction of risks associated with pesticide use as a way of minimizing damage to the environment and harm to human health while sustaining reasonable crop productivity by reducing losses due to pests.
• Supporting enhanced knowledge and information exchange for the use and management of Plant Genetic Resources for Agriculture and improved seed system delivery.

What are the major challenges in agricultural development in Africa?
They include the low levels of productivity that most smallholder farmers realize from their farming practices. The factors causing this situation are degraded soils and the general poor soil fertility, unreliable and erratic rainfall characterized by droughts and floods, the high prevalence of pests and diseases, and so on.

Challenges also include those related to poor cropping practices and in particular to the suboptimal use of inputs, such as the use of seeds of low quality (mostly on-farm saved grain as opposed to purchased certified seeds) and the significantly low rates of fertilizer use.

Other challenges are related to an unfavorable policy environment and a generally low investment in agriculture by the national governments, manifested by inadequate support for research, poor infrastructure, poor input and output markets, and inadequate capacities for extension service delivery at the farm level.

The problem of low investment continues to be a challenge even though the countries agreed to contribute 10% of national budgets to Agriculture under the Maputo Declaration. These challenges need concerted efforts and an improved information exchange to achieve better coordination and synergies from the various interventions implemented by the development agencies that support the agricultural sector by addressing these issues. However, the most important factor for the efforts to yield results is adequate political will from the governments to make things happen and especially to encourage public-private partnerships to adequately exploit the potential opportunities that a well developed agriculture sector can provide towards economic development.

What efforts are required to address biotic and abiotic threats in African agriculture?
What is required is more collaboration and better coordination among the different organizations that are involved in working on addressing the challenges so that there is more effective and efficient delivery of interventions and results to the national systems. For instance, the work of CGIAR through the CGIAR Research Programs should involve national partners more closely to achieve impact. This also requires that CGIAR works very closely with the regional economic communities to improve regional coordination and effective information exchange among the national programs.

How can countries overcome the challenges resulting from weak capacities?
This is a major challenge as adequate capacities are necessary for implementing the various programs that are meant to address the challenges highlighted. The ideal solution is for governments to increase their investment in the agricultural sector to address the capacity gaps. However, given that most countries are not able to provide adequately for the sector, the best strategy is to develop the capacities of farmers’ groups, and producers’ associations to provide support for fellow farmers so that there is enough social capacity at the farm level for the transfer of knowledge and skills. A conducive environment for the active participation of the private sector to contribute to providing more innovative extension support and improving access to markets is also the key to addressing weak capacities.

Who are FAO-RAF’s partners?
The key partners for RAF are the African Union and the relevant technical units and RECs (ECOWAS, SADC, EAC, COMESA, IGAD), the Regional Research Organizations (CORAF, ASARECA, CCARDESA), CGIAR centers, NGOs, and most of the various development agencies actively supporting agriculture. These include the relevant ministries that support agriculture programs in the countries (Ministry of Agriculture, Ministry of Environment, Ministry of Health).

How do farmers and producers benefit from your office?
FAO’s support to farmers and producers largely involves normative work that is provided through policymakers and national structures. However, there is also direct involvement with producers and farmers through facilitating the implementation of projects/programs (e.g., convening training events, workshops, facilitating field days etc.).

How could IITA and FAO work together?
Stronger collaboration is required between IITA and FAO. Both organizations can add value to the common areas of each other’s work as they have different comparative advantages. FAO can benefit from the immense knowledge generated by R&D programs of IITA for enriching the technical quality of the support that FAO provides to the countries. IITA can also benefit from the increased visibility of their work provided to the wider and varying levels of actors that FAO has access to; particularly at the policy making level of governments.

What is your advice for IITA?
My advice is that IITA should continue to build on the good efforts already started of building alliances. The approach is effective, enhances linkages and collaboration, contributes to capacity development, and is a sure way of achieving lasting results.