Research on maize improvement by IITA and partners, including CIMMYT, shows increased harvests and enhanced livelihoods of farmer-beneficiaries in sub-Saharan Africa. Total net benefit from maize research in West Central Africa from 1981 to 2005 alone using varieties from IITA, CIMMYT, and national programs is estimated at US$6.8 billion.
Breakthroughs in maize breeding
Extra early white maize hybrids
Ensuring the safety of African crops
Helping farmers benefit from drought tolerant maize
New maize brings hope
Promoting drought tolerant maize
Saving maize from Striga
Drought tolerant maize for Mali
Joseph Atehnkeng, email@example.com, Joao Augusto, Peter J. Cotty, and Ranajit Bandyopadhyay
Aflatoxins are secondary metabolites mainly produced by fungi known as Aspergillus flavus, A. parasiticus, and A. nomius. They are particularly important because of their effects on human health and agricultural trade. Aflatoxins cause liver cancer, suppress the immune system, and retard growth and development of children. Aflatoxin-contaminated feed and food causes a decrease in productivity in humans and animals and sometimes death. Maize and groundnut are particularly susceptible to aflatoxin accumulation, but other crops such as oilseeds, cassava, yam, rice, among others, can be affected as well. Aflatoxin accumulation in crops can lower income of farmers as they may not sell or negotiate better prices for their produce. Because of the high occurrence of aflatoxin in crops, many countries have set standards for acceptable aflatoxin limits in products that are meant for human and animal consumption.
Natural populations of A. flavus consist of toxigenic strains that produce variable amounts of aflatoxin and atoxigenic strains that lack the capability to produce aflatoxin. Carefully selected and widely distributed atoxigenic strains are applied on soil during crop growth to outcompete and exclude toxigenic strains from colonizing the crop. The biocontrol technology has been used extensively in the USA with two products AF36 and afla guardÂ® available commercially. In Africa, aflasafeTM was first developed by IITA in partnership with the United States Department of Agriculture â€“ Agricultural Research Service (USDA-ARS) and the African Agriculture Technology Foundation (AATF). It is currently at different stages of development, adoption, and commercialization in at least nine African countries. Multiyear efficacy trials in farmersâ€™ fields in Nigeria have showed reduced aflatoxin concentration by more than 80%.
Survey to collect and dispatch samples
Product development begins with the collection of crop samples in farmersâ€™ stores across different agroecological zones in each country. Samples collected are mainly maize and groundnut because they are the most susceptible to aflatoxin accumulation at crop maturity, during processing, and storage. Soil samples are collected from fields where these crops were grown to determine the relationship between the Aspergillus composition in the soil and the relative aflatoxin concentration in the crop at maturity.
Import and export permits are required if crop and soil samples are shipped outside a country. The crop samples are analyzed for aflatoxin to obtain baseline information on aflatoxin levels in the region/country and the relative exposure of the population to unacceptable limits of aflatoxin.
Isolation and characterization of Aspergillus species
Aspergillus species are isolated from the crop samples to identify the non-aflatoxin-producing species of A. flavus for further characterization as biocontrol agents. The isolates are identified and grouped into L-strains of A. flavus, SBG, A. parasiticus, and further characterized for their ability to produce aflatoxin by growing them on aflatoxin-free maize grain. Aflatoxin is extracted from the colonized grain using standard protocols to determine isolates that produce aflatoxin (toxigenic) and those that do not produce aflatoxin (atoxigenic). The amount of aflatoxin produced by toxigenic strains is usually quantified to determine the most toxigenic strains that will be useful for competition with atoxigenic strains.
Understanding genetic and molecular diversity
The genetic diversity of the atoxigenic strains is also determined molecularly by examining the presence or absence of the genes responsible for aflatoxin production in each strain. The absence of these genes explains why potential biocontrol isolates would not produce aflatoxin after release into the environment. Amplification of any given marker is taken to mean that the area around that marker is relatively intact, although substitutions and small indels outside the primer binding site may not be detected. Non-amplification could result from deletion of that area, an insertion between the primers that would result in a product too long to amplify by polymerase chain reaction (PCR), or mutations in the priming sites. Non-amplification of adjacent markers is probably best explained by very large deletions.
Identification of vegetative compatible groups
Vegetative compatible group (VCG) is a technique used to determine whether the highly competitive atoxigenic isolates are genetically related to each other. In nature A. flavus species that are genetically related belong to the same VCG or family; those that do not exchange genetic material belong to different VCGs. This is an important criterion for selecting a good biocontrol agent to ensure that the selected biocontrol strains do not â€œintermateâ€ with aflatoxin-producing strains after field application. With this technique, the distribution of a particular VCG within a country or region is also determined. A VCG that is widely distributed is likely to be a good biocontrol agent because it has the innate ability to survive over years and across different agroecologies. On the contrary, atoxigenic VCGs that have aflatoxin-producing members within the VCG are rejected; atoxigenic VCGs that are restricted to a few locations may also not be selected.
Initial selection of competitive atoxigenic strains
The in-vitro test determines the competitive ability of the atoxigenic isolate to exclude the toxigenic isolate on the same substrate. The competition test is conducted in the laboratory by co-inoculating the most toxigenic isolate with atoxigenic strains on aflatoxin-free maize grains or groundnut kernels. Grains/kernels inoculated with the toxigenic strain or not inoculated at all serve as controls. After incubation and aflatoxin analysis, atoxigenic isolates that reduce aflatoxin by more than 80% in the co-inoculated treatments are selected for unique vegetative compatible grouping.
Selection of candidate atoxigenic strains and multiplication of inocula
aflasafeâ„¢ is composed of a mixture of four atoxigenic strains of A. flavus previously selected from crop samples. To select the four aflasafe strains, initially 8-12 elite strains belonging to atoxigenic VCGs are evaluated in large farmersâ€™ fields. Two or three strain mixtures, each with 4-5 elite strains, are released in separate fields by broadcasting at the rate of 10 kg/ha in maize and groundnut at about 30-40 days after planting. The atoxigenic strains colonize organic matter and other plant residues in the soil in place of the aflatoxin-producing strains. Spores of the atoxigenic strains are carried by air and insects from the soil surface to the crop thereby displacing the aflatoxin-producing strains. The four best strains to constitute aflasafeTM are selected based on their ability to exclude and outcompete the toxin-producing isolates in the soil and grain, move from the soil to colonize the maize grains or groundnut kernels in the field, and occur widely and survive longer in the soil across many agroecological zones. The use of strain mixture in aflasafeâ„¢ is likely to enhance the stability of the product as more effective atoxigenic strains replace the less effective ones in specific environments. The long-term effect is the replacement of the toxigenic strains with the atoxigenic VCGs over years.
Assessing relative efficacy of aflasafeâ„¢
Field deployment to test efficacy of aflasafeâ„¢ is carried out in collaboration with national partners and most often with the extension services of the Ministry of Agriculture. Awareness is created by organizing seminars with extension agents and farmers. During the meetings presentations are made on the implication of aflatoxin on health and trade thereby increasing their knowledge on the impact of aflatoxins. aflasafeâ„¢ is then introduced as a product that prevents contamination and protects the grains before they are harvested and during storage. Efficacy trials are carried out in fields of farmers who voluntarily agree to test the product. Field demonstrations on the use of aflasafeTM are supervised and managed by the extension agents and farmers. Farmers are trained not only on the biocontrol technology but also on other management practices that enhance better crop quality.
Farmers are also educated on the need to group themselves into cooperatives, aggregate the aflasafeâ„¢-treated grains to find a premium market with companies that value good quality products. Market linkage seminars and workshops are organized between aflasafeâ„¢ farmers, poultry farmers, and the industries to ensure that the farmers get a premium for producing good quality grains and the industries get value for using good quality raw materials for their products.
Vincent Defait, firstname.lastname@example.org
Excellent outcomes in farmersâ€™ tests of drought tolerant maize in Maliâ€”where rainless spells persistently wilt harvests and hopesâ€”have increased the demand for maize seeds and raised the cropâ€™s appeal.
Finishing his meal, 67-year-old Malian farmer Bakary TourÃ© smiles and looks over his homesteadâ€™s courtyard where friends are eating a traditional corn paste. Some children watch; some women wash pots; a goat wanders among scrawny hens; and a donkeyâ€™s sporadic braying shakes the dusty afternoon. This is Kolokani, a village in the heart of a town of 7800 homes some 120 km north of Maliâ€™s capital, Bamako.
â€œIn September 2011, I had nothing to eat, so I sold my goats and chickens to feed my family,â€ says TourÃ©, referring to a particularly poor harvest. As the head of a household of 22 people he was ready to abandon his homestead at the time but, as he says, â€œâ€¦Maize saved me.â€ On the advice of fellow farmers in a local cooperative in May 2012, TourÃ© bought 20 kg of seeds of Brico, a drought tolerant (DT) variety with yellow kernels. Sown and managed using recommended practices, the US$15 purchase of seeds grew into a 1.6 t harvest that brought food security to TourÃ© and his homestead. â€œI gave three bags to friends who will pay me back later,â€ he says, standing in front of his storage room. â€œWith the 13 bags I have, I can feed my family for six months.â€
Other Kolokani farmers have profited by producing and selling seeds of the DT varieties. Near a small warehouse that stores grain sacks, Oumar TraorÃ©, president of the cooperative â€œThe Good Seedâ€, remembers the first trials with the varieties. â€œWe usually grew more groundnut and sorghum,â€ he says, â€œbut when we learned that this maize was profitable and drought tolerant, we wanted to try it.â€ He and his peers grew it on small areas the first year but soon expanded their plots. â€œThe following 2 years, I produced 6 t of maize, mainly to sell as seeds,â€ TraorÃ© says, as his friends nod in agreement. â€œIt brought me 1.5 million FCFA ($2900) and I bought cows and a motorcycle. Today, our main problem is the cost and availability of mineral fertilizer on the market. If we cannot buy enough in a timely manner, we have to cut back the maize area,â€ says TraorÃ©. Despite this, he says that production of DT maize allows him to easily feed his family with 13 members and sell seeds for as much as $1/kg.
A new movement toward maize
That maize can save the day is surprising news in Kolokani where the yearly rainfall, 600 mm or less, has favored more water-sparing crops, such as sorghum, groundnut, and sesame. But Bakary TourÃ© and Oumar TraorÃ© are among thousands of Malian farmers taking up DT maize varieties.
â€œMali is one of the countries in West Africa where maize production has expanded into areas where drought stress occurs intermittently,â€ says Abebe Menkir, IITAâ€™s Maize Breeder, who works with Maliâ€™s Institute of Rural Economy (IER) to develop DT maize varieties and make them available to farmers. â€œWith these varieties, Mali has the opportunity to expand maize production into areas where it was not possible before because of droughts.â€
â€œIn Mali, DT maize could revolutionize the lives of farmers,” says N’Tji Coulibaly, an IER agronomist and head of its maize research program who is testing and promoting the new varieties with farmers. Mali is a landlocked country in West Africa of 15.5 million inhabitants. Less than 4% of the land is arable; 8 of every 10 citizens are engaged in agriculture or fishing around the Niger River. Since the mid-1990s, domestic maize production and consumption have grown significantly, based on the cropâ€™s high yield potential and responsiveness to fertilizer, its capacity to alleviate food deficits, as well as its export potential and value for processing and food industries. â€œThe introduction of DT maize seeds can speed the attainment of the Government’s main objective of food sufficiency for Malian farmers.â€
Smallholder farmers earn a surplus by growing seeds
The varieties that Coulibaly and Menkir test and promote are products of the Drought Tolerant Maize for Africa (DTMA) project, implemented since 2006 by IITA and the International Maize and Wheat Improvement Center (CIMMYT), with funding from the Bill & Melinda Gates Foundation, the Howard G. Buffet Foundation, USAID, and the British Department for International Development.
In the IER office in Bamako, Coulibaly traces the beginnings of the DTMA project in Mali. â€œWe worked with farmers to select the best seeds, those that adapt best to areas where drought is endemic,â€ he says. â€œFrom 2009, two early maturing open-pollinated varieties were released that farmers have dubbed Brico, the name of a town in Mali, and Jorobana, which means â€œno worriesâ€ in the Bambara language. In areas where drought can reduce production by 70%, DT maize is a godsend. Ideally, we should introduce one or two new DT varieties each year.â€
IER also helps to teach farmers the skills and know-how to produce certified seeds. Among other things, this requires them to follow a schedule for applying fertilizer, weeding the plots, and maintaining enough separation between maize crops to avoid cross-pollination.
Best and timely practices
Coulibaly describes a series of marketing challenges that need to be addressed. â€œWe must find a way to produce more basic seeds,â€ he says, referring to the seeds that are multiplied by companies and other commercial seed producers. â€œIn particular, it is often necessary (for someone) to quickly buy the seeds the farmers produce because without money (from those sales), they have nothing to eat; they cannot wait for a potential buyer to knock on their door.â€ Coulibaly adds that, by the same token, farmers are not able to plan well for their own needs over the medium term. â€œIn general, when a drought is looming, they all want DT seeds at the same time.â€
These considerations do not seem to have reached Tanabougou, a village where only the minaret of the tiny mosque stands over the lot of concessions. The capital is only 40 miles away, but to get there one first needs to reach the paved road along a track on which only a few vehicles raise clouds of sand. Run down and often closed businesses in the city of Koulikoro, the capital of the eponymous region, give the impression that there has never been any impact on life in the villages. The Niger River is close, but it seems to belong to another world. In Tanabougou, it is the rain that supplies water to the crops. Animals, mainly goats and donkeys, crop the residues of harvest and the few tufts of grass under the trees.
In his banco concession where bright yellow maize cobs dry on a nga, a wooden roof and branches, another farmer, Benkeba TraorÃ©, 56, says, “With traditional maize varieties, I was producing about 300 kg per year. Last year, with the drought tolerant variety Brico, I produced 2 t of maize and sold 800 kg as seeds to Faso Kaba, a seed business owned by a woman entrepreneur.â€ In two seasons Benkeba TraorÃ©, who has to feed four adults and 12 children from 3.5 ha, was able to buy a pair of oxen and a plow, â€œSoon,â€ he says, â€œI will replace the branches which surround the concession with corrugated iron.â€
The progress was also made possible by the training provided by the agronomists of IER and the technicians of Faso Kaba. For the past 3 years, the farmer has learned to isolate his seed production from other plots, to meet deadlines when spreading fertilizer, to recognize the quality of the soil, and to sow suitable seed varieties.
When asked if he was not tempted to abandon the other crops, given the high yield of DT maize and the money it generates, farmer TraorÃ© replies, â€œLast year, I reduced the area of sorghum and groundnut in favor of maize. Sorghum was a failure and maize saved me. But next year, it may be the other way round, so I prefer to continue to grow more cereal crops.â€
The farmer now hopes to marry off his two oldest children and buy a motorcycle (about 300,000 FCFA or US$580) to travel to the village. â€œToday, I have no problems with the soudure,â€ Traore insists. All farmers in West Africa know about this difficult time between the end of the stock and the next harvest.
Lassana Diakite, 64, is reassured too. He chairs the cooperative from Koula, a neighboring village at the center of a little town with 25,000 inhabitants, several hours walk from the marketplace. Sitting on a wooden bench in the shade of a tree overlooking his concession, the farmer describes in a serious voice the various stages of maize cropping. â€œFrom plowing to sowing and harvesting, each step is recorded. I know when I need to weed, when I have to spread fertilizer, when I have to harvest … I even know my yields in advance. â€ That is a lot of advantages for this head of a family of 35 people who inhabit parts of the banco concession.
In the first year, the farmer used 1.5 of his 12 ha for production of Jorobana seeds. The result: 1.7 t of maize harvested. Three years later, production has climbed to 4.6 t. â€œDrought tolerant maize beats conventional maize as the horse beats the donkey,â€ asserts the farmer.
The next tcheba seedsâ€¦
Looking at the nga, where the sun shines on his maize spread like gold nuggets, the farmer adds, â€œNext year I will sow 3 or 4 ha.â€ It is impossible for him to devote all his 12 ha to maize. â€œI do not have the labor,â€ he continues. â€œI would have to stagger the fields and interventions and that would compromise performance.â€
DiakitÃ© acknowledges his new comforts, the oxen he recently acquired, the taxes he pays “with ease,” the education of his children, which is now more affordable, and the fertilizer for the sorghum that he can buy with the money generated by maize.
Back in Bamako, in his office at IER, Coulibaly dreams of the next generation of DT maize varieties. His team has just completed tests on hybrid varieties which are more productive. In 2013, Malian farmers should be able to grow the Tcheba variety meaning â€˜bigâ€™ in Bambara. The agronomist said, â€œIn Mali, with DT maize, we can speak of a success story…
B. Badu-Apraku, email@example.com, 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 â€œgreen maizeâ€ 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 IITAâ€™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 (6Âº 53â€™N, 3Âº 42â€™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 (9Âº 18â€™N, 5Âº 4â€™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 Ã— 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 Ã— TZEEI 13 to 2734 kg/ha for TZEEEI 29 Ã— TZEEI 21. The top-ranking hybrid, TZEEI 29 Ã— 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 Ã— TZEEI 13 (5868 kg/ha) while the lowest was TZEEI 14 Ã— TZEEI 13 (2749 kg/ha). Under artificial Striga infestation, TZEEI 29 Ã— 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 Ã— TZEEI 14 as the second highest yielding and most stable single-cross hybrid across research environments; the highest-yielding single-cross hybrid, TZEEI 6 Ã— 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 Ã— 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.
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: 99â€“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: 9â€“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.
BÃ¤nziger, 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: 865âˆ’870.
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Yan, W. and J. FrÃ©geau-Reid. 2008. Breeding line selection based on multiple traits. Crop Science 48: 417-423.
aflasafeâ„¢ team: Ranajit Bandyopadhyay, Joseph Atehnkeng, Charity Mutegi, Joao Augusto, Juliet Akello, Adebowale Akande, Lawrence Kaptoge, Fen Beed, Olaseun Olasupo, Tahirou Abdoulaye, Peter Cotty, Abebe Menkir, and Kola Masha, with several national partners
Ground-breaking research by scientists at IITA and partners is ensuring safe food and health for Africans.
IITA, in collaboration with the United States Department of Agriculture â€“ Agricultural Research Service (USDA-ARS) and the African Agriculture Technology Foundation (AATF), has developed a natural, safe, and cost-effective biocontrol product that drastically cuts aflatoxin contamination in African food crops.
Aflatoxins are highly toxic chemical poisons produced mainly by the fungus Aspergillus flavus in maize and groundnut, and on yam chips, but which also affect other high-value crops such as oilseeds and edible nuts. The fungal chemicals cause liver cancer and also suppress the immune system, retard growth and development, lead to chronic liver disease and cirrhosis, and death in both humans and animals. Livestock are also at risk and poultry are particularly susceptible. Cattle are not so susceptible but if they are fed with contaminated feed the toxin â€œAflatoxin M1â€ passes into the milk.
The biocontrol product â€“ aflasafeâ„¢ uses native strains of A. flavus that do not produce aflatoxins (called atoxigenic strains) to â€œpush outâ€ their toxic cousins so that crops become less contaminated in a process called â€œcompetitive exclusionâ€. When appropriately applied before the plants produce flowers these native atoxigenic strains completely exclude the aflatoxin producers.
IITA recommends broadcasting 10 kg/ha aflasafeâ„¢ by hand on soil 2â€“3 weeks before the flowering stage of maize to prevent the aflatoxin- producing fungus from colonizing and contaminating the crop while it remains in the field and subsequently in storage. Even if the grains are not stored properly, or get wet during or after harvest, the product continues to prevent infestation and contamination.
The reduction of aflatoxin in maize fields is greater with the application of aflasafeâ„¢ than with the deployment of putative low-aflatoxin maize lines. For example, field studies during 2010 and 2011 in Nigeria established that aflatoxin reduction was 16â€“72%, due to resistant maize hybrids, 80â€“92% with aflasafeâ„¢, and 80â€“97% with the combined use of resistance and aflasafeâ„¢.
Field testing of aflasafeâ„¢ in Nigeria between 2009 and 2012 consistently showed a decrease in contamination in maize and groundnut by 80â€“90% or more.
In 2009, Nigeriaâ€™s National Agency for Food and Drug Administration and Control registered aflasafeâ„¢ and permitted treatment of farmersâ€™ fields to generate the data on product efficacy for obtaining full registration. In 2011, IITA distributed about 14 t of aflasafeâ„¢ to more than 450 maize and groundnut farms, enabling farmers to achieve an 83% reduction in contamination.
The success of the project has led to the expansion of biocontrol research in Burkina Faso, Ghana, Kenya, Mozambique, Senegal, Tanzania, and Zambia.
Between 2004 and 2006, nearly 200 Kenyans died after consuming aflatoxin-contaminated maize. In 2010 over 2 million bags of maize in Kenyaâ€™s Eastern and Central provinces were found to be highly contaminated and were declared as non-tradable.
Research conducted by Leeds University and IITA found that 99% of children at weaning age are exposed to health risks linked to aflatoxin in BÃ©nin and Togo.
Across the world, about US$1.2 billion in commerce is lost annually due to aflatoxin contamination, with African economies losing $450 million each year. Aflatoxins are also non-tariff barriers to international trade since agricultural products are rejected that have more than the permissible levels of contamination (4 ppb for the European Union and 20 ppb for USA).
IITA has identified separate sets of four competitive atoxigenic strains isolated from locally grown maize to constitute a biocontrol product called aflasafe KE01â„¢ in Kenya and aflasafe BF01 in Burkina Faso and aflasafe SN01 in Senegal.
The adoption of this biocontrol technology with other management practices by farmers will reduce contamination by more than 70% in maize and groundnut, increase crop value by at least 5%, and improve the health of children and women.
In 2012, G20 leaders launched a new initiative â€“ AgResults â€“ which included aflasafeâ„¢ in Nigeria as one of the first three pilot projects to encourage the adoption of agricultural technologies by smallholder farmers.
IITAâ€™s experience in Nigeria has shown that the cost of biocontrol (about $1.5/kg with a recommended use of 10 kg/ha) is affordable for most farmers in the country.
The biocontrol product aflasafe SN01 can potentially reinstate groundnut exports to the European Union lost by Senegal and The Gambia due to aflatoxin contamination. The World Bank has estimated that in Senegal, an added capital investment cost of $4.1 million and 15% recurring cost would attract a 30% price differential to groundnut oil cake. Exports are expected to increase from 25,000 to 210,000 t. The increased export volume and price would annually add $281 million to groundnut exports. For confectionery groundnut, adherence to good management practices would increase export value by $45 million annually.
Currently, a demonstration-scale manufacturing plant for aflasafeâ„¢ is under construction at IITA with a capacity to produce 5 t/h. Market linkages between aflasafeâ„¢ users, poultry producers, and quality conscious food processors are also being created to promote aflasafeâ„¢ adoption, in collaboration with the private sector.
Costs and benefits
Biocontrol of aflatoxin is one of the most cost-effective control methods, with the potential to offer a long-term solution to aflatoxin problems related to liver cancer in Africa. Cost-effectiveness ratio (CER) of treating all maize fields in Nigeria with aflasafeâ„¢ is between 5.1 and 9.2, rising to between 13.8 and 24.8 if treatments were restricted to maize intended for human consumption. Up to 162,000 disability-adjusted life years (DALYs) can be saved annually by biocontrol in Nigeria.
Initial data from a separate study in Nigeria suggest that farmers will receive a return of from 20 to 60% on investment in aflasafeâ„¢ from the sale of maize harvested from treated fields to poultry feed manufacturers and quality-conscious food processors.
Research and development efforts on aflasafeâ„¢ have been supported by the following donors: Bill & Melinda Gates Foundation, USAID, USAID-FAS, AATF, Commercial Agriculture Development Project of the Government of Nigeria, The World Bank, Austrian Development Cooperation (ADC), Deutsche Gesellschaft fÃ¼r Internationale Zusammenarbeit, GmbH (GIZ), the European Commission (EC KBBE-2007-222690-2 MYCORED), and Meridian Institute. In addition, IITA has received support from Belgium, Denmark, The German Federal Ministry for Economic Cooperation and Development (GTZ BMZ), Ireland, Norway, Sweden, Switzerland, and the UK Department for International Development (DFID).
Atehnkeng, J., P.S. Ojiambo, M. Donner, T. Ikotun, R.A. Sikora, P.J. Cotty, and R. Bandyopadhyay. 2008. Distribution and toxigenicity of Aspergillus species isolated from maize kernels from three agroecological zones in Nigeria. International Journal of Food Microbiology 122 (1-2): 74-84.
Atehnkeng, J., P.S. Ojiambo, T. Ikotun, R.A. Sikora, P.J. Cotty, and R. Bandyopadhyay. 2008. Evaluation of atoxigenic isolates of Aspergillus flavus as potential biocontrol agents for aflatoxin in maize. Food Additives and Contaminants 25 (10): 1266-1273.
Bandyopadhyay, R., M. Kumar, and J.F. Leslie. 2007. Relative severity of aflatoxin contamination of cereal crops in West Africa. Food Additives and Contaminants 24 (10): 1109-1114.
Diedhiou, P.M., R. Bandyopadhyay, J. Atehnkeng, and P.S. Ojiambo. 2011. Aspergillus colonization and aï¬‚atoxin contamination of maize and sesame kernels in two agroecological zones in Senegal, Journal of Phytopathology 159 (4): 268-275.
Donner, M., J. Atehnkeng, R.A. Sikora, R. Bandyopadhyay, and P.J. Cotty. 2009. Distribution of Aspergillus section flavi in soils of maize ï¬elds in three agroecological zones of Nigeria. Soil Biology and Chemistry 41 (1): 37-44.
Donner, M., J. Atehnkeng, R.A. Sikora, R. Bandyopadhyay, and P.J. Cotty. 2010. Molecular characterization of atoxigenic strains for biological control of aflatoxins in Nigeria. Food Additives 27(5): 576-590.
Egal, S., A. Hounsa, Y.Y. Gong, P.C. Turner, C.P. Wild, A.J. Hall, K. Hell, and K.F. Cardwell. 2005. Dietary exposure to aflatoxin from maize and groundnut in young children from BÃ©nin and Togo, West Africa. International Journal of Food Microbiology 104 (2): 215-224.
Kankolongo, M.A., K. Hell, and I.N. Nawa. 2009. Assessment for fungal, mycotoxin and insect spoilage in maize stored for human consumption in Zambia. Journal of the Science of Food and Agriculture 89 (8): 1366-1375.
Oluwafemi, F., M. Kumar, R. Bandyopadhyay, T. Ogunbanwo, and K.B. Ayanwande. 2010. Bio-detoxification of aflatoxin B1 in artificially contaminated maize grains using lactic acid bacteria. Toxin Reviews 29 (3-4): 115-122.
Wu, F. and Khlangwiset, P. 2010. Health and economic impacts and cost-effectiveness of aflatoxin-reduction strategies in Africa: case studies in biocontrol and postharvest interventions. Food Additives and Contaminants: Part A, 27: 496-509.
Florence Sipalla, firstname.lastname@example.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. â€œI planted just before the season began, to ensure that the crop would sprout when the rain came,â€ 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 areaâ€™s climate, from Dryland Seed Company in Machakos town. â€œFor these dryland varieties, the first rains are very important,â€ explains Peter Mutua, a Dryland agronomist. â€œIt 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.â€
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.
â€œWe try to improve the existing varieties and come up with more that are better than those in the market,â€ says Peter Setimela, a CIMMYT maize breeder. â€œWith climate change, varieties developed 20 years ago are no longer suitable for the changing environment.â€ 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 1â€“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 Mativoâ€™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 farmersâ€™ other needs â€“ proper milling and cooking quality or flavor, for example. â€œThis is why we have farm trials,â€ explains Peter Setimela. These trials are done in collaboration with the national research organizations, such as KARI in Kenya. â€œWe 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.â€
The seed companies and KARI multiply seeds to furnish supplies adequate to the farmersâ€™ demands, but they also depend on farmers they hire to produce those seeds. â€œWe work with groups of farmers who each have at least 5 acres (2.5 ha),â€ 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 â€œrisk-free planting. This is because you are planting for a known market; as you plant, you donâ€™t have to start worrying about where to sell the produce. An additional perk is that the company provides the seeds.â€
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. â€œThese are interactive shows. We have farmers calling in to find out the best variety to grow, when and where to obtain the seeds,â€ 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.
â€œThe basic need in the dry areas is food security,â€ 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. â€œEven students buy it for their parents to try,â€ 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 Mativoâ€™s farm, he spreads the risk by planting hybrids alongside beans and cowpea. â€œWhen 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,â€ says Mativo. â€œIt would be very sad for a farmer to lack food. When I have food, then my neighbors are also food secure.â€ 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. â€œWorking 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,â€ 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.
Wandera Ojanji, email@example.com
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 harvestsâ€•neither via miracles nor witchcraftâ€•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 varietyâ€•31 to 45 bags/ha, according to Stephen Mugo, CIMMYTâ€™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. â€œFrom the information provided by KARI, I felt CKIR04003 was the variety I wanted. I did not need any further prodding before trying it out.â€
It was a decision that paid off, despite less than perfect preparation. â€œI got the seeds towards the end of March. Because I was in a rush to plant before the onset of rains, I didnâ€™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,â€ states Ndambuki. â€œBut my worries gradually turned into amazement. In complete contrast to my neighborsâ€™ farms, under local varieties or other hybrids, my maize was so green and robust. It looked like a crop under irrigation.â€
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 Ndambukiâ€™s enthusiasm, KARI has named the variety Pamuka1, in honor of Paul, his wife Jane Mumbua, and the Kamba community.
B. Badu-Apraku, firstname.lastname@example.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).