Viral disease threats to yam in West Africa

Lava Kumar, l.kumar@cgiar.org

Virus diseases pose serious challenges to seed and ware yam production and also impede international exchange of yam planting material in West Africa, which is home to about 91% of the global edible yam production. Current efforts to control virus threats are directed towards propagation of virus-free seed yam. However, deployment of genetic resistance in farmer-preferred cultivars is critical for sustainable virus disease control in West Africa.

One disease and several viruses

‘Mosaic disease’ is a common disorder caused by several different viruses infecting yam in West Africa. About 17 viruses have been identified in edible and medicinal yam in different parts of the world1. The virus species belonging to the genera Potyvirus and Badnavirus are most widespread. Two potyviruses, Yam mosaic virus (YMV) and Yam mild mosaic virus (YMMV), and several badnaviruses—generically referred as yam badnaviruses (YBVs) —are frequently detected in farmer-grown yam in the West African yam belt that stretches from western regions of Cameroon to Cote d’Ivoire, including Nigeria, Bénin, Togo, and Ghana. About 88% of the global yam production area and 91% of the global production is confined to this region. Six Dioscorea species, viz., D. rotundata (white yam), D. alata (water yam), D. cayenensis (yellow yam), D. dumetorum (bitter yam), D. bulbifera (aerial yam), and D. esculenta (lesser yam) are widely cultivated for food use in West Africa. Virus infections are known in all these species but most prevalent in D. rotundata and D. alata, the two most predominant species covering >70% of the cultivated area in West Africa.

Different viruses cause almost similar symptoms and are difficult to distinguish from one another based on symptoms alone. In general virus symptoms in yam consist of deformation of leaf lamina, mottling, yellowing, vein banding, mosaic pattern on leaves, stunting, and poor growth (Fig. 1). Symptom expression can differ based on the genotype, time of infection, environmental conditions and cultivar. Mixed infection with more than one virus often results in severe symptoms. Although effects of virus infection on tuber size have not been accurately quantified, data from published and unpublished studies suggest about 20 to 50% reduction in tuber yield. In addition, ‘internal brown spot disease’ reported from Côte d’Ivoire is known to cause dry corky necrosis in tubers (Fig. 1b). The cause of this disease is not known, but based on symptoms it is regarded as viral in nature. In addition, badnavirus sequences have been found to be integrated in the yam genome. These are termed as endogenous pararetrovirus sequences (EPRVs) or endogenous yam badnaviruses (eYBVs) and have been detected in almost all yam species grown in West Africa, the Caribbean, and South-Pacific regions2. However, the pathological significance of yam EPRVs is not known.

Virus spread along with plant parts and insect vectors

Viruses infecting yam are systemically distributed in all plant tissues, including tubers. Consequently, tubers, setts, or any plant tissue from infected plants serves as a source for virus spread through vegetative propagation (Fig. 2). In addition, some of the yam viruses are transmitted from plant to plant by insect vectors. For instance, YMV and YMMV are transmitted by aphids and YBVs are transmitted by mealybugs. Insect vectors play an important role in spreading virus from infected plants to uninfected plants. A recent study demonstrated YMV transmission through botanical seeds of yam, albeit only a small percentage of seed serves as virus carriers.

Infected seed yams contributing to high virus incidence in West Africa

Farmers in West Africa mainly cultivate yam by planting small tubers (seed yam) or pieces of tubers (setts and minisetts) derived from larger tubers, which are sourced from their own harvest, brought from neighbors, or markets. This practice contributes to the accumulation and perpetuation of tuber-borne viruses. Considering that about one quarter of the yam tuber harvest each year in West Africa is used for propagation, the risk of virus perpetuation dramatically increases through infected tubers from generation togeneration. Historical data and recent surveys conducted as part of the Yam Improvement for Income and Food Security in West Africa (YIIFSWA) project estimated an average virus incidence of >70% in almost all the farmers’ fields, reflecting the perpetual use of infected tubers due to lack of availability of virus-free seed yams. Lack of virus resistance in the popular landraces and improved cultivars, poor awareness about viral diseases, and severe shortage of virus-free planting material are other factors that continue this prevailing situation in West Africa. Coordinated action is required to control the unabated spread of yam viruses through use of virus-infected seed yams.

Multipronged approach for yam virus disease control

Virus disease management of clonally propagated crops which are also transmitted by insect vectors requires a multipronged strategy: (i) reduce virus inoculum in the field by phytosanitation (removal and destruction of infected sources) and replacement of infected seed stock with virus-free propagation material, (ii) use resistant cultivars to prevent infection, and (iii) control insect vectors to prevent further spread. Unfortunately, many of these tactics are not being practiced due to lack of appropriate resources such as virus-free seed stock or highly resistant varieties.

YIIFSWA impetus

In the ongoing Bill & Melinda Gates Foundation-funded YIIFSWA initiative, surveys were conducted in the major yam production regions in Ghana and Nigeria to determine the situation of virus incidence and severity during the 2012-13 seasons. Mean virus disease incidence in both countries was greater than 85% and mean severity was 3, based on a 1 to 5 rating scale (1 = no symptoms and 5 = most severe symptoms). Local landraces were dominantly used by farmers compared to released cultivars. Virus diagnostics tests by reverse-transcription polymerase chain reaction (RT-PCR) assays detected YMV in D. rotundata in all the locations, sometimes in mixed infection with YMMV. YBVs were also detected in all the locations, however it was not clear if these positive results were from episomal? infection or eYBVs. Knowledge on virus diversity determined by sequencing of portion of viral genomes was incorporated into the diagnostic test development to further enhance sensitivity and specificity of yam virus diagnostic tools.

Efforts are also ongoing to produce virus-free yam stocks of the most popular farmer-preferred cultivars (landraces and improved cultivars) in Nigeria and Ghana. A suite of macro and micropropagation technologies combined with thermo- and chemotherapy techniques have been employed to generate stocks free of YMV, YMMV, and CMV. Such virus-free stocks have been established for the cultivars Adaka, Aloshi, Alumaco, Ame, Amula, Danachia, Gbangu, Kemi, Makakusa, Obiaturugo, Ogini, Ogoja, TDr 89/02475, and TDr 89/02665. They are being mass propagated for use as nucleus stock for breeder-class seed yam production. Similar efforts are ongoing to generate virus-free stocks of a wider range of D. rotundata and D. alata cultivars. This, in combination with YIIFSWA activities on strengthening the seed yam systems through improved seed production techniques and capacity development is anticipated to regularly infuse stocks of high quality seed yams produced from virus-free sources by specialist seed growers and contribute to productivity gains.

‘Positive selection’ (PS) is another approach piloted as part of YIIFSWA and allied initiatives to prevent reuse of tubers from severely infected plants for seed purpose. PS is a simple on-farm method of selectively harvesting seed yam tubers from healthy looking plants or plants showing mild symptoms, when asymptomatic plants are not available. This eliminates tubers with high virus concentration and infected with multiple viruses, the two conditions responsible for severe symptoms, poor plant performance, and degeneration of seed yams. Implementation of PS over several seasons is expected to reduce virus inoculum in the fields, improves the quality of farmer-saved seed yam, and reduces the need for regular seed replacement. However, this approach requires additional effort in the form of monitoring crops before senescence, tagging, and separate harvesting of tubers from selected plants. Awareness creation among growers about the benefits of PS and training in selection of healthy looking plants is critical to the sustainable implementation of this approach.


Resistant varieties required for sustainable management

Resistant varieties offer the most convenient, economical, and sustainable option for controlling virus diseases. In addition, they are easy for dissemination and adoption. Almost all the popular landrace cultivars were found to be susceptible. Some were found to have tolerance showing mild symptoms at the later crop growth stage (e.g., Amula). Germplasm sources with high levels of host plant resistance to virus diseases have been identified in the Dioscorea landraces3. However, all the improved varieties released as of 2013 were found to be susceptible. Limited breeding efforts for virus disease resistance demonstrated dominantly inherited resistance to YMV in certain D. rotundata crosses4,5, indicating the promise of breeding for developing cultivars with high levels of virus resistance with end-user preferred traits.

Conclusions

Virus diseases pose a major threat to West African yam production, affecting tuber yields and seed yam quality. Reuse of farmer-saved seed in successive seasons has contributed to high virus incidence and seed yam degeneration. In the absence of high levels of virus resistance in farmer-preferred varieties, it is imperative to infuse clean stocks of popular cultivars through seed systems, coupled with approaches such as phytosanitation and positive selection to reduce virus inoculum in the fields. Concerted efforts in this direction started recently through initiatives such as YIIFSWA. However, these efforts need to be complemented with breeding programs to develop cultivars with high levels of resistance and end-user preferred attributes for sustainable control of virus diseases and also to ensure sustainability of quality seed yams.

References

1. Kenyon et al. 2003. An overview of viruses infecting yams in sub-Saharan Africa. In: Eds. Hughes, J. d’A and Odu, B.O. Plant virology in sub-Saharan Africa, Proceedings of a conference organized by IITA, IITA, Nigeria. pp432-439.

2. Seal et al. (2014). The prevalence of badnaviruses in West African yam (Dioscorea cayenensis-rotundata) and evidence of endogenous pararetrovirus sequences in their genomes. Virus Research (in press) [doi:10.1016/j.virusres.2014.01.007]

3. Asiedu R. 2010. Genetic improvement of yam. In: Yam Research for Development in West Africa – Working Papers. IITA-BMGF Consultation Documents, IITA. pp 81-108.

4. Mignouna J. et al. 2002. Identification and potential use of RAPD markers linked to Yam mosaic virus resistance in white yam (Dioscorea rotundata Poir.). Ann. Appl. Biol. 140: 163­169.

5. Odu et al. 2011. Analysis of resistance to Yam mosaic virus, genus Potyvirus, in white guinea yam (Dioscorea rotundata) genotypes. J. Agri. Sci. 56: 1-13.

A new paradigm for improving yam systems

N. Maroya, R. Asiedu, P. Lava-Kumar, D. Mignouna, T. Abdoulaye, B. Aighewi, M. Balogun, U. Kleih, D. Phillips, A. Lopez-Montes, F. Ndiame, J. Ikeorgu, E. Otoo, N. McNamara; S. Abimiku, Sara Alexander, and R. Asuboah

In West Africa, yam (Dioscorea spp.) plays a very important role as a source of income, food security, and livelihood systems for at least 60 million people. The crop also makes a substantial contribution to protein in the diet, ranking as the third most important source. Farmers engage in yam cultivation for cash income and household food supply. Yam traditionally plays a significant role in societal rituals such as marriage ceremonies and annual festivals, making the crop a measure of wealth. Yams therefore have significance over and above other crops in the region. At the regional level, yam seems to be a superior economic good in all countries. As incomes increase, consumers shift from cassava to yam. This is related in part to regional cultural values and consumer preferences, which is mainly due to the relative ease in consumer food preparation.


Despite its importance in the economy and lives of many people, yam faces many constraints that significantly reduce its potential to support rural development and meet consumers’ needs as an affordable nutritional product. Unavailability and high cost of high quality disease-free seed yam is a major constraint in West Africa. This is followed by high levels of on-farm losses of tubers during harvesting and storage, low soil fertility, and high labor costs associated with land preparation and staking. Other constraints include losses due to diseases caused by viruses and fungi and nematode attack. Scale insects, tuber beetles, and termites affect the tubers in some areas. These effects are experienced more in the dry savannah agroecologies where yam cultivation is rapidly expanding due to the shrinking arable land in the traditional moist humid areas. In addition, the seed yam system in West Africa is mainly informal and entirely market driven.


Yam Improvement for Income and Food Security in West Africa (YIIFSWA) was initiated to increase yam productivity of 200,000 smallholder farmers (90% with less than 2 acres) in Ghana and Nigeria by 40% (2011 to 2016), and deliver key global goods research products that will contribute to the sustainable development of the yam sector.


Early gains

The project started by identifying yam production systems with partners (Fig. 1).

The yam value chain surveys with farmers, marketers (including exporters), transporters, and processors helped to estimate the cost of production of ware and seed yam, analyze costs and benefits of yam transaction, and identify major ware yam supply and distribution routes in both Nigeria and Ghana. Detailed value chain analysis has shown that yam production is a profitable business and yam farmers are able to generate substantial income from the production of tubers. But at the same time, production costs tend to be high (in particular for seed yam and hired labor) and selling prices depend on the season. There is significant price variability between the new yam season (August to October), the peak season (November to April), and the slack season (May to July). During peak seasons there is much yam in the markets but because of unavailability of good storage facilities, yam are sold at the lowest prices (Fig. 3). The gross margins can be negative if farmers get the timing of their harvest wrong, or are unable to sell at times when prices are higher.


YIIFSWA baseline studies conducted in 600 and 800 households, respectively in Ghana and Nigeria, indicated that only 3% and 10% households are headed by females in Nigeria and Ghana. Land was by far the major natural capital for small-holder farmers in yam-growing areas. The average farmland available was about 2.4 ha in Nigeria and 2.7 ha in Ghana. Priority has been given by households to yam over other food and cash crops. The areas under yam cultivation are generally small and the primary objective of small-holder farmers is to meet subsistence needs.

To develop the capacity of farmers organizations (FOs) by linking them to service providers (SPs) that would offer demand-driven services, a profiling exercise was conducted on 77 and 44 FOs and 40 and 17 SPs in Nigeria and Ghana, respectively. Overall, the performance indicators revealed that the selected FOs in Nigeria performed better than the ones in Ghana, in terms of quality of governance, internal management, value chain management, and marketing strategy. However the selected Nigerian FOs performed poorly, compared to Ghana counterparts, in the internal management and operations indicators.


Over 90% of the farmers use tubers harvested from the previous season as ‘seed yam’ or sourced from local markets, which are of poor quality due to pest and disease attack and lack of seed yam replacement. To improve the quality of farmer-saved seed yam, two NGOs—the Missionary Sister for Holy Rosary (MSHR) in Nigeria and Catholic Relief Services (CRS) in Ghana—have taken on the responsibility to train yam growers on seed yam multiplication using minisett technique combined with seed treatment to protect them from nematodes and fungal attack. So far, about 16,784 farmers were trained in Nigeria and Ghana.


The seed and ware yam sanitation challenges were also tackled. Surveys were conducted to identify pest and disease prevalence to establish appropriate strategies to control biotic threats to seed yam and ware yam. Virus diagnostics has been simplified to detect major yam-infecting viruses, Yam mosaic virus (YMV), Yam mild mosaic virus (YMMV), and Cucumber mosaic virus (genus, Cucumovirus), through a multiplex PCR-based assay.


Breeder seed yams produced in 2012 by Crops Research Institute (CRI) in Ghana and National Root Crops Research Institute (NRCRI) in Nigeria were handed over respectively to the Grain and Legume Development Board (GLDB, Ghana) and National Agricultural Seeds Council (NASC, Nigeria) for generation of foundation seed yam.


The breeder seed yam under production in 2013 is 0.8 ha and 0.5 ha, respectively for Nigeria and Ghana. GLDB has taken the challenge in Ghana and has a 1.5-ha foundation seed production site at Afraku (Ashanti region); while in Nigeria NASC selected two private seed companies (Greengold Construct Nigeria Ltd. and Romarey Ventures Nigeria Ltd.) that were engaged in foundation seed yam production for the first time.


New techniques such as aeroponics and temporary immersion bioreactors systems (TIBS) were effectively established at Ibadan. Results of experiments on the use of aeroponics system were encouraging for both pre-rooted planted and direct planting of vine cuttings of D. rotundata and D. alata. The successful growth of yam on the aeroponics system is reported for the first time with production of microtubers and mini-bulbils.


The TIBS is reported on yam in general, and in only one article for D. rotundata. YIIFSWA established a TIBS running on automated computer system with remote control through Internet. The 128 units of TIBs can produce a minimum of 12,800 plantlets per cycle. The running of the TIBs and the aeroponics systems for breeder or foundation seed yam production will speed up the generation of initial stocks of seed yam to supply the formal seed system.


Integrating available technologies, local and improved varieties to increase yam productivity is also another key objective of the project. Improved varieties with good performance in low soil fertility and drought stressed environments, and in staked and no staked system have been identified (table). The integration of landraces with seed selection and treatment, effective weed control, fertilizer application under no-stake system has indicated yields of 50% above the local technology. Studies have also determined that choice of yam varieties could be same for both men and women farmers and sometimes preferences differ.


For an effective operational seed system the capacity building of the players is key. To that effect national training workshops were organized: breeder and foundation seed production training workshop in Ghana and Nigeria; seed yam quality management protocol (QMP), yam virus disease diagnostics. In addition many partners (NASC, GLDB, CRI; SARI, CRS, MSHR, etc.) have organized training workshops for different stakeholders mainly on minisett technique for yam propagation.


Conclusions

In 24 months of project implementation, significant results were achieved on baseline studies, value chain analysis, farmers’ organization profiling, farmers training, and participatory selection of new genotypes. New techniques on high ratio propagation (aeroponics and TIBS), novel methods to develop virus-free planting materials, and the multiplex RT-PCR test for simultaneous detection of major viruses infecting yam, were successfully established. The formal seed yam system has been initiated and training have started. These initial successes are expected to pave a way to tackle greater challenges confronting the seed yam sector in West Africa.




Amazing maize

maize_100Research 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.

Issue 10, March 2013


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
Ecofriendly bioherbicide
Developing aflasafeTM
Drought tolerant maize for Mali

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Drought tolerant maize is good for farmers and business in Mali

Vincent Defait, v.defait@gmail.com

Excellent outcomes in farmers’ tests of drought tolerant maize in Mali—where rainless spells persistently wilt harvests and hopes—have increased the demand for maize seeds and raised the crop’s appeal.

Finishing his meal, 67-year-old Malian farmer Bakary Touré smiles and looks over his homestead’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 donkey’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 Mali’s capital, Bamako.

“In September 2011, I had nothing to eat, so I sold my goats and chickens to feed my family,” says Touré, 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, “…Maize saved me.” On the advice of fellow farmers in a local cooperative in May 2012, Touré 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 Touré and his homestead. “I gave three bags to friends who will pay me back later,” he says, standing in front of his storage room. “With the 13 bags I have, I can feed my family for six months.”

Other Kolokani farmers have profited by producing and selling seeds of the DT varieties. Near a small warehouse that stores grain sacks, Oumar Traoré, president of the cooperative “The Good Seed”, remembers the first trials with the varieties. “We usually grew more groundnut and sorghum,” he says, “but when we learned that this maize was profitable and drought tolerant, we wanted to try it.” He and his peers grew it on small areas the first year but soon expanded their plots. “The following 2 years, I produced 6 t of maize, mainly to sell as seeds,” Traoré says, as his friends nod in agreement. “It 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,” says Traoré. 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 Touré and Oumar Traoré are among thousands of Malian farmers taking up DT maize varieties.
“Mali is one of the countries in West Africa where maize production has expanded into areas where drought stress occurs intermittently,” says Abebe Menkir, IITA’s Maize Breeder, who works with Mali’s Institute of Rural Economy (IER) to develop DT maize varieties and make them available to farmers. “With these varieties, Mali has the opportunity to expand maize production into areas where it was not possible before because of droughts.”

“In 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 crop’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. “The introduction of DT maize seeds can speed the attainment of the Government’s main objective of food sufficiency for Malian farmers.”

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. “We worked with farmers to select the best seeds, those that adapt best to areas where drought is endemic,” he says. “From 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 “no worries” 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.”

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. “We must find a way to produce more basic seeds,” he says, referring to the seeds that are multiplied by companies and other commercial seed producers. “In 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.” Coulibaly adds that, by the same token, farmers are not able to plan well for their own needs over the medium term. “In general, when a drought is looming, they all want DT seeds at the same time.”

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 Traoré, 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.” In two seasons Benkeba Traoré, who has to feed four adults and 12 children from 3.5 ha, was able to buy a pair of oxen and a plow, “Soon,” he says, “I will replace the branches which surround the concession with corrugated iron.”

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.

Rotating crops
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 Traoré replies, “Last 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.”

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. “Today, I have no problems with the soudure,” 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. “From 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. ” 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. “Drought tolerant maize beats conventional maize as the horse beats the donkey,” asserts the farmer.

The next tcheba seeds…
Looking at the nga, where the sun shines on his maize spread like gold nuggets, the farmer adds, “Next year I will sow 3 or 4 ha.” It is impossible for him to devote all his 12 ha to maize. “I do not have the labor,” he continues. “I would have to stagger the fields and interventions and that would compromise performance.”

Diakité 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 ‘big’ in Bambara. The agronomist said, “In Mali, with DT maize, we can speak of a success story…

Tanzanian president inaugurates new science building

The President of the United Republic of Tanzania, His Excellency, Dr Mrisho Jakaya Kikwete, in May, inaugurated IITA’s new science building in Dar es Salaam, Tanzania.

The construction of the science building represents an investment of over US$4 million and is part of IITA’s efforts to strengthen its research capacity and that of its partners in sub-Saharan Africa.

“The science building is a symbol of IITA’s commitment to continue waging the fight against hunger and poverty and boost agriculture through capacity development and improve the livelihoods of smallholder farmers in East Africa through its research-for-development efforts,” says Dr Nteranya Sanginga, IITA Director General.

Citing IITA for its R4D work in http://pangeagiving.org/cheap/ sub-Saharan Africa, President Kikwete lauded the construction of the science building, saying that any effective socioeconomic transformation which would have levitra online cheap a significant impact on poverty reduction in Tanzania and Africa should be anchored on agriculture.

The inauguration was followed by a tour of the new building and exhibition booths showcasing IITA’s work in East Africa, and a workshop with the theme “Grow Africa and the role of agricultural research by national systems, IITA, and its partners.”

The state-of-the-art and environmentally friendly Science Building has five modern laboratories with a capacity to host 70 researchers.

Nigeria releases improved cassava varieties

Nigeria has released two new improved cassava varieties developed through a collaborative effort between IITA and the Nigerian Root Crops Research Institute (NRCRI), Umudike. The two varieties are originally recognized as IITA-developed genotypes IITA-TMS-I982132 and IITA-TMS-I011206, now known as UMUCASS 42 and UMUCASS 43, respectively.

Both varieties performed well in different cassava production regions of Nigeria with high yield, high dry matter, and good disease resistance. The roots of these varieties are yellow and contain moderate levels of provitamin A.

The potential maximum yield of the two varieties is between 49 and 53 t/ha, according to pre-varietal release trials that were conducted between 2008 and 2010. Local varieties produce less than 10 t/ha. The varieties are also resistant to major pests and diseases that affect cassava in the country including cassava mosaic disease, cassava bacterial blight, cassava anthracnose, cassava mealybug, and cassava green mite.

The varieties are good for high quality cassava flour—a trait sought after by researchers for the cassava transformation agenda in Nigeria; have high dry matter which is positively related to starch and important for cassava value chain development; have high leaf retention which is positively related to drought tolerance and is crucial for cassava production in the drier regions and in mitigating the impact of climate change, with moderate levels of betacarotene for enhancing nutrition.

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.