Abdoulaye, Tahirou

Agrama, H.

Boahen, S.

Boukar, O.

Fatokun, C.A.

Tamo, Manuele

Tefera, H.

English

CGSpace

Special 45th Anniversary EditionR4D Review1967-201245Edition 8March 2012contentsMind the gap...2 EDITOR’S NOTEBoosting yam productivity in Ghana and Nigeria  Pro-vitamin A cassava released  Multi-CGIAR center initiative launched  Plant Virology Symposium slated in 20134IITA R4D Review Issue 8, March 2012Editors Lava Kumar and Katherine Lopez   Production team Copy editor: Rose Umelo Creative production: Godson Bright        Adegboyega Juba, and      Clement Ono-Raphael  Editorial board  Robert Asiedu, David Chikoye, and  Victor ManyongThe IITA R4D Review is published by IITA, 		solutions for hunger and poverty. Copyright  IITA holds the copyright to its publications but encourages duplication of these materials for noncommercial purposes. 		of these materials is prohibited. Permission to make digital or hard copies of part or all of this work for personal or classroom use is hereby granted without fee and without a formal request provided that copies are not 	advantage and that copies bear this notice 	for components not owned by IITA must be honored and permission pursued with 	permission is required to copy otherwise, to republish, to post on servers, or to redistribute to lists.   Disclaimer We do not endorse, approve, or give any warranty on the content of this publication. All liability for loss and damage arising from your use of our content is excluded (except where death or personal injury arises from our negligence or loss or damage arises from any fraud on our part).  ISSN 2071-3681 Maize genetic improvement for enhanced productivity gains     6A success tale on improving two legume crops in Africa    11Breeding superior banana hybrids    16Cassava improvement in the era  of “agrigenomics”    21Yam breeding at IITA    27 Genomics for yam breeding   31A ‘Green Revolution’ in the West African  cocoa belt   356 FEATURESTOOL BOX45!"#$%		&		'	 Nteranya Sanginga:  “Science can solve agriculture's problems”52 LOOKING IN Valerie Bemo:  ‘‘Collaboration required for major breakthroughs  in African agriculture’’"Agrigenomics" for crop improvement    55 Transgenics in crop improvement research at IITA   58Molecular diagnostic tools for plant health protection  61Partnerships as relationships for agricultural development 42 BEST PRACTICEF R O N T I E R S5548    WHO’S WHO	collecting tassels for hand pollination.  Photo by C. Ono-Raphael.11Cowpea and soybean are cultivated by poor and middle-income farmers as a sole crop or as intercrop with maize and other cereals for their protein-rich grains which are consumed in different forms. The haulms from plant residues and the dry pod walls of both crops are good sources of quality fodder for livestock. The two crops contribute substantially to sustain crop production through 	atmospheric nitrogen, some of which is left behind in the soil after harvesting for subsequent crops. IITA and its partners have been involved in improving legume production systems for several decades. An overview of these efforts is presented in this article. A success tale on improving two legume crops in Africa  Ousmane Boukar (o.boukar@cgiar.org), Tahirou Abdoulaye, Manuele Tamó, Hesham Agrama, Hailu Tefera, Christian Fatokun, and Steve Boahen Cowpea to sub-Saharan Africa (SSA), is grown n about 14 million ha worldwide, with over 84% of this area in SSA. Between 1985 and 2007, the rate of growth was 4.5% in land area planted to cowpea, 4.5% in grain yields/ha, and 5.9% in quantity of cowpea produced. These data indicates that the increase in the quantity of grain produced over the period resulted mainly from an expansion in the land area and less from an improved yield/unit area. In well-managed experimental stations, yields of up to 2 t/ha can be obtained but globally the average yield is about   375 kg/ha. 			 Photo by L. Kumar.O. Boukar, Cowpea Breeder; T. Abdoulaye, Socioeconomist, IITA, Ibadan, Nigeria;  M. Tamó, Legume Entomologist, IITA, Benin; H. Agrama and H. Tefera, Soybean Breeders, IITA, Malawi; C. Fatokun, Cowpea Breeder, IITA, Ibadan, Nigeria; S. Boahen, Legume Specialist/Agronomist, IITA, Mozambique.12Several abiotic and biotic factors keep the productivity of cowpea low in African 	among these are drought, poor soil fertility, inappropriate agronomic practices, an array of fungal, viral, and bacterial diseases, and parasitic Striga and Alectra). Cowpea is particularly susceptible to infestation by several insects with devastating effects on seeds in storage. Efforts in genetic improvement have been and are still being made to develop varieties with resistance to these various yield-limiting factors and in various research institutions across SSA, IITA, and other advanced research institutions. Cowpea breeders from these various institutions meet regularly to share information and exchange ideas on the way forward. Elite lines generated from IITA’s breeding nurseries are shared with interested colleagues from the national research institutions who evaluate these at their stations and in that perform well are recommended for release in the respective countries. For example, in Mali, a cowpea line IT99K-499-35 was recently adopted by many farmers in the Segou area and because of its superior performance and resistance to Striga, given a local name, Jinguiya which  means ‘hope’. Under the Tropical Legumes II (TL II) !"#$cowpea varieties [IT97K-499-35 (in 2008), IT89KD-288 and IT89KD-391 (in 2009), IT99K-573-1-1 and IT99K-573-2-1 (in 2011)] were released in Nigeria. Regional trials are being conduced for two cowpea lines (IT97K-1122 and &''*+6:;<=through farmers’ participatory selection as part of the TL II !">""release. In 2011, three IITA cowpea lines (IT97K-1069-6, IT00K-1263, and IT82E-16) were released in Mozambique; and IT99K-494-6 was released by Bunda College in Malawi as an Alectra-resistant variety in 2011.Research on integrated pest management (IPM) for cowpea has resulted in the development and deployment of biopesticides including the use of entomopathogenic organisms combined with botanicals, and biological control agents such as hymenopteran parasitoids which attack and feed on some of the cowpea pests. An example is the ""entomopathogenic virus capable of infecting and killing the legume pod borer Maruca vitrata with aqueous formulations of neem oil. This has proved to be as effective as the use of conventional insecticidal sprays. With regard to biological control, a small parasitic wasp which attacks the 	#!"#been introduced and established in most of Bénin and parts of Ghana, It has been reported to reduce the thrips population on wild alternative host plants by up to 40%.The development of improved cowpea varieties has so 13far depended on conventional breeding methods. However, efforts are being made to apply molecular breeding tools to cowpea improvement. Fairly saturated genetic linkage maps of cowpea have been produced in several laboratories. The linkage maps have been used for the detection of DNA markers associated with resistance/tolerance to Striga, drought, macrophomina, and bacterial blight, and seed characteristics such as size. A few of the markers have been converted to user-friendly markers which will make them readily available for breeders in the national systems. Molecular markers are contributing to progress in variety development.IITA is collaborating with Purdue University, USA, in implementing the Purdue Improved Cowpea Storage (PICS) !""storage of cowpea grain in Nigeria, Bénin, Togo, and Cameroon. From 2008 to 2010, IITA and its partners disseminated hermetic triple-layer bags for storage in more than 13,500 villages in the cowpea-producing areas of Nigeria, Cameroon, Togo, and VX!"addresses one of the most important constraints to cowpea production which is grain damage in storage. Furthermore, by not using any type of chemical, this hermetic storage method is protecting farming families and consumers from accidents from the mishandling of and poisoning by the chemicals used in cowpea storage. To date, farmers have purchased more than 30,000 PICS bags in these countries. IITA is also collaborating in an adoption study that will provide information about the reach of the Legume scientists in a disease resistance screening trial. Photo by L. Kumar.14technology. Another study on analysis of the supply chain of the PICS bags in the same four countries will help to improve the farmers’ access to the PICS bags through a better distribution network.Soybean  Soybean is a fairly new crop in SSA and has few biotic constraints. Fewer than 400 ha were planted to soybean in SSA during the 1980s but this exceeded the 1-million ha mark by 2007. Grain yield/ha increased from about 900 kg/ha in the 1980s to >1000 kg/ha between 2005 and 2007. Initially most varieties grown in parts of SSA had the problem of seed longevity. Farmers could not store seeds successfully from one cropping season to the next. This problem has now been solved so that seeds of the newly developed varieties remain viable over a longer period. Another constraint to soybean production was pod shattering, which resulted in seeds being lost in Zcould not leave their "before harvesting without losing some of the grain. The varieties that have been developed at IITA have tolerance to pod shattering, and resistance to rust\a fungus (Phakopsora pachyrhizi) that causes "#especially in the moist savanna agroecology. Some genotypes of soybean are noted for their abilities to reduce the seed bank of Striga hermonthica, a parasitic weed which can cause serious damage to cereal crops.Several elite lines from IITA’s breeding nursery have been evaluated in many countries in SSA and found to perform Some of these have been recommended for release in the different countries. For example, rust-resistant TGx1835-10E and TGx1987-62F have been released in Nigeria; TGx1740-2F was released in Malawi; TGx-1485-1D, TGx1740-2F, TGx1904-6F, TGx1908-8F, and TGx1937-1F were released in Mozambique in 2011. batch of varieties ever released in Mozambique. The development of improved varieties also involved farmers’ participation in selection, which made it possible for farmers to have some knowledge on performance of the lines being selected, thus facilitating rapid adoption and dissemination. IITA, in collaboration with Laval University in Canada, completed genotypic [using single nucleotide polymorphism (SNP) markers] and phentotypic characterization of 300 soybean genotypes for rust resistance and symbiotic performance.Improved soybean varieties. Photo by IITA.15In addition to efforts on genetic improvement 	#!emphasis has been placed on promoting and using soybean to encourage consumption, and thus create markets for farmers to sell their produce. Recipes were developed to promote the use of soybean grain for food. This promotional activity was necessary because the crop was new in many parts of the region and people were not familiar with how it could be best used as food. Vegetable oil millers were also encouraged to accept soybean as a raw material from where good quality oil could be extracted.    _atmospheric nitrogen in their root nodules through the symbiotic association between the crop and rhizobium, a free-living soil bacterium. Legume seeds are inoculated with the rhizobium before sowing to increase the number of rhizobium available to the plant for infection and nodule formation, and subsequently enhance the quantity Soybean is one such crop that requires rhizobium inoculation if a good crop is to be established on soils with no existing rhizobia or inadequate number if rhizobia. At IITA, some soybean varieties have been developed which are capable of "nitrogen using the native rhizobium present in the soil. These varieties which require no inoculation before sowing are characterized by promiscuous nodulation. Growing such varieties will save the farmers some expense and the time needed to purchase the inoculants with which the seeds are treated.  Conclusions  Decades of collaborative research efforts on genetic improvement of these two important legume crops involving scientists in the national agricultural research systems of different countries in SSA, IITA, and advanced research institutions in Europe and North America have resulted in the development and promotion of different improved varieties to meet the preferences of farmers and consumers. Improved varieties developed through this partnership have been released in over 70 countries around the #"the success of this partnership for legume crop improvement.  Further efforts will focus on use of innovative approaches to pyramid pest and disease resistance genes into improved lines and varieties; application of molecular markers to rapidly introduce genes for simply inherited desirable traits into popular varieties; and ""using recombinant DNA technology to produce insect-resistant cowpea varieties (Bacillus thuringiensis or Bt cowpea for resistance to the Maruca pod borer). Efforts will be continued to address diseases, such as the need to develop improved cowpea and soybean lines with combined resistance to different fungal, bacterial, and viral pathogens. The ""tolerance to drought in cowpea requires further elucidation, as this would facilitate progress in developing new varieties with enhanced drought tolerance. Join the discussions online atwww.r4dreview.orgISSN: 2071-3681 

A success tale on improving two legume crops in Africa

https://cgspace.cgiar.org/bitstream/10568/77452/1/U12ArtBoukarSuccessNothomNodev.pdf

A success tale on improving two legume crops in Africa

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