Development of resilient cowpea varieties by the application of Marker Assisted Breeding (MAB) for the West and Central Africa Sub-Region
The cowpea improvement research team at the Institute of Agricultural Research for Development (IRAD), Centre de Maroua, Cameroon. Left to right: Dr Liliane Iyale, Dr Arlette Zaiya Zazou, Dr Sobda Gonné, Ms Merline Fankou, Ms Yvonne Djeoufo, Mr Dieudonné Gnapou and Mr David Amedep.
PROJECT OVERVIEW
Background
The Kirkhouse Trust (KT) cowpea breeding programme in Cameroon focuses on the improvement of two varieties important in the country: Lori and Vya. In the first phase of the project, Lori and Vya were respectively crossed to IT98K-205-8 and IT99K-573-1-1, two varieties resistant to the parasitic weed Striga, a major constrain to cowpea production in Cameroon. Backcross breeding populations were developed, and selection was assisted by the use of C42B-2B, a molecular marker linked to the gene conferring Striga resistance in IT98K-205-8 and IT99K-573-1-1. Resistance to Striga was also confirmed by growing the plants in the screen house in pots with soil containing Striga seeds: the weed is only able to germinate and grow on susceptible plants.
Two Striga resistant improved Lori derived varieties IR15 MA02 and IR15 MA33 (Lori-2 and Lori-3) were released in 2019. They are very similar but differ in seed size. The release of Vya derived Striga varieties is to follow: three promising lines were identified in 2019 (IR16 MA-P; IR16 MA-K and IR16 MA-A) and are currently being evaluated.
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Improved Striga resistant Lori-derived varieties released in Cameroon in 2019: IR15 MA02 (i and ii); and IR15 MA33 (iii and iv).
Efforts to introduce other key characteristics into the improved Lori and Vya varieties were also started in the previous phase of the project: an aphid resistant variety originally from Ghana, SARC1-57-2, was crossed to IR15MA 02 and to IR15MA 33. Insect resistance in the breeding population is traced using the molecular marker CP171/CP172 to select plants that combine Striga and insect resistance.
The July 2021 edition of the Kirkhouse Trust newsletter was dedicated to the Cameroon team. Read it here.
Objectives
The overall goal of the cowpea improvement programme is to develop farmer preferred cowpea varieties resistant or tolerant to multiple constraints to production (Striga, insects, and key diseases in the region) which are well adapted to the Sudano-Sahelian zone of Cameroon, using modern molecular breeding tools. The objectives of the current grant (Jan 2020-Dec 2022) are:
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To complete the development and release of a Striga resistant improved Vya variety.
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To complete the introduction of resistance to aphids into the Striga resistant improved Lori and Vya varieties.
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To initiate a marker assisted backcross breeding programme to develop cowpea varieties resistant or tolerant to Brown blotch disease, caused by the fungal pathogen Colletotrichum capsici.
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To initiate a marker assisted backcross breeding programme to develop cowpea varieties resistant or tolerant to Fusarium, another important fungal pathogen.
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To initiate a marker assisted backcross breeding programme for early maturing cowpea.
Progress to date
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The Striga resistant improved Vya varieties (IR16 MA-K and IR16 MA-P) were evaluated in four field locations with high levels of Striga infestation: Guiring, Soukoundou, Djlingo and Yagoua. In terms of yield, the highest values of 1,869.8 Kg/ha (pod yield) and 1,632.1 Kg/ha (grain yield) were obtained from lines IR16 MA-P at Guiring followed by 1,481.1 Kg/ha (pod yield) and 1,375.8 Kg/ha (grain yield) from lines IR16-MA-K at Yagoua.
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BC2F1 breeding populations developed from a cross between the Striga resistant Vya derived varieties (IR16 MA-K and IR16 MA-P) and the aphid resistant donor variety SARC-1-57. BC4F3 populations were developed from the cross between the Striga resistant Lori-derived varieties (IR15 MA02 and IR15 MA33) and SARC-1-57.
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Disease resistant and early maturing cowpea varieties used in other West African cowpea breeding programmes were gathered to identify potential donors. Screen house trials to identified sources of Colletotrichum and Fusarium resistance were performed.
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Colletotrichum infected cowpea samples were collected from farmers’ fields the main cowpea production areas in the Northern Cameroon (Mayo Danay, Mayo sava, Mayo Tsanaga, Mayo Kani, Diamaré and Bénoué). Single spore isolation and characterisation have been completed, and the pathogenicity test was performed.
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Cowpea samples infected with Fusarium were collected at IRAD in the 2020 cropping season. Ten Fusarium strains were isolated, and the pathogenicity test was carried out on known Striga resistant Lori-derived varieties resistant and susceptible varieties (CB46 and IT99K-573-2-1, respectively, both from Nigeria).
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A total of twenty-five (25) cowpea genotypes were collected and screened at the experimental farm of IRAD Maroua at Guiring during 2020 cropping season under natural rainfall conditions. Agronomic characteristics, including time to maturity, were recorded. Sanzi, CB27 and IT00K-1217 recorded the shortest duration for flowering. CB27 had the largest seed size, followed by Sanzi and IT00K-1217.
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Backcross breeding programmes to introduce earliness and Fusarium resistance into Striga resistant Lori-derived varieties have been initiated.
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Cowpea plants growing in pots on soil containing seeds of Striga to select resistant plants resistant to the parasitic weed, pictured are (i); susceptible plants because Striga weed were able to germinate and grew (arrow); (ii); aphids feeding on the young leaves of a cowpea seedling; (iii); Dr Gonné making crosses in the greenhouse; (iv); IR19 MA33 field trials, 2019.
PROJECT TEAM MEMBERS
Principal Investigator, Institut de Recherche Agricole pour le Développement (IRAD), Centre de Maroua, Cameroon.
Dr Gonné, a former KT PhD Scholar, has led the KT-funded cowpea improvement programme in Cameroon since its inception in 2008. He holds a Master's degree in Crop Protection from the Catholic University of Leuven, Belgium, and a PhD from the West Africa Centre for Crop Improvement (WACCI), entitled “Genetic studies of cowpea [Vigna unguiculata (L.) Walp.] for resistance to thrips (Megalurothrips sjostedti Trybom) in Cameroon".
Dr Arlette Zaiya Zazou
Molecular Breeder
Dr Liliane Iyale Laboratory Technician
Mr David Amedep Data Management Scientist
Mr Dieudonné Gnapou
Data Management Scientist
Ms Yvonne Djeoufo
Data Management Scientist
Mr Pierre Metsena
PhD Student
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PUBLICATIONS
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Metsena, P., Kosma, P., Fankou, D.M.Y and Ndouvahad, L. (2021). Identification of Fusarium oxysporum sf tracheiphilum strains responsible of cowpea wilt in Far-north region of Cameroon. Journal of Applied Biosciences 164: 17001-17011.
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Iyale L., Noubissie J.B., Mapongmetsem P.M., . and Djile B. (2018). Genetic screening of cowpea varieties [Vigna unguiculata (L.) Walp.] for Aphis craccivora resistance in the Sudano-Sahelian Zone of Cameroon. Asian Journal of Biotechnology and Genetic Engineering 1: 1-15.
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Gonné, S., Mewounko, A., Sakati, P.D. and Ndaodeme, K., 2018. Farmers' cowpea production constraints and varietal preferences in the Sudano-Sahelian zone of Cameroon. International Journal of Innovation and Applied Studies 24: 968-977.
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Gonné, S., Atemkeng, F.M., Boukar, O., Fatokun, C., Tongoona, P.B., Ayertey, J. and Offei, S.K., 2018. Generation mean analysis in cowpea [Vigna unguiculata (L.) Walp.] under flower thrips infestation. Journal of Agricultural Science 10: 86.
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Gonné, S., Boukar, O., Tongoona, P.B., Ayertey, J. and Offei, K.S., 2017. Quantitative trait loci (QTL) for cowpea resistance to flower bud thrips (Megalurothrips sjostedti Trybom). International Journal of Plant Breeding and Genetics 4: 292-299.
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Gonné, S., Venasius, W.L. and Laminou, A., 2013. Characterization of some traditional cowpea varieties grown by farmers in the Sudano-Sahelian zone of Cameroon. International Journal of Agriculture and Forestry 3: 170-177.