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Tracking adoption of improved varieties in informal seed systems using GBS markers: A case study using cassava
January 19, 2019

Cassava farmer appreciating his yield.

Assessing the impact of crop improvement has been a concern for agricultural researchers as varieties tend to look alike. Improved varieties of cassava, a clonally propagated crop, were mostly disseminated through informal seed systems, making the task of variety tracking difficult. However, researchers from IITA, Michigan State University, and Ghana’s Council for Scientific and Industrial Research-Crop Research Institute, took advantage of rapid advances in DNA sequencing to carry out a pilot study on cassava varietal identification through DNA fingerprinting. This study was conducted in three regions of Ghana covering the largest cassava producing area accounting for 61% of cassava production in the country in 2010. The three study regions were Brong Ahafo, Ashanti, and Eastern. Before 2010, traditional methods such as household survey, morphological descriptors, and expert knowledge were employed in cultivar identification, but these methods were not very reliable. Thus, researchers including Ismail Rabbi, Peter Kulakow, Joseph Manu-Aduening, Ansong Dankyi, James Asibuo, Elizabeth Parkes, Tahirou Abdoulaye, Gezahegn Girma, Melaku Gedil, Punna Ramu, Byron Reyes, and Mywish Maredia took a step further in tracking crop varieties. In carrying out this research, samples were collected from 495 cassava growing households in the three regions and a “library” of improved varieties and landraces maintained by the Crop Research Institute of Ghana. Each accession was genotyped-by-sequencing. Single Nucleotide Polymorphisms (SNPs) were identified. A total of 1045 clones, including 63 “library clones” representing improved varieties and known landraces were genotyped. The accurate cultivar identification and ancestry estimation was accomplished through two complementary clustering methods (distance-based hierarchical clustering and model-based maximum likelihood admixture analysis). The researchers found that 30% of the cassava collected on the farms matched specific released varieties, which is consistent with the results of a prior impact assessment. However, their analysis revealed widespread discrepancies in the names of varieties and landraces. While the farmers provided 180 different variety names for 917 accessions collected, genetic analysis revealed that many were actually the same variety, whereas some accessions with the same name were genetically different. While concluding the study, the researchers affirmed that the traditional methods used to assess the impact of crop improvement are not as reliable as DNA fingerprinting. They therefore advised that the increasingly affordable DNA fingerprinting methods such as Genotyping-By-Sequencing (GBS) should be employed as the primary variety identification tool in agricultural surveys and impact studies, because accurate identification of crop cultivars is crucial in assessing the impact of crop improvement research outputs.

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Olaosebikan, Olamide

Olamide Deborah Nwanze is a Senior Research Associate specializing in gender mainstreaming research to inform participatory and inclusive breeding, variety development, and seed systems policies regarding root, tuber, and banana (RTB) crops in the International Institute of Tropical Agriculture Headquarters, Ibadan, Nigeria. She is a PhD candidate at the University of Ibadan and holds an MSc and B. Agric in Agricultural Extension and Rural Development. Olamide is a fellow of the African Women in Agricultural Research and Development – Gender Responsive Agricultural Systems Policy (AWARD-GRASP) and the Gender Responsive Researchers Equipped for Agricultural Transformation (GREAT). She seeks to apply her gender-mainstreaming learnings, gender-responsive research, and policy development, and review expertise to facilitate women, youth, children, and vulnerable social group’s access to and adoption of agricultural Innovations that guarantee food, nutrition, income, and livelihood security in Africa. Her current roles include mentoring research fellows, development of guides and training manuals, implementation and adaptation of gender frameworks and tools, value chain actors’ engagement as citizen science partners, policy review and redesign, data management, and analysis. Her current research explores mixed methods and participatory and interdisciplinary approaches to capture and highlight gender dynamics, needs, preferences, and challenges stakeholders face within the agricultural livelihood value chain to prioritize gender-inclusive strategies in breeding programs, policy design, and implementation.

At IITA, she contributes to the implementation of the CGIAR Accelerated Breeding Initiative and Genetic Innovation Programs; participatory and gender research within the NextGen Cassava, HarvestPlus, RTBFoods, and Tricot-ClimMob 1000Farms Projects; and gender knowledge communication via the G-LENS webinar series, video documentary, policy briefs, publications, and blogs.

 

Recent publications

de Sousa, K., van Etten, J., Manners, R. Bello, A., Teeken, B., Olaosebikan, O., et al. 2024. The tricot approach: an agile framework for decentralized on-farm testing supported by citizen science. A retrospective. Agron. Sustain. Dev. 44, 8. https://doi.org/10.1007/s13593-023-00937-1

Madu, T., Onwuka, S., Nwafor, S., Onyemauwa, N., Ejechi, M., Ofoeze, M., Ukeje, B., Eluagu, C., Olaosebikan, O., Okoye, B., 2024. Gender-Inclusive Consumer Studies Improve Cassava Breeding in Nigeria in: Frontiers in Sociology, volume 9, number: 1224504, doi: 10.3389/fsoc.2024.1224504

Olaosebikan, O.; Bello, A.; Utoblo, O.; Okoye, B.; Olutegbe, N.; Garner, E.; Teeken, B.; Bryan, E.; Forsythe, L.; Cole, S.; Madu, T. 2023.  Stressors and Resilience within the Cassava Value Chain in Nigeria: Preferred Cassava Variety Traits and Response Strategies of Men and Women to Inform Breeding. Sustainability 15, 7837. https://doi.org/10.3390/su15107837

Okoye, B., Ofoeze, M., Ejechi, M., Onwuka, S., Nwafor, S., Onyemauwa, N., Ukeje, B., Eluagu, C., Obidiegwu, J.*, Olaosebikan, O., Madu, T.* 2023. Prioritizing preferred traits in the yam value chain in Nigeria: a gender situation analysis in: Frontiers in Sociology, volume 8, number: 1232626, pages 1 – 9, ISSN 2297-7775, 2023. https://www.frontiersin.org/articles/10.3389/fsoc.2023.1232626/full

Olaosebikan, O., Bello, A. A., de Sousa, K., Ndjouenkeu, R., Adesokan, M., Alamu, E. O., Agbona, A., van Etten, J., Kegah, F. N.*, Dufour, D., Bouniol, A., Teeken, B. 2023. Consumer acceptability of cassava gari-eba food products across cultural and environmental settings using the triadic comparison of technologies approach (tricot) in: Journal of the Science of Food and Agriculture,

Teeken, B., Olaosebikan, O., Bello, A. A., Madu, T.*, Cole, S. M. 2023. Qualitative assessment on the positionality and preferences of dyads in relation to cassava-related activities: working with tricot trial citizen scientists https://hdl.handle.net/10568/138326 Type: Manual

Bouniol, A., Ceballos, H., Bello, A. A., Teeken, B., Olaosebikan, O., Owoade, D., Agbona, A., Fotso Kuate, A., Madu, T.*, Okoye, B.*, Ofoeze, M.*, Nwafor, S.*, Onyemauwa, N.*, Adinsi, L.*, Forsythe, L., Dufour, D. 2023. Varietal impact on women’s labour, workload and related drudgery in processing root, tuber and banana crops: focus on cassava in sub-Saharan Africa in: Journal of the Science of Food and Agriculture, pages 1 – 25, ISSN 0022-5142,

Bello, A. A., Agbona, A., Olaosebikan, O., Edughaen, G., Dufour, D., Bouniol, A., Iluebbey, P., Ndjouenkeu, R.*, Rabbi, I. Y., Teeken, B. 2023. Genetic and environmental effects on processing productivity and food product yield: drudgery of women’s work in: Journal of the Science of Food and Agriculture, pages 1 – 32, ISSN 0022-5142, 5

Cavicchioli, M., Zimbiti, T., Teeken, B., Nwanze, D.O., Liani, M., Parkes, E. & Bello, A. 2023. IITA-Gender Responsive Breeding Training Report. Genetic Resources Center, IITA-HQ, Ibadan, 21-23 September, 2022. Ibadan, Nigeria: IITA, (34 p.).https://hdl.handle.net/10568/131368

Agbona, A. Peteti P., Teeken B., Olaosebikan O. Bello, A. A., Parkes, E., Rabbi, I. Y., Mueller, L., Egesi, C., Kulakow, P. 2022. Data Management in Multi-disciplinary African RTB Crop Breeding Programs. In: Williamson, H.F., Leonelli, S. (eds) Towards Responsible Plant Data Linkage: Data Challenges for Agricultural Research and Development. Springer, Cham. https://doi.org/10.1007/978-3-031-13276-6_5

Lora Forsythe, Pricilla Marimo, Sarah Mayanja, Olamide D. Olaosebikan, Esme Stuart, Bela Teeken, Benjamin Okoye, Tessy Madu, (2021). Cross-product Gender Analysis of RTBfoods Step 2 Gendered Food Mapping on RTB Products. Understanding the Drivers of Trait Preferences and the Development of Multi-user RTB Product Profiles, WP1. London, UK: RTBfoods Field Scientific Report, 30 p.

Teeken, B., Garner, E., Agbona, A., Balogun, I., Olaosebikan, O., Bello, A., Madu, T., Okoye, B., Egesi, C., Kulakow, P. and Tufan, H.A. 2021. Beyond “Women’s Traits”: Exploring How Gender, Social Difference, and Household Characteristics Influence Trait Preferences. Frontiers Sustainable Food Systems 5:740926. https://doi.org/10.3389/fsufs.2021.740926

Teeken, B., Agbona, A., Bello, A., Olaosebikan, O., Alamu, E., Adesokan, M., Awoyale, W., Madu, T., Okoye, B., Chijioke, U., Owoade, D., Okoro, M., Bouniol, A., Dufour, D., Hershey, C., Rabbi, I., Maziya‐Dixon, B., Egesi, C., Tufan, H. and Kulakow, P. (020. Understanding cassava varietal preferences through pairwise ranking of gari‐eba and fufu prepared by local farmer–processors. Int J Food Sci Technol. https://doi.org/10.1111/ijfs.14862

Bela Teeken, Olamide Olaosebikan, Ireti Balogun, Benjamin Okoye, Tessy Madu, Steven Cole, Abolore Bello, Elizabeth Parkes. (2020). Piloting the G+ customer and product profile tools for gender-responsive cassava breeding in Nigeria. Nigeria: International Institute of Tropical Agriculture (IITA). https://hdl.handle.net/20.500.11766/13000