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Rabbi IY, Kayondo SI, Bauchet G, Yusuf M, Aghogho CI, Ogunpaimo K, Uwugiaren R, Smith IA, Peteti P, Agbona A, Parkes E, Lydia E, Wolfe M, Jannink JL, Egesi C, Kulakow P. Genome-wide association analysis reveals new insights into the genetic architecture of defensive, agro-morphological and quality-related traits in cassava. PLANT MOLECULAR BIOLOGY 2022; 109:195-213. [PMID: 32734418 PMCID: PMC9162993 DOI: 10.1007/s11103-020-01038-3] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/10/2020] [Accepted: 07/20/2020] [Indexed: 05/05/2023]
Abstract
More than 40 QTLs associated with 14 stress-related, quality and agro-morphological traits were identified. A catalogue of favourable SNP markers for MAS and a list of candidate genes are provided. Cassava (Manihot esculenta) is one of the most important starchy root crops in the tropics due to its adaptation to marginal environments. Genetic progress in this clonally propagated crop can be accelerated through the discovery of markers and candidate genes that could be used in cassava breeding programs. We carried out a genome-wide association study (GWAS) using a panel of 5130 clones developed at the International Institute of Tropical Agriculture-Nigeria. The population was genotyped at more than 100,000 SNP markers via genotyping-by-sequencing (GBS). Genomic regions underlying genetic variation for 14 traits classified broadly into four categories: biotic stress (cassava mosaic disease and cassava green mite severity); quality (dry matter content and carotenoid content) and plant agronomy (harvest index and plant type) were investigated. We also included several agro-morphological traits related to leaves, stems and roots with high heritability. In total, 41 significant associations were uncovered. While some of the identified loci matched with those previously reported, we present additional association signals for the traits. We provide a catalogue of favourable alleles at the most significant SNP for each trait-locus combination and candidate genes occurring within the GWAS hits. These resources provide a foundation for the development of markers that could be used in cassava breeding programs and candidate genes for functional validation.
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Affiliation(s)
- Ismail Yusuf Rabbi
- International Institute of Tropical Agriculture (IITA), Ibadan, 200001, Oyo State, Nigeria.
| | - Siraj Ismail Kayondo
- International Institute of Tropical Agriculture (IITA), Ibadan, 200001, Oyo State, Nigeria
| | | | - Muyideen Yusuf
- International Institute of Tropical Agriculture (IITA), Ibadan, 200001, Oyo State, Nigeria
| | - Cynthia Idhigu Aghogho
- International Institute of Tropical Agriculture (IITA), Ibadan, 200001, Oyo State, Nigeria
| | - Kayode Ogunpaimo
- International Institute of Tropical Agriculture (IITA), Ibadan, 200001, Oyo State, Nigeria
| | - Ruth Uwugiaren
- International Institute of Tropical Agriculture (IITA), Ibadan, 200001, Oyo State, Nigeria
| | - Ikpan Andrew Smith
- International Institute of Tropical Agriculture (IITA), Ibadan, 200001, Oyo State, Nigeria
| | - Prasad Peteti
- International Institute of Tropical Agriculture (IITA), Ibadan, 200001, Oyo State, Nigeria
| | - Afolabi Agbona
- International Institute of Tropical Agriculture (IITA), Ibadan, 200001, Oyo State, Nigeria
| | - Elizabeth Parkes
- International Institute of Tropical Agriculture (IITA), Ibadan, 200001, Oyo State, Nigeria
| | - Ezenwaka Lydia
- National Root Crops Research Institute (NRCRI), PMB 7006, Umudike, 440221, Nigeria
| | - Marnin Wolfe
- Section on Plant Breeding and Genetics, School of Integrative Plant Sciences, Cornell University, Ithaca, NY, 14850, USA
| | - Jean-Luc Jannink
- Section on Plant Breeding and Genetics, School of Integrative Plant Sciences, Cornell University, Ithaca, NY, 14850, USA
- United States Department of Agriculture - Agriculture Research Service, Ithaca, NY, 14850, USA
| | - Chiedozie Egesi
- International Institute of Tropical Agriculture (IITA), Ibadan, 200001, Oyo State, Nigeria
- National Root Crops Research Institute (NRCRI), PMB 7006, Umudike, 440221, Nigeria
- Global Development Department, College of Agriculture and Life Sciences, Cornell University, Ithaca, NY, 14850, USA
| | - Peter Kulakow
- International Institute of Tropical Agriculture (IITA), Ibadan, 200001, Oyo State, Nigeria
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