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bioRxiv · 10.1101/031179

Genome-wide association and prediction reveals the genetic architecture of cassava mosaic disease resistance and prospects for rapid genetic improvement

Marnin Wolfe·Ismail Y Rabbi·Chiedozie Egesi·Martha Hamblin·Robert Kawuki·Peter Kulakow·Roberto Lozano·Dunia Pino Del Carpio·Punna Ramu·Jean-Luc Jannink
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Abstract

Cassava (Manihot esculenta) is a crucial, under-researched crop feeding millions worldwide, especially in Africa. Cassava mosaic disease (CMD) has plagued production in Africa for over a century. Bi-parental mapping studies suggest primarily a single major gene mediates resistance. To be certain and to potentially identify new loci we conducted the first genome-wide association mapping study in cassava with 6128 African breeding lines. We also assessed the accuracy of genomic selection to improve CMD resistance. We found a single region on chromosome 8 accounts for most resistance but also identified 13 small effect regions. We found evidence that two epistatic loci and/or alternatively multiple resistance alleles exist at major QTL. We identified two peroxidases and one thioredoxin as candidate genes. Genomic prediction of additive and total genetic merit was accurate for CMD and will be effective both for selecting parents and identifying highly resistant clones as varieties.

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Marnin Wolfe, Ismail Y Rabbi, Chiedozie Egesi, Martha Hamblin, Robert Kawuki, Peter Kulakow, Roberto Lozano, Dunia Pino Del Carpio, Punna Ramu, Jean-Luc Jannink. 2015-11-11. Genome-wide association and prediction reveals the genetic architecture of cassava mosaic disease resistance and prospects for rapid genetic improvement. https://doi.org/10.1101/031179

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