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Poster: Biology & Disease Mgmt: Genetics of Resistance


Assessment of genetic diversity and virulence spectrum of Magnaporthe oryzae population from sub-Saharan Africa
DEVI GANESHAN (1), S. Mutiga (2), F. Rotich (3), D. Mwongera (4), J. Harvey (5), B. Zhou (6), L. Wasilwa (7), G. Wang (1), D. Silue (8), O. Ibrahima (9), J. Correll (3), N. Talbot (10), T. Mitchell (1) (1) The Ohio State University, Department of Plant, (

Rice Blast Disease (RBD), caused by the fungus Magnaporthe oryzae is a devastating disease found throughout the world and is particularly damaging to rice production in sub-Saharan Africa (SSA). Yield losses of 50-80% are common not only leading to net imports from abroad but also invasion of new pathotypes. An effective strategy to control RBD is to utilize resistant cultivars, but M.oryzae evolves rapidly due to genome instability, frequent loss/break of resistance genes occurs, overcoming resistance within few years of deployment. Breeding for durable resistance requires knowledge of pathogen’s genetic diversity and virulence spectrum. In our study, genetic diversity of M. oryzae field isolates from 9 SSA countries (Benin, Burkina Faso, Ghana, Kenya, Nigeria, Tanzania, Mali, Togo, and Uganda) were assessed by SNPs using GBS technology. Phylogenetic analysis of SNPs from 78 isolates, revealed 7 distinct clades differing in virulence. PCA showed that isolates from East were genetically distinct from West Africa. Further, standard least square regression analysis of virulence spectrum in the 7 clades revealed 4 major groups which differed in disease scores highlighting the association between genetic diversity and virulence. GWAS will be performed to further strengthen the association between genetic diversity and virulence and map the putative avirulence (AVR) genes for functional characterization facilitating an informed deployment of RBD resistance programs.