Assessment of the virulence spectrum and its association with genetic diversity in Magnaporthe oryzae populations from sub-Saharan Africa

S. K. Mutiga, F. Rotich, V. Devi Ganeshan, D. T. Mwongera, E. M. Mgonja, V. M. Were, J. W. Harvey, B. Zhou, L. Wasilwa, C. Feng, I. Ouedraogo, G. -L. Wang, T. K. Mitchell, N. J. Talbot, J. C. Correll

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12 Citations (Scopus)


A collection of 122 isolates of Magnaporthe oryzae, from nine sub-Saharan African countries, was assessed for virulence diversity and genetic relatedness. The virulence spectrum was assessed by pathotype analysis with a panel of 43 rice genotypes consisting of differential lines carrying 24 blast resistance genes (R-genes), contemporary African rice cultivars, and susceptible checks. The virulence spectrum among isolates ranged from 5 to 80%. Five isolates were avirulent to the entire rice panel, while two isolates were virulent to similar to 75% of the panel. Overall, cultivar 75-1-127, the Pi9 R-gene donor, was resistant to all isolates (100%), followed by four African rice cultivars (AR105, NERICA 15, 96%; NERICA 4, 91%; and F6-36, 90%). Genetic relatedness of isolates was assessed by single nucleotide polymorphisms derived from genotyping-by-sequencing and by vegetative compatibility tests. Phylogenetic analysis of SNPs of a subset of isolates (n = 78) revealed seven distinct clades that differed in virulence. Principal component analysis showed isolates from East Africa were genetically distinct from those from West Africa. Vegetative compatibility tests of a subset of isolates (n = 65) showed no common groups among countries. This study shows that blast disease could be controlled by pyramiding of Pi9 together with other promising R-genes into rice cultivars that are adapted to East and West African regions.

Original languageEnglish
Pages (from-to)852-863
Number of pages12
Issue number7
Early online date5 May 2017
Publication statusPublished - Jul 2017


  • resistance breeding
  • rice blast
  • virulence spectrum
  • SITE

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