Genome-Wide Association Mapping Indicates Quantitative Genetic Control of Spot Blotch Resistance in Bread Wheat and the Favorable Effects of Some Spot Blotch Loci on Grain Yield.

Philomin Juliana, Xinyao He, Sandesh Shrestha, Arun K Joshi, Julio Huerta-Espino, Velu Govindan, Leonardo Abdiel Crespo-Herrera, Suchismita Mondal, Uttam Kumar, Pradeep K Bhati, Manish Vishwakarma, Ravi P Singh, Pawan K Singh

Research output: Contribution to journalArticlepeer-review

10 Scopus citations


Spot blotch caused by the fungus $\textit{Bipolaris sorokiniana}$ poses a serious threat to bread wheat production in warm and humid wheat-growing regions of the world. Hence, the major objective of this study was to identify consistent genotyping-by-sequencing (GBS) markers associated with spot blotch resistance using genome-wide association mapping on a large set of 6,736 advanced bread wheat breeding lines from the International Maize and Wheat Improvement Center. These lines were phenotyped as seven panels at Agua Fria, Mexico between the 2013-2014 and 2019-2020 crop cycles. We identified 214 significant spot blotch associated GBS markers in all the panels, among which only 96 were significant in more than one panel, indicating a strong environmental effect on the trait and highlights the need for multiple phenotypic evaluations to identify lines with stable spot blotch resistance. The 96 consistent GBS markers were on chromosomes 1A, 1B, 1D, 2A, 3B, 4A, 5B, 5D, 6B, 7A, 7B, and 7D, including markers possibly linked to the $\textit{Lr46}$, $\textit{Sb1}$, $\textit{Sb2}$ and $\textit{Sb3}$ genes. We also report the association of the 2NS translocation from $\textit{Aegilops ventricosa}$ with spot blotch resistance in some environments. Moreover, the spot blotch favorable alleles at the 2NS translocation and two markers on chromosome 3BS (3B_2280114 and 3B_5601689) were associated with increased grain yield evaluated at several environments in Mexico and India, implying that selection for favorable alleles at these loci could enable simultaneous improvement for high grain yield and spot blotch resistance. Furthermore, a significant relationship between the percentage of favorable alleles in the lines and their spot blotch response was observed, which taken together with the multiple minor effect loci identified to be associated with spot blotch in this study, indicate quantitative genetic control of resistance. Overall, the results presented here have extended our knowledge on the genetic basis of spot blotch resistance in bread wheat and further efforts to improve genetic resistance to the disease are needed for reducing current and future losses under climate change.
Original languageEnglish (US)
JournalFrontiers in plant science
StatePublished - Mar 21 2022
Externally publishedYes

Bibliographical note

KAUST Repository Item: Exported on 2022-03-24
Acknowledgements: This research was supported by the Accelerating Genetic Gain (AGG) in Maize and Wheat Project Grant INV-003439 funded by the Bill and Melinda Gates Foundation (BMGF), the Foreign and Commonwealth Development Office (FCDO), and the Foundation for Food and Agriculture Research (FFAR), Feed the Future project #AID-OAA-A-13-00051 funded by the United States Agency for International Development (USAID), USAID-Crops to End Hunger (CtEH)-AGG Supplement grant, the CGIAR Research Program on wheat and the Indian Council of Agricultural Research (ICAR).

ASJC Scopus subject areas

  • Plant Science


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