Screening and mapping for head blast resistance in a panel of CIMMYT and South Asian bread wheat germplasm

Authors: HE, XINYAO - International Maize & Wheat Improvement Center (CIMMYT); JULIANA, PHILOMIN - International Maize & Wheat Improvement Center (CIMMYT); KABIR, MUHAMMAD - Bangladesh Wheat And Maize Research Institute; ROY, KRISHNA - Bangladesh Wheat And Maize Research Institute; ISLAM, RABIUL - Bangladesh Wheat And Maize Research Institute; MARZA, FELIX - Collaborator; Peterson, Gary; SINGH, GYANENDRA - Icar-Indian Institute Of Maize Research; CHAWADE, AAKASH - Swedish University Of Agricultural Sciences; JOSHI, ARUN - International Maize & Wheat Improvement Center (CIMMYT); SINGH, RAVI - International Maize & Wheat Improvement Center (CIMMYT); SINGH, PAWAN - International Maize & Wheat Improvement Center (CIMMYT)

Submitted to: Frontiers in Genetics
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/21/2021
Publication Date: N/A
Citation: N/A

Interpretive Summary: Wheat blast (WB) is a destructive disease in South America and its first outbreak in Bangladesh was in 2016, exposing great risk to food security of South Asian countries. A genome wide association study (GWAS) of 184 wheat lines from South Asia and International Maize and Wheat Improvement Center (CIMMYT) discovered 11,401 genetic markers. These wheat lines were evaluated for their resistance to wheat blast disease in several field trials in Bangladesh, Bolivia and in containment greenhouse evaluations in the United States. An association study was conducted comparing wheat lines with resistance to wheat blast and the genetic markers identified during the GWAS study and 4 markers previously associated with a known source of resistance from a translocated gene fragment (2NS) from the wild goatgrass onto the 2AS wheat chromosome. Significant marker associations were identified in the study on wheat chromosomes 1BS, 2AS, 6BS and 7BL; but only the ones on 2AS region were consistently associated with wheat blast resistance. The study identified a number of wheat lines that could be potentially used in a future disease management program. The results of the association study confirmed the linkage of wheat blast resistance to the 2NS/2AS chromosome while underlining the importance of identifying new sources of resistance to the ever-evolving wheat blast pathogen.

Technical Abstract: Wheat blast (WB) is a destructive disease in South America and its first outbreak in Bangladesh was in 2016, exposing great risk to food security of South Asian countries. A genome wide association study (GWAS) was conducted on a diverse panel of 184 wheat genotypes from South Asia and CIMMYT. Phenotyping was conducted in eight field experiments in Bolivia and Bangladesh and a greenhouse experiment in the USA. Genotypic data included 11,401 SNP markers of the Illumina Infinium 15K BeadChip and four additional STS markers on the 2NS/2AS translocation region. Accessions with stably WB resistance across experiments were identified, which were all 2NS carriers. Additionally, four 2AS accessions exhibited good WB resistance in field but not greenhouse experiment, along with a dozen moderately resistant 2AS lines that showed big variation among experiments. Significant marker-trait associations (MTA) were identified on chromosomes 1BS, 2AS, 6BS and 7BL; but only the ones on 2AS at the 2NS/2AS translocation region were consistently significant across experiments, and the rest three were significant only in two of the nine experiments. The resistant accessions identified in this study could be used in production in South Asian countries as a preemptive strategy to prevent WB outbreak.