Multi-environment multi-QTL association mapping identifies disease resistance QTL in barley germplasm from Latin America

Lucia Gutiérrez, Silvia Germán, Silvia Pereyra, Patrick M. Hayes, Carlos A. Pérez, Flavio Capettini, Andres Locatelli, Natalia M. Berberian, Esteban E. Falconi, Rigoberto Estrada, Dario Fros, Victor Gonza, Hernan Altamirano, Julio Huerta-Espino, Edgar Neyra, Maria Gisella Orjeda Fernandez, Sergio Sandoval-Islas, Ravi Singh, Kelly Turkington, Ariel J. Castro

Research output: Contribution to journalArticlepeer-review

34 Scopus citations

Abstract

Key message: Multi-environment multi-QTL mixed models were used in a GWAS context to identify QTL for disease resistance. The use of mega-environments aided the interpretation of environment-specific and general QTL.

Abstract: Diseases represent a major constraint for barley (Hordeum vulgare L.) production in Latin America. Spot blotch (caused by Cochliobolus sativus), stripe rust (caused by Puccinia striiformis f.sp. hordei) and leaf rust (caused by Puccinia hordei) are three of the most important diseases that affect the crop in the region. Since fungicide application is not an economically or environmentally sound solution, the development of durably resistant varieties is a priority for breeding programs. Therefore, new resistance sources are needed. The objective of this work was to detect genomic regions associated with field level plant resistance to spot blotch, stripe rust, and leaf rust in Latin American germplasm. Disease severities measured in multi-environment trials across the Americas and 1,096 SNPs in a population of 360 genotypes were used to identify genomic regions associated with disease resistance. Optimized experimental design and spatial modeling were used in each trial to estimate genotypic means. Genome-Wide Association Mapping (GWAS) in each environment was used to detect Quantitative Trait Loci (QTL). All significant environment-specific QTL were subsequently included in a multi-environment-multi-QTL (MEMQ) model. Geographical origin and inflorescence type were the main determinants of population structure. Spot blotch severity was low to intermediate while leaf and stripe rust severity was high in all environments. Mega-environments were defined by locations for spot blotch and leaf rust. Significant marker-trait associations for spot blotch (9 QTL), leaf (6 QTL) and stripe rust (7 QTL) and both global and environment-specific QTL were detected that will be useful for future breeding efforts.

Original languageEnglish
Pages (from-to)501-516
Number of pages16
JournalTheoretical And Applied Genetics
Volume128
Issue number3
DOIs
StatePublished - Mar 2015
Externally publishedYes

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