High-density molecular characterization and association mapping in Ethiopian durum wheat landraces reveals high diversity and potential for wheat breeding.

Dejene Kassahun Mengistu,Mario Enrico Pè,Matteo Dell'Acqua,Marcello Catellani,Carlo Fadda,Yosef Gebrehawaryat Kidane,Elisabetta Frascaroli

doi:10.1111/pbi.12538

Dejene Kassahun Mengistu, Mario Enrico Pè + Show 5 more

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https://doi.org/10.1111/pbi.12538

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Abstract

SummaryDurum wheat (Triticum turgidum subsp. durum) is a key crop worldwide, and yet, its improvement and adaptation to emerging environmental threats is made difficult by the limited amount of allelic variation included in its elite pool. New allelic diversity may provide novel loci to international crop breeding through quantitative trait loci (QTL) mapping in unexplored material. Here, we report the extensive molecular and phenotypic characterization of hundreds of Ethiopian durum wheat landraces and several Ethiopian improved lines. We test 81 587 markers scoring 30 155 single nucleotide polymorphisms and use them to survey the diversity, structure, and genome‐specific variation in the panel. We show the uniqueness of Ethiopian germplasm using a siding collection of Mediterranean durum wheat accessions. We phenotype the Ethiopian panel for ten agronomic traits in two highly diversified Ethiopian environments for two consecutive years and use this information to conduct a genome‐wide association study. We identify several loci underpinning agronomic traits of interest, both confirming loci already reported and describing new promising genomic regions. These loci may be efficiently targeted with molecular markers already available to conduct marker‐assisted selection in Ethiopian and international wheat. We show that Ethiopian durum wheat represents an important and mostly unexplored source of durum wheat diversity. The panel analysed in this study allows the accumulation of QTL mapping experiments, providing the initial step for a quantitative, methodical exploitation of untapped diversity in producing a better wheat.

Highlights

Wheat is the second largest cereal commodity grown worldwide, with ever-increasing land allocation and production
Durum wheat (Triticum turgidum subsp. durum) is a key crop worldwide, and yet, its improvement and adaptation to emerging environmental threats is made difficult by the limited amount of allelic variation included in its elite pool
New allelic diversity may provide novel loci to international crop breeding through quantitative trait loci (QTL) mapping in unexplored material

Summary

Introduction

Wheat is the second largest cereal commodity grown worldwide, with ever-increasing land allocation and production (http://faostat3.fao.org). Most wheat production is bread wheat (Triticum aestivum L.), the allotetraploid macaroni or durum wheat Durum) is a key resource for both sustenance and high-value food production. The pace of durum improvement increased during the 1970s, when CIMMYT started releasing internationally tested varieties (Maccaferri et al, 2008; Sauer, 1993). Interest in durum wheat breeding is burgeoning and, to bread wheat, has been supported by the increased availability of genomic tools (Tuberosa and Pozniak, 2014). After the release of good-quality genome drafts (Brenchley et al, 2012; Mayer et al, 2014), a high-quality reference sequence for bread wheat, useful for durum wheat, is under production (http://www.wheatgenome.org)

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