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

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.

Genome Wide Association Study to Identify the Genetic Base of Smallholder Farmer Preferences of Durum Wheat Traits

“…The marker-trait associations (MTA) identified for DB and DF in either or both locations combined (Mengistu et al, 2016) were jointly identified by earliness FT (Figure 1B; Table S3). An MTA on chromosome (Chr) 1B was identified by earliness FT and related MTs in both locations.…”

Genetic Diversity within a Global Panel of Durum Wheat (Triticum durum) Landraces and Modern Germplasm Reveals the History of Alleles Exchange

“…Landraces from this country have unique morphology (Sakamoto and Fukui, 1972; Porceddu et al, 1973; Pecetti et al, 1992) and represent a separate sub-species under the name T. durum subs. abyssinicum or T. aethiopicum (Mengistu et al, 2015, 2016). Figure 4 clearly shows that this germplasm is distinct from the primary region of origin of durum wheat (Middle-East landraces) with substantially no kinship to it.…”

Novel Sources of Stripe Rust Resistance Identified by Genome-Wide Association Mapping in Ethiopian Durum Wheat (Triticum turgidum ssp. durum)

“…An estimated 85% of durum wheat cultivars grown in Ethiopia in recent decades are landraces (Bechere et al, 1996; Badebo et al, 2009) and over 7,000 accessions have been conserved in the Ethiopian Biodiversity Institute gene bank (Mengistu and Pè, 2016). The investigation of genetic diversity has been initiated in Ethiopian durum wheat landraces at both morphological and molecular levels (Alamerew et al, 2004; Mengistu et al, 2016), and confirmed the uniqueness of Ethiopian wheat to various degrees (Alamerew et al, 2004; Gashaw et al, 2007; Hailu et al, 2010; Mengistu et al, 2016). Although, Porceddu et al (1975) reported Ethiopian landraces were unique sources for rust resistance in early years, no recent studies have characterized the genetic architecture of rust resistance using the genome-wide high-density genetic markers.…”